Basic Oilfield Equipment - Remote Desktop Webamusement21.com/testcdl/EO-Library/EOT-EO1 Folder/EOT-EO1 Jet... · JET 04 - Basic Oilfield Equipment| 9 2.0 Basic Engines and Transmissions

JET Manual 04Basic Oilfield

EquipmentVersion 1.1

JET Manual 04 Basic Oilfield EquipmentInTouch content ID# 4127828 Version: 1.1 Release Date: January 31, 2007 Owner: Well Services Training & Development, IPC

Schlumberger private

Document Control

Revision History

Rev Effective Date Description Prepared by

Copyright © 2007 Schlumberger, Unpublished Work. All rights reserved.This work contains the confidential and proprietary trade secrets of Schlumberger and may not be copied or stored in an information retrieval system, transferred, used, distributed, translated, or retransmitted in any form or by any means, electronic or mechanical, in whole or in part, without the express written permission of the copyright owner.

Trademarks & service marks“Schlumberger,” the Schlumberger logotype, and other words or symbols used to identify the products and services described herein are either trademarks, trade names, or service marks of Schlumberger and its licensors, or are the property of their respective owners. These marks may not be copied, imitated or used, in whole or in part, without the express prior written permission of Schlumberger. In addition, covers, page headers, custom graphics, icons, and other design elements may be service marks, trademarks, and/or trade dress of Schlumberger, and may not be copied, imitated, or used, in whole or in part, without the express prior written permission of Schlumberger. A complete list of Schlumberger marks may be viewed at the Schlumberger Oilfield Services Marks page: http://www.hub.slb.com/index.cfm?id=id32083

An asterisk (*) is used throughout this document to designate a mark of Schlumberger.

Other company, product, and service names are the properties of their respective owners.

iiiJET 04 - Basic Oilfield Equipment |

Table of Contents

1.0 Introduction 71.1 Learning objectives 71.2 Safety warning 7

2.0 Basic Engines and Transmissions 92.1 Types of engines 9

2.1.1 Electricmotors 92.1.2 Gasolineengines 92.1.3 Dieselengines 10

2.2 Engine comparisons 112.2.1 Internalcombustionengines 112.2.2 Intakeandcombustion 112.2.3 Compression 112.2.4 Horsepowerandtorqueversusrpm 11

2.3 Diesel engines—Schlumberger’s main prime movers 122.3.1 Strokecycles 122.3.2 Dieselenginecomponents 13

2.4 Transmissions 192.4.1 Clutches 202.4.2 Manualgearbox 212.4.3 Powershifttransmission 222.4.4 Torqueconverter 222.4.6 Drivelines 242.4.7 Routinemaintenanceoftransmissions 24

3.0 Basic Pneumatic Systems 253.1 Types of pneumatic systems 253.2 Parts of pneumatic systems 263.3 Pneumatic systems components 26

3.3.1 Compressor 263.3.2 Blowers 283.3.3 Airreservoirs(tanks) 293.3.4 Governors(pressureregulator) 293.3.5 Pressure-reliefvalves 303.3.6 Checkvalves 31

iv | Table of Contents

3.3.7 Draincocks 313.3.8 Dryers(waterseparators) 313.3.9 Lubricators 32

3.4 Applications 323.5 Safety 33

4.0 Basic Electrical Systems 334.1 Basic circuit 334.2 Electric current 344.3 Voltage 354.4 Resistance 354.6 Ohm’s law and power formula 364.7 Conductors and insulators 374.8 Batteries 384.9 Generators and alternators 414.10 Regulators, breakers, and fuses 434.11 Applications 444.12 Safety 45

5.0 Basic Hydraulic Systems 475.1 Why use hydraulic power? 475.2 Maintenance of hydraulic components 485.3 Stem I auxiliary posttrip inspection 48

5.3.1 Allfluidlevels 495.3.2 Allbelts 495.3.4 Engineandtransmissionpowertake-offs 505.3.6 Exhaustsystem 515.3.7 Instrumentation 515.3.8 Clutchoperation 515.3.9 Hydraulicsystem 515.3.10 Airtanks 525.3.12 Chemicaladditivesystems 525.3.13 Suction/dischargepiping 525.3.14 Centrifugalpumps 525.3.15 High-pressuretriplexpumps 535.3.16 Bulkcementtransport 535.3.17 Displacementtanks 535.3.18 Safetysystems 545.3.19 Domelids 545.3.20 Tanktestdate 54

vJET 04 - Basic Oilfield Equipment |

5.3.21 Placarding 545.3.22 Blinds/caps 545.3.23 Radiationpapersanddecals 545.3.24 Densitometerlock 555.3.25 Auxiliaryposttripinspectorsignature 55

5.4 Stem I repair process 556.0 Stem I Diesel Engine 577.0 Stem I Compressor 638.0 STEM I Acid Transport 679.0 Stem I Cement Bulk Equipment 7110.0 Stem I Batch Mixers 7511.0 Equipment Modifications 7712.0 References 7913.0 Check Your Understanding 81

This page left intentionally blank

vi | Table of Contents

7JET 04 - Basic Oilfield Equipment |

1.0 Introduction

The objective of JET manual 04, Basic Oilfield Equipment, is to familiarize personnel with the equipment used in pumping services. The training will provide a better understanding of Schlumberger equipment design and performance and reduce service incidents and operating failures.

Schlumberger has in place the Standard Equipment Maintenance (STEM) program to help outline the procedures needed for the preventive maintenance of all Schlumberger units. The program consists of the STEM I, STEM II, and STEM III inspection procedures; each is done at various intervals.

Guidelines are in place regarding the STEM I for the primary pieces of equipment used in pumping jobs.

One section in this manual outlines the procedures that are necessary for the STEM I inspection on many of the common pieces of basic equipment.

Use of the STEM procedures for all pumping equipment will minimize job failures, decrease excessive, premature, expensive repairs, help ensure that equipment lasts longer, and increase customer satisfaction.

1.1 Learning objectivesAfter completion of this training, you should be able to do the following:

identify advantages and disadvantages, principles of operation, and maintenance requirements for various types of drivers and transmissions

•

explain the principles of operation and components of different types of pneumatic systems and compressors

explain the principles of operation of electricity, electrical circuits, batteries, and circuit components

explain the principles of operation and maintenance for various types of hydraulic system components

describe the process for each of the following:

STEM I Auxiliary Posttrip

STEM I Diesel Engines

STEM I Compressors

STEM I Sand Chief

STEM I Acid Transport

STEM I Cement Bulk Equipment

STEM I Batch Mixers.

1.2 Safety warningProper supervision is required during hands-on training. Request assistance from your supervisor if you are unfamiliar or uncomfortable with an operation.

Ensure that all safety devices are in place and operational before you perform any activities associated with this training.

Always allow enough time to ensure that the prejob and postjob checks can be performed correctly.

Remember that any safety check item omitted is an opportunity for equipment failure.

•

•

•

•

○

○

○

○

○

○

○

Before you perform the STEM I on the unit, the correct protective clothing is required:

Nomex coveralls

hard-toed boots

hard hat

safety glasses

and, if needed:

gloves

goggles

dust mask

ear protection.

Be aware of all other unsafe situations when performing routine maintenance. Safety is basically common sense and training, but each situation has its own peculiarities, which are not always addressed by rules. Your training and experience will be helpful guides for safe work habits. Watch out for hazards, and correct them promptly.

General guidelines for safe operation:

Do not wear loose clothing or jewelry that can catch on controls.

Use steps and rails or handlebars when mounting and dismounting from the truck.

