AAL Acoustic Amplitude Log Abandon To cease efforts to produce fluids from a well in a depleted formation and to plug the well without adversely affecting the environment. Abnormal BHP A reservoir is set to have an abnormal bottomhole pressure when its pressure is appreciably greater than that of a saltwater column which height is equivalent to the depth of the reservoir. Abnormal Operating Condition A condition which occurs in a process components when an operating variable ranges outside of its normal operating limits. Absolute Pressure This is the gauge pressure plus atmospheric pressure. Pressure measured from absolute zero pressure, ordinarily expressed as gauge pressure (the reading obtained from a pressure measuring instrument) plus atmospheric pressure, denoted in pounds per square inch absolute (psia) or kilopascal (kpa). Absolute Volume The volume per unit mass, reciprocal of absolute density. Absorption A process for separating mixtures into their constituents, by taking advantage of the fact that some components are more readily absorbed than others. An example is the extraction of the heavier components from natural gas. AC Borehole Compensated Acoustilog Accumulator A pressure vessel typically charged with nitrogen gas used to store hydraulic fluid under pressure for operation of pressure control equipment or other hydraulically operated equipment components. Accumulator Precharge | Precharge | An initial charge of gas (typically nitrogen) within an accumulator which is further compressed when the hydraulic fluid is pumped into the accumulator storing potential energy. ACE Acoustic Casing Evaluation Acid Any chemical compound containing hydrogen capable of being replaced by positive elements or radicals to form salts. In terms of the dissociation theory, it is a compound which, on dissociation in solution, yields excess hydrogen ions. Acids lower the pH.

Acid Brittleness Brittleness induced in steel, when it is pickled in dilute acid. Commonly attributed to absorption of hydrogen. Acid Rain Develops when sulphur oxides (SOx) and nitrogen oxides (NOx), released by the combustion of fossil fuels (particularly coal), combine with moisture in the atmosphere to form sulphurous, sulphuric, nitrous and nitric acids. Because SOx and NOx are gases and because the formation of acid rain takes tie, acid rain damage often occurs far from the source of the problem. Acidizing A technique used in oil and gas wells to increase permeability immediately around the wellbore by injecting hydrochloric acid through the completion into the formation. Acidizing is also used to clean the walls of the borehole or the completion interval through circulation or injection of the low pH chemical. ACL Borehole Compensated Long-spaced Acoustilog Acoustic Log A record of the time taken by an acoustic (sound) wave to travel over a certain distance through the geological formations. Also called a sonic log. See also: seismic survey. Acreage Area covered by a lease granted for oil and gas exploration and for possible future production. Actuation Test The closing and opening of a pressure sealing component or flow control device to assure mechanical functioning. Additive Chemical added to a product to improve its properties. Adjustable Choke A choke equipped with a variable aperture which is used to vary the rate of flow of liquids and/or gas, or to control the back pressure applied to the well, either through manual or automatic adjustment. Adsorption A separation process for removing impurities based on the fact that certain highly porous materials fix certain types of molecules onto their surface. ADT Azimuthal Density Log Aeration

The technique of injecting air or gas in varying amounts into a fluid for the purpose of reducing hydrostatic head. Aerosol Suspension of liquid or solid particles in air or gas. AFE Authorisation For Expenditure Aggregate An essentially inert material of mineral origin having a particle size predominantly greater than 10 mesh. Also a group of two or more individual particles held together by strong forces which are not subject to dispersion by normal mixing or handling. The mineral matter used together with bitumen to create asphalt for road construction. AIL Acoustic Impedance Log Air Gun Chamber from which compressed air is released to produce shock waves in the earth. The air gun array is the most common technique used for seismic surveying at sea. AIT Array Induction Imager AKO Adjustable Kick-Off Sub ALARP As low as reasonably practical Alcohols A class of compounds, of which ethanol (the alcohol of beer and wine) is the best known. They react with acids to form esters. They are widely used as solvents. Alkalinity The combining power of a base measured by the maximum number of equivalents of an acid with which it can react to form a salt. In water analysis, it represents carbonates, bicarbonates, hydroxides, and occasionally the borates, silicates, and phosphates in the water. It is determined by titration with standard acid to certain datum points. Ammonia Manufactured by the direct combination of hydrogen and nitrogen under pressure over a catalyst. Anhydrous ammonia is mainly used for the manufacture of nitrogenous fertilisers. AMS Auxiliary Measurement Tool

Anaerobic Refers to microbial life or processes that occur in the absence of oxygen. Anchor A device for holding, fixing, or fastening an object which may tend to change its position (for example, deadline, wireline or derrick anchor). Also, an anchor may be a length of tubing extending below the working barrel in a pumping well such as a gas anchor or mud anchor. Angle of Inclination The angle in (degrees) taken at one or at several points of variation from the vertical revealed by a deviation survey. Sometimes called the inclination or angle of deviation. Angle of Twist The azimuth change through which a work string or drill stem must be turned to offset the twist caused by the reactive torque of a downhole motor. ANHYD Anhydrite Anhydrous Without water or dried. Annealing A process involving heating and cooling, usually applied to induce softening. The term also refers to treatments intended to alter mechanical or physical properties, produce a definite microstructure or to remove gases. Annular Preventer A large bag-type pressure isolation component, usually installed above the ram preventers, which forms a seal in the annular space between the drill pipe or tubing and the wellbore. Compression of a reinforced elastomer packing element by hydraulic pressure effects the seal. Some annular preventers are capable of creating a pressure seal, even if pipe or tubing is not present in the wellbore. Annular Velocity The average velocity of a fluid moving within the annulus. Annulus The space between the casing and the wall of the wellbore, between two strings of casing, between production tubing and casing or between coiled tubing and tubing or casing. Anti-Foam A substance used to prevent foam formation by greatly decreasing the surface tension within the fluid mixture. Anticline A fold in layered rocks originating below the surface in the form of an elongated dome. Anticlines make excellent drilling prospects since any oil in the deposit will naturally rise to the

highest point of the structure because oil has a lower specific gravity than water. See also: syncline. AOF Absolute Open Flow Potential API Gravity The gravity (weight per unit volume) of crude oil or other related liquids as measured by a system recommended by the American Petroleum Institute. API Gravity is expressed in degrees, a specific gravity of 1.00 being equivalent to 10 API. API gravity is related to specific gravity (SG) by the following formula: API Gravity = (141.5 /Specific Gravity) - 131.5. Apparent Viscosity The viscosity a fluid appears to demonstrate on a given instrument at a stated rate of shear. It is a function of the plastic viscosity and yield point of the given fluid. The apparent viscosity in centiPoise (cP) as determined by the direct-indicating viscometer is equal to 1/2 of the 600 RPM reading. Appraisal Well A well drilled as part of a programme to determine the size and likely yield of an oil or gas field. Approach The number of degrees temperature difference between the hot fluid inlet and cold fluid outlet, or between the hot fluid outlet and cold fluid inlet, whichever is smaller. APS Accelerator Porosity Sonde (IPL) Aquifier An underground zone of permeable rock saturated with water under pressure. For gas storage applications, an aquifer will need to consist of a permeable lower layer of rock and an impermeable upper layer (or "cap"), with a cavity for storing gas. ARG Argillaceous ARI Azimuthal Resistivity Imager Aromatics Hydrocarbons with a ring structure, generally with a distinctive aromatic odour, and good solvent properties (e.g. BTX). Artificial Lift Any means of lifting liquid from a wellbore that has ceased to flow due to inadequate reservoir energy. These methods include rod pumps, electric submersible pumps (ESP), gaslift, plunger pumps, and hydraulic jet pumps.

ASI Array Seismic Imager ASL Above Sea Level Asphalt The mixture of bitumen and aggregate used for road surfacing. Associated Gas Natural gas found in association with oil in a reservoir, either dissolved in the oil or as a cap above the oil. ASSY Assembly AST Acoustic Scanner Tool ASV Annular Safety Valve AT | A.T. | Average Tide Atmospheric Pressure The weight of the atmosphere on the surface of the Earth. At sea level this is approximately 1.013 bars, 101,300 Newtons per square metre, 14.7 pounds per square inch or 30 inches of mercury. ATS Borehole Audio Tracer ATT Auxiliary Telemetry Log Attapulgite Clay A colloidal, viscosity-building clay used principally in saltwater drilling fluids. Attapulgite, a special fullers earth, is a hydrous magnesium, aluminum silicate. Austenite A solid solution of one or more elements in face-centered cubic iron. AZI Azimuth Azimuth

Direction of a course measured in a clockwise direction from 0 through 360 degrees, with 0 degrees established as North. B/O Back-Off B/OUT Break Out B/U Bottoms Up BA Breathing Apparatus Back Pressure The pressure retained in a pipeline, flowline, vessel, or reservoir resulting from restrictions of the outflow of gas or liquids. Back Tension The tension developed by the service reel drive system needed to bend the coiled tubing over the tubing guide arch and onto the service reel, maintaining control of the tubing. Backoff To unscrew one threaded piece within a connection (e. g. a section of pipe) from another. Backoff Joint The point where the drill pipe, casing, tubing, or rod segment connection is unscrewed above such a point at which it is stuck in the hole. Backup The act of holding one section of tubing near a connection while a separate segment of tubing is screwed into or out of the connection. A backup wrench refers to any wrench being used to hold the pipe securely. Backup tongs are applied to the drill pipe or production tubing and are used to hold the section of pipe while another segment is screwed into through use of other tongs. Backwashing The process of cleaning a completion interval by injecting fluids into the formation and permitting the well to backflow. Bail To recover bottomhole fluids, samples or drill cuttings by lowering a cylindrical vessel, called a "bailer" to the bottom of the well, filling it, and retrieving it. Also refers to a link of steel attached to pipe elevators used for lifting. Bailer

A long tubular vessel fitted with a bail at the upper end and a valve at its lower extremity. Bailers are used to remove water, oil and solids from a wellbore. When fitted with a plunger to which a line is attached, a bailer can draw materials into the vessel as it is lifted. BAL Bond Attenuation Log Balance Point Length of tubing within the wellbore where generates a tubing weight equal to the well pressure acting against the cross-sectional area of the tube. Note that this is a static condition with the tubing full of fluid and does not include frictional forces of the stripper assembly and/or tubing rams, if engaged. Ball Valve A valve whose mechanism consists of a ball with a through-bore hole oriented along the same axis as the direction of fluid flow. Turning the plug 90 degrees opens or closes the valve. The valve may or may not be full-bore opening. Banding Layers of oxides or other inclusions inside the steel from which coiled tubing is manufactured. Barite Barium sulfate (BaSO4), a mineral used to increase the weight of drilling fluids. Barite has an approximate specific gravity of 4. 2. Barrel | bbl | Barrel (bbl), a standard measure for oil and oil products. One barrel = 35 imperial gallons, 42 US gallons, or 159 litres. Barrel Oil Equivalent | boe | Barrel Oil Equivalent (boe), a term frequently used to compare gas with oil and to provide a common measure for different quality gases. It is the number of barrels of stabilised crude oil, which contains approximately the same amount of energy as the gas: for example: 5.8 trillion cf (of lean gas) approximates to 1 billion boe. Barrels Per Day | bpd | bopd | b/d | Barrels Per Day (bpd, bopd, or b/d) , in production terms, the number of barrels of oil produced from a well over a 24 hour period, normally an average figure from a longer period of time. (In refining terms, the number of barrels input or production of a refinery during a year, divided by 365 less the downtime needed for maintenance). Base Chemicals Basic building blocks for the chemical industry, which are converted to other chemicals (e.g. aromatics and olefins converted into polymers). Baseload The basic, underlying level of demand, or system minimum. used in the context of gas supply and power generation. The opposite of peak load.

Basket Sub A fishing accessory typically run above the bit to permit recovery of small amounts of metal or junk from the wellbore. Bauschinger Effect An effect wherein strain cycling of tubing causes a lowering of the yield strength of the material. BBL Barrel Bcf | BN cf | Billion (10^9) cubic feet (cf), unit of measurement. BCM | BN CM | Billion (10^9) cubic metres (cm), unit of measurement. Beach Price Price applying to gas at landfall, when water and liquid hydrocarbons have been removed. Bell Nipple A flow-diverting nipple installed above the well control stack. The top end of the nipple is expanded (belled) to guide workstring tools into the hole and usually has side connections for attaching the fill line and the mud returns line. Bellows An expandable accordion-shaped device used to impart motion to a recording or controlling element within an instrument or to provide a flexible seal for pump shafts, etc. In gaslift technology, the bellows acts as the pressurized accumulator used to operate the valve. Bending Cycle The completion of two bending events whereby the axial strain returns to zero from a loaded condition. A cycle therefore consists of one bending event and one straightening event. The axial strain in coiled tubing is zero when the tubing is straight. Bending Moment The moment tending to bend the workstring or bottomhole assembly measured in Lb-ft or Newton-meters. Bending Strength Ratio | Stiffness Ratio | Bending Strength Ratio, (Stiffness Ratio) ratio Of Box To Pin Modulus. Used as a measure of how well "balanced" the mating pin and box rotary connections are in their ability to resist any bending moment. Bent Sub A sub used on top of a downhole motor to give a "non-straight" bottom assembly. One of the connecting threads is machined at an angle to the axis of the body of the sub.

Bentonite A plastic, colloidal clay largely composed of the mineral sodium montmorillonite (a hydrated aluminum silicate) and having the property of swelling when hydrated in an aqueous solution. The generic term "bentonite" is neither an exact mineralogical name nor is the clay of definite mineralogical composition. Bentonite has a specific gravity ranging from 2. Benzene The simplest aromatic compound with a ring of six carbon atoms and six hydrogen atoms. one of the most important feedstocks for the chemical industry. BGL Borehole Geometry Log BHA Bottom Hole Assembly BHC Borehole Compensated Sonic BHFP Bottom Hole Flowing Pressure BHP Bottom Hole Pressure BHT Borehole Televiewer BHTV Bore Hole Tele Viewer Biodegradable Material that can be decomposed or rotted by bacteria or other natural agents. Biomass Plant matter, such as wood, which can be used as source of energy. Biomass Conversion The conversion of biochemically derived material for the production of energy. Bit The cutting or boring element used in drilling oil and gas wells. The bit consists of a cutting element and a circulating element. The cutting element may be steel teeth, tungsten carbide buttons, industrial diamonds or polycrystalline diamond compacts (PDCs). Bit Breaker

A heavy plate which fits within the rotary table and holds the drill bit while it is being made up or broken out of the drill stem. Bitumen Extremely heavy semi-solid product of oil refining, made up of heavy hydrocarbons, used for road-building and roofing. Black Products Diesel oils and fuels oils, i.e. products from the low or heavy end of the distillation process. See also: white products. Blind Rams The rams in a well control stack which are designed to seal against each other to effectively close the wellbore when there are no tools or tubing through the well control stack. The blind rams are not intended to seal against coiled tubing or any other tubular products. BLKY Blocky Block The subdivision of a nation's exploration and production acreage. Blocks are generally defined in terms of latitude and longitude, at one-degree intervals. Blowdown A method of producing a gas/condensate reservoir by letting the reservoir depressure over time without re-injecting any gas. With this method of production some condensate may condense within the reservoir, where its recovery is no longer a practical proposition. Blowout An uncontrolled flow of pressurized wellbore fluids and/or formation fluids out of the wellbore or into lower pressured subsurface zones (underground blowout) due to the release of pressure in a reservoir or the failure of containment systems. Blowout Preventer A heavy wellhead control device equipped with opposed rams or an annular device which may be closed around the workstring or completely close off the top of the well control stack if the workstring is withdrawn. BO String Shot Back-off Booster Station A platform on a section of subsea gas pipeline, designed to boost the flow of gas. BOP Blow Out Preventer BOPD

Barrels Oil Per Day BOPE Blow Out Preventer Equipment Borcholt <img src="-B30D3D5F.jpg" width="54" height="77"> Matthias Borcholt created this Glossary. Borcholt@GMX.de Bottled Gas LPG stored in the liquid state at moderate pressure in steel containers. Bottomhole Assembly An arrangement of downhole tools comprised of the bit, motor (if applicable), stabilizers, reamers, collars, subs, etc. , which are installed at the bottom of the workstring or drillstring and used to perform milling or drilling operations. Bottomhole Flowing Pressure The flowing pressure at or near the bottom of the wellbore. The bottomhole flowing pressure is usually determined at the face of the producing formation by means of pressure-recording instruments which can be lowered into the well. Bottomhole Pressure The static pressure at or near the bottom of the wellbore. Bottomhole pressure (BHP) is usually determined at the face of the formation by means of pressure-recording instruments which can be lowered into the well. BHP may be calculated by adding the surface pressure to the wellbore fluid hydrostatic pressure if the density(s) of the fluid(s) is known. BP Beam Pump BPR Bridge Plug Setting Record Braking Systems Mechanisms operating on the injector and service reel which prevent uncontrolled or undesirable movement of the coiled tubing string. These braking systems may be mechanically or hydraulically operated. Brent Blend A blend of North Sea crudes, used as an international marker for crude oil pricing. Bridge An obstruction in the wellbore. A bridge may be formed by sloughing of the borehole into the wellbore or the accumulation of formation solids in sufficient volume to create physical blockage within the wellbore. Bridge Plug

A downhole flow control device composed primarily of slips, block mandrel, and rubber-sealing element which is run and set into tubing or casing to isolate pressure and fluid in the lower portion of the wellbore. British Thermal Unit | BTU | British Thermal Unit, BTU, the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. BRNG Bearing BS&W Basic Sediment and Water BTM Bottom BTU British Thermal Unit BTX Abbreviation of the aromatic hydrocarbons, benzene, toluene and xylene. BU Bottoms Up Buckling A large deformation of the tube body resulting from a sight increase of an existing load under which the tube had previously exhibited little, if any, deformation before the load was increased. In unsupported tube lengths, the deflection of the lateral axis of the tube body can rapidly become large, resulting in catastrophic failure. In bounded environments where the tube is concentric to tubing or casing, the buckling can take a sinusoidal or helical form, depending upon the applied load and ratio of tubing (or casing) ID and concentric tube OD. Buckup To tighten up a threaded connection (such as two joints of tubing). Build-And-Hold Borehole A borehole configuration where the inclination is increased to some terminal angle of inclination and maintained at that angle to the specified target. Build Angle The act of increasing the inclination of the drilled hole. Also the rate of change represented in degrees per 100 feet (30 meters) of the increasing angle in the hole. Buildup The portion of the borehole in which the inclination angle is increased. The rate of buildup is usually expressed as the angular increase in degrees per 100 feet (30 meters) of measured depth.