Know hand signals and who gives them.

Clear personnel from the machine area before starting equipment.

Be sure all tools and electrical cords have been removed from the unit before starting.

Start the engine only in well-ventilated areas.

Check the functioning of safety devices: lights, horn, brakes, etc.

Observe engine gauges frequently. Be alert to unusual noises.

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

Use LOTO (lock-out/tag-out) whenever performing maintenance on equipment.

•

8 | Introduction


2.0 Basic Engines and Transmissions

In this chapter, you will learn about the basic types of engines used at Schlumberger, including electric motors, gasoline engines, and diesel engines. The chapter compares the three types and provides details about diesel engines, the principal engine used at Schlumberger. Detail is also given about transmissions.

2.1 Types of enginesSchlumberger equipment uses electric motors, gasoline engines, and diesel engines. These are sometimes called prime movers, which are power plants or sources of energy that transform a natural energy source into motive power.

2.1.1 Electric motorsSchlumberger uses electric motors on offshore skids (Fig. 2-1).

Figure 2-1. Electric Motor Used in Cement Pump Skid

Advantages of electric motors

The advantages of using electric motors include the following:

no exhaust emissions: Electric motors are noted for their environmentally clean operation because they produce no exhaust emissions.

size: Electric motors are very compact relative to their power output and, therefore, can easily be adapted to areas where a normal engine will not fit. Electric motors are also very quiet and operate with little vibration.

Disadvantages of electric motors

Electric motors are the best option for most Schlumberger applications, but they have some serious disadvantages:

initial high cost: They are more expensive than most other power sources, costing three times more than comparable horsepower diesel engines.

power requirements: Electric motors require a power plant or electrical power supply, which is often not available.

packaging requirements: Electric motors are limited by their packaging. They are highly inflexible and must be precisely mounted or installed.

2.1.2 Gasoline enginesAlthough diesel engines provide the greatest number of advantages for Schlumberger applications, gasoline engines are useful in many situations (Fig. 2-2).

•

•

•

•

•

10 | Basic Engines and Transmissions

Figure 2-2. Gasoline Engine

Advantages of gasoline engines

Their advantages include the following:

initial low cost: Typically, the initial cost of gasoline engines is considerably lower than that for other forms of power.

power versus weight: Gasoline engines are recognized for their good power-versus-weight ratio.

portability: Because of their light weight, gasoline engines are also one of the most portable forms of power and can be used in a large variety of situations.

Disadvantages of gasoline engines

The disadvantages of gasoline engines include the following:

limited durability: Because gasoline engines reach their peak horsepower at a higher speed than diesel engines do, they are less durable. Their light weight also tends to limit engine life.

power range versatility: Because they reach peak horsepower at a higher speed

•

•

•

•

•

than diesel engines do, their power range is less versatile.

fuel requirements: Octane ratings and lead content vary from country to country, making it almost impossible to maintain consistent, dependable fuel quality.

2.1.3 Diesel enginesDiesel engines are designed to fit a wide variety of applications and requirements (Fig. 2-3).

Figure 2-3. Diesel Engine

Some diesel engines are built to operate at many revolutions per minute (rpm), with little concern for long-term operation. Others, such as the engine on a coiled tubing unit, produce less horsepower but also require less maintenance and can last longer.

Advantages of diesel engines

The highly reliable diesel engine provides the following advantages over other prime movers:

durability: A diesel engine is built on a heavier scale than a gasoline engine because of the high internal pressures that it produces. It also operates at a lower speed with higher torque.

•

•


no ignition components: There are no ignition components, and the diesel fuel lubricates and cools the injectors, providing durability and long life.

low maintenance: When supplied with clean fuel, a diesel engine can operate continuously for long periods with minimum danger of breakdown.

global fuel compatibility: Diesel fuel can be found around the world and, unlike gasoline, is universally consistent.

low exhaust emissions: Because diesel fuel burns more air than spark-ignition engines do, the fuel is very free from hydrocarbon and carbon monoxide exhaust emissions.

portability: Despite their weight, diesel engines are portable and can be positioned almost anywhere.

Disadvantages of diesel engines

The disadvantages of using diesel engines include the following:

weight: The heavier weight of a diesel engine can affect the ability to mount the appropriate horsepower engine.

difficulty starting: Diesel fuel is more difficult to ignite than gasoline, and this can make a diesel engine harder to start. Ether is sometimes used to start older units. In colder climates, heating and circulating the engine coolant during transit can keep the engine warm.

2.2 Engine comparisonsGasoline and diesel engines are similar in some respects, different in others. For example, both are classified as internal combustion engines, but they differ in design and operation.

•

•

•

•

•

•

•

2.2.1 Internal combustion enginesBoth gasoline and diesel engines are classified as internal combustion engines because they burn fuel inside the engine. To operate efficiently and meet specifications, all internal combustion engines require these things:

clean air

clean fuel

clean lubricant

clean coolant.

Internal combustion engines must use the recommended fluids and filters. Also, the coolant requires corrosion-fighting additives to eliminate rust and other damage.

2.2.2 Intake and combustionThe gasoline engine’s intake is a mixture of fuel and air that is ignited by a spark plug after the air mixture is compressed. A diesel engine’s air intake is compressed until it becomes hot enough (about 538 degC [1,000 degF]) that when liquid diesel fuel is forced into the cylinder, it ignites instantly.

2.2.3 CompressionGasoline engines compress the fuel/air mixture at a ratio of 8.0–10.5 to 1. Diesel engines compress at a higher ratio of 18–26 to 1. This ratio is the relationship of the maximum volume of an engine cylinder with the piston at the bottom of its stroke to the minimum volume of the cylinder with the piston at the top of its stroke.

2.2.4 Horsepower and torque versus rpmGasoline and diesel engines differ in the horsepower and torque they are capable of delivering in relation to the rpm generated. Gasoline engines achieve maximum

•

•

•

•


horsepower at high rpm and deliver maximum torque at mid to high rpm. In contrast, diesel engines can achieve maximum horsepower at mid to high rpm’s and maximum torque at mid rpm’s. This characteristic enables the diesel engine to perform at maximum output with less wear and tear than the gasoline engine.

2.3 Diesel engines—Schlumberger’s main prime movers

Diesel engines offer many advantages for Schlumberger applications and are the prime movers used to power equipment. One example is the cement pump truck (CPT)-372 powered by Caterpillar engines, which produces high-pressure pumping services of up to 570 hhp.

2.3.1 Stroke cyclesDiesel engines are built with four-stroke cycles and with two-stroke cycles.

2.3.1.1 Four-stroke diesel engine cycleIn a four-stroke diesel engine, four strokes of the piston are required to complete one cycle (Fig. 2-4):

intake stroke: The piston moves downward, and air, without fuel, is drawn into the cylinder. The intake valve is open and the exhaust valve is closed.

compression stroke: Both valves are closed, and the piston moves upward into the closed part of the cylinder to squeeze the air into a tiny space until it becomes hot enough for liquid diesel fuel forced into the cylinder to burn instantly.

power stroke: The rapid buildup of burning gases in the cylinder forces the piston down, making this the power

1.

2.

3.

stroke. Once again, both valves are closed.

exhaust stroke: When the piston reaches the bottom of its stroke, the cylinder is filled with burned gases, and the piston moves upward to push them out. During this stroke, the exhaust valve opens while the intake valve remains closed.

Figure 2-4. Four-Stroke Diesel Engine Cycle

2.3.1.2 Two-stroke diesel engine cycleAs the name indicates, the two-stroke cycle has two strokes (Fig. 2-5). One stroke is up; the other is down. Each down stroke is a power stroke. In the two-cycle diesel, all four valves are exhaust valves.

Ports in the cylinder wall are opened and closed by the movement of the piston. These ports permit air to be blown into the cylinder. When the piston is at the bottom of the stroke, the ports are open and a blower forces air into the cylinder under high pressure. At the same time, exhaust gases are blown out through the open valves at the top of the cylinder.

As the piston rises, the intake ports are covered, the exhaust valves close, and air in the cylinder is compressed. When the piston is near the top of the stroke, fuel is injected. The fuel is ignited by heat developed from compression, and expanding gases force the piston down to develop power.

4.


Fuel injected

Power strokeFuel injected

Figure 2-5 . Two-Stroke Diesel Engine Cycle

2.3.2 Diesel engine componentsThis section describes the following components of diesel engines:

air systems

fuel systems

fuel management systems

lubrication systems

cooling systems.

Figure 2-6 shows the components of a diesel engine.

Figure 2-6. Diesel Engine Components

1-primary fuel filter 2-secondary fuel filter 3-air compressor 4-air intake filter

•

•

•

•

•

5-engine oil filter 6-power steering oil reservoir 7-truck engine start relay.

2.3.2.1 Air systemsComponents of a diesel engine air system can include

an air filter

a blower/supercharger

a turbocharger

an air filter restriction indicator

a plumbing

an emergency air shutoff valve.

Air filters

Many air filters reverse the direction of airflow one or more times as air enters the unit. During the first cleaning stage, centrifugal action is used to remove 90% or more of the foreign matter contained in air. This centrifugal action is used in two types of air filters typically found in diesel engines:

wet or oil bath filters

dry or cartridge filters.

Wet or oil bath filters

In this type of filter, the direction of the incoming air is reversed and directed over the surface of the oil bath (Fig. 2-7). As a result, a large portion of the foreign matter is retained in the oil bath. In some filter designs, the air is then passed through an oil-wetted copper mesh screen.

•

•

•

•

•

•

•

•


Figure 2-7. Wet or Oil Bath Filters

Wet filters are used less frequently because of the following:

Environmental problems are posed by disposal of the filtering fluids.

More maintenance effort is required for wet filters than for dry filters.

They are less efficient than paper element filters.

Dry or cartridge filters

The dry-type filter is a highly efficient paper element filter. It is typically an accordion-pleated ring of specially treated paper, sealed top and bottom with a plastic ring. This is the type of filter most commonly used today (Fig. 2-8).

Figure 2-8. Dry or Cartridge Filters

•

•

•

Replacing dry filter elements at scheduled maintenance intervals or whenever they are seen to be plugged is recommended.

Today, most filter housings are equipped with an indicator (vacuum restriction gauge), which indicates when the filter should be cleaned or changed.

If a replacement filter is not readily available, you may either

remove the old one and tap it to knock off the accumulated dirt

wash it in water with a nonsudsing detergent.

Blower or supercharger

A blower, or supercharger, is a device that forces additional air into the engine to increase its efficiency and horsepower (Fig. 2-9).

Figure 2-9. Blower or Supercharger

Turbocharger

A turbocharger is a blower, powered by engine exhaust gases, that forces air into the intake manifold at higher than atmospheric pressure to increase engine power and performance (Fig. 2-10).

•

•


Figure 2-10. Turbocharger

A turbocharger rotates at very high speeds and is very hot. Therefore, it requires both lubrication and cooling. Typically, oil from the engine is used for this purpose. The oil is routed through the turbocharger and returned to the engine where it is cooled and filtered on an ongoing basis as the engine is running. (For this reason, you should let the engine idle for several minutes before killing the engine.) In some applications, additional water cooling is used.

Air filter restriction indicator

The air filter restriction indicator measures the degree of vacuum existing in an engine chamber. A complete vacuum is undesirable and can be created by clogged or dirty filters. The indicator indicates when air filters should be cleaned or changed. This device can be mounted either on the filter or on the dashboard console.

Plumbing (pipes and fittings)

Various pipes and fittings are required to connect components of the air system, such as intake and exhaust pipes.

Emergency air shutoff valve (emergency kill)

Air shutoff valves cut off all air to a diesel engine (Fig. 2-11). They are required when operating near gas wells because a diesel engine may continue to run even after fuel

has been shut off. This occurs when airborne natural gas is drawn into the engine, providing the air/gas mixture that enables the engine to operate without diesel fuel being injected.

Figure 2-11. Air Shutoff Valve (Emergency Kill)

Emergency kill

2.3.2.2 Fuel systemsThe principal job of the fuel system is to start, deliver, regulate, and inject fuel into the combustion chamber.

Components of diesel engine fuel systems include

fuel pump

filters

reservoir

plumbing

shutoff valve

check valve

injectors.

Fuel pump

The fuel pump transfers fuel from the fuel tank or reservoir to the engine or engines. Diesel engine fuel pumps may require priming, especially if the fuel tank has been run until empty. To avoid engine damage, the operator

•

•

•

•

•

•

•


should prime both the pressure side and the suction side of the pumping unit.

Filters

A diesel engine fuel system typically has two filters. Once fuel is drawn from the tank or reservoir, it flows to the inlet on the first, or primary, fuel filter. The fuel continues from the primary filter to the fuel pump. Fuel is then sent through the second filter and on to the injectors.

Reservoir

The reservoir, or fuel tank, holds and supplies diesel fuel for use by the engine.

Plumbing (hoses, pipes, and fittings)

Fuel, exhaust, and other materials are carried to various components of the engine through a network of hoses, pipes, and fittings called plumbing.

Shutoff valve (normal kill)

The shutoff valve terminates the flow of fuel from the reservoir to the engine (Fig. 2-12). This mechanism applies to two-stroke Detroit engines. It does not apply to current CAT engines.

Figure 2-12. Shutoff Valve

Shut-off valve

Check valve

The check valve is mounted on the fuel tank to prevent fuel from returning to the reservoir and from losing prime when the engine is shut off.

Injectors

Fuel injection is a method to control the amount of fuel delivered to an internal combustion engine. In the engine, the fuel is burned in air to produce heat.

Fuel injectors are the most important parts of a fuel system. These high-precision devices calculate the right amount of fuel, inject it into the cylinder under high pressure, and atomize the fuel for combustion. Fuel not injected into the combustion chamber cools the injector and returns to the fuel tank through a bypass system.

2.3.2.3 Fuel management systemsFuel management refers to the amount of fuel fed to the injector heads for combustion. The equipment used to force fuel into the combustion chamber not only meters the quantity of fuel required for each cycle of the engine in accordance with the load and speed of the engine, but also develops the high pressure required to inject fuel into the cylinder at the correct instant of the operating cycle. Fuel injection must start and end abruptly.

The two types of fuel management systems used by diesel engines are mechanical fuel injection and electronic fuel injection.

Mechanical fuel injection

A mechanical fuel injection system forces fuel through spray nozzles with fuel pressures of up to 2,000 psi (Fig. 2-13). Typically, the metering rack to the injector controls the amount of fuel that is injected.


Mechanical fuel injection systems require frequent maintenance by a mechanic because of the number of moving parts.

This diesel fuel injection system is an example of a mechanical-type system. As the piston passes the intake ports during the compression stroke, the fuel injector is opened by the eccentric cam. The injector orifice is adjusted by movement of the pivot point in the pivot linkage to control the amount of fuel injected.