Bulk Cargo Any liquid or solid cargo loaded on to a vessel without packaging (e.g. oil or grain). Bullhead Squeeze The process by which hydraulic pressure is applied to a well to force fluids such as acids or cement outside the wellbore. Annular flow (returns) is prevented by a packer set in the casing above the perforations and/or in open hole, or by sealing off the returns flow path at the surface. Bunker Fuel Any diesel or fuel oil supplied to fuel a ship's engines. i.e. to run the ship rather than as cargo to be transported for sale. The 'bunkers' are the place where it is stored on the ship. Butane A hydrocarbon consisting of four carbon atoms and ten hydrogen atoms. Normally a gas, but easily liquified for transport and storage. used in gasolines, and for cooking and heating. See also: LPG. Butt Welding See Tube-to-Tube Welding. Bypass Usually refers to a plumbing connection around a valve or other flow control mechanism. A bypass is installed in such cases to permit passage of fluid through the diverting line when the maximum flow rate and/or pressure desired downstream is reached. C Compressibility C.I.P. Casing In Place C&C Condition And Circulate C/L Control Line C/W Complete With Ca Calcium CAC Circumferential Acoustilog Caisson

A single-wellhead marine completion structure. CAL Caliper CAL2 2-arm Caliper CAL4 4-arm Caliper CALC Calcareous Calcium Carbonate | CaCO3 | Calcium Carbonate (CaCO3): An insoluble calcium salt sometimes used as a weighing material (limestone, oyster shell, etc. ) in specialized drilling fluids. It is also used as a standard unit for expressing hardness of water. Calcium Chloride | CaCl2 | Calcium Chloride (CaCl2): A highly soluble salt which imparts special properties to drilling and completion fluids, but primarily for increasing the density of the fluid phase and/or accelerate the hydration reaction of cement and water. Calibration Comparison and adjustment of instruments, prior to use, to known basic reference points often traceable to the National Bureau of Standards. When calibrating instruments, often one of the reference points is "zero", thereby providing the means to establish the gain (slope) and the offset (y-intercept). Caliper Logging An operation used to determine the diameter of the wellbore or the internal diameter of casing, drill pipe or tubing. In the case of wellbore calipers, the logging operation is used to determine restrictions or enlargement in the wellbore. In the case of tubular goods, the caliper log indicates where internal corrosion or scale accumulation is prevalent. Calorific Value The quantity of heat produced by the complete combustion of a fuel. This can be measured dry or saturated with water vapour. and net or gross. ("Gross" means that the water produced during combustion has been condensed to liquid and thus released its latent heat, "net" means the water remains as vapour). The general convention is dry and gross. Cap Rock An impervious layer of rock which overlies a reservoir rock and so prevents the hydrocarbons escaping to the surface. CAPO Computer Assisted Production Operations

Capping The term referring to the method by which uncontrolled flow from a wellbore is halted or placed under control. Carbon A solid element which exists in many forms, including diamonds, graphite, coke and charcoal. The combinations of carbon with hydrogen are known as hydrocarbons and can consist of very large molecules (e.g. polypropylenes) or very short ones (e.g. methane). Carbon Black A carbon product obtained from liquified carbon feedstock and used mainly in the rubber industry (e.g. in tyres). Carbon Dioxide | CO2 | Carbon Dioxide (CO2) : A greenhouse gas, created when carbon containing compounds are oxidised. Casing The steel pipe placed in an oil or gas well which prevents the wall of the borehole from caving in, restricts movement of the borehole fluids from one formation to another, and improves the efficiency of extracting petroleum in productive wells. Casing Point The depth within a well at which the casing is set, generally the depth at which the casing shoe rests. Also, the objective depth in a drilling contract, either a specified depth or the depth at which a specific zone is to be penetrated. Casing Pressure The pressure in the annular space between two casing strings or the casing string and tubing string. Casing String The entire length of all joints of casing run into a wellbore. Casinghead A heavy flanged steel fitting which is connected to the first string of casing set within the borehole. The casinghead provides a housing for slips and packing assemblies, provides suspension of intermediate and production casing, as well as a means to seal off the annulus. CAT Category Catalyst A substance which aids or promotes a chemical reaction without forming part of the final product. It enables the reaction to take place faster or at a lower temperature, and remains unchanged at the end of the reaction. In industrial processes, nevertheless, the catalyst must be changed periodically to maintain economic production.

Cathodic Protection A method employed to minimise the rate of electrochemical corrosion of structures such as oil drilling and production platforms, pipelines and storage tanks. CB Core Barrel CBIL Circumferential Borehole Imager CBL Cement Bond Log CC Chemical Cutter CCL Casing Collar Locator CDL Compensated Densilog CDN Compensated Densi-Neutron Log (MWD) Cellar Excavation around the wellhead usually dug prior to drilling a deep well which provides space for items of equipment at the top of the wellbore. Also serves as a pit to collect drainage of water and other liquids. CEM Cement Cement A mixture of calcium aluminates and silicates made by combining lime and clay while heating. Slaked cement contains approximately 62. 5% calcium hydroxide. Cement Bond Log A well log of the vibrations of an ultrasonic acoustical signal as it passes through a four-phase system of fluid, pipe, cement and formation. If the pipe is not acoustically coupled tightly with a dampening material such as cement, very little of the acoustical energy signal is lost. If the cement is bonded or acoustically coupled tight to the pipe, the energy is extremely dampened and the signal nearly disappears, thereby indicating that the casing is well cemented. Cement Dump Bailer A cylindrical container with a valve that is used to release small batches of cement downhole in a remedial cementing operation or for other special purposes.

Cement Plug A portion of cement placed at some point in the wellbore to effect a seal used to isolate pressure or eliminate liquid movement. Cementing Conventional: The operation by which a cement slurry is pumped down a string of tubing and displaces the annular space to a predetermined height above the end of the cement string. In drilling and completion operations, cementing is used to secure the casing in place and isolate formations for control of fluids. In remedial operations cementing is used to seal holes in the wellbore for fluid control. Squeeze:The process of forcing cementing material under pressure into a specific portion of a well, such as fractures, openings, perforations or other permeable zones. Centipoise | Cp | Centipoise (Cp): A unit of viscosity equal to 0. 01 Poise. A Poise equals 1 gram per meter-second, and a centiPoise equals 1 gram per centimeter-second. CERT Correlatable Electromagnetic Recovery Tool CET Cement Evaluation Log Cetane Number A measure of the ignition quality of diesel fuels. See also: octane number. CF/D Cubic feet per day. CFM Flowmeter/Spinner Log CGEL CGEL Casing Evaluation Check Valve A valve that allows flow through it in one direction only. This device (also called a one-way valve) is installed near the coiled tubing connector and allows fluid to be circulated down the string but prevents backflow. This device may be a ball-and-seat type or flapper type. Chemical Oxygen Demand | COD | Chemical Oxygen Demand (COD): An indicator of the potential environmental impact of discharges to water. The COD is a laboratory measure of the quantity of oxygen required to oxidise the constituents of a liquid discharge CHFT Cased Hole Formation Tester

CHGR Cased Hole Gamma Ray Chloride Stress Cracking The stress corrosion cracking of ferrous-based alloy steels which may result when exposed to well streams containing water and chlorides under certain conditions of concentration and temperature. Other constituents present such as oxygen may contribute to chloride stress cracking. Chlorofluorocarbons | CFC | CFCs | Chlorofluorocarbons (CFCs): Man-made gases contributing to stratospheric ozone depletion and global warming. They are being phased out under the Montreal Protocol (see Halons, TCE and HCFCs). Choke A device with a fixed aperture used to control the rate of flow of liquids and/or gas, or to control the back pressure applied to the well. Choke Line Valve The valve(s) connected to the well control stack which controls the flow to the choke. CHP Combined Heat and Power CHRFT Cased Hole Repeat Formation Tester Christmas Tree A term applied to the combination of valves and fittings assembled above the top of the tubing hanger spool on a completed well to contain well pressure and control the flow of hydrocarbons and other well effluents. CIF Cost, insurance and freight. CIL Casing Inspection Log CILD Conductivity Dual Induction Log Deep CILM Conductivity Dual Induction Log Medium CIRC Circulate

Circulation The movement of fluid from the surface tank through the pump, coiled tubing, bottomhole assembly, annular space within the wellbore, and back to the surface tank. Circulation Rate The volume flow rate of the circulated fluid usually expressed in gallons per minute (gpm), barrels per minute (bpm) or cubic meters per minute (m3/m). CITHP Closed-In Tubing-Head Pressure City Gate This refers to the point where gas passes from a main transmission system to a local distribution system. There is not necessarily a change of ownership. CKS Checkshot Survey CL Chlorides Clay A term used for particles smaller than 4 microns regardless of mineral composition. Closing Ratio The ratio of the wellhead pressure to the hydraulic actuation pressure required to effect the closure of the well control component. CMPT Centre for Marine & Petroleum Technology CMT Circumferential Microsonic Tool CNL Compensated Neutron Log CO Carbon Monoxide Coal Gas Manufactured gas made by the destructive distillation of bituminous coal. The chief components are methane (20% to 30%) and hydrogen (about 50%). Coating The process of covering a tube of a specific material with another material, primarily for corrosion resistance, but could also be applied for reduction of pipe/borehole-to-coiled tube friction.

COD Chemical Oxygen Demand Coefficient of Friction The ratio of the force required to move one surface over another to the normal force between the two surfaces. COGR Core GR Coiled Tubing Any continuously-milled tubular product manufactured in lengths which require spooling onto a take-up reel during the primary milling or manufacturing process. Conventional coiled tubing (CT) is constructed of carbon steel using the high-frequency induction welding process. Advanced metallic coiled tubing strings are constructed using corrosion resistant alloys or titanium, with the seam weld formed using the TIG process. Coiled Tubing Unit The assembly of the major equipment components needed to perform a continuous-length tubing service. These basic equipment components include (as a minimum) an injector, service reel, control console, power supply, and well control stack assembly. Coking A thermal cracking process to break up large molecules into smaller ones with the generation of quantities of petroleum coke. COL Collar Cold Weld A metallurgical inexact term generally indicating a lack of adequate weld bonding strength of the abutting edges, due to insufficient heat and/or pressure. A cold weld may or may not have separation in the weld line. Other, more definitive terms, should be used whenever possible to describe this condition. Cold Working Deforming a metal plastically at such a temperature and rate that substantial increases occur in the strength and hardness of the metal occurs. Visible structural changes include changes in grain shape and, in some instances, mechanical twinning or banding. The upper limit of temperature for this process is the recrystallization temperature of the material. Collapse Flattening of the coiled tubular product due to the application of an external pressure of such magnitude as to exceed the hoop yield stress of the tube. Collapse pressure is measured as the pressure differential of external to internal tube pressure and is significantly reduced when the tube is subjected to tension or bending.

Collar A coupling device used to join two lengths of threaded pipe, tubing or tool components. Collar Locator A logging device that detects casing or tubing collars for depths correlation purposes. The collar locator may be operated mechanically or electrically to produce a log showing the location of each casing or tubing collar within the wellbore. When properly interpreted, this log provides an accurate means for depths measurements in a wellbore. Colloidal Suspension A stable, homogenous system of very fine particles of matter dispersed uniformly throughout a liquid medium, having properties which differ both from a true solution and from a suspension of larger particles. True colloidal suspensions have particle size range of 5 to 200 micrometers. Combined Carrier Ship that can carry oil or dry bulk cargoes. Combined-Cycle Gas Turbine | CCGT | The generation of electric power by a combination of a gas-turbine cycle and a steam-turbine cycle. Combined Heat and Power | CHP | The combination of heat and power generation in the same plant: In circumstances where process heat is not required, the generated steam can be used to generate additional electricity in a steam turbine. This method reduces the overall consumption of fuel by exploiting the otherwise wasted heat from conventional electricity generation. It provides low-grade heating for domestic and industrial uses. This is described as Combined Cycle Power Generation. Common Carriage 1) The transport of gas through a pipeline system on behalf of a third party. 2) The obligation on transmission or distribution companies to allocate gas transport to customers on a pro rata basis, without discrimination between new and existing clients. COMP Completion Completion String A string of tubing placed within a productive well to serve as an exhaust or delivery duct for produced wellbore fluids. Compound Chemical term referring to a substance made up of two or more elements chemically united in fixed proportions by weight. Compressibility Factor The factor which compensates for the deviation of a giving gas from the ideal gas law when calculating the pressure-volume-temperature relationship.

Compressive Yield Strength The maximum stress a material can withstand without a predefined amount of permanent deformation when subjected to compression loading. Compressor Station Used during the transportation of gas. Gas loses pressure as it travels long distances: to ensure an even flow it must be recompressed at the stations located every 60 km to 80 km along the route. CONCAWE The Oil Companies European Organisation for Environmental and Health Protection, based in the Hague. Concentric Operations Well servicing operations conducted within the existing production tubing or within tubingless completions. This type of operation is normally performed with the christmas tree in place using a coiled tubing unit, hydraulic workover unit, wireline unit, hoisting unit, or small rig using smaller diameter jointed tubing. Concession A defined licence area granted to a company for the exploration of oil and/or gas under specified terms and conditions and for a fixed period of time. Condensate This can refer to any mixture of relatively light hydrocarbons which remain liquid at normal temperature and pressure. There will be some propane and butane dissolved in it. Unlike crude oil, there is little or none of the heavy hydrocarbons which constitute heavy fuel oil. There are three main sources of condensate: a) The liquid hydrocarbons which are separated out when raw gas is treated. This condensate typically consists of C5 to C8. b) The liquid hydrocarbons which are recovered at the surface from non-associated gas. c) The liquid hydrocarbons which are produced from gas/condensate reservoir. This may be only slightly distinguishable from a light stabilised crude oil. Conductor Casing Generally, the first string of casing in a wellbore. Its purpose is to prevent soft formations near the surface from caving in and to conduct drilling mud from the bottom of the hole to the surface when drilling commences. Also called conductor pipe and drive pipe. Connectors | CT | Devices used to connect coiled tubing and equipment components. There are several types of connectors in use as described below:. CONT Continue Continental Shelf The edge of a continent which lies under shallow seas (less than 200 metres deep).

Continuously-Milled Tubing Carbon steel coiled tubular products manufactured using high frequency induction welding processes in milled length segments greater than 500 feet. Continuously Tapered Skelp Skelp material having a variable wall thickness. This skelp is milled having a specified wall thickness at the lead end of the steel strip, progressively increasing in wall thickness along the length of the strip to a second specified wall thickness at the tail end of the skelp strip. Control Console An enclosure displaying an array of switches, push buttons, lights, valves, various pressure gauges, and/or meters to control or monitor coiled tubing operating functions. Conventional Operations Well operations conducted using a rig equipped with fluid pumps, rotary table, and other equipment designed to perform well workovers, recompletions, and other work which requires removal of the christmas tree and pulling or manipulation of the tubing. CORIBAND Coriband Analysis CORR CAP Corrosion Cap Corrosion Gradual chemical or electro-chemical attack on a metal by the atmosphere, moisture or other agents. CPI Computer Processed Interpretations CPU Control Panel Unit Crack A stress-induced separation of the metal which, without any other influence, is insufficient in extent to cause complete rupture of the material. Cracking | Cat. Cracker | The process of breaking down large molecules of oil into smaller ones. When this process is achieved by the application of heat only, it is known as thermal cracking. If a catalyst is used as well it is known as catalytic (cat.) cracking. It is known as hydrocracking if the catalytic process is conducted in a hydrogen atmosphere. Creep Time-dependent increase in strain during a state of constant stress. Critical Flow

The rate of a compressible fluid flow through an orifice or small opening in which the velocity of the fluid reaches a maximum and remains constant. The rate of the fluid flow is directly proportional to upstream pressure and changes only with upstream pressure. Changes in downstream pressure have a negligible effect on flow rate when critical velocity is obtained. Critical Pressure The minimum pressure required to liquefy a gas at its critical temperature. Critical Temperature The temperature above which a gas cannot be liquefied whatever the pressure. Crossover Flange A double or single studded adapter flange with a restricted area sealing means and with a top connection pressure rating above that of the lower connection. Crowd The Bit Term used to indicate that more weight is applied to the bit than is needed for efficient drilling. A crowded bit will usually increase the inclination or cause an azimuth change. Crown Block Assembly The stationary sheave or block assembly mounted at the top of the derrick or mast and over which the drilling line is reeved. CRT Cement Retainer Record Crude Oil A mixture of hydrocarbons that exists in the liquid phase in the underground reservoir and remains liquid at atmospheric pressure after passing through surface separating facilities (separation from any associated gas). Cryogenics The process of producing, maintaining and utilising very low temperatures (below -46 Crystallization The formation of a crystal by the atoms assuming definite positions in the crystal lattice. CSG Casing CSGC Casing Cutter CSI Combinable Seismic Imager CSP Contract Service Personnel

CST Core Sample Taker CT Coiled Tubing Cubic Foot | Cubic Feet | cf | The amount of gas required to fill a volume of one cubic foot. Unit of measurement applied to the volume of gas produced or consumed. Cubic Metre | CM | Unit of measurement for gas volume. The amount of gas required to fill the volume of one cubic metre. CUM Cumulative Cumulative Fatigue Damage The total of fatigue damage caused by repeated cyclic stresses. Cuttings Earth and rock removed during a drilling operation to make an exploration or production well for oil and gas production. Cuttings are invariably contaminated with oil from drilling fluids (oil-based and other muds). CVEL Calibrated Velocity Log CVL Cement Volume Log CYBERDIP Cyberdip Interpretation CYBERLOOK CYBERLOOK Analysis D/O Drop Off DAC Digital Array Acoustilog Daily Average Send-Out Total volume of gas delivered during a period of time, divided by the total number of days in the period.

Daily Contracted Quantity | DCQ | The average daily quantity of gas which is contracted to be supplied and taken. Daily Peak The maximum volume of gas delivered in any one day during a given period (usually one year). Daisy Chain The process by which a cargo of oil or oil products is sold many times before being delivered to the customer. Darcy A unit of permeability. A porous medium has a permeability of 1 Darcy when a pressure of one (1) atmosphere is applied to force a liquid of one (1) cP viscosity through a sample one (1) cm long and one (1) cm2 in cross section at a rate of one (1) cm3 per second. Darcy's Law The rate of flow of a homogenous fluid through a porous medium is proportional to the pressure or hydraulic gradient and to the cross-sectional area normal to the direction of fluid and inversely proportional to the viscosity of the fluid. DBS Dual Ball Safety Valve DC Drill Collar DCAL Dual Caliper DCQ Daily Contracted Quantity DD Depth Determination DDR Daily Drilling Report DDST Deflate Drag Spring Tool DEA Drilling Engineering Association; <BR>Deutsche Erdöl Aktiengesellschaft Dead Oil Crude containing essentially no dissolved gas when it is produced. Dead Well

A well that has ceased to produce oil or gas either temporarily or permanently. Ultimately, a well that has suffered a kick or a blowout and has been killed. Defect An imperfection whose size, shape, orientation, location or other properties make it detrimental to the useful service of the tube or exceed the accept/reject level of the applicable specification. DEG Degree Degree Day A measure of the extent to which the mean daily temperature falls below an assumed base, say 65° F. thus each degree by which the mean temperature for any day is less than 65°F would represent one degree day. (In Continental Europe, °C are used instead of °F and the assumed base temperture is generally taken as 16°C, equivalent to 60.8°F). DEMINEX | Deutsche Erdölversorgungsgesellschaft | DEMINEX GmbH (Deutsche Erdölversorgungsgesellschaft mbH) of Essen, Germany. Active in Argentina, Egypt, Norway, Russia, Syria, UK. Split in 1998. Density | Absolute Density | Bulk Density | Absolute: Mass per unit volume. Absolute density considers only the actual volume occupied by the material expressed in pounds per gallon (ppg) or pounds per cubic foot (lb/cu. ft. Bulk: Mass per unit volume. Bulk density is a mass per unit bulk volume which includes the actual volume of the material plus the volume of trapped air. Dent A local change in surface contour caused by a mechanical impact, but not accompanied by the loss of metal. Departure Horizontal displacement of one station from another in an east or west direction. Derrick Steel structure mounted over the bore hole to support the drill pipe and other equipment which is lowered and raised during drilling operations. This semi-permanent structure of square or rectangular cross-section having members that are latticed or trussed on all four sides must be assembled in the vertical or operation position as it includes no erection mechanism, this derrick may or may not be guyed. Design Load That force or combination of forces which a structure or mechanical component is designed to withstand without exceeding the allowable stress within any member. Design Pressure | Rated Working Pressure | Maximum allowable working pressure at the design temperature and operating conditions. Design Verification

The process of proving design by testing. Designated Representative Individual selected or assigned by the employer or the employer's representative as being qualified to perform specific duties. DEV Development Development Well A well drilled in proven territory in a field for the purpose of completing the desired spacing pattern for production optimization. Deviation Bit A bit specifically designed to reduce the tendency to drill a crooked hole. Deviation Control Techniques The techniques typically used to control the deviation of the borehole when performing steered-drilling operations are shown below:. Deviation Well A well drilled at an angle to the vertical (deviated drilling), to cover the maximum area of an oil or gas reservoir, or to avoid abandoned equipment in the original hole. DGR Dual Gamma Ray (MWD) DHPT Downhole Pressure Temperature (Gauge) DHSV Down Hole Safety Valve Diameter Tape A measuring device consisting of a thin flexible metallic tape which can be wrapped around the circumference of a pipe, and is graduated such that diameter can be read directly from its scale. Also called a "Pi Tape". Diametral Growth The increase in the outer diameter of the tube which occurs as a consequence of performing repeated bend cycles of the tube with an internal pressure greater than the external pressure acting on the tube. DIEL Dielectric Log Diesel Fuel | Diesel Oil | DERV |

A general term covering light fuel oil derived from gas oil used in diesel engines. Sometimes called Diesel Engine Road Vehicle (Derv) fuel. Differential Pressure The difference between two fluid pressures. This difference in pressure may be between points in a fluid pumping system, may represent the loss in pressure within the fluid when pumped through a specific length of tubing, or when fluid flows between two systems (e. g. DIFL Dual Induction Focused Log DIL Dual Induction Log Diluent Liquid which is added to dilute or thin a solution. Dimple Type Connection which is secured onto the coiled tubing body through the use of numerous blunt-tip screws loaded into dimpled recesses formed in the tube body. As the mechanical blunt-tip screws are loaded onto the tube body, forces exceeding the material yield strength of the tube create "dimples" in the tube body. These dimples serve as mechanical loading recesses for the blunt-tip screws which secure the connection to the CT body. DIP unspecified Dipmeter DIP EVAL Dipmeter Evaluation DIP4 4-Arm Dipmeter DIP6 6 Arm Dipmeter DIR Directional Survey Data Direction See azimuth. Direction of vertical projection of the wellbore onto a horizontal plane. Direction of Inclination The direction of the course. Directional Drilling The planned drilling of an off-vertical wellbore at a controlled, pre-determined angle and direction using special equipment and orienting devices.

Discharge General term for all releases of contaminants into the environment, be they gas, liquid, or solid. The term emission is used exclusively for releases into the atmosphere, effluent is restricted to releases into surface water and waste is used for remaining releases, such as disposal to landfill or treatment by incineration. Discontinuity Any interruption in the normal physical structure or configuration of a tube such as cracks, laps, seams, pits and laminations. A discontinuity may or may not affect the usefulness of a pipe or exceed critical flaw size. Also called a flaw or imperfection. Discovery Well An well that encounters a new and previously untapped petroleum deposit. DISP Displace Dispersant A chemical agent used to break up or disperse concentrations of various liquid or solid materials. Displacement The lateral distance from the surface location to the primary target. Distillate The condensed hydrocarbons which are produced with gas from a single or two-phase reservoir. Condensation occurs as pressure is reduced below specific critical pressures. Distillates The products of condensation during the fractional distillation process (gaseous fuels, naphtha, gasoline, kerosine and gas oils). Distillation (Fractional distillation) A process based on the difference in boiling points of the liquids in the mixture to be separated. Successive vaporisation and condensation of crude oil in a fractionating column will separate out the lighter products, leaving a residue of fuel oil or bitumen. Distillation is carried out in such a way as to avoid any cracking. It is the basic process that takes place in an oil refinery. Distribution After gas has been processed, it is transported through transmission trunk lines to local distribution centres, for metered delivery to customers. Diurnal Storage Literally, daily storage. Refers to short-term or peak storage in pipelines or gas holders, as opposed to seasonal storage.

DL Dog Leg DL SEV Dog Leg Severity DLL Dual Laterolog DLRS Dollars DO Drop Off Dog Leg The total curvature in the wellbore consisting of a change of inclination and/or direction between two points. Dog Leg Severity A measure of the amount of change in the inclination and/or direction of a borehole, usually expressed in degrees per 100 feet (30 meters) of course length. DOL Days On Location DOLO Dolomite Dolomite A type of sedimentary rock similar to limestone but rich in magnesium carbonate. Sometimes dolomite is found as the reservoir rock for petroleum-bearing zones. Dope A viscous material used on casing or tubing threads as a lubricant and to prevent corrosion. Double Bottom Tanker A tanker in which the bottom of the cargo tanks is separated from the bottom of the ship by a space of up to 2 to 3 metres. The space is empty when the tanker carries cargo, but full of sea water on the ballast voyage. See also: double hull tanker. Double Hull Tanker A tanker in which the bottom and sides of the cargo tanks are separated from the bottom and sides of the hull by spaces of up to 1 to 3 metres width or depth. These spaces are empty when the tanker carries cargo but full of sea water on the ballast voyage. See also: double bottom tanker. Double-Wall Drill Pipe

A two-tube concentric drill pipe assembled with the inner pipe in compression and the outer pipe in tension. Used to replace drill collars in directional holes. Downhole Motor A power source located just above the bit which is used to rotate the bit while the drill string remains fixed. Downstream Those activities which take place between the loading of crude oil at the export terminal and the use of the oil by the end-user. This encompasses the ocean transportation of crude oil, supply and trading, refining and the distribution and marketing of the oil products. See also: upstream. DP Drill Pipe DPHI Density Porosity DPIL Dual Induction Phasor Logs DR Damage Ratio Drag The algebraic sum of the resistance due to (1) the friction between the coiled tubing and the well control equipment, (2) the friction between the coiled tubing and the wall of the wellbore, (3) the friction due to the coiled tubing passing through fluid, and (4) the friction due to the flow of fluids either inside or outside of the coiled tubing. Drawdown The differential pressure in a constant-rate producing well between the static (shut-in) bottomhole pressure and the flowing bottomhole pressure. The location of this pressure condition is generally found within the wellbore directly across the completion interval. Drawworks The hoisting mechanism on a drilling rig which is essentially comprised of a large winch which spools off or takes in the drilling line. This action raises or lowers the drillstem and bit. DRIFT Drift Analysis Drill To bore a hole within the earth, usually to find and remove subsurface formation fluids such as oil and gas. Drill Bit The part of a drilling tool that actually cuts through the rock.

Drill Collar A heavy, thick-walled tube, usually constructed of steel, placed between the drill pipe and the bit in the drill stem which provides stiffness and concentration of weight at the bit. Drill Collar Sub A sub made up between the drill string and the drill collars that is used to ensure that the drill pipe and the collar may be joined together properly. Drill Pipe The tubular member of the drill string which transmits power to the bit to which tool joints are attached. Drill Stem The entire drilling assembly, from the swivel to the bit, composed of the kelly, drill string, subs, drill collars, and other downhole tools such as stabilizers and reamers. This assembly is used to rotate the bit and carry the drilling fluid to the bit. Drill Stem Test The conventional method of formation testing. The basic drill stem test tool consists of a packer or packers, valves or ports that may be opened or closed from the surface, and two or more pressure-recording devices. Drill String Steel pipes roughly 10m long joined together to form a pipe from the drill bit to the drilling platform. It is rotated to carry out the drilling operation, and also is the conduit for the drilling mud. Drilling Fluid A fluid circulated through the bit which serves to carry cuttings from the bit to the surface. Hole conditions may dictate other necessary functions for this fluid, such as cooling the bit and to counteract downhole formation pressure. The most common drilling fluid is a mixture of clay and other minerals with water, but can also be air, gas, water or foam systems. Drilling Mud A mixture of clays, water and chemicals used in drilling operations to lubricate and cool the drill bit, carry drilling wastes to the surface, prevent the walls of the well from collapsing, and to keep the upward flow of oil or gas under control. It is circulated continuously down the drill string and up to the surface between the drill pipe and the wall of the hole. Drop-Off Rate The rate of change of the inclination in the part of the wellbore where the inclination angle is purposely returned to the vertical orientation and usually expressed in degrees per 100 feet (30 meters) of course length. Dry Gas Natural gas that is produced without liquid hydrocarbons. Also gas that has been dehydrated to remove water. a) The same as lean gas, i.e. the gas contains no hydrocarbons which will liquefy

at ambient temperature and pressure. b) Gas containing no water vapour, i.e. the gas is "water dry". Dry Gasfield The production from such a reservoir will yield dry/lean gas and very small quantities of condensate. typically less than 10 barrels per million cubic feet. Dry Hole An unsuccessful well, drilled without finding commercial quantities of oil or gas. DSHV Down Hole Safety Valve DSI Dipole Shear Sonic Imager DSS Days Since Spud DST Drill Stem Test DSV Diving Support Vessel DT Interval Travel Time DTL Long-spaced Interval Travel Time DUAL DIP Dual Dipmeter DUAL WATER Dual Water Quicklook Analysis Ductility The property that permits permanent deformation before fracture by stress in tension occurs. Dwt (Dead Weight Tonnage) | Dwt | The weight of cargo, stores and fuel which a vessel carries when fully loaded. Dynamic Loading Loads introduced into any mechanical component which is required to operate in the presence of accelerating or decelerating forces. Dynamic loading can be experienced in the tubing string, tube handling equipment, or in any component which may experience rapid force loading or unloading.

Dynamic Positioning A method by which a floating vessel is maintained in position (on station) over an offshore well location without the use of mooring anchors. Generally, several propulsion units called thrusters are located on the hulls of these structures and are actuated by a sensing system which is directed by computer. Dynamic Stress Varying or fluctuating stress occurring in a structural member as a result of dynamic loading. Eccentricity (Fluid Flow) The degree to which a concentric tubing string is decentralized within an annulus with consideration for calculating the effects of frictional pressure loss. An eccentricity value of 0. 0 indicates perfectly centralized tubing within the annulus. (Tube Mill) A condition of tubing geometry in which the OD and ID axes are not coincident, resulting in wall thickness variation around the circumference at a given section plane. ECP External Casing Packer ECR Emergency Control Room ECT Energy Charter Treaty - signed by 45 governments and the EU in Lisbon, Portugal on 17 December 1994. ECU European Currency Unit. Eddy Current A circulating current caused to flow in the tubing by varying magnetic fields. Eddy Current Inspection Performing a nondestructive inspection using the eddy current method. EDP Emergency Disconnect Package EDR Estimated Damage Ratio EFF Efficiency Effective Permeability The permeability of a rock to a specified fluid when the rock is not 100 percent saturated with the fluid.

Effective Porosity The percentage of the bulk volume of a rock sample that is composed of interconnected pore spaces, allowing the passage of fluids through the sample. Effective Size A term used in specifying sand size. It is the sieve size in millimeters that permits 10 percent (by weight) of the filter sand to pass. Effective Thread Length Connector threads having fully-formed roots but not necessarily finished crests. EL Electrical Log ELAN ELAN Interpretations Elastic A gas, e.g. , a condition of matter in which the molecules flow apparently without resistance. Elastic Aftereffect A slight contraction that occurs slowly while metal is standing with no load, subsequent to plastic tensile flow and immediate elastic recovery. Microscopic stresses acting in compression are responsible for this condition as well as for the Bauschinger effect. Elastic Buckling Stress The buckling stress of a cylinder based upon elastic behavior. Elastic Deformation Temporary changes in tube dimensions caused by stress. The material returns to the original dimensions after removal of the stress. Elastic Hysteresis Energy absorbed by reversed deformation, represented by the closed loop of stress-strain curves in the elastic range, formed by curves for loading and unloading. Elastic Limits The maximum stress which a material is capable of sustaining without any measurable permanent extension remaining after complete release of the applied force. Elastomer Any of the class of materials, including natural rubber and synthetic compounds, which return to their original shape after being subjected to large deformations. Electric Logging An instrument measurement of resistivity and self-potential of formations immediately adjacent to the wellbore. These measurements are obtained by passing electrodes across the formations

of interest within the wellbore. Electric logs are typically run on wireline to obtain information concerning the porosity, permeability, fluid content of the formations drilled, etc. Element A chemical term referring to a substance that cannot be chemically broken down into a simpler form. Elevation Measurement of a well location or a plane on a drilling well above a specified datum, usually sea level. Elevators Mechanical device attached to the traveling block which latches around and supports the pipe during hoisting or lowering operations. Elongation The amount of permanent extension in the vicinity of the fracture in a tension test specimen, with the increase in length expressed as a percentage of the original gage length. ELTSR Extended Length Tubing Seal Receptacle EMMS Electro-Magnetic-Multi-Shot EMS Electric Multi Shot Emulsion A substantially permanent heterogeneous mixture of two or more liquids which do not dissolve in each other but are held in suspension or dispersion (one in the other) by mechanical agitation or, more frequently, by adding small amounts of substances known as emulsifiers. Emulsions may be mechanical, chemical or a combination of the two (commonly oil and water). EMW Equivalent Mud Weight Encircling Coil A coil surrounding the tube under test, used in eddy current testing. Endurance Limit The maximum stress that a metal will withstand without failure during a specified large number of cycles of stress. If the term is employed without qualification, the cycles of stress are usually such as to produce complete reversal of flexural stress. Endurance Ratio The ratio of the endurance limit for cycles of reversed flexural stress to the tensile strength.

ENERJET ENERJET Perforation Entrained Gas Gas suspended in bubbles in a stream of liquid such as water or oil. Entrained Liquids Mist-size liquid droplets transported in a gas stream. Environmental Impact Assessment (EIA) | Environmental Impact Assessment | An assessment of the impact of an industrial installation or activity on the surrounding environment, conducted before work on that activity has commenced. The original baseline study, a key part of this process, describes the original conditions. EOR (Enhanced Oil Recovery) The recovery of oil from a reservoir other than by the use of natural reservoir pressure. This can involve increasing the pressure (secondary recovery) or heating or increasing the pore size of the reservoir (tertiary recovery). See also: acidizing. EPT Electromagnetic Propagation Log EQT Equipment Equity Crude The proportion of crude oil to which a producing company is entitled as a result of its financial contribution to the project. Equivalent Circulating Density For a circulating fluid, the equivalent circulating density in lbs/gallon is equal to the hydrostatic head of the annular fluid (psig) plus the total annular frictional pressure loss (in psig) caused by the fluids circulating in the annulus, divided by the depth (feet) and a conversion factor of 0. 52. ERD Extended Reach Development Erosion The abrasion of metal or other material by liquid or gas usually accelerated by pressure of solid particles of matter in suspension and sometimes by corrosion. ES Electrical Survey ESD Emergency Shutdown ESDV

Emergency Shut Down Valve ESP Elecric Submersible Pump Esters Compounds formed by the combination of acids and alcohols. Feedstock for the chemical industry. ESV Emergency Shutdown Valve Ethane A hydrocarbon consisting of two carbon atoms and six hydrogen atoms. Normally a gas, present in most natural gas occurrences. Ethanol | Ethyl Alcohol | A chemical formed by fermentation or synthesis. used as a raw material in a wide range of industrial and chemical processes. Ethylene | Ethene | An olefin consisting of two carbon atoms and four hydrogen atoms. a very important base chemical in the chemical and plastics industries. ETT Electromagnetic Thickness Tool EU European Union. Evaluation Process of determining the severity of the flaw which leads to determining whether the tube is acceptable or rejectable under the appropriate specification. EWR Electromagnetic Wave Resistivity (MWD) EWT Extended Well Test Excessive Reinforcement Also referred to as excessive over-fill. The outside weld beads which extend above the prolongation of the original surface of the tube. Exfoliation A type of corrosion that progresses parallel to the outer surface of the metal, causing layers of the metal to be elevated by the formation of the corrosion product.

Exposure Hours This is the total number of hours of employment including overtime and training but excluding leave, sickness and other absences. One million exposure hours is roughly equivalent to 600 people working for one year. EZSV External Zentralized Safety Valve FACT Flux Array Analysis Log False Indication An indication that may be interpreted erroneously as an imperfection or defect. An irrelevant indication, sometimes called an artifact. Fatality A death resulting from either a work injury or occupational illness, regardless of the time intervening between the injury or the onset of the illness and death. Fatigue | Fatigue Classification | The process of progressive localized permanent structural change occurring in a material subjected to conditions which produce fluctuating stresses that may culminate in cracks or complete failure after a sufficient number of fluctuations. Fatigue is often identified within the following classes: High Cycle Fatigue - Loading is primarily elastic and material failure occurs in excess of 10,000 stress cycles. Low Cycle Fatigue - Loading is mostly elastic and material failure occurs in 1,000 to 10,000 stress cycles. Fatigue Ultra-Low Cycle Fatigue - Loading is plastic and material failure typically occurs in less than 1,000 stress cycles. Fatigue Crack | Failure | A fracture starting from a nucleus where there is an abnormal concentration of cyclic stress and propagating through the metal. The surface is smooth and frequently shows concentric (sea shell) type markings with a nucleus as a center. Fatigue cracks which penetrate the OD surface of the tube body are incorrectly referred to as "pinholes". Fatigue Life Number of cycles a material (typically metal) can endure at a given stress level before failure will occur. Fatigue Limit The maximum stress that a material (typically metal) will withstand without failure for a specified number of stress cycles. Fault | Faulting | A geological structure consisting of a fracture in the rock, along which there has been an observable amount of displacement. FB HRT Full Bore Hydrostatic Reference Tool

FB PCT Full Bore Pressure Controlled Tester FBHP Flowing Bottom-Hole Pressure FBU Flowing Build Up survey FCNL Far Count CNL FCON Fluid Conductivity Log FDC Compensated Formation Density FDDP Differential Pressure Fluid Density FDN Nuclear Fluid Density FE Flow Efficiency Feedstock Raw material for a processing unit. FERC Federal Energy Regulatory Commission FH Full Hole Field Appraisal The process of quantifying reserves levels and production potential of a newly-discovered petroleum reservoir, usually by drilling a delineation well. FIL Fracture Identification Log Filler Material A material added to a cement or cement slurry for the primary purpose of increasing the yield for the slurry.