Figure 2-13 Mechanical Fuel Injection

Electronic fuel injection

The most efficient method of fuel injection is the electronically controlled system. This method uses a computer to control the timing of fuel delivery and the precise amount of fuel flowing to the injector. Electronic fuel injectors require less maintenance, but they need a qualified mechanic for regular maintenance (Fig. 2-14).

Fine mist

Plunger

To engine

Figure 2-14. Electronic Fuel Injection

2.3.2.4 Lubrication systemsThe primary purpose of the lubrication system is to reduce friction in the engine (Fig. 2-15). Its secondary purpose is to assist in cooling the engine.

Components include the following:

reservoirs/sumps: Reservoirs are the source of oil for the engine and are sometimes referred to as oil pans. Oil is automatically transferred to the

•


crankcase from the reservoir, which holds approximately 7 galUS of oil.

strainers/filters: After oil is pumped from the reservoir, it passes through a filter that removes suspended debris from the oil.

coolers: Heat must be removed from the lubricating oil so that it will retain viscosity and other lubricating qualities. The lubrication cooling system works like a heat exchanger. Oil heated by the engine circulates through tubing in the cooler body or shell and is carried back to the engine.

filter bypass valve: This pressure-regulated valve allows a percentage of the oil pumped from the reservoir to bypass the filter and flow directly to the engine. This is done because filters often become clogged, restricting the oil flow.

oils: Two types of oil are used to lubricate diesel engines. Petroleum-based oils are the most common because of their relatively low cost and availability. Synthetic oils are more effective, but they are more expensive.

Figure 2-15. Basic Lubrication System

Oil filter

Camcase dead space

Oilways

Galleries

Rear bearing seal

Sump“MAX” level on dipstick

Front bearing seal

•

•

•

•

Various factors affect engine lubrication, including engine speed, engine condition, and power demand:

engine speed: High-rpm engine operation creates the need for more lubrication because of increased friction. Low rpm, or low speeds, can also create problems. At idle speeds, the compression ratio is not dependent on rpm’s. Idle speeds can cause incomplete combustion due to lower combustion chamber temperatures. Unburned fuel can wash down the cylinders, leading to increased friction. The least amount of friction is created at mid-range rpm or speeds.

engine condition: Excessive bearing clearance and cylinder wear affects engine lubrication. Oil can collect, leaving residues or preventing other parts of the engine from receiving lubrication.

power demand (engine load): The more load, or power, required from an engine, the more lubrication it needs.

2.3.2.5 Cooling systemsThe intense heat of the diesel engine can physically melt engine components. The cooling system dissipates heat fast enough so that it does not damage the engine.

There are two types of cooling systems: air and liquid cooled systems.

There are diesel engines that use air to cool the engine rather than a water/antifreeze mixture. This method is used primarily in small engines and uses fans and cooling fins to dissipate engine heat.

The engine is cooled by circulating the coolant (a water/antifreeze mixture) through passages around the cylinder heads and walls in the block. A pump creates a flow within the system to ensure positive circulation. The water/

•

•

•


antifreeze mixture collects the heat and flows into the radiator to be cooled. Simultaneously, cooler water replaces the hot water, and another cycle begins.

Cooling system components include the following:

liquid-to-air exchange (radiator): The water/antifreeze mixture passes through and is cooled in the radiator before passing through the engine block.

liquid-to-liquid exchange (tube and shell): In many offshore applications, cooling coils are used in the vessel. These dissipate heat from the engine by circulating engine coolant through tubes that are cooled by seawater.

plumbing: Pipes and hoses are used to circulate coolant from the radiator to the engine.

thermostat: This device controls the flow of coolant in relation to temperature.

pressurization: Pressure on the system is required to move the coolant from the radiator to the engine and back. Pressure also raises the boiling point of the water and antifreeze mixture.

Routine maintenance

The routine STEM (standard equipment maintenance) procedure for diesel engines should include checks of the following:

fuel system: First check the fuel level. Then look for leaks in the lines and connections. Drain a small amount of fuel from the reservoir (making sure not to spill any) to remove any water that may be in the system due to condensation or impure fuel.

air system: Ensure that air can flow unrestricted to the engine by checking the vacuum restrictor gauge.

•

•

•

•

•

•

•

oil system: Check the oil level and oil condition by looking at the dipstick. The oil on the dipstick should have the same overall appearance and be somewhat transparent.

coolant system: Check for adequate fluid levels. Check both the fan and the fan belts for damage, and ensure that the fan can turn unrestricted. Also check the radiator for any leaks or damage.

2.4 TransmissionsThe transmission’s basic function is to allow the engine to operate in its limited range of speeds but to output a broader range of speeds (Fig. 2-16).

Figure 2-16. Transmission

The transmission, in most cases, is connected to the back of the engine and sends power from the engine to other mechanisms. The engine runs best at certain rpm ranges. The function of the transmission is to ensure that the power is delivered to the wheels or pumps while the engine is kept within the optimal range.

Transmissions are divided into manual and automatic. Manual transmissions are equipped with a clutch and a gearshift. The automatic transmission does not have this component, and when it has been put into drive, it

•

•


changes gears automatically. The automatic transmission does have a torque converter.

In this training manual, automatic transmission refers to the transfer of engine torque to other mechanisms. A number of methods are used to transmit the torque, or rotating force, that is generated by electric motors, diesel engines, and gas engines to external devices.

2.4.1 ClutchesAn engine is connected to the transmission via the clutch (Fig. 2-17). The clutch provides a smooth connection and disconnection of engine power flow to the transmission. It is located between the engine and transmission assemblies.

Figure 2-17. Clutches

Many clutches incorporate disks that are brought together to transmit torque.

In a heavy-duty disk clutch, both driving and driven members are used.

Driving members use opposed metal disks and flywheel.

•

Driven members include sandwiched friction or clutch disks and the input shaft of the transmission.

To disengage the clutch and interrupt the flow of power, a release bearing is pushed forward by the clutch fork. When the release bearing contacts the release levers, it causes them to pivot and pull the clutch plate away from the clutch disk. The driving parts now rotate without moving the clutch disk, and power is interrupted.

Spring pressure holds the clutch engaged. When engaged, the clutch springs exert full pressure on the clutch plate, holding the clutch disk against the flywheel.

The force required to activate or control clutches may be supplied by actuators that are

electrical

mechanical

pneumatic.

Electric clutches

Electric current flowing through a field coil activates electric clutches. The current engages and disengages the clutch.

•

•

•

•


Mechanical

Mechanical clutches use linkages and springs to manually engage and disengage. The two basic types of mechanically operated clutches are

standard

over-center.

Standard clutches

With standard clutches, foot motion on the clutch pedal moves through the linkage to the clutch-release-bearing fork (Fig. 2-18). This pushes the release bearing against the clutch release levers, disengaging the clutch. Some clutches use springs, which serve as aids in disengaging, and as return springs when the clutch is engaged.

Figure 2-18. Standard Clutch

Driven-plate assemblyDriving surface

Pressure plate

Clutch springRing gear Clutch cover

Flywheel

Pilot-bearing

Crank shaft

Clutch shaft

Throwout bearing

PedalThrowout

collar

Transmission main gear

Throwout leverLever pivot pointRelease lever

Over-center clutch

The over-center clutch can lock in the engaged or disengaged position without the lever or pedal being continually held (Fig. 2-19). An over-center clutch is used for many power-take-off applications, such as compressors.

•

•

Figure 2-19. Over-Center Clutch

Over-cent clutch

Pneumatic

The pneumatic, or air-actuated, clutch is a double-positioned air cylinder hooked to the shaft that engages and disengages the clutch.

2.4.2 Manual gearboxA manual gearbox is a train of gears that transfers and adapts engine power to the drive wheels or pump of the machine. An operator must engage the clutch and position the gear lever to select speed ratios for various travel speeds or to reverse the direction of travel.

The gears have two or more parallel shafts arranged to

mesh together to provide a change in speed or direction (sliding gear)

remain in constant mesh (collar or synchromesh).

In neutral, the gears are free running. When shifted, they are locked to their shafts.

A special friction clutch called a synchronizer is used to equalize the speed of mating parts before they engage.

In most transmissions, a countershaft allows one set of gears to be shifted without disturbing

•

•


the other gear ratios in the transmission. This method is commonly used when reversing direction (Fig. 2-20).

From engine

Gear selector fork

Countershaft

Idle gear

To differential

Main shaft

Figure 2-20. Single Countershaft (upper) and Twin Countershaft Transmission (lower)

To lubricate the gearbox, an 80/90W oil is typically used. The oil is circulated or applied to the gears by a method referred to as splash sump oiling, which slings oil around the gearbox as some or all of the gears rotate within the sump area.

2.4.3 Power shift transmissionA power shift transmission has positive control on the gears and stays in one gear. This type of automatic transmission is typically used for pumping (Fig. 2-21).

Power shift transmissions are typically used in fracture pumps, among others, when pumping. These controls are such that the transmission will not down-shift once set, allowing the operator control of the pump speed.

Automatic transmissions have no clutch that disconnects the transmission from the engine; they use a torque converter.

Figure 2-21. Transmission

2.4.4 Torque converterA torque converter is a large donut-shaped device that is mounted between the engine and the transmission (Fig. 2-22). It transmits power to the transmission. It allows the engine to spin somewhat independently of the transmission. By inputting rpm, the engine speeds up and pumps more fluid into the torque converter, causing more torque to be transmitted to the wheels or triplex pump.

Figure 2-22. Torque Converter in Relation to the Whole Transmission

Forward clutch Fourth

clutch

Torque converter

Third clutchSecond clutch

First clutch

Low clutch

Speedometer drive gear

Lockup clutch

Modulated lockup valve (optional)

Converter-driven power takeoff drive gear

Oil filterControl valve body

Governor-driven gear

MT 653DR

The automatic transmission of an automobile uses a torque converter to shift gears in response to torque requirements. A gear train is used with the torque converter to provide extra speed ranges. Acting as a clutch, the torque converter connects and disconnects power between the engine and the gear train. As a transmission, the converter gives many more


speed ratios than are practical with a strictly mechanical gearbox.

Torque converters allow the following modes:

lock-up mode: The torque converter acts as a simple fluid coupling, sending the same torque it receives to the drive wheels. Input rpm cannot be exceeded.

free-wheeling mode: Input rpm can easily be exceeded by means of a device called a stator. A stator acts as a fluid lever or fulcrum to multiply torque for output.

The lock-up type converter includes an additional mechanical clutch and must achieve 1,400 to 1,600 rpm for lockup. This type of converter is best for prolonged and pump operations but is undesirable for testing procedures.

The figure below shows the torque converter in relation to the whole transmission.

2.4.5 Couplings

A coupling connects two ends of shafts in the same line, transmitting power (or torque) from one shaft to the other. This connection results in synchronized rotation for the shafts at the same rpm.

Shafts are joined with a coupling for the following reasons:

to join units that are in different locations or that are more convenient to handle as smaller units

to join standard units to accomplish a special purpose

to allow for misalignment of the shafts

to reduce the transmission of shock or vibration

to rapidly connect or disconnect the shafts as required by the operation of the machine

•

•

•

•

•

•

•

to allow for axial motion of the connected shafts caused by thermal expansion.

To meet these different requirements, various types of couplings are used, for example:

U-joint

metallic grid-type coupling

jaw-type electrometric coupling with spider

electrometric donut-type coupling, clamped or restrained.

Direct couplings

A direct coupling is a direct or uninterrupted connection between an engine and the device it powers (Fig. 2-23). An example of direct coupling is the power-take-off device used to drive centrifugal pumps on many Schlumberger skid units.

Flange yoke

Journal and bearing Sleeve yoke

Slip tub shaft

Tubing

Stub yoke

End yoke

Slip u-joint Permanent u-joint

Figure 2-23. Direct Couplings

Flexible couplings

If two shafts joined by a coupling are not in perfect alignment, stresses are induced due to bending. These stress greatly reduce the life of shafts and cause an additional load on the bearings that support the shafts. Consequently, a flexible coupling (Fig. 2-24) is typically used to join shafts of two units, such as a motor and a pump. Flexible couplings not only permit axial and radial misalignment, but they also provide vibrational dampening and overload protection. One drawback of flexible couplings is the requirement for close-proximity mounting.

The vee of a flexible joint is a universal joint, like the drive shaft in a car. The joint ends of the

•

•

•

•

•


shaft are U-joint yokes. They join together and are flexible. This flexibility allows side-to-side and up-down movement while still transmitting torque.

Figure 2-24. Flexible Coupling

2.4.6 DrivelinesThe driveline transmits torque smoothly to the vehicle’s driving wheels. In front-wheel-drive vehicles, the driveline connects the transaxle assembly to the front driving wheels. In rear-wheel-drive, the driveline connects the transmission to the rear-driving axle.

Driveline variations include the following:

standard universal joint: This joint transmits rotary motion from one shaft to another shaft at varying angles. This type of joint allows a vehicle wheel to move up and down, as well as to turn corners.

constant velocity joint: This joint also permits each shaft to maintain the same driving or driven speed, regardless of operating angle.

•

•

2.4.7 Routine maintenance of transmissions

When checking the automatic transmission fluid level, do the following:

Check for leaks or stains under the unit or vehicle. If there is a persistent red oil leak below the unit or vehicle, check the transmission fluid and monitor often. If the fluid levels are below minimum levels, serious damage can occur.

Perform the check at a normal operating temperature.

Check oil levels by removing the level indicator plug on the side of the gearbox. Some manual gearboxes are equipped with a dipstick.

Check the color and odor of the fluid. It should look transparent and red.

Make sure the unit is level.

Shift through all the gears, put the unit into neutral, and drop it down to idle.

Monitor new noises, vibrations, and shift behavior. If shifts are erratic or noises are heard while shifting, have the unit checked by a mechanic. Problems can be solved with no costly repairs if they are detected early.

•

•

•

•

•

•

•


3.0 Basic Pneumatic Systems

Pneumatics deals with the use of compressed or pressurized gas or air as a source of power. Air is extremely compressible, elastic, and capable of absorbing large amounts of potential energy. Once compressed, it exerts an outward force, much like a coiled spring.

At Schlumberger, compressed air is used to move diaphragms and pistons and to fluidize and carry bulk solids such as cement and sand. For example, in air silos (Fig. 3-1), compressed air is used to pressurize the vessel and push the cement through the lines.

Figure 3-1. Silos

3.1 Types of pneumatic systemsThere are three categories of pneumatic, or air systems:

high-pressure/low-volume systems

high-pressure/high-volume systems

low-pressure/high-volume systems.

High-pressure/low-volume systems operate at a pressure range of 90 to 120 psi and have system charge rates of 10 to 15 ft3/min. These

•

•

•

systems are found on many Schlumberger trucks and are used to power brakes (Fig. 3-2), horns, and cab tilt controls, and to start deck engines.