Filler Metal The metal added in making a welded, brazed or soldered joint. Filter Cake The accumulation of suspended solids deposited on a porous medium during the process of filtration. Filtrate The liquid that is forced through a porous medium during the filtration process. Fish Any object left in the wellbore during drilling or workover operations which must be recovered before work below the object can proceed. Fishing Operations within a wellbore which focus on retrieving objects (fish) left in the borehole. FISS Fissure FIT Formation Integrity Test Flange A protruding rim extending completely around the tube or pipe with holes positioned to accept bolts and having a sealing mechanism used to join pressure-containing equipment. Flare Test An expansion of the tube body when forced over a cone-shaped mandrel having a given tapered angle and a given cone length. The specimen lengths of coiled tubing (approximately 4" in length) are flared over a mandrel having a 60 included angle. For CT-90 Grade and lower, the ID at the mouth of the tube is flared until it is expanded to at least 21% of original ID without cracking. Flaring The controlled and safe burning of gas which cannot be used for commercial or technical reasons. Flaring and Venting Flaring is the burning of hydrocarbon gases, and venting is the release of gases to the atmosphere without burning. Flash (OD/ID) | Flash | A thin fin or web of metal formed at the joining edges of a weld when a small portion of metal is extruded during the high frequency induction seam-forming process. This flash extends above the plane of the OD surface as well as the plane of the ID surface. Flash Free CT

Coiled tubing from which the inside longitudinal weld flash has been removed. Flattening Test A weld integrity test procedure which customarily uses a ring or crop end section from the tube, positioning the weld either 0 or 90 degrees to the applied force, and flattening between parallel plates without cracking or showing flaws. Flaw A discontinuity or irregularity in the tubular product. Fleet Angle The maximum lateral bending angle imposed onto the coiled tubing as seen at the entrance to the tubing guide arch. After the injector and service reel are properly positioned, a reference line is run from the center of the tubing guide arch through a point on the service reel located midway between the reel flanges. The fleet angle is represented as the angle between the reference line and a second line run from the entrance to the tubing guide arch to the wall of either the reel flange, as measured along the same plane. Flotel The floating accommodation used as quarters for offshore personnel. Flow Coupling A heavy-walled nipple incorporated within the production tubing string designed to resist erosion that may result from turbulence created by a restriction within the flow string. Flow Cross A pressure fitting with a minimum of four openings. Usually all four openings are oriented at 90 degrees to each other in the same plane. Crosses may be threaded, studded or flanged. Flow Tee A pressure fitting with the straight (run) segment sized to be full bore and the side outlet (branch) sized to connect a high-pressure line. The flow tee is a well control stack component typically used to provide the returns fluid outlet. Flowing Bottomhole Pressure The pressure existing at the depth of the producing formation in a wellbore flowing with a constant rate of fluid production. Flowing Wellhead Pressure The pressure existing at the wellhead of a flowing well. Fluid A form of matter which cannot permanently resist a shearing force which causes flow. Also a generic term meaning a gas, vapor, liquid or combinations thereof. Fluid Analysis Examination and testing of fluids to determine physical and chemical properties and condition.

Fluorescent Magnetic Particle Inspection The magnetic particle inspection process employing a finely divided fluorescent ferromagnetic inspection medium that fluoresces when activated by ultraviolet light and is used for the detection of two-dimensional surface imperfections. FMBK Basket Flowmeter FMCS Continuous Spinner Flowmeter FMDIP Formation Dip Evaluation FMF Folding Impeller Flowmeter FMI Fullbore Micro Scanner FMS Formation Micro Scanner FMS ANAL FMS Analysis FMT Formation Multi-Tester Foam A two phase fluid system similar to an emulsion where the dispersed phase is a gas. Foaming Agent A substance that produces fairly stable bubbles at the gas-liquid interface due to agitation, aeration, or ebullition. In air or gas drilling, foaming agents are added to turn water influx into aerated foam, commonly called mist drilling. FOB Free on board. FORM FAC Formation Factor Analysis Formation Damage The reduction of permeability in the reservoir at the completion interval arising from invasion of drilling fluids, treating fluids, or any fluid incompatibility with the native reservoir condition. Formation Pressure

The pressure exerted by fluids within a formation, recorded in the borehole at the true vertical depth of the formation with the well shut-in. Formation pressure may also be referred to as "reservoir pressure" or "shut-in bottomhole pressure". FOS Fall-Off Survey FOT Fall-Off Test FPI Free Point Indicator FPS Floating Production System FPSOV Floating Production Storage And Offloading Vessel FPV Floating Production Vessel Fractional Distillation See Distillation. Fractionating Column See Distillation. Fractionation The general name for the process of separating a mixture into its constituents or fractions. See also: absorption, adsorption, distillation. FS Fluid Sampler FSC Fail Safe Close FSU | Floating Storage Unit | A large moored chamber in which oil produced from an offshore production platform is stored before being transferred to a tanker. See also: SBM (Single Buoy Mooring). FT/HR Feet Per Hour Fuel Cell

An electric cell used to generate electrical energy from the reaction of a number of chemicals, without the need for combustion and without producing noise or pollution. Can use natural gas as a feed-stock. Fuel Gas Refers to gaseous fuels, capable of being distributed by pipeline, such as natural gas, liquefied petroleum gas, coal gas and refinery gas. Fuel Oils The heavy oils from the refining process. used as fuel for power stations, industry, ships etc. Futures (oil). The sale and purchase of oil at a price agreed upon in advance for delivery at a future date. The seller may not yet have the oil and both buyer and seller are speculating on how prices will change in the future. Fugitive Emissions Emissions which escape from a system which is intended to be closed. Fulcrum Utilizes the bending moment principle to create a force on the bit which counteracts the reaction forces which tend to push the bit in a given direction Function Operation of a well control component, choke or kill valve, or any other component in one direction. For example, closing the blind rams is one function and opening the blind rams is a separate function. Function Pressure Test The pressure test which requires the well control component or flow control device to undergo actuation to demonstrate its ability to effect a seal. Fusible Plug A plug or portion of the sub-surface safety valve (SSSV) surface control system which is designed to melt in case of a fire, allowing the SSSV system failsafe features to activate. Fusion The melting together of base metal, or a base metal with a filler metal to produce a weld. Fusion Zone The area of base metal melted as determined on the cross-section of a weld. FUT Flushing Up To FV Funnel Viscosity G/L Gas Lift

GAL Gallon Gas A state of matter, in which the molecules move freely and consequently the entire mass tends to expand indefinitely, occupying the total volume of the container in which it is confined. A gas is compressible, therefore, volume is dependent on the size and pressure exerted on the container. Gas Cap In a field containing both gas and oil, some gas will often collect at the top of the reservoir in a single deposit, known as a gas cap. Gas Cycling | Re-Cycling | A process in which produced gas is re-injected into the reservoir after removal of the condensate. This is to maintain the reservoir pressure and prevent condensate from "condensing" in the reservoir and then becoming difficult to recover. This is called retrograde condensation. Gas Detector An instrument to detect the presence of various gases, often as a safety precaution to guard against flammable or toxic gases. Gas Gathering System A central collection point for offshore gasfields, with pipelines from a number of fields, often owned by a number of different companies. From there, the gas is transported to a central processing system onshore. Gas Grid The term used for the network of gas transmission and distribution pipelines in a region or country, through which gas is transported to industrial, commercial and domestic users. GAS GUN Gas Gun Record Gas Lift A method of artificial lift in which the energy of compressed gas entrained within a column of liquid is used to lift the fluid to the surface. This process of producing fluids from a well incorporates the continuous or intermittent injection of gas through the tubing or the tubing casing annulus to a point below the liquid level in the wellbore. The injected gas aerates the fluid to reduce the exerted pressure at the formation consequently allowing fluids to flow from the formation. Gas Liquefaction The process of cooling natural gas to a temperature of -162°C, thereby reducing its volume by a factor of 600, and making it liquid. The resulting LNG is then transportable by purpose-designed ships (LNG carriers) or may be stored in tanks.

GAS LOG Gas Log Analysis Gas Metal-Arc Welding The welding process that produces coalescence of metals through heat generated by an arc (or arcs) created between a continuous consumable electrode and the work product. All gas used for shielding during the welding process is externally supplied and may be pure inert gas or a mixture of inert gases. Gas metal-arc welding does not require pressure, and the electrode provides the filler metal. Gas Oil The medium oil from the refining process. used as a fuel in diesel engines, burned in central heating systems and as a feedstock for the chemical industry. Gas Processing The separation of oil and gas, and the removal of impurities and natural gas liquids from natural gas. Gas Treatment Removal of impurities, condensate, hydrogen sulphide and any liquids from the raw natural gas contained in a gasfield. Gas Tungsten Arc Welding The welding process that produces coalescence of the metals through heat generated by an arc created between a single tungsten electrode and the work product. Gas tungsten arc welding does not require pressure, and filler metal may or may not be used. Pure inert gas is used for shielding during the welding process. Gas Turbine A turbine propelled by the combustion of a compressed mixture of natural gas and air, used for power generation. Gas Well A borehole sunk into the ground with the objective of bringing natural gas to the surface. Gas/Condensate Field A reservoir containing both natural gas and oil, with a greater proportion of gas. Condensate appears when the gas is drawn from the well, and its temperature and pressure change sufficiently for some of it to become liquid petroleum. Gas/Condensate Ratio a) For a gas/condensate reservoir this is the ratio of the condensate to the gas. As for oil it can be measured in scf per bbl. Alternatively the inverse is used and the typical units are bbl per mmscf. b) For a dry gas field only the inverse is normally used. Typical units are again bbl per mmscf, but grammes per cubic metre may well be used. Gas/Condensate Reservoir

A reservoir in which neither natural gas nor crude oil is the predominant production stream. To increase the recovery of the condensate, the gas may be re-cycled for the early years and produced at a later date. Gasfield A field or group of reservoirs of hydrocarbons, containing natural gas, but insignificant quantities of oil. Gasification The production of gaseous fuel from solid or liquid fuel. Gasoline | Petrol | The fuel used in cars and motorcycles etc (also known as petrol). Naturally occurring gasoline is known as condensate. Gate Valve A valve which employs a sliding gate to open or close the flow passage. The valve may or may not be full-opening. Gatt The General Agreement on Tariffs and Trade. Gauge Ball A ball constructed from one of various materials which is supplied in a specified diameter and pumped through the finished coiled tube to verify the minimum ID clearance. Gauge Pressure The pressure exerted on the interior walls of a containment vessel as indicated by the device capable of measuring this pressure, commonly in units of psig or kpa. Absolute pressure is equal to gauge pressure plus atmospheric pressure. Gel A semi-solid state of colloidal suspension in which shearing stresses below a certain finite value fail to produce permanent deformation. The minimum shearing stress that will produce permanent deformation is known as the shear or gel strength. Gels commonly occur when the dispersed colloidal particles have a great affinity for the dispersing medium, i. GEOGRAM Geogram GEOPH REC Geophone Record Geothermal Energy Energy obtained from the heat below the Earth's surface. Gigajoule | GJ |

The joule is a measure of energy. 1 gigajoule equals 1 billion joules. This is equivalent to approximately 278 kilowatt hours, or the energy content of 25 liters of gasoil Gigawatt Thousand megawatts. GJ Gigajoule GL Gas Lift GLC Gas Lift Compression GLM Gas Lift Mandrel GLOBAL Global Analysis Global Warming Potential | GWP | GWP is a measure for the relative warming effect of releasing the same mass of greenhouse gas into the atmosphere. One tonne of methane has 21 times the GWP of one tonne of CO2 over a 100 year period. GLT Geochemical Logging Tool Analysis Gooseneck The curved tubular connection located between the rotary hose and kelly swivel components of a completion or drilling rig. Within the CT industry, gooseneck is sometimes used to refer to the tubing guide arch. Gouge Elongated grooves or cavities caused by mechanical removal of metal. GPIT General Purpose Inclinometry Tool GPM Gallons per Minute GR Gamma Ray Grade Classification of tubing based on minimum yield strength, tensile strength and chemistry.

Gradient Pressure exerted by a unit height of fluid column. GRADIO Gradiomanometer Sonde Gravity (Specific) The density expressed as the ratio of the weight of a specified volume of substance to the weight of an equal volume of another standard substance. In the case of liquids and solids, the standard used is fresh water. In the case of natural gas or other gaseous fluids, the standard used is air. Greenfield Often used to refer to a planned LNG facility which must be built from scratch. without existing infrastructure. Greenhouse Gases | GHG | Gas that contributes to the formation of an insulating blanket around the earth. Water vapour, carbon dioxide, methane, nitrous oxide and halogenated hydrocarbons are the main GHGs. GRING Gauge Ring Gripper Blocks The traction system gripping mechanism used in chain drive injectors. The machined blocks are applied to the coiled tubing with hydraulic rams which apply normal forces, when accounting for the static coefficient of friction between the two surfaces, is sufficient to maintain control of the tubing without slipping. GST Induced GR Spectrometry Tool H2S Hydrogen Sulfide Halons Halogenated carbon compounds used in fire extinguishing equipment and contributing to stratospheric ozone depletion. There are United Nations agreements (Montreal Protocol) for the phase-out of halons production. Hardness The measure of the material hardness as demonstrated by one of the following tests: Brinnell Hardness: Material hardness determined as a measurement of the depth of residual penetration of a test piece upon the surface of the material after a specified load is applied. The Brinnell Hardness (HB) is determined with a ball pressure test using a steel ball having a diameter of 0. 413 inch (10. 5 mm) or 0. - Knoops Hardness: Material hardness readings taken with a microhardness tester using a load of 1. - Microhardness:The hardness measured in a very small

area with a specified type of indenter that has a small specified load, relative to the standard hardness tests described above. - Rockwell Hardness: Material hardness determined as a measurement of the depth of residual penetration of a test piece upon the surface of the material after a specified load is applied. A Rockwell B Hardness test (HRB) uses a steel ball having a 0. 0625 inch diameter (1. 59 mm) with an initial test force of 22 lbs (98 N) and a test force of 198. - Vickers Hardness: Material hardness determined as a measurement of the depth of residual penetration of a test piece upon the surface of the material after a specified load is applied. The Vickers Hardness (HV) test uses a diamond pyramid having a four-sided surface and an apex angle of 136 , conducted in accordance with DIN 50 133. HAZOP Hazard and Operability (Study) HCIIP Hydrocarbons Initially in Place HDS Hydrodesulphurisation HDT High Resolution Dipmeter HDT ARROW HDT Arrow Plot HDT AZI HDT Azimuth Plot HDT BH HDT Borehole Plot HDT CLUSTER HDT Cluster Plot HDT FAST HDT Fast Plot HDT FREQ HDT Frequency Plot HDT POL HDT Polar Plot HDT SCHMIDT HDT Schmidt Plot HDT SODA HDT Soda Plot

HDT STEREO HDT Stereo Plot HDT STICK HDT Stick Plot Heat Affected Zone The zone directly adjacent to the weld fusion zone in a longitudinal seam weld, circumferential tube-to-tube weld, and skelp-end weld. The mechanical properties in the heat affected zone (HAZ) are affected by the resultant heat produced during the welding process. Heat Treatment A combination of heating and cooling operations, timed and applied to a metal or alloy in the solid state in a way that will produce desired properties. Heating for the sole purpose of hot working is excluded from the meaning of this definition. Heaving The partial or complete collapse of the walls of a borehole resulting from internal pressures due primarily to swelling from water absorption or the formation of gas pressure (see Sloughing). Heavy Fractions Also known as heavy ends, these are the oils made up of the large molecules that emerge from the bottom part of the fractionating column during oil refining. Heavywall End | Thickwall End | A term used in describing a segment of a tapered wall thickness coiled tubing string. The "Heavywall End" is the heaviest or thickest wall thickness within the string. Note: Some tubing strings may have heavy wall ends at both ends of the string. Helical Buckling Buckling in which the pipe forms a helix or spiral shape within a host conduit. Hesitation-Squeeze Cementing - The process of forcing cementing material under pressure into The desired areas with a final pressure equal to or greater than The formation fracture pressure and with a final temperature equal to The bottomhole static temperature. HGR Hanger HGS High Gravity Solids HI-VIS High Viscosity High-Angle Hole

Generally conceded to be boreholes for which the inclination angle from vertical exceeds 50 degrees. High-Frequency Induction Weld (Seam) | High Frequency Induction Weld | A longitudinal seam weld produced through electric induction welding, where the heat for welding is generated by resistance to flow of electric current, and the edges to be welded are mechanically pressed together. This process does not use filler metal. High Pressure Squeeze Cementing - The forcing of cement slurry into the desired position with a final pressure equal to or greater than the formation fracture pressure. High Strength Low Alloy Steel Low alloy steel forming a specific class in which enhanced mechanical properties and, in most cases, good resistance to atmospheric corrosion are obtained by the incorporation of moderate proportions of one or more alloying elements other than carbon. The preferred terminology is "High Strength Low-Alloy" (HSLA) steels. HMST Hybrid Multiset Tester Hole Azimuth Angle The angle between north and the projection of the borehole axis onto a horizontal plane. Angle is referred to either true north, magnetic north, or grid north. Hole Curvature Refers to the changes in inclination and direction of the borehole. HRT High Resolution Temperature Log HSD High Shot Density HSE Health And Safety Executive HSG Housing HTHP High Temperature High Pressure HUD Hold Up Depth HWDP Heavy Weight Drill Pipe

HWO Jack | hydraulic workover jack | The HWO (hydraulic workover) jack is comprised of two or more hydraulic cylinders which provide the forces needed to deploy or retrieve the jointed tubing. The hydraulic jack is also equipped with at least one set of stationary tube slips (located near the base of the jack) and a set of traveling slips (located at the top of the jack). Piston rods exit the top of the hydraulic cylinders and manipulate the position of the traveling slip assembly. Hydrate A hydrocarbon and water crystalline substance which form in gas gathering and compression systems or in wellbores under reduced temperature and pressure. In appearance, hydrates resemble snow or ice. Hydraulic Control Manifold A system of valves and piping used to control the flow of hydraulic fluid for the operation of hydraulic power components (typically the well control stack). Hydraulic Horsepower | HHP | Power term typically calculated as the product of liquid circulation rate (in gallons per minute) and differential pressure (in psig), divided by the value 1,714 (constant). Hydrocarbon Any compound or mix of compounds, solid, liquid or gas, comprising carbon and hydrogen (e.g. coal, crude oil and natural gas). Hydrochlorofluorocarbons | HCFCs | HCFC | Cooling agents which are an alternative to the more ozone depleting CFCs, but which are also GHGs. Hydrocracking See Cracking. Hydrodesulphurisation | HDS | Process to remove sulphur from molecules, using hydrogen under pressure and a catalyst. Hydrogen The lightest of all gases, occurring chiefly in combination with oxygen in water. Hydrogen combines with carbon to form an enormous variety of gaseous, liquid and solid hydrocarbons. Hydroskimming Refinery A refinery with a configuration including only distillation, reforming and some hydrotreating. Hydrostatic Head The pressure which exists at any point in the wellbore due to the weight of the column of fluid above that point. Hydrostatic Testing

A proof test method wherein the test segment is filled with liquid and held at high pressure for a specified period of time. Hydrotreating Usually refers to the hydrodesulphurisation process, but may also be applied to other treating processes using hydrogen. I.D. Inner Diameter I/P In Places IATA International Air Travel Authority ICE Independent Completions Engineering ICON Intelligent Completions on the Net ICV Injection Check Valve ID Inside Diameter IDPH Phasor Induction Log Deep IEA | International Energy Agency | Established in 1974 to monitor the world energy situation, promote good relations between producer and consumer countries and develop strategies for energy supplies during times of emergency. IES Induction Electrical Survey IF Internalflush IFO Injection Fall Off survey Igneous Rocks Rocks formed from the solidification of molten magma.

II Injectivity Index ILD Induction Log Deep ILM Induction Log Medium Impeder A ferrite cylinder placed inside the tube at the weld point to control the electrical impedance of the local weld area. Imperfection A discontinuity or irregularity in the tubular product. Also commonly referred to as a flaw. IMPH Phasor Induction Log Medium Impression Block A lead block which is run into a well and dropped onto the top of lost tools or other fish to obtain an impression of the top profile of the obstruction or fish lost in the hole. Inadequate Flash Trim A condition in which height of the weld flash after trimming exceeds the limits set in the specification to which the tube was manufactured. Inboard The segment of the coiled tubing which is spooled in close proximity to the drum of the service reel. INC Inclination Incident An unplanned event or chain of events which has, or could have caused injury or illness and/or damage to the environment, third parties or company assets. Inclination The angle of the wellbore as measured from a true vertical reference. Inclination Survey A survey to obtain the angle through which the bit was deflected from the vertical during drilling operation. Usually implies a survey where no azimuth readings are taken. Inclusion Particles of non-metallic impurities, usually oxides, sulfides and silicates that are mechanically held within steel during and after solidification.

Incomplete Fusion Lack of complete coalescence of some portion of the metal in a weldment. Typically referred to as "lack of fusion". Incomplete Penetration A condition where the weld metal does not continue through the thickness of the work. Typically referred to as "lack of penetration". Indication A deviation of a non-destructive test inspection device from baseline and exceeding a specified threshold level set by a test imperfection that is caused by a material change which may or may not be considered as a discontinuity or defect. In non-destructive test usage, an indication requires prove-up. Induction The magnetism induced in a ferromagnetic body by an outside magnetizing force. Inelastic A liquid, e.g. , a condition of matter in which the molecules move freely but are restricted by gravitation. Inert Gas A chemically inert gas, resistant to chemical reactions with other substances. Inflow Performance Relationship The relationship of flowing bottomhole pressure to the gross liquid producing rate for a particular well. Inhibitor (Corrosion) Any agent which, when added to a system, slows down or prevents a chemical reaction or corrosion. Corrosion inhibitors are used widely in drilling and production operations to prevent corrosion of metal equipment. Injector The equipment component which is used to grip the continuous-length tubing and provide forces and control for tube deployment into and retrieval out of the wellbore. Designs for injector tubing gripper systems include opposed counter-rotating chains, sheave drive, arch-chain roller, and single-chain opposed grippers. Inside Diameter The distance between the inside tube walls as measured along a line bisecting the tube cross-section. The inside diameter (commonly referred to as ID) is a specified dimension of the tube, typically defined in inches or millimeters. Inspection The process of examining materials and tubes for possible defects and imperfections or for deviation from established standards.

Internal Yield Pressure An internal pressure which produces a stress in the tube equal to the specified minimum yield strength, based on the specified outside diameter and wall thickness. Interruptible Gas Gas made available under agreements permitting the termination or interruption of delivery by the suppliers, usually for a limited number of days in a specific period. The opposite is "firm gas". IOR Improved Oil Recovery IPIECA International Petroleum Industry Environmental and Conservation Association. IPR Inflow Performance Relationship ISF Induction Spherical Focused Log ISPH Phasor Induction Log Shallow ITBP Injection Tubing-Head Pressure ITF Industry Technology Facilitator IWC Intelligent Well Completions Jack-Up Vessel An offshore drilling or well service structure with tubular or derrick legs that can be moved vertically to lift and support the deck and hull above the water level. Jacket The structure used to support an offshore steel production platform. Jar A percussion tool that operates on a mechanical or hydraulic principle and is designed to deliver a impact to objects in which it is attached within the borehole. Jars are typically used for the purposes of freeing stuck objects within the borehole during fishing operations or imparting a jarring motion to downhole devices. The design of the jar often permits impacts to be delivered in either a downward or upward direction, with control being effected at the surface.

Jar Accelerator A hydraulic or pneumatic tool used in conjunction with a jar. The accelerator is made up in the fishing string above the jar and serves to provide free travel of the jar rod once the restriction is released. The free travel of the jar rod increases the magnitude of the jarring impact delivered to the fish. JB Junk Basket JC Jet Cutter JCGR Junk Catcher Gauge Ring Jet Nozzle Port A fluid flow port in a wash nozzle, drill bit or similar tool. Jetting The action of causing erosion by fluid impingement on the formation. JIP Joint Industry Project JTS Joints Junk Refers to metal debris lost in a borehole. Junk may be lost tools, pieces of wire, or any relatively small object that impedes activity to the extent that it must be removed from the hole. Junk Basket A fishing tool run into the wellbore when it is necessary to retrieve small parts or lost tools. K/O Kick Off Kelly The square or hexagonal-shaped steel pipe connecting the swivel to the drill pipe. The kelly moves through the rotary table and transmits torque to the drillstring. Kerogen A bituminous material occurring in certain oil shales which yield a type of oil when heated. Kerosine | Kerosene | A medium-light oil from the oil refining process intermediate between gas oil and gasoline. used for lighting and heating and as fuel for jet and turbo-prop aircraft engines.

Kick Intrusion of formation liquids or gas into the wellbore. This influx of fluids commonly results in an increase in pit volume or an increase in observed wellhead pressure. Kill To control a kick by taking suitable preventive measures (e. g. , to shut in the well with the blowout preventers, circulate the influx of fluids out of the wellbore, and increase the weight of the fluids to render it incapable of flowing). Kill Line A high-pressure fluid pump line run between the pumps and some point below a well control component. This line allows fluids to be pumped into the well or annulus with the well control component closed. Killed Steel Steel treated with a strong deoxidizing agent such as silicon or aluminum used to reduce the oxygen content to a minimum so that no reaction occurs between carbon and oxygen during solidification. Kilocalorie A thousand calories. A unit of heat used in the chemical processing industry. Kilowatt Hour | KWh | Unit of measurement in electric power. One kilowatt hour is equivalent to 0.0949 cubic metres of gas. KLB 1000 Pounds KLBS 1000 Pounds Knocking A metallic rattling sound in an engine caused by a mismatch between the fuel characteristics and the engine's design, particularly its compression ratio, resulting in pre-ignition (also known as 'pinking'). Knuckle Joint A deflection tool placed above tools within the workstring that employs a ball-type universal joint, allowing the toolstring to be deflected at an angle. L.I.B Lead Impression Block L/D Lay Down L/O

Lay Out L/OUT Lay Out Ladle Analysis The term applied to the chemical analysis representative of a heat of steel and is typically one of the analyses reported to the purchaser. The ladle analysis is determined by analyzing (for such elements as have been specified) a test ingot sample obtained from part of the heat during the pouring of the steel from a ladle. Laminar Flow Fluid elements flowing along fixed stream lines which are parallel to the walls of the channel of flow. In laminar flow, the fluid moves in plates or sections with a differential velocity across the front which varies from zero at the wall to a maximum at the center of flow. Lamination An internal metal separation creating layers generally parallel to the surface. LAT Lowest Astronomical Tide LCM Lost Circulation Material LDL Litho Density Log LDSA Lock Down Seal Assembly LDT Litho-Density Tool Lean Gas | Dry Gas | Gas with relatively few hydrocarbons other than methane. The calorific value is typically around 1,000 Btu per scf, unless there is a significant proportion of non-hydrocarbon gases present. Levelwind Mechanism used to control the position of the coiled tubing on the tubing wrap as it is spooled off and onto the service reel. LGS Low Gravity Solids Licence Block

A section of continental shelf area bounded by latitude and longitude lines, generally at one degree intervals, and subdivided into smaller areas. The 'licences' are sold to companies giving them oil exploration rights. Licence Round A period during which a state offers and then allocates a number of specified areas within its national boundaries to oil companies. Lift Frame A structural device used support the injector and well control stack on floater rig operations. The lift frame is suspended by the traveling block, which is motion compensated to maintain position and weight of the drill string or riser within the derrick. Lifting Sub A short piece of pipe with a pronounced upset (or shoulder) on the upper end which is screwed into drill collars to provide a positive grip for the elevators. Light Crude Crude oil with relatively high proportions of light fractions, and low specific gravity. Light Fractions The low molecular weight, low boiling point fractions that emerge from the upper part of the fractionating column during oil refining. Lightering | Lightening | A ship-to-ship cargo transfer operation to enable a vessel to enter a draft-restricted port. Lightwall End | Thin Wall End | A term used in describing a segment of a tapered wall thickness coiled tubing string. The "Lightwall End" is the lightest or thinnest wall thickness within the string. Limestone A type of sedimentary rock rich in calcium carbonate. Limestone sometimes serves as a reservoir rock for petroleum accumulations. Line Pack The ability to increase the amount of gas in a pipeline by increasing the pressure above the normal pressure of the system, but still within a safe limit. Used as a method of peak or diurnal storage. Linear Imperfection Linear discontinuities or irregularities which include, but are not limited to, seams, laps, cracks, plug scores, cuts, and gouges. Liner Partial length of pipe string extending between the bottom of a borehole to an elevation above the bottom of the previous casing string. Liners perform the same function as production casing

in sealing off productive zones and water-bearing formations. Liners may or may not be cemented in place. Liquid A substance which flows readily, does not tend to expand indefinitely like a gas, assumes the form of its container while retaining its independent volume, and has form which can be seen and felt. Liquid Penetrant Inspection A nondestructive method for determining the presence of two-dimensional and small three-dimensional surface-breaking flaws wherein a dyed fluid is allowed to be absorbed by surface tension into the flaw and leached out with a developer. This process is used for weld inspections and prove-up inspections. LITHOPLOT Litho-Porosity Plot Live Oil Crude oil that contains gas and has not been stabilized or weathered. LKDC International Association of Drilling Contractors LL Laterolog LLD Laterolog Deep LLM Laterolog Medium LLS Laterolog Shallow LNG | Liquefied Natural Gas | Natural gas that for ease of transport has been liquefied by cooling to approximately minus 161øC at atmospheric pressure. Natural gas is 600 times more bulky than LNG. LNG Carrier A tanker specially designed to carry LNG, fitted with insulated pressure tanks made of stainless steel or aluminium. The load is refrigerated to -162°C. LNG Terminal A receiving station for LNG shipments, typically with storage and regasification facilities. LNG Train

An LNG plant comprises one or more LNG trains, each of which is an independent unit for gas liquefaction. It is more cost-effective to add a train to an existing LNG plant, than to build a new LNG facility (known as a greenfield project), because infrastructure, such as ship terminals, does not have to be built for a new LNG train. LNR Liner (Pump) LNS LASMO North Sea Plc LO-VIS Low Viscosity Load Factor The ratio of the average load to the peak load during any particular period. Load-On-Top A system of cleaning tanks in an oil tanker by collecting washings in one 'slop' tank, allowing the water to separate from the oil, then discharging the clean water overboard, leaving the oil residues in the tank and minimising pollution at sea. LOC Locally Log A detailed record of the physical nature of formations and/or fluids contained within formations penetrated during drilling operations. Data recorded may consist of electrical, radioactive or acoustic surveys, descriptions of borehole cuttings, core analysis, or any other physical correlation with depth. LOG EVAL Log Evaluation LOG INJECT Injection Log LOGPLOT Wireline Log Display Longitudinal Imperfection An imperfection which has its principal direction or dimension in the approximately longitudinal direction. Lost Circulation A condition which occurs when the fluid pressure within the wellbore acting at the formation face exceeds reservoir pressure, resulting in loss of fluids from the wellbore into the formation.

This loss of fluids into the formation may result in reduced or interrupted fluid circulation at the surface. Lost Time Injury | Lost Time Injuries | LTI | The sum of injuries resulting in Fatalities, Permanent Total Disabilities, Permanent Partial Disabilities and Lost Workday Cases, but excludes Restricted Workcases and Medical Treatment Cases. Lost Time Injury Frequency | LTIF | The number of Lost Time Injuries per million exposure hours worked during the period. LOT Leak Off Test Low Pressure Squeeze Cementing - The forcing of cement slurry into the desired position with a pressure less than the formation fracture pressure. LPG | Liquefied Petroleum Gas | LPG consists of propane, butane or a mixture of the two which may be wholly or partially liquefied under pressure in order to facilitate transport and storage. LPG can be used for cooking and heating or as an automotive fuel. LPR Lower Pipe Rams LRA Lower Riser Assembly LTA Lost Time Accident LTI Lost Time Injury LTOBM Low Toxicity Oil Based Mud LTRS Liters Luboil Lubricating oil used to grease and ease the working of mechanical joints and moving parts. M Million (10^6) or thousand (10^3) M/U

Make Up M/UP Make Up MAASP Maximum Allowable Annulus Surface Pressure MAC Multipole Array Acoustilog Magma The molten material that makes up the Earth's crust. When extruded onto the Earth's surface and cooled it becomes igneous rock. Magnetic Particle Inspection An inspection process that requires magnetizing of the material and applying a prepared magnetic powder which adheres to the test specimen along lines of flux leakage. Magnetic particle inspection also shows the existence of surface and subsurface non-uniformities. Majors The world's largest privately / publicly owned oil companies (Shell, Exxon, Texaco, Mobil, Chevron and BP). National oil companies can be much larger. Malleability The property that determines the ease of deforming a metal when the metal is subjected to rolling. A highly malleable metal can be rolled into thin sheets easily. Manifold An assemblage of pipe, valves, and fittings by which fluid from one or more sources is selectively directed to various systems or components. Marine Riser A pipe that connects an offshore platform to a sub-sea wellhead or pipeline for drilling or production purposes. Martensite An unstable constituent in quenched steel, formed without diffusion and only during cooling below a certain temperature. The structure is characterized by its acicular appearance on the surface of a polished and etched specimen. Martensite is the hardest of the transformation products of austenite. Mast The steel tower component of a drilling or well servicing rig which supports the crown block, traveling block and hoisting lines and is capable of being raised as a unit. Derricks and masts may be stationary structures normally requiring dismantling and disassembly when moved from location to location or may be portable with the capability of being laid down and raised to and from ground level fully assembled.