Figure 3-2. Power Brakes

High-pressure/high-volume systems operate at pressure ranges between 100 and 110 psi at system charge rates of 250 ft3/min. Schlumberger uses this type of system only in liquid additive system (Fig. 3-3) applications such as fracturing or cementing.

Figure 3-3. Liquid Additive Systems

26 | Basic Pneumatic Systems

Low-pressure/high-volume systems operate at pressure ranges of 7 to 30 psi and system charge rates of 65 to 600 ft3/min. These systems are typically used to convey and fluff bulk materials such as sand and cement. Because of their dangerous potential, low-pressure/high-volume systems typically include relief valves, overpressure shutdown valves, and rupture discs.

3.2 Parts of pneumatic systemsMost pneumatic systems, regardless of their volume capacities and pressure ranges, contain very similar basic components. Figure 3-4 shows the basic components of the pneumatic system.

Figure 3-4. Pneumatic System Components

Compressor

Air tank

Check valve

Pressure release valve

Drain cock

DryerUnloader

Governor

The compressor is a motor that compresses air from the atmosphere and discharges it through a heat-resistant line to a check valve and into the tank. The line must be able to withstand high temperatures because engine and compressor heat is transferred to discharge air during compression.

Even though the lines are heat resistant, they may crack or leak, causing a loss of line pressure. If a crack or leak does occur, the check valve acts as a shut-off device. It

permits flow in only one direction: from the compressor to the tank. If pressure is lost on the compressor side, the check valve will shut off flow, maintaining pressurized air in the tank.

Downstream from the compressor’s discharge valve, a governor is fed system pressure. The governor is set to respond to excess system pressure and will trigger the unloader to release compressor pressure when the preset level is reached.

The air tank, or reservoir, is outfitted with a popoff valve and drain cock. The popoff valve remains closed unless the tank pressure reaches a predetermined level, at which point it will open to release the excess. The drain cock is used to remove condensation and air from the air storage tank, but only when the unit is not operating.

From the tank, air flows through a dryer, which removes moisture from the system while it is in operation. When the governor signals the unloader to release pressure from the compressor, it also signals the dryer to release accumulated moisture.

3.3 Pneumatic systems componentsThe pneumatic system is composed of a compressor, blowers, air reservoirs, governors, pressure-relief valves, check valves, drain cocks, dryers, and lubricators.

3.3.1 CompressorCompressors can be found in either high-pressure or low-pressure systems (Fig. 3-5). Compressors installed on Schlumberger trucks are driven by

belts

gears

power take-offs.

•

•

•


Figure 3-5. Compressor Unit

Belt-driven compressors are powered by a dedicated diesel engine or may be connected to a hydraulic motor mounting on the engine of a truck.

Meshed gear assemblies are driven by a directly geared mounting to the truck engine.

Power take-offs, also called PTOs, also are powered by the truck’s engine, but not by a direct connection. Found on most bulk equipment, this type of compressor requires a method of engaging or disengaging the power source. This is typically accomplished manually or through the use of a clutch.

Compressors are sometimes cooled by the engine’s cooling system. Either air or a combination of water and antifreeze can serve as the coolant, according to the type of compressor and engine used. Other air compressors are cooled only by air, and these have a fan connected to them to circulate air across the outside of the cylinders.

The engine may also lubricate the compressor. The compressor is connected by a hose to the engine’s lubrication system, allowing the oil to flow into the top of the compressor and down through system components. In a meshed

gear compressor, oil flows through the direct gear connection into the compressor, internally lubricating the system. Other compressors have their own dedicated oil lubrication system, very similar to that of an engine.

Parts of a compressor

A compressor includes these basic components:

intake valve

discharge valve

piston

rod

flow line to and from the governor

unloader poppet

plunger

air filter

line to the reservoir or tank for holding the compressed air.

The compressor components for a high-pressure/low-volume system are nearly identical to those of a low-pressure/high-volume system. The only difference is the position of the intake or suction valve. On a high-pressure system, this valve is typically mounted on the side of the compression chamber, whereas on a low-pressure system it is mounted on top of the chamber next to the discharge valve.

Compressor cycle

A compressor goes through stages, during a complete cycle:

intake stage, when air is drawn into the cylinder or chamber

compression stage, when air is compressed in the chamber and discharged to the reservoir

unloading stage, when any unnecessary pressurized air is unloaded.

•

•

•

•

•

•

•

•

•

•

•

•


Intake (suction) stage

During the intake stage, the piston travels downward, opening the intake valve (Fig. 3-6).

Figure 3-6. Compressor

As air is drawn into the chamber, the exhaust valve is closed so that air does not escape. At this point, the air pressure has not reached the upper limit, and therefore the compressor continues to run.

Exhaust (compression) stage

During the compression stage, the intake valve closes and the piston starts moving upward, building air pressure in the chamber (Fig. 3-7). The pressure causes the exhaust valve to open, forcing air into the system and into the reservoir.

At this point, the governor (pressure regulator) senses an increase in pressure but does not force the system to unload or shut down because the system has not reached maximum operating pressure.

IntakeAir is drawn intothe cylinder or chamber

CompressionAir is compressed inthe chamber and dischargedto the reservoir.

UnloadingAny unecessary pressurizedair is unlocked.

.

Figure 3-7. Compressor Cycle

Unloading stage

The unloading stage occurs when the system has finally reached maximum operating pressure. The governor (pressure regulator) sends system pressure to the unloader, forcing the system to unload to the atmosphere or to shut down the compressor.

During this stage, the exhaust valve is closed. Air is expelled (and drawn in) with each cycle of the piston through the intake manifold. Because the piston is not compressing during the unloading stage, the cylinder temperature drops, which allows the compressor to cool.

3.3.2 BlowersAlthough compressors are an integral part of most pneumatic systems, blowers are often used in applications requiring low pressure. Blowers are sized for the application and typically range in delivery from 250 to 400 ft3/min. Blowers typically deliver about 400 ft3/min of air at a maximum pressure of 7 to 10 psi. They are most often powered by hydraulic deck motors and include brands such as Roots


or Hibon. A typical blower application is silo aeration (Fig. 3-8).

Figure 3-8. Silo Aeration

3.3.3 Air reservoirs (tanks)Air reservoirs, or tanks, are used to store various volumes of pressurized air (Fig. 3-9). One compressor may feed into a single reservoir or multiple reservoirs. This allows multiple functions to be performed by a single compressor. For example, many trucks use only one compressor to feed separate tanks for the brake and auxiliary air systems.

Figure 3-9. Air Reservoirs

For safety reasons, reservoirs must be rated to handle higher pressures than those normally associated with the system. They must also be equipped with safety devices, such as a popoff

valve, which opens and releases pressure once a preset level is achieved.

There is also a drain valve, mounted on the bottom of the tank, which is used to drain accumulated condensation from the tank.

3.3.4 Governors (pressure regulator)The governor plays an essential role in maintaining maximum and minimum system pressure (Fig. 3-10). It is an adjustable device that can be set to trigger the unloader when system pressure falls outside a preset range. The reservoir or system line downstream of the compressor’s discharge valve is connected to the input of the governor, whereas the output of the governor flows (when triggered) to the unloader.

If, for example, the governor is set to a maximum of 120 psi and system pressure climbs to that preset level, the governor will allow system pressure to flow to the unloader, which in turn releases pressure, thereby returning the system to its normal operating range.

The governor also helps control the function of the intake valve, thus allowing the compressor chamber to operate in a zero-pressure state. This reduces heat when a charge is not required.