Master Coil The wide coil of skelp that is originally supplied by the manufacturer of the skelp. The master coil is then slit into several narrower coils of skelp, each of the appropriate width for the manufacture of the specified coiled tubular products. Master Valve A large, produced fluid control valve located in the vertical run of the christmas tree. The master valve is usually positioned as the lower-most flow control valve and is used to open or close the well. Maximum Allowable Working Pressure The maximum pressure permissible by the ASME Code in any component other than a pipe line during normal operation or static conditions. Maximum Anticipated Surface Pressure The highest pressure calculated to be encountered at the surface of the well. Typically, the "anticipated surface pressure" prediction is obtained by subtracting the hydrostatic pressure exerted by a column of given fluid within the wellbore from the static reservoir pressure. However, the "maximum anticipated surface pressure" prediction assumes that the hydrostatic pressure is derived only from a column of dry gas within the wellbore acting against the static reservoir pressure. MBT Methylene Blue Test MCCV Multi Cycle Circulating Valve MDBRT Measured Depth below Rotary Table MDC Monel Drill Collar (Non-Mag) MDRKB Measured Depth Below Rotary Kelly Bushing MDRT Measured Depth Rotary Table MDST Mudstone MDT Modular Formation Dynamics Tester Measured Depth

Actual length of the wellbore as measured from surface to a specified depth. Mechanical Utilizes bottomhole orienting equipment which is not normally part of the conventional drill string to aid deviation control. This equipment acts to force the bit to turn the borehole in inclination. Mechanical Properties Those properties of a material that reveal the elastic and inelastic reaction when force is applied, or that involve the relationship between stress and strain (for example, the modulus of elasticity, tensile strength and fatigue limit). These properties have often been designated as "physical properties", but the term "mechanical properties" is preferable. MED Medium Mercaptans Strong-smelling compounds of carbon, hydrogen and sulphur found in gas and oil. Sometimes added to natural gas for safety reasons. MEST Micro-electrical Scanner Tool Metamorphic Rocks Rocks changed considerably from their original structure and form by the action of heat and / or pressure. Meter A mechanical device for automatically measuring and recording quantities of gas. Methane (CH4) | Methane | A GHG. Conventionally not included in the category of gases called volatile organic compounds (VOCs). Methanol | Methyl Alcohol | An alcohol used as a raw material in a wide range of industrial and chemical processes. Metric Ton | Metric Tonne | See ton(ne) MFC Multi-Finder Caliper MFCT Multi Finger Caliper Log MFE Multi Flow Evaluator

MG Magnesium Migration The movement of liquids or gases within the pore spaces of the formation or vertically within the flow pathways of the borehole or wellbore. Mill A tool configured with a rough, sharp and extremely hard cutting surface used for removing metal or resistive materials by grinding, cutting or chipping. Mill Scale An oxide of iron which forms on the surface of hot steel. Milled Length Single length of CT created during the continuous HFI milling operation of a tubing manufacturer. A milled length of tubing may include a number of lengths of skelp having a single wall thickness or several lengths of skelp having various specified wall thicknesses. Milliard Synonymous with billion (10^9). Minimum Internal Yield Pressure The lowest pressure at which permanent deformation of the pressure containing vessel or tube will occur. MINU Micro Inverse MIRV Multi Id Reverse Tool MIS Multiparameter Spetroscopy Instrument (MSI) MJ | MMJ | Megajoule. equivalent to one million watts. ML Mud Line MLL Micro-Laterolog MLT Multi-Layer Test

MMBBL Million barrels. MMBTU Million British thermal units. MMSCF Million standard cubic feet. MMSCF/D Million standard square feet per day. MNC Multi-National Company MNOR Micronormal MOD Moderately Moderate Angle Wellbore Generally conceded to be wellbores which have an inclination from vertical between 20 degrees and 50 degrees. Module A package of plant and equipment for installation, or installed, on an offshore platform. Modulus of Elasticity The ratio of the unit stress to the unit strain of a structural material, resulting in a defined slope for the elastic portion of the stress-strain curve in mechanical testing. The tensile or compressive elastic modulus is called "Young's modulus". the torsional elastic modulus is known as the "shear modulus" or "modulus of rigidity". MOL Main Oil Line Molecule The smallest particle to which a compound can be reduced without losing its chemical identity. MONITOR Monitor Record Monomer A single molecule which can be chemically joined into long chains known as polymers. Montmorillonite

A clay mineral commonly used as an additive to drilling fluids. Sodium montmorillonite is the main constituent in bentonite. The structure of montmorillonite is characterized by a form which consists of a thin platy-type sheet with the width and breadth indefinite, and thickness that of the molecule. MOVOILPLOT Moveable Oil Plot MOVS Mechanical Operated Valves MPBT Mechanical Plug-Back Tool (through-tubing plug) MPR Middle Pipe Rams MRT Multi Rate Test MSA Multi-Straddle Assembly MSCF Thousand standard cubic feet. MSFL Microspherical Focused Log MSI Multiple Spectroscopy Instrument MSL Mean Sea Level MSRV Multi Stage Relief Valve MSS Multi Shot Survey MT Metric Tonne MTT Multi-Isotope Tracer Log Mud

The liquid circulated through the wellbore during drilling operations. In addition, to its function of bringing cuttings to the surface, drilling muds cool and lubricate the bit and drill stem, protect against blowouts by holding back subsurface pressure, and deposit a mud cake on the wall of the borehole to prevent loss of fluids to the formation. Mule Shoe A shaped form resembling a mule shoe or that of the end of a pipe cut both concave and diagonally which is used on the bottom of orienting tools to position the tool. The shaped end forms a wedge which causes the tool to rotate when lowered into a mating seat for the mule shoe. Multi-National Company | MNC | A company with investments and operating activities in many countries around the world. Multi-Phase Flow The flow of fluids in which gas and liquids are commingled. MUST Multiple Shut In Tool MWD Measurement While Drilling N/D Nipple Down Nafta North American Free Trade Agreement: its members currently comprise Canada, Mexico and the United States. Naphtha A range of distillates lighter than kerosine. used as feedstock for motor gasoline production and the chemical industry (e.g. ethylene manufacture). Natural Gas A mixture of generally gaseous hydrocarbons and varying quantities of non-hydrocarbons that exist either in the gaseous phase or in solution with crude oil in natural underground reservoirs. Natural gas consists mainly of methane (80%) and significant proportions of ethane, propane and butane. There will always be some condensate and/or oil associated with the gas. The term is also used to mean treated gas which is supplied to industrial, commercial and domestic users and meeting a specified quality. NBS Near Bit Stabiliser NCNL Near Count CNL

NDL Neutron Depth Log Near-Bit Stabilizer A stabilizer placed in the bottomhole assembly and located in close proximity to the bit. Neat Cement A slurry composed of portland cement and water. Necking Down The narrowing or constriction into a smaller cross-sectional area, which occurs at a localized place on a tensile test piece while it is being pulled. Needle Valve A valve having a tapered gate that rests in a tapered orifice and used for extremely fine regulation of flow. Netback The value of gas sold to the customer at the burner-tip, less the cost of transportation through the pipeline system and cost of production. NEU Neutron Log Newtonian Fluid The basic and simplest fluids from the standpoint of viscosity consideration in which the shear force is directly proportional to the shear rate. These fluids will immediately begin to move when a pressure or force is applied. Examples of Newtonian fluids are water, diesel oil and glycerine. NFL Nuclear Flowlog NGL | Natural Gas Liquids | There is no precise definition. NGLs are essentially those hydrocarbons which can be extracted in liquid form from natural gas as produced. Typically ethane, LPG, and Pentanes will be the predominant components, but there will be some heavier hydrocarbons present. NGS Natural Gamma Ray Spectra NGT Natural Gamma Ray NGT RATIO NGT - Ratio Display Nitrogen Oxide | NOx |

A general term for nitrogen oxide gases. These are produced by combustion and contribute to the formation of smog and acid rain. NL Neutron Log NMDC Non Magnetic Drill Collar NML Nuclear Magnetism Log NMPDC Non Magnetic Pony Drill Collar NOL Noise Log Non-Associated Sometimes called unassociated gas. Dry gas that is not associated with oil in a productive reservoir, or where only gas can be produced economically. Non-Newtonian Fluid A fluid whose consistency is a function of shear stress, and the shear rate-shear stress relationship is non-linear. The non-Newtonian class of fluids can be further divided in pseudo-plastic, dilatant, Bingham plastic, and thixotropic categories. Examples of non-Newtonian fluids are highly viscous and complex polymers, drilling mud gels, cement, high-density sand slurries and foam. Nondestructive Testing Inspection to detect internal, surface and concealed defects or flaws in materials using techniques that do not damage or destroy the items being tested. Normal Circulation The smooth, uninterrupted circulation of fluids pumped down the tubular conduit within the wellbore, up the annular space between the tube and the borehole, and back to the surface. Normalize A heat treatment of steel whereby the steel is heated to a temperature above the upper critical temperature to achieve transformation to austenite and then allowed to cool in still air to a temperature substantially below the lower critical temperature. NPHI Neutron Porosity NPLC Nuclear Porosity Lithology Log

NPT Non Productive Time NRDPP Non-Rotating Drill Pipe Protector O.D. Outer Diameter O/PULL Overpull O/SHOT Over Shot OAJ Orientation Adapter Joint Oapec Organisation of Arab Petroleum Exporting Countries OBDT Oil Base Mud Dipmeter OBM Oil Based Mud OCC Occasional Occupational Illness A work-related abnormal condition or disorder, other than that resulting from a work injury, caused by, or mainly caused by, exposures at work. It includes acute and chronic illnesses or diseases which may be caused by inhalation, absorption, ingestion or direct contact. OCT Orientation Check Tool (Trees) Octane Number A measure of the resistance to pre-ignition (which leads to knocking) of a gasoline. OD Outside Diameter Odorant Substance such as mercaptan with a characteristic smell, added to odourless natural gas or NGLs when they are used as fuel, in order to enable detection.

ODT Oil Down To OECD Organisation for Economic Cooperation and Development, based in Paris. OECT Orientation and Elevation cheek Tool OEDP Open End Drill Pipe Off-Peak The period during a day, week, month or year when the load being delivered by a gas system is not at its maximum volume. Offtake The point in a gas distribution system where gas is taken by supply pipe to a major consumer. Ofgas Office of Gas Supply, the UK gas industry regulator. OGITF Oil & Gas Industry Task Force Oil Gasification The conversion of petroleum into gas to be used as a fuel. Oil In Place | OIP | The estimation of the real amount of oil in a reservoir, and so a higher figure than the recoverable reserves of the reservoir. Oil Shale A compact sedimentary rock impregnated with organic materials (mainly kerogen) which yields oil when heated. OIM Offshore Installation Manager OIP Oil In Place Olefins A class of hydrocarbons, including ethylene and propylene, of particular importance as feedstock to the chemical industry. See also: polypropylene. OODT Original Oil Down To

OOWC Original Oil Water Contact OPEC Organisation of Petroleum Exporting Countries. Formed in 1960, its member countries are Algeria, Ecuador, Gabon, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, United Arab Emirates and Venezuela. Open Hole Borehole in which casing or liner has not been set. Opening Ratio The ratio of the well pressure to the hydraulic actuation pressure required to operate the well control component. Operator A company, organisation or person with the legal authority to drill wells and extract hydrocarbons. A drilling contractor may be employed to undertake the drilling itself. The operator is often part of a consortium, and acts on its behalf. OPS Operations Orientation The process of positioning a deflection tool within the wellbore so that it faces in the direction necessary to achieve the desired direction and drift angle for a directional hole. OSVS Overpressure Safety Valve And Sampler OTC Offshore Technology Conference OTM Offshore Technology Management OTT One Way Travel Time Outside Diameter The distance between the outside surface of the tube walls as measured along a line bisecting the tube cross-section. The outside diameter (commonly referred to as the OD) is a specified dimension of the tube, typically defined in inches or millimeters. Ovality The term used to represent the physical condition of a tube which has assumed an oval geometry. The calculation used to quantify ovality is obtained by dividing the maximum

difference in outer diameter tube measurements (taken about the circumference) by the specified diameter of the tube. Ovality is generally represented as a percent change in tube roundness. Overpull The tension load applied on the tubing in excess of the buoyed load of the tubing string and tools hanging below the injector (CT) or jointed tubing lift mechanism. Overpull loads are the combined loads resulting from tubing-to-pipe friction and anticipated axial downhole service loads. Overshot A fishing tool which is lowered over the stuck pipe or fish and affixes itself to the outside diameter of the stuck pipe or fish through a frictional grip. The overshot is the female counterpart of a spear. OWC Oil Water Contact Oxide In the steel industry, this term usually refers to oxide of iron, of which there are three principal types: FeO, Fe3O4 and Fe2O3. In addition, there are many mixtures of these oxides which form on the surface of steel at different temperatures and give the steel different colors, such as yellow, brown, purple, blue and red. Oxides must be thoroughly removed from the surface of steel objects which are to be coated. Ozone A reactive form of oxygen. In the stratosphere it acts as filter for ultraviolet radiation but is destroyed by CFCs and halons. At ground level it is produced by reactions between VOCs and NOx, and as a constituent of photochemical smog, it is an irritant and can cause breathing difficulties. P/P Pin Pin Sub P/T Pressure Test P/TEST Pressure Test P/TOOL Pulling Tool PA Public Address Pack-Off The process by which a pressure isolation device is installed and activated within the wellbore such that it forms a seal between the concentric tubulars.

Packed-Hole Utilizes the hole wall to minimize bending of the bottomhole assembly. Packer Downhole equipment consisting essentially of a sealing device, a holding or setting device, and an inside passage for fluids. The packer is used to block the flow of fluids through the annular space between the tubing and the wall of the wellbore (or between tubing and casing) by sealing off the space between them. PAL Pipe Analysis Log Paraffin UK name for a premium kerosine. used in lamps and space heaters. Passivating Immersion of steel in an acid bath to remove surface impurities and to render the surface passive. PBR Polished Bore Receptacle PBTD Plug Back Total Depth PBU Pressure Build Up PC Pipe Cutter PCA Post Completion Audit PCNT Percent PCT Production Combination Tool PDC Polycrystalline Diamond Compacts PDK Pulsed Decay Log PDL

Petrophysical Data Log PEA Production Engineering Association Peak Load The maximum load produced or consumed by a unit in a stated period of time. Peak Lopping See peak shaving. Peak Shaving Increasing the normal supply of gas from another source during emergency or peak periods. Pendulum The basic principle involved is gravity or the "plumb-bob effect". Penetrameter A small steel shim of known thickness with machined holes of a calculated size used to determine the sensitivity of the radiographic inspection technique. PERF Perforations Perforating The act of making holes in pipe, cement, or formation at desired depths (usually formed with an explosive device utilizing bullets or shaped charges). Permeability | Magnetic Permeability | Reservoir Rock Permeability | Magnetic permeability is the ratio of the magnetic induction to the intensity of the magnetizing field. Reservoir Rock Permeability The measure of the ability of a rock to transmit fluids. The unit of measurement for permeability is the Darcy. Petrochemical A chemical derived from petroleum or natural gas (e.g. benzene, ethylene). Petroleum The general name for hydrocarbons, including crude oil, natural gas and NGLs. The name is derived from the Latin oil, oleum, which occurs naturally in rocks, petra. PEX Platform Express PFO Pressure Fall-Off PGB Permanent Guide Base

Photovoltaics Generation of electricity from the sun using man-made light-sensitive cells. PI Productivity Index Pig A device used for cleaning a pipeline or separating two liquids being moved down the pipeline. It is inserted into the pipeline and carried along by the flow of oil or gas. An 'intelligent pig' is fitted with sensors which an check for corrosion or defects in the pipeline. PIL Phasor Induction Logs Pinhole A short, unwelded area in the weld line extending through the entire tube thickness so that fluid will leak out through the area very slowly. Although an incorrect term, the CT industry sometimes uses "pinholes" to describe fatigue cracks which have penetrated through the tube wall. Pinking See Knocking. Pipe Body Yield Load The axial tension load (in the absence of pressures or torque) which produces a stress in the tube equal to the specified minimum yield strength in tension. Pipe Ram The rams in a well control stack which are designed to seal around coiled tubing to close and isolate pressure in the annular space below the rams. Pipe/Slip Ram The rams in a well control stack which are designed to provide the functions of both a pipe ram and a slip ram in one ram body. Pipeline A tube for the transportation of crude oil or natural gas between two points, either offshore or onshore. Pipeline Capacity The amount of oil or gas required to keep a pipeline full, or the amount that can be passed through a pipeline over a given period of time. Pit An irregularly-shaped depression resulting from the removal of foreign material rolled into the surface during manufacturing.

PIVOT PIVOT Perforations Plasma Arc Welding The welding process that produces coalescence of metals through heat generated by a constricted arc created between a continuous consumable electrode and the work product, or the continuous consumable electrode and a constricted nozzle. The gas used for shielding during the welding process is provided by the hot ionized gas discharging from the torch and may be supplemented by additional pure inert gas or a mixture of inert gases. Plasma arc welding may or may not use pressure in creating the weld, and the electrode provides the filler metal. Plastic Deformation Permanent distortion of a material under the action of applied stresses. Plastic Viscosity A measure of the internal resistance to fluid flow attributable to the amount, type and size of solids present in a given fluid. It is expressed as the number of dynes per square centimeter of tangential shearing force in excess of the Bingham yield value that will induce a unit rate of shear. This value, expressed in centiPoise, is proportional to the slope of the consistency curve determined in the region of laminar flow for materials obeying Bingham's law of plastic flow. Plasticity The ability of a metal to be deformed extensively without rupture. Platform A fixed for floating offshore structure from which wells are drilled. Drilling platforms can become production platforms once the wells are producing oil. Platforming A catalytic reforming process using a platinum catalyst. PLQL Production Logging Quicklook Analysis PLT Production Logging Tool Plug And Abandon The process of permanently sealing off an uneconomic completion interval, wellbore sections or a dry hole by placement of a cement plug or plugs. Plug Back To place cement or other material at or near the bottom of a well to exclude bottom water or to perform other operations such as sidetracking or producing from another depth. Plug Valve

A valve whose mechanism consists of a plug with a through-bore hole oriented along the same axis as the direction of fluid flow. Turning the plug 90 opens or closes the valve. The valve may or may not be full-bore opening. PNDS Pounds Sterling POH Pull Out Of Hole Poissons Ratio The ratio of the lateral or perpendicular strain to the longitudinal or axial strain. Polycrystalline Diamond Compacts | PDC | PDCs | Polycrystalline Diamond Compacts (PDCs) are industrial diamonds used for drilling bits. Polyethylene A polymer formed by the joining of ethylene molecules. one of the most important plastics. Polymer A complex compound in which single molecules (monomers) are chemically joined together in long chains (e.g. plastics). Polypropylene A polymer formed by joining propylene molecules. See also: olefins. POOH Pull Out Of Hole Porosity (Reservoir Rock) | Porosity | The percent of void space in a formation rock usually expressed as percent voids per bulk volume. Absolute porosity refers to the total amount of pore space in a rock, regardless of whether or not that space is accessible to fluid penetration. Effective porosity refers to the amount of connective pore spaces, i. Porosity (Welding) | Porosity | Voids in a metal, usually resulting from shrinkage or gas entrapment occurring during solidification of a weldment. Possible Reserves An estimate of possible oil and/or gas reserves based on geological and engineering data from undrilled or untested areas. Pour Point The temperature below which an oil tends to solidify and will no longer flow freely. POWER DEN Power Density

Power Fluid Pressurized hydraulic fluid dedicated to the operation of mechanical functions. POWER SPEC Power Spectrum Power Supply | Prime Mover | The equipment component which provides all of the power requirements to operate the coiled tubing unit. This power supply is typically provided with hydraulic power. PPB Pounds Per Barrel PPG Pound Per Gallon PPM Parts per million. PPS Packer Setting Record PRESS Pressure Survey Pressure The force exerted by one body on another, either by weight (gravity) or by the use of power. Measured as force over area, such as newtons per cubic metre. Pressure Gauge An instrument for measuring fluid pressure. A pressure gauge usually registers the difference between atmospheric pressure and the pressure of the fluid being measured by indicating the effect of such pressure on a measuring element (such as a column of liquid, a bourdon tube, a weighted piston, a diaphragm, or other pressure-sensing devices). Pressure Survey An operation designed to measure and record the pressures at various depths in the wellbore with the well either producing or shut-in. The pressures may be measured and recorded by memory tools installed within a self-contained unit run on slickline or with tools which transmit data immediately to surface through electrical conductors (electric wireline) within the wireline cable. Pressure Test The process of performing an internal pressure test on any device or containment vessel required to perform services with internal pressure present. Primary Barrier

The primary barrier is the means which allows the coiled tubing and HWO services to be performed in underbalanced conditions. Coiled tubing and HWO service units are designed to operate with surface well pressure present. Therefore, the primary barrier for coiled tubing and HWO services is the "well control stack", which includes the stripper assembly and the multi-ram well control assembly. Primary Recovery The recovery of oil and gas from a reservoir using only the natural pressure of the reservoir itself to force the oil or gas out. See also: secondary and tertiary recovery. Probable Reserves An estimate of oil and/or gas reserves based on penetrated structures, but needing more advanced confirmation to be classified as proven reserves. Produced Water Water naturally present in the reservoir or injected into the reservoir to enhance production, produced as a co-product when oil is produced. Project Finance A method of financing in which the lender has a claim to receive loan repayments only out of the revenues earned by the project he helped finance. In this type of finance, the lender has no recourse to the borrower's other assets. Propane | C3H8 | C3 | A hydrocarbon, small quantities of which are found in natural gas, consisting of three carbon atoms and eight hydrogen atoms. a gas under normal conditions. Used as automotive fuel and for cooking and heating purposes. At atmospheric pressure, propane liquefies at -42°C. See also: LPG. Proportional Limit The greatest stress a material is capable of sustaining without a deviation from the law of proportionality of stress and strain. If the load is removed for any stress up to this point, the material will assume its original dimension. Propylene | Propene | An olefin consisting of a short chain of three carbon atoms and six hydrogen atoms. a very important base chemical for the chemical and plastics industries. Prove-Up In non-destructive testing practices, the act of using several nondestructive methods in accordance with written procedures for the location, assessment and measurement of imperfections detected during full body nondestructive examination of a tube. Proven Reserves The quantity of oil and gas estimated to be recoverable from known fields under existing economic and operating conditions. PROX

Proximity Log PRSM PRISM Log PS Plug Setting PSD Packer Setting Depth PSI Pounds per Square Inch PSIA Pounds per Square Inch Atmosphere PSIG Pounds per Square Inch Gauge PTD Planned Total Depth Pulling Force The maximum tensile force that the injector can apply to the CT above the stripper at the hydraulic operating pressure recommended by the manufacturer. PUNCH Puncher Purchase Order A legal contract between a buyer and a seller. PV Plastic Viscosity PVT Pressure Volume Temperature Q Flow Rate QSFMT Quartz Selective Formation Tester Quality The suitableness of the material used to construct the tube or component for the purpose or purposes for which it is intended.