Figure 3-10. Governor

Reservoir

Unloader

3.3.5 Pressure-relief valvesMost reservoirs are equipped with pressure-release or popoff valves that relieve excess pressure from the air-storage container (Figs. 3-11 and 3-12). They protect the system in the event of a governor failure and, like a governor, can be adjusted to respond to a range of pressures. The operation of a popoff valve is fairly simple. A needle is held in place by an adjustable spring over a small port. If the spring is set to 120 psi and the tank air pressure rises to that level, the spring will allow the needle to be pushed back, opening the port and releasing pressure.

Figure 3-11. Pop-Off Valve

Figure 3-12. Pressure-Relief Valve

Popoff valves are frequently a source of leakage in the air system. They can collect debris around the needle and port, especially if located in a position other than on top of the reservoir.


3.3.6 Check valvesCheck valves, which are located between the compressor and reservoir inlet, seal the tank or reservoir in the event of an upstream failure (Fig. 3-13). If the compressor fails, system pressure will be maintained in the tank because the check valve seals the tank and prevents pressurized air from backing up. This safety feature is especially important in systems such as truck brakes, where a total system failure could be catastrophic.

Figure 3-13. Check Valve

3.3.7 Drain cocksDrain cocks are valves that allow condensation and air to be drained from the reservoir (Fig. 3-14). They are typically located at the lowest point on the reservoir and should be opened for drainage before and after each operation.

Figure 3-14. Drain Cock

3.3.8 Dryers (water separators)Dryer, or water separators, remove water vapor and contaminants from the air system downstream from the reservoir (Fig. 3-15). On cementing trucks, the dryer is located behind the operator’s console.

Unlike the drain cock, the dryer functions continuously. The dryer also offers finer filtering than the drain cock because it uses micro-fine media to remove moisture from micronic particles, fumes, and compressor oil.

A regulator is attached to the dryer to control filtering levels, and a drain is on the bottom of the dryer. The drain is either a rubber, needle-type valve or a screw-type valve that must be removed for drainage.

It is essential that the dryer be serviced frequently to remove moisture and clean the filter media.


Figure 3-15. Dryer

Regulator

Water separator

Drain

3.3.9 LubricatorsAfter the compressed air leaves the dryer, it passes through the air lubricator (Fig. 3-16). The air lubricator injects a fine mist of oil into the air, which lubricates downstream components.

On air systems used for fluidizing bulk materials such as cement, this lubrication method is not used because the downstream components do not require lubrication and because the oil would contaminate (clog) the fluidizing systems used on most bulk handling equipment.

The lubricator has an adjustable regulator that should be checked regularly to ensure that the unit is providing adequate oil or lubrication per volume of air. There is also a sight glass that provides a quick visual check of oil level. It is the operator’s responsibility to add oil when needed.

It is important to service the lubricator regularly to ensure equipment longevity.

Figure 3-16. Lubricator

3.4 ApplicationsHigh-pressure/low-volume pneumatic systems are used in many ways. Here are the most common applications:

brakes

tractor protection valves

front brake limiting valves

clutches

gear shifts

power divider lock control

parking brakes

dash gauge warning buzzer

air cylinders

pumping equipment.

•

•

•

•

•

•

•

•

•

•


3.5 SafetyWhen working with pressurized air, make sure that you follow basic safety policies:

Never work on vessels that are pressurized. Also, make sure you never hammer on tanks or reservoirs. If you need to check the product level of a vessel, use your hand to tap on the side of the tank to determine its product level.

A pressure of 30 psi found in low-pressure systems can be very dangerous since these systems develop tremendous forces because of their large tank areas. These tanks can explode if pressures become even slightly excessive.

Never remove air components or plugs until you are sure all air pressure has been bled from the system. Do not rely on gauges only. They can become stuck, or you could be monitoring pressure from a point upstream of components under pressure. Open the popoff or other valves to make sure there is no pressure in the system.

Never look into jets or aim air at someone. Debris or just pressurized air by itself can cause serious injury.

Some components contain powerful springs. Be sure to disassemble them properly to avoid injury. Vehicle brakes contain spring elements that could injure someone if not properly removed.

Service pressure-release valves (popoffs) regularly. These valves release excess pressure in the system. If they become stuck or nonfunctional, the system can cause serious damage and injury.

•

•

•

•

•

•




4.0 Basic Electrical Systems

Schlumberger uses electricity to power starter motors, lighting systems, instruments, data acquisition systems, ignition systems and even to control valves in hydraulic systems. This section covers some of the basic terms and components used in electrical systems. Most of these electricity basics deal with direct current (DC). DC circuits are the foundation of Schlumberger mobile and skid-mounted equipment.

4.1 Basic circuitAn electrical circuit can be compared to a water circuit (Fig. 4-1). Imagine that you want a cup of water and have gone to a nearby faucet.

If you turn the knob to the open position, water begins to pour out.

This simulates an electrical circuit and current flow. How?

Figure 4-1. Basic Electrical Circuit

Negative terminal

Wire conductor

Positive terminal

Incandescent lamp

Switch

Conductor

Insulation

•

•

The water is equivalent to the current (the electrons). The knob is the switch. The water pipe is the circuit (Fig. 4-2).

Figure 4-2. Water Pipe Circuit

When you turn on the water, you switch the current on to allow the current to flow. The current flows because of the potential pressure difference: on one side of the valve of the faucet there is no pressure, and on the other side there is water pressure. This difference makes up the voltage, or electromotive force, sometimes referred to as EMF.

To continue the comparison, the resistance is the size of water lines and the openings on the

34 | Basic Electrical Systems

valve and the end of the faucet. This resistance determines how much water will flow in a given time. The smaller the pipe opening is, the more resistance there will be to the water flow.

In an electrical circuit, the smaller the wire is, the more resistance there will be to the current flow; the wire and components determine how much current will flow in a given time; this current is known as amperage.

Note:Electricity is not just something supplied by batteries and used up in a light bulb. It is a form of energy that circulates and requires a complete circuit to flow.

Refer to the Figures 4-1 and 4-2 for a comparison of a basic electrical circuit and a water pipe circuit.

4.2 Electric currentCurrent is the flow of electrons in an electric circuit. Flowing water is a good analogy of electricity. When water flows through a pipe or down a stream, there is a current. Sometimes the current flows faster than normal, and sometimes it flows more slowly. If you measured how fast the water current was flowing through a pipe with a flowmeter, you would measure the flow by so many gallons per minute.

When a coulomb (C) of electrons (1 C=6.24 billion-billion electrons) passes through a wire in 1 second, that is 1 ampere of current. An ampere is the basic unit of electric current. It is sometimes referred to as an amp. Amps are abbreviated with an “A” (e.g., 1 ampere = 1 A). Since electrons or coulombs of electrons are not visible, an ammeter is used to measure electric current (Fig. 4-3).

Figure 4-3. Examples of Amperage

Conventional current

When Ben Franklin discovered electric current, he had no idea that electrons existed. Having a positive attitude, he arbitrarily said that current flowed from positive to negative. Much later, scientists discovered that current was a flow of electrons and that the electrons traveled in the opposite direction, that is, from negative to positive. In the late 1960s, only a few textbooks and school curricula taught negative-to-positive current flow. In fact, today most of the world is still using Franklin’s conventional current flow theory, that is, positive to negative, to explain and dissect electrical circuits. No matter which way the current flows, it still produces the same amount of work (Fig. 4-4).


Figure 4-4. Current Flow

When connecting electrical devices, be very careful. Connect positive to positive and negative to negative. Otherwise, the device will smoke and then stop working.