R.H. WALK Right Hand Walk R/P Run/pull R/T Running Tool R/TABLE Rotary Table R/TOOL Running Tool R/UP Rig Up RA Radioactive RAM Radioactive Marker Raw Natural Gas Natural gas containing impurities and unwanted substances such as. water, nitrogen, carbon dioxide, hydrogen sulphide gas and helium. Before the gas is marketed, these are removed. Reamer Tool employed to smooth the wall of a wellbore, enlarge the borehole, stabilize the bit, and straighten the wellbore where kinks or doglegs are encountered. Reaming The operation of enlarging the borehole. Reaming can be used to enlarge an undersized borehole or to remove obstructions and return the borehole to its original ID size. Recommended Practice A standard to facilitate the broad availability of proven sound engineering and operating practices. The Recommended Practice (RP) is generally non-mandatory unless specified by the customer or by a government agency. Recoverable Reserves The proportion of hydrocarbons that can be recovered from a reservoir using existing techniques. Reduction of Area

The difference between the original cross-sectional area and that of the smallest area at the point of rupture. usually stated as a percentage of the original area (also called "contraction of area"). Reef Effect The increase in marine life on and around an offshore structure. Reel Core Radius The smallest bend radius imposed onto the coiled tubing when spooled onto the service reel or shipping reel. Reel Swivel The high-pressure component which connects the stationary piping to the coiled tubing and is used to direct fluids into or out the tubing on the service reel. The reel swivel is mounted either on the axial hub of the service reel or on the reel frame at a point which corresponds to the axis of reel rotation. Reference End The reference end of the coiled tubing string is the end of the tubing segment which is intended to be connected to the reel with a high-pressure fitting. Reference Standard A tube containing machined notches or holes used to establish a baseline for comparison and standardization of non-destructive test inspection equipment. This section of material contains one or more reference discontinuities used for standardizing the inspection equipment. Refinery A complex of facilities where crude oil is separated into light or heavy fractions, which are then converted into useable products or feedstocks. Refining Energy Index A measure of energy efficiency in refineries, equal to the actual fuel consumption divided by the theoretical fuel consumption Ð taking account of refinery configuration and utilisation Ð times 100. Reforming A process which improves the anti-knock quality of gasoline fractions by modifying the molecular structure. When achieved by heat and pressure the process is known as thermal reforming, and as catalytic reforming when aided by a catalyst. See also: Knocking. REG Regular Regulator (Pressure) A hydraulic device that reduces or regulates upstream supply pressure to a desired pressure. It may be manual or remotely operated and, once set, will automatically maintain the regulated output pressure unless reset to a different pressure. Relevant Indication

An indication resulting from a discontinuity in the tube. Renewable Energy Energy resources that are continually available or can be replenished (e.g. solar, wind, wave, biomass, hydroelectric, geothermal). REP Repair Reportable Illness All identified occupational illnesses are reportable. RES Resistivity Logs Reserves See proven reserves, probable reserves, possible reserves and recoverable reserves. Reserves-to-Production Ratio For any given well, field or country. The length of time that reserves would last if production continued at its current rate, at the current level of technology. Reservoir (Geology) An accumulation of oil and/or gas in a porous rock such as sandstone. A petroleum reservoir normally contains three fluids (oil, gas and water), which separate into distinct sections, owing to their varying gravities. Gas occupies the upper part of the reservoir as it is the lightest, oil the middle section, while water and rocks occupy the lower section. (Hydraulics) A storage tank for control fluids used to operate the well control components and other hydraulically-actuated devices. Reservoir Rock The porous rock containing interconnected pores or fissures in which oil or gas may be found. Residual Bend The post-bend cycle deflections along the longitudinal axis of the coiled tube body which are the result of unbalanced stresses within the tube body material after all bending loads have been removed. Residue The heavy, non-volatile components of crude oil that flow from the bottom of the fractionating column during fractional distillation. Resin Solid or semi-solid mixture of complex substances, with no definite melting point. Reverse Circulate The method by which the normal flow of a fluid is reversed by circulating down the borehole through the annulus and back up to surface through the tubing conduit.

RFT Repeat Formation Tester RGB Rotary Guide Base Rheology The study of the deformation and flow of matter. Rich Gas Gas which is predominantly methane but with a relatively high proportion of other hydrocarbons. Many of these other hydrocarbons would normally be separated out as NGLs. Rig The derrick, drawworks and attendant surface equipment of a drilling or workover unit. Rigidity Usually refers to the stiffness or flexibility characteristics of a bottomhole assembly or an element thereof. RIH Run In Hole Riser The assembly of high-pressure tubing sections which are installed within the well control stack to space out equipment components or provide the desired length of pressurized tube to allow deployment of long tool segments in pressurized wellbores. RKB Rotary Kelly Bushing RNG Running Roll-On Type Connection which incorporates a machined insert mandrel designed to fit inside the CT. The mandrel is machined with circular recesses or "furrows" which serve as the force loading shoulders for the connection. The connector is secured to the CT body by means of mechanically yielding the tube into machined groove recesses on the mandrel. Rolled-In Slug A foreign metallic body rolled into the metal surface, usually not fused. Root Face The surface which is perpendicular to the tube axis between the bevel and the inside surface of the tube. Also referred to as "land" or "root land".

ROP Rate Of Penetration Rotary Shoulder Connection Tool joint and similar connections where the mating surface is the shoulder and not within the threads. ROV Remote Operated Vehicle RPI-X Retail price index minus x (x is a variable): a price-setting formula used in the UK. RPM Revolutions Per Minute RTE Rotary Table Elevation RTS Radio Tracer Survey RTTS Retrievable Through Tubing Set (Packer) S/BY Stand By S/T Shoetrack Sales Gas Raw gas, after processing to remove LPG, condensate and carbon dioxide. Sales gas consists of methane and ethane. Sand Pump A cylindrical tool with a plunger inside and a valve at the bottom which is used to remove solids and accumulated debris from within the wellbore. SAS Seismic Acquisition Survey SAT Seismic Acquisition Tool Satellite Subsea completion installation, including the template.

SBBP Static Bottom-Hole Pressure SBL Segment Bond Log Scab Also known as "mill scab". An imperfection in the form of a shell or veneer, generally attached to the surface by sound metal. It usually has its origin as an ingot defect. SCF standard cubic feet. SCM Sub Sea Control Module SCR Slow Circulation Rates Scrubbing The process of purifying a gas or liquid by washing it in a contact vessel. SCSSSV Surface Controlled Sub Surface Safety Valve SDT Array Sonic (Sonic Digital Tool) Secondary Barrier The secondary barrier is the means which provides a contingency for maintaining well control in the event the primary barrier is unable to function properly. For coiled tubing and HWO service units, the secondary barrier may include additional surface well control components or kill weight fluids. Secondary Recovery The recovery of hydrocarbons from a reservoir by increasing the reservoir pressure by injecting gas or water into the reservoir rock. See also: primary and tertiary recovery. Sedimentary Rocks Rocks laid down by the accumulation of sediments at the bottom of a sea, lake or swamp over millions of years. SEIS CALIBR Calibrated Log SEIS CPI Seismic Computer Processed Analysis

Seismic Survey A method of establishing a detailed subsurface structure of rocks, by detecting and measuring the reflection of acoustic shock waves from the various layers of rock. It is used to locate potential oil or gas bearing structures before drilling. Modern data processing enables the generation of 3D images of these underground structure. See also: acoustic log, air gun, anticline, syncline. SEM Sub Sea Electronics Module Send-Out The quantity of gas delivered by a plant or system during a specified period of time. Sensitivity The size of the smallest discontinuity detectable by a nondestructive test method with a reasonable signal-to-noise level. Service Reel A cylindrical-shaped core drum typically fabricated from steel and bounded by parallel flanges mounted transverse to the core for use in storing and transporting coiled tubing. The service reel is generally equipped with a self-contained hydraulic drive system to control rotation of the reel, an onboard hydraulic levelwind apparatus, and onboard high-pressure piping which connects to the coiled tubing through a high-pressure rotating swivel. The diameters of the cylindrical core and boundary flanges will vary relative to the tube diameter and length to be spooled onto the reel. Service String The construction of a specific length of coiled tubing used for concentric well intervention operations. SFC Surface SFLA Spherical Focused Log Averaged SFLU Spherical Focused Log Unaveraged SFT Selective Formation Tester Shall Denotes requirements which must be satisfied or performed in order to comply with specifications dictated by regulatory agencies. SHDT Stratigraphic High Resolution Dipmeter

Shear Ram The rams in a well control stack which are designed to mechanically separate the coiled tubing which is located at the point directly across the shear ram position. Shear/Seal Ram The rams in a well control stack which are designed to provide the functions of both a shear ram and a blind ram in one ram body. Ship To-Ship Transfer|STS The transfer of crude oil or products from one ship to another while both are at sea. Shipping Reel A cylindrical-shaped piece of equipment fabricated from wood or steel and used to store and ship coiled tubing. The reel consists of the cylindrical core and parallel flanges mounted transverse to the core. The diameters of the internal core and flanges vary accordingly to the tube diameter and length. SHORT Single Shot Hydrostatic Overpressure Reverse Tool Should Denotes a recommended practice (1) where safe, comparable alternative practices are available, (2) that may be impractical under certain circumstances, or (3) that may be unnecessary under certain circumstances. Shoulder (Make-Up) Flat surface at the extremities of rotary pins and boxes lying at right angles to the longitudinal axis of the connection. When pin and box are fully engaged, the shoulders are forced together and provide a seal which prevents leakage into or out of the connection. Shut-In To close valves on a well to halt the flow of fluids to the surface. Shut-In Bottomhole Pressure The pressure observed as the bottom of a wellbore when the well is completely closed to flow. Shut-In Tubing Pressure The pressure observed at the wellhead when the well is not flowing. Shut-Off Valve A valve that closes a hydraulic or pneumatic supply line. Sidetrack An operation performed to redirect the wellbore by starting a new hole at a position above the bottom of the original hole.

SIGNAL ANALYSIS Signal Analysis Single Buoy Mooring | SPM | SBM | Also known as single point mooring (SPM), this consists of a single floating chamber moored near an offshore production platform to serve as a connection to a tanker. It has no storage capacity. See also: FSU (Floating Storage Unit). SIP Selective Inflow Performance SITHP Shut In Tubing Head Pressure SL Spectrolog Slag Inclusions Non-metallic solid material entrapped in the weld deposit or between weld metal and base metal. SLIMKONE Perforations Slip Cut Transverse indentation or mark made in drill pipe or tubing by rotating it in the slips. Such cuts may develop fatigue cracks. Slip Ram The rams in a well control stack which are equipped with tubing slips that, when engaged, prevent upward and downward movement of the coiled tubing but do not isolate pressure or control flow. Slip Type Connection which requires the use of a slip or grapple-type load ferrule placed on the OD of the tube body. The load ferrule is typically constructed with sharp "spiraled" teeth which secure the ferrule onto the CT body. The load ferrule is mechanically wedged onto the coiled tubing OD during connection make-up. Sloughing The partial or complete collapse of the walls of a borehole resulting from incompetent, unconsolidated formations, high angle repose, and/or wetting along internal bedding planes. SLS Long spaced Sonic Slug Catcher Plant installed in a gas pipeline system to catch unwanted "slugs" of liquid.

SN Short Normal SNP Sidewall Neutron Log Snubbing Condition for working tubing through an energized stripper, where wellbore pressure applied against the cross-sectional area of the tube creates an upward acting force greater than the weight of the tubing in the wellbore. In this condition, mechanical assistance is required to apply thrust to the tubing while injecting or to maintain control of the tubing when extracting. This condition is commonly called "pipe-light operations". Snubbing Force The maximum compressive force the injector can apply to the coiled tubing immediately above the stripper at the hydraulic operating pressure recommended by the manufacturer. SOFC Solid oxide fuel cell Solution Gas Natural gas which is dissolved in the crude oil within the reservoir. Solvent Common name for a liquid which is capable of dissolving or dispersing other substances. SONIC Sonic unspecified Sour Gas Natural gas containing significant quantities of hydrogen sulphide. Sour gas is usually treated with triethanolamine to remove the unwanted elements. Sour Oils Oils containing high levels of hydrogen sulphide or mercaptans. Treatment of such oils to convert them to marketable products is known as sweetening. Source The origin of radiation such as an x-ray tube or radioisotope. Sox Sulphur oxides SP Spontaneous Potential SPE

Society of Petroleum Engineers Spear A fishing tool which is designed to stab inside of lost or stuck pipe within the wellbore. This stabbing action creates an internal friction grip sufficient to recover the fish. The spear is the male counterpart of an overshot. Specific Gravity The ratio of the density of a substance at a particular temperature to the density of water at 4øC. Specified Wall Thickness Published wall thickness values for coiled tubing. Note that actual wall thicknesses may differ from the specified wall thickness due to engineering tolerances and imperfection removal. Speed The rate at which the tubing is deployed or retrieved during the prescribed service. The speed of the tubing movement is typically stated in terms of "feet per minute" or "meters per minute". SPF Shot Per Foot SPI Stuck Point Indicator Spill A spill is any unexpected loss to water or land of crude oil, condensate, feedstocks, intermediates, products, brine or processed materials, irrespective of the amount recovered. This excludes any spill which is wholly contained by an impervious surface. All spills exceeding 100kg must be reported. SPL Simultaneous Production Logs SPM Stroke Per Minute Spool The total length of "as manufactured" coiled tubing product which is placed either on the service or shipping reel for storage and/or transport. A spool may contain one or more coiled tubing "strings". Spooling The act of transferring tubing from one reel to another by means of unwinding the payout string and rewinding the take-up string, or from the injector to the service reel. Spooling Radius Ratio

The ratio of the radius of the service reel or shipping reel to the radius of the coiled tube. This ratio is used in determining the minimum recommended bending radius when spooling coiled tubing onto the reel. Spot Market An international market in which oil or oil products are traded for immediate delivery at the current price (the 'spot price'). SPRO Surface Pressure Read Out Spume Small particles of metal ejected from the welding "vee" during the high frequency induction welding operation as a result of electromagnetic forces produced by the weld current. Spume tends to take the form of very small, spherical particles of metal and refractory oxides. If spume is deposited on the weld pressure rolls, it can become rolled into the tube surface. SQL Seismic Quicklook Analysis SQPERF Squeeze Gun Perforations Squeeze Cementing Refers to a secondary cementing job where cement is pumped through tubing to a specific location within the wellbore to seal off holes or undesired flow paths within the wellbore. SRPL Surface Recorded Pressure Log SRT Step-rate injection Test SSARV Single Shot Annulus Operated Reverse Valve SSD Sliding Side Door SSSV Sub Surface Safety Valve ST Sidetrack STAB Stabiliser

Standard A prescribed set of voluntary rules, conditions, or requirements concerned with the definition of terms. classification of components. delineation of procedures. specification of dimensions. construction criteria, materials, performance, design or operations. measurement of quality and quantity in describing materials, products, systems, services, or practices. or descriptions of fit and measurement of size. Stenching The process whereby odourless natural gas is given a smell for safety reasons by injecting small quantities of organic sulphur compounds, typically at the rate of 30 ppm. See also odorant. Stiff Wireline Term commonly used to refer to a string of coiled tubing with electric wireline installed internal to the string. This service string is designed to perform basic logging services. STKS Strokes STOIIP Stock Tank Oil Initially in Place Storage Facilities For natural gas, these fall naturally into two categories, according to the IEA. The first is seasonal storage sites, which comprise aquifers (including depleted oil and gasfields). salt caverns. mined caverns. and disused mines. For peak storage, gasholders - originally used to store town gas - and linepacking are used. In addition, LNG storage tanks exist for either baseload or peak-shaving duties, depending on the market. of organic sulphur compounds, typically at the rate of 30 ppm. See also odorant. Stored Hydraulic Fluid Volume The fluid volume recoverable from the accumulator system between the maximum designed accumulator operating pressure and the precharge pressure. Straight-Run A description applied to a product of crude oil that has been made by distillation with no chemical conversion. Straightener A mechanical device used to remove the residual bend in coiled tubing. A straightener is typically constructed of opposed rollers which are adjusted to create a reverse bend in the coiled tube sufficient to straighten the tube prior to entering the wellbore. On some injector designs, the straightener is located directly below the tubing guide arch, where other injectors locate the straightener directly above the stripper. STRATDIP Stratigraphic Dip Evaluation Stratigraphic Trap

A hydrocarbon trap formed at the time the sediments were laid down and where the hydrocarbons are enclosed as a result of a change from porous to non-porous rock, rather than by structural bending or faulting of rock layers. Stress The load per unit area. Stress Relieving A process of reducing residual stresses in a metal object by heating the object to a suitable temperature and holding at that temperature for the prescribed time to produce the desired effect. This treatment may be applied to relieve stresses induced by cold working or welding. STRG String String The makeup of a specific length of coiled tubing used for well intervention or other concentric wellbore operations. Stripper A device with a resilient elastomeric element used to effect a seal in the annulus. This device is used primarily to isolate well pressure from the atmosphere when injecting or extracting the coiled tubing in pressurized wellbores. Stripping Condition for working tubing through an energized stripper, where wellbore pressure applied against the cross-sectional area of the tube creates an upward acting force less than the weight of the tubing in the wellbore. In this condition, mechanical assistance is required to support the tensile load of the tubing and maintain control when injecting or extracting. This condition is commonly called "pipe-heavy" operations. STRK Side-track Structural Trap A hydrocarbon trap formed by the distortion of layers of rock by movements in the Earth's crust. See also: fault. STS Ship-To-Ship Transfer Sub-Surface Safety Valve | SSSV | A device installed in the production tubing in a well below the wellhead and designed to prevent uncontrolled well flow when actuated. These devices can be installed and retrieved by wireline and pump-down methods or may be installed as an integral part of the tubing string. Sulphur Dioxide | SO2 | Contributes to acid rain and other air quality problems such as arctic haze formation.

Surge The increase of pressure in a liquid filled wellbore due to the interaction of the wellbore liquids in contact with the concentric pipe and tools when the tubing and attached tool string are moved downward within the wellbore. The drag forces created through the relative motion of the liquid and the tube generate an increased wellbore pressure similar to that of equivalent circulating density. Sustainable Development The meeting of present needs without compromising the ability of future generations to meet their own needs. SV Safety Valve Swab The decrease of pressure in a liquid filled wellbore due to the interaction of the wellbore liquids in contact with the concentric pipe and tools when the tubing and attached tool string are moved upward within the wellbore. The drag forces created through the relative motion of the liquid and the tube generate an decrease in wellbore pressure. Swab Valve The uppermost valve in a vertical line on the christmas tree, always located above the production flow-tee or flow-cross. SWC Sidewall Coring Sweet Gas Natural gas containing very small amounts of hydrogen sulphide gas and carbon dioxide. Sweet gas reduces sulphur dioxide emissions into the atmosphere. Sweetening See Sour oils. Swing The amount by which the rate of gas to be supplied under a contract at any one time may differ from the daily contracted quantity at the buyer's choice. Swivel Joint Metal pipe fittings equipped with one or more elbows and integral ball-bearing points of rotation which provides a means to assemble surface piping systems in any orientation as required. SWL Safe Working Load SWN

Sidewall Epithermal Neutron Log SWP Safe Working Pressure Syncline A fold in layered rock in the form of a dip or bowl. See also: anticline. SYNTH Synthetic Seismogram SYNTH AC IMPED Synth. Seismogramm Acoustic Impedance SYNTH BLACK Synth. Seismogram Black SYNTH LAND Synth. Seismogram Land SYNTH MAR Synth. Seismogram Marine Synthetic Gas Methane-rich gas manufactured from oil or coal that has the same basic characteristics and chemical composition as natural gas. After treatment to remove carbon dioxide, it is suitable as low-calorific town gas. System Pressure Test The integrity test used to verify the ability of the pipe and pressure containment equipment in service to maintain a pressure seal. T/D Tonnes per day. T/Y tonnes a year. TA Temporary Abandonment TAC Technology Advisory Committee Take-or-Pay A contractual clause obliging a gas buyer to pay the seller for a contracted amount of gas in a fixed period, whether or not he takes physical delivery of it.

Tally Measured record of the total length of pipe, casing, or tubing that is to be run into a well. Tapered String Coilde Tubing: A coiled tubing string manufactured with a constant outside diameter and variable wall thicknesses within the length of the spooled tube. The tapered string may be constructed (1) as a continuously-milled string incorporating multiple, single wall thickness skelp segments joined using skelp-end welds, (2) as a continuously-milled string incorporating single wall thickness skelp segments with continuously-tapered skelp segments joined using skelp-end welds, or (3) continuously-milled coiled tubing segments of single wall thickness joined to other finished tube segments of increased wall thickness using the tube-to-tube welding process. Jointed: A string of tubing assembled for deployment into the wellbore with segments of the string comprised of tubing joints having either a variable ID, variable OD, or both. Tar Sands Mixture of sand, water and heavy hydrocarbons. a potential alternative source of hydrocarbons. TBBP Through Tubing Bridge Plug Setting TBG Tubing TBRT Tubing Hanger Running Tool TC Tubing Cutter TCE Trichloroethane TCF Trillion (10^12) cubic feet. TCP Tubing Conveyed Perforation TCRT Tree Cap Retrieval Tool TCS Through Tubing Caliper Sonde TD Top Drive

TD CONV Time Depth Conversion TDS Top Drive System TDT Thermal Decay Time Log TEL Tubing End Locator Telescoping Joint A device used in the marine riser system of a mobile offshore drilling rig to compensate for the vertical motion of the rig caused by wind, waves, or weather. TEMP Temperature Survey Tensile Strength The maximum tensile stresses which a material is capable of sustaining. Tensile strength is calculated using the maximum load observed during a tension test (carried to rupture) divided by the original cross-sectional area of the specimen. Tensile Test Test which is used to determine the actual tensile strength of the tube. The tensile test involves cutting a section of tubing, carefully measuring the cross-sectional area, mounting the tube section within a tensile test fixture and applying a tensile load onto the tube sufficient in magnitude to pull the tube to destruction. The load at which the specimen breaks is divided by the original cross-sectional area to obtain the ultimate tensile stress or strength. Tensioner System A system of devices installed on a floating offshore drilling rig to maintain a constant tension on the riser pipe despite any vertical motion made by the rig. Terajoule | TJ | One trillion (10^12) joules. Terminal An onshore transit installation that receives and stores crude oil and products from offshore production facilities via pipeline and / or tankers. Tertiary Recovery Recovery of hydrocarbons from a reservoir over and above what can be recovered using primary and secondary recovery. It usually means employing a sophisticated method such as heating the reservoir or enlarging the pore spaces using chemicals. See also: acidizing. TFL

Through Flow Line TGB Temporary Guide Base TGT Tubing Geometry Log Third-Party Access | TPA | A TPA regime obliges companies operating gas transmission or distribution networks to offer terms for the carriage of gas on their systems by other gas distribution companies or particular consumers. THP Tubing Head Pressure Thread Type Connection which is secured onto the CT with threads. This connection requires that the end of the CT be threaded to mate with the connector threads. THROT Tubing Hanger Running and Orientation Tool THRT Tubing Hanger Running Tool TIME Time Log TLC Tough Logging Conditions TNEU Thermal Neutron Log TNS Thomson North Sea TOC Top Of Cement TOL Top Of Liner Tolerance The permissible deviation from the specified value. Tonne | Ton |

A metric measure of weight: 1 tonne equals 1000 kilograms (kg). 1 kilotonne equals 1000 tonnes. Tonnes of Coal Equivalent | TCE | A method of assessing the work or calorific value of different sources of energy in terms pertaining to one tonne of coal. Tonnes of Oil Equivalent | TOE | A method of assessing the work or calorific value of different sources of energy in terms pertaining to one tonne of oil. Tool String An assembly of downhole tool components used to perform specified service(s) within the wellbore during the operation. Top Drive A device similar to a power swivel that is used in place of the rotary table on a drilling rig to turn the drill stem. Hung from the hook of the traveling block, a top drive also suspends the drill stem in the hole and includes power tongs. Modern top drives combine elevators, tongs, swivel and hook. TOPD Top Drive Torque In engineering mechanics usage, a torque often refers to the torsional or twisting moment or couple which tends to twist a rigidly fixed object, such as a shaft, about an axis of rotation. Torque is generally measured in Lb-ft or meter-Newtons. Torsion Strain created by twisting action. The stress within the material resisting the twisting. Torsional Strength The maximum torque (twisting force) above which tubular goods or any other device will suffer permanent dimensional change or fracture. Total Depth | TD | The maximum measured depth of the wellbore. Total Reportable Case Frequency | TRCF | The number of Total Reportable Cases per million exposure hours worked during the period. Total Reportable Cases | TRC | The sum of fatalities, permanent total disabilities, permanent partial disabilities, lost workday cases, restricted work cases and medical treatment cases (first aid cases are excluded). Total Reportable Occupational Illness | TROI |

The number of occupational illnesses. Any identified occupational illness is to be included, even if no lost/restricted workdays are involved and/or no medical treatment is given. Total Reportable Occupational Illness Frequency | TROIF | The number of Total Reportable Cases per million exposure hours worked during the period. Town Gas Gas piped to consumers from a gas plant. It can comprise manufactured gas, as well as natural gas for enrichment. TPA Third-Party Access Traction The maximum axial traction force that the injector can apply to push or pull the coiled tubing. A gripping force normal to the coiled tubing axis must be applied to the OD of the coiled tubing body. Transition Point The point on the tapered coiled tubing string where tubing segments of different wall thicknesses are joined together. Transmission The transport of large quantities of gas at high pressures, often through national or regional transmission systems. From the latter, gas is transferred into local distribution centres, for supply to customers, at lower pressures. Transmission Pipeline A network of pipelines distributing natural gas from an onshore station, via compressor stations, to storage centres or distribution points. Transverse Literally means "across", usually signifying circumferential in direction. Trap A geological structure in which hydrocarbons build up to form an oil or gas field. See also: structural trap. TRC Total Reportable Cases TRCF Total Reportable Case Frequency Trichloroethane | TCE | A solvent, when vaporised contributing to stratospheric ozone depletion. It is being phased out under the Montreal Protocol. (see also CFCs, Halons and HCFCs)

Trip Coiled Tubing: The event which describes the complete deployment and retrieval of a segment of coiled tubing. Specifically, a trip occurs when an identified point on the coiled tubing string (originally on the service reel) is spooled off, deployed below the stripper into the wellbore and subsequently retrieved back onto the reel. Jointed Tubing: The event which describes the complete deployment and retrieval of a string of jointed tubing. Specifically, a trip occurs when an identified point on the tubing string is deployed into the wellbore and subsequently retrieved back to surface. TRO Test Rack Opening (Pressure) TROI Total Reportable Occupational Illness TROIF Total Reportable Occupational Illness Frequency TRSSSV Tubing Retrievable Sub Surface Safety Valve True Vertical Depth The depth within a given borehole as measured vertically from the surface reference. TT Technology Transfer TTBP Through Tubing Bridge Plug TTRBP Through Tubing Retrievable Bridge Plug TTT Two-Way Times TTWO Through Tubing Workover Tube-To-Tube Weld A circumferential seam weld used to join two segments of tube together. Tube-to-tube welds may be performed using gas metal arc welding, plasma arc welding, gas tungsten arc welding or a combination of such welding processes and shall be made in accordance with qualified welding procedures. Tubing Guide Arch The equipment component which provides support of the continuous-length tube and guides the tubing from the service reel through a bend radius (ranging from 45 to as much as 180 ) prior to

entering the injector gripping mechanism. In general, the tubing guide arch incorporates a series of upper and lower rollers which center the tubing as it travels over the guide arch. The number, size, material, and spacing of the rollers varies significantly with different tubing guide arch designs. Turbulent Flow Fluid flow in which the velocity at a given point changes constantly in magnitude and direction of flow. This fluid flow pursues erratic and continually varying courses. TVD True Vertical Depth TVDRKB True Vertical Depth Below Rotary Kelly Bushing TVDSS True Vertical Depth Sub Sea UBI Ultrasonic Borehole Imager UKCS United Kingdom Continental Shelf. ULCC Ultra-Large Crude Carrier Ullage The space in a tank not occupied by its contents. Used as a measure of storage space still available. Ultrasonic Testing A nondestructive inspection method which uses compression and shear waves in the frequency range 2. 25 - 10 MHZ to detect and size material imperfections. In coiled tubing, ultrasonic testing is used for wall thickness measurements or prove-up of imperfections. UMC Underwater Manifold Center Unbundling The separation of the gas transport, storage and merchandising functions. Under-Cut Under-cutting on tube welding is the reduction in thickness of the tube wall adjacent to the weld where it is fused to the surface of the tube. Union A coupling device used to connect pipe without requiring rotation of the pipe.

Unloading The act of returning an inactive well to a flowing condition. This activity generally requires underbalancing the hydrostatic fluid column within the wellbore to initiate flow. UPR Upper Pipe Rams Upstream Those activities relating to the exploration, production and delivery to an export terminal of crude oil. UR Ultimate Recovery Useable Hydraulic Volume The hydraulic fluid volume which can be recovered from the accumulator system between the maximum designed accumulator operating pressure and the minimum operating pressure. Valve A device used to control the rate of flow in a line, to open or shut off a line completely, or to serve as an automatic or semiautomatic safety device. Valves which find extensive use in the oil and gas industry include the gate valve, plug valve, needle valve, check valve, and relief valve. VBR Variable Bore Rains VDL Variable Density Log VEL Velocity VEL LOG Velocity Log VEL SURV Velocity Survey Velocity String Term commonly used to describe a string of tubing installed concentric to an existing production tubing string. This concentric string is used to enhance production from the wellbore through increased flow velocity, derived from the reduced ID of the string. Also referred to as "Siphon String". Very large crude carrier | VLCC | Very large crude carrier. A large ocean-going tanker, over 200,000 metric tonnes dwt, used to transport crude oil.

VFP Vertical Flow Performance VGS Variable Gauge Stabiliser VIS Viscosity Viscosity The internal resistance offered by a fluid to flow. This phenomenon is attributable to the attractions between the molecules of a liquid, and is a measure of the combined effects of adhesion and cohesion to the effects of suspended particles, and to the liquid environment. The greater this resistance, the greater the viscosity. Viscosity Index A measure of the relationship between temperature and viscosity of an oil. VJB Ventum Junk Basket VLCC Very large crude carrier Volumetric Efficiency The percentage relation between the actual delivered capacity of a pump and the calculated displacement of the pump. W/H Well Head W/HEAD Well Head W/L Wire Line W/LINE Wire Line W/O without Wall Thickness The thickness of the finished tube wall. WBM

Water Base Mud WCA Well Head Conversion Area WEG Wireline Entry Guide Weight Air: The weight of an empty string of tubing, typically given as weight per unit length. Buoyed:The weight of the tubing string immersed in a fluid. The tubing may be gas filled (maximum buoyancy), filled with a reference fluid (conventional buoyancy), or filled with a heavier fluid. Weight Indicator Coiled Tubing: A device which measures the hanging weight of the tubing string and drag forces associated with deployment and retrieval of the tubing string. The weight indicator is typically installed at a location which measures the weight of the chain drive section and tubing deployed through the stripper assembly. The weight of the chain drive assembly is "zeroed" prior to deployment, yielding readings for load resulting from tubing weight and drag. HWO: The weight indicator is typically determined through the hydraulic pressure readings observed when operating the hydraulic jacks during tubing deployment and retrieval. Jointed Tubing Rigs: The weight indicator is typically installed at the base of the derrick and connected to the drill line (cable), taking the weight indication as a measurement of the amount of tension in the cable. The loads associated with weight of the traveling block and cable is "zeroed" prior to rig operations, yielding readings for load resulting from tubing weight and drag. Weight On Bit The amount of downward force applied to the bit through slackoff of the surface weight of the string or as applied through a mechanical thruster device. Weld The fusion of materials, with or without the addition of filler materials. Weld Area Crack A crack that occurs in the weld deposit, the fusion line, or the heat affected zone. Note that a crack is a stress-induced separation of the metal, which, without any other influence, is insufficient in extent to cause complete rupture of the material. Weld Type Connection secured to the CT through welding. This connection may be a Figure 1502 union used to connect the CT string to the service reel fluid manifold, or a threaded union located on the outboard end of the tubing string for use in installing downhole tools. Welding | Welding Processes | Gas Metal-Arc Welding | Arc Welding | Gas Tungsten Arc Welding | High-Frequency Induction Welding | Plasma Arc Welding | Skelp-End Welding | The welding practices commonly used in manufacturing coiled tubular products are described below.<BR>- Gas Metal-Arc Welding<BR>The welding process that produces coalescence of

metals through heat generated by an arc (or arcs) created between a continuous consumable electrode and the work product. All gas used for shielding during the welding process is externally supplied and may be pure inert gas or a mixture of inert gases. Gas metal-arc welding does not require pressure, and the electrode provides the filler metal.<BR>- Gas Tungsten Arc Welding<BR>The welding process that produces coalescence of the metals through heat generated by an arc created between a single tungsten electrode and the work product. Gas tungsten arc welding does not require pressure, and filler metal may or may not be used. Pure inert gas is used for shielding during the welding process.<BR>- High-Frequency Induction Weld (Seam)<BR>A longitudinal seam weld produced through electric induction welding, where the heat for welding is generated by resistance to flow of electric current, and the edges to be welded are mechanically pressed together. This process does not use filler metal.<BR>- Plasma Arc Welding<BR>The welding process that produces coalescence of metals through heat generated by a constricted arc created between a continuous consumable electrode and the work product, or the continuous consumable electrode and a constricted nozzle. The gas used for shielding during the welding process is provided by the hot ionized gas discharging from the torch and may be supplemented by additional pure inert gas or a mixture of inert gases. Plasma arc welding may or may not use pressure in creating the weld, and the electrode provides the filler metal.<BR>- Skelp-End Weld<BR>A weld which is used to join skelp ends together. Skelp-end welds are performed on flat skelp and are typically made using plasma arc welding methods in accordance with qualified welding procedures. Welding Stress The stress resulting from localized heating and cooling of metal during welding. Well Control Component, Ram Type A device designed to form a seal on the wellbore with or without coiled tubing in the well or to perform a specific operation on the coiled tubing body. Ram-type well control components include a set of blind rams, shear rams, slip rams and pipe rams to effect the required wellbore seals or perform the specific physical action on the coiled tube body. Combination shear/seal and pipe/slip rams are available. Well Control Equipment Drill A training procedure to ensure that onsite service and operations personnel are familiar with correct operating practices to be followed in the use of well control equipment for blowout prevention. Well Control Stack An integral body or an assembly of well control components including ram-type components, annular-type components, spools, valves and nipples connected to the top of the wellbore to control well fluids. Wellhead An assemblage of valves and spools located below the christmas tree and above the casing strings for the purpose of hanging and isolating the various tubular strings. WHP Well Head Pressure

WHT Well Head Temperature WIQI Well Inflow Quality Indicator WKST Wackestone WLRG Wire Line Re-Entry Guide WOB Weight On Bit WOC Wait On Cement WOR Workover Record Work Hardening Hardness developed in metal as a result of cold-working. WTS Well Test Services X/O Cross Over X/OVER Cross Over XPLOT Cross Plot Yield Point For carbon steel material, the yield point is the stress at which a marked increase in deformation occurs without an increase in load. Also the point where permanent set occurs. Yield Strength The stress required to produce a specified limiting deviation from the proportionality of stress to strain. This deviation may be expressed in terms of strain, percent offset or total elongation under load. Young's Modulus

The ratio of stress-to-strain in measuring the stiffness of a material. This ratio is also referred to as "modulus of elasticity" and is the slope of the straight line portion of the stress-strain diagram. YP Yield Point