4.3 VoltageWater flows through a pipe because of water pressure. Water pressure forces the water to flow. Likewise, electromotive force is the pressure that forces electrons to flow through a circuit. Electromotive force is also known as voltage. The basic unit of electromotive force is the volt (V). In formulas, volt is sometimes abbreviated E (for energy).

If you wanted to measure how much voltage a circuit or battery has, you would use a voltmeter (Fig. 4-5).

In a house, wires in the walls carry electricity to lights, plugs, and appliances. The voltage in those circuits (if you live in the U.S.) is about 120 V. Likewise, in a typical American automobile or Schlumberger unit, a battery runs the electrical systems. The voltage of that battery is about 12 V (Fig. 4-6).

Voltage can be considered the pressure in the system. The more pressure there is, the more current is forced through a system.

Figure 4-5. Voltmeter

Figure 4-6. Battery Components

Potential difference (in volts)

Positive terminal

Negative terminal

Electrons flow through the circuit due to voltage pressure

Return of electrons

The increase in force (pressure) caused by the voltage is called the electromotive force (EMF) provided by the battery

Electrons

Positive ions

4.4 ResistanceIn the same way that only a certain amount of water can flow through a pipe, only a certain amount of electric current can flow in a circuit.

Water is limited by the amount of friction it encounters as it flows. Electricity is limited by the amount of resistance it meets as it passes through a circuit.

However, if you increased the water pressure in a pipe, more water would flow. Likewise, if you turned up the voltage, more current would flow. Resistance limits the current that


flows through a circuit for a particular applied voltage (Fig. 4-7). The resistance of a material is directly proportional to its length. Therefore, reducing the length reduces the resistance. A long wire will have a higher voltage drop across it (due to the larger resistance) than a short wire. So, a long extension cord that is used for an electrical appliance that draws a large current will need to be made of heavier (larger cross-sectional area) gauge wire than a shorter extension cord.

Figure 4-7. Resistors

The basic unit of resistance is the ohm. One ohm can be written as the Greek letter “omega.” An ohmmeter is used to measure the amount of resistance in a circuit. Resistance, or impedance, is the opposition to the pressure applied and is measured in ohms.

4.5 Power (wattage)

When discussing electricity, you often hear the term wattage or watts. Wattage is the amount of power that a device uses. This is an instantaneous value and does not have time attached to it. Watt-hours or kilowatt-hours is the amount of energy consumed over time; 1,000 watthours (W-hr) = 1 kilowatthour (kW-hr). A watt is a unit of electrical power (P).

A 1-volt circuit with a 1-amp current flow has 1 watt of electrical power. The power

companies sell electricity by the kilowatt-hour (kW.h). Electrical appliances and components are rated in watts or kilowatts. Light bulbs are rated at 60 W and 100 W, and hair dryers are rated at 1,600 W.

4.6 Ohm’s law and power formulaAlthough there are literally thousands of formulas, for a simple circuit you need to remember two only: Ohm’s law and the power formula.

Ohm’s Law: E = I x R

Ohm’s law, states that E = I x R (or electromotive force in volts = intensity in amps times resistance).

Those who are good at math games already know that you can change the formula to read R = E/I or I = E/R.

The formula is sometimes taught as a magic circle.

E – Voltage (ELECTRICAL PRESSURE)

I – Amperage (CURRENT FLOW)

R – Resistance (OPPOSITION TO CURRENT FLOW)

If you change one of the three components of the equation, you will affect only one other component. For example, increase the voltage without changing the resistance, and the amperage will increase. Lower the resistance


without changing the voltage, and the amperage will increase.

Note:You cannot change the amperage by itself because amperage is a function of voltage over resistance: E / R = I.

Power formula: P = E x I

The power formula states that P = E x I (or power in watts = volts times amps).

The formula can also be changed to either E = P/I or I = P/E.

Light bulbs are rated in watts; the higher the wattage, the brighter they are. To shine brighter, a bulb has to draw more current (amps); the same is true in your house. A 60-W bulb draws ½ A in a 120-V system.

To find the current draw, using the power formula and you have I = P/E or 60/120 = .5 AMP.

A 100-W bulb draws almost 1 A (100/120 = .83 A).

A baseboard heater of 1,500 W draws 12.5 A (1,500/120 A =12.5 A).

A toaster rated at 600 W draws about 5 A. A kettle rated at 1,500 W draws 12.5 A. The two together draw 17.5 A. Circuit breakers are usually rated at 15 A, so these two appliances used together would trip a breaker.

Why do you need to remember these formulas? Suppose you are required to add two additional work lights to a truck or skid-mounted unit. The formulas will help you determine the electric current and thus the wire size you will need. In

addition, it will also help you determine what fuse size is required.

4.7 Conductors and insulatorsElectricity flows through some materials easily. These materials are called conductors. All conductors have some resistance. Most conductors are metals. Any metal will conduct electricity.

Gold, aluminum, mercury, and copper are the most efficient conductors of electricity. Gold is very expensive. Aluminum is inexpensive but has a corrosive nature. Mercury is difficult to contain. Copper is relatively inexpensive and only mildly corrosive (Fig. 4-9).

Figure 4-9. Conductivity in Different Materials

Highly conductive material Poorly conductive material

Conductors are used in electrical applications to support current flow, just as pipes are used to conduct fluid or gases. The flow in a wire is supported by a solid conductor such as copper. Copper is the most commonly used material to carry electricity. Copper is also flexible, which adds to its usefulness.

Insulators are materials that do not let electricity flow easily through them. Four good insulators are glass, air, plastic, and porcelain (Fig. 4-10).


Figure 4-10. Conductor and Insulator

4.8 BatteriesA battery is an electrical reservoir from which a system such as a pumping unit draws electrical power. It is charged or refilled with a charging device.

The heart of the Schlumberger mobile and skid-mounted electrical system is the battery. There are different types of batteries: lead acid, gel cell, and other newer batteries (Fig. 4-11).

Figure 4-11. Truck Battery

A lead acid battery (the same as in a car) contains a mixture of water and sulfuric acid in very specific proportions. The sulfuric acid reacts with the lead plates in the battery to produce electricity. As the chemical reaction continues, lead sulfate forms on the lead plates, and the amount of sulfuric acid gradually decreases as the battery discharges.

Charging the batteries transforms the lead sulfate back into sulfuric acid, and the mixture (electrolyte) is restored almost to its original level. All batteries and cells require an electrolyte.

An electrolyte is a chemical that acts on one or both of the electrodes to provide the chemical action necessary for current flow. The electrolyte can be in liquid (wet), paste (dry), or gel form.

When this process is repeated many times, lead sulfate gradually builds up on the plates, and the amount of sulfuric acid in the electrolyte decreases. This decrease lessens the ability of the battery to take a full charge and therefore to produce electricity.

When a battery is recharged, some of the water (H2O) in the electrolyte is transformed into hydrogen (H2). and oxygen (O). These gases, which can become explosive, escape through the breather holes of the battery. This is why you must add water. (There is no such thing as a maintenance-free battery.) It must also breathe to prevent a pressure buildup.

Ideally, a battery should be recharged at 13.75 V to 14.25 V to achieve its fully charged voltage of 12.5 V to 12.6 V. If the charging voltage is higher than 14.25 V, more water will be transformed into hydrogen and oxygen, and more frequent topping up with water will be required. In this case, check the output voltage of the alternator while it is charging the battery. When topping up, add distilled water until the plates are covered, plus about ¼ in.


If the charging voltage is much lower than 13.75 V, the battery will not reach its full charge capacity. Follow all safety precautions when performing this activity, and refer to the battery maintenance section.

If the alternator output is normal but you find that the battery is always weak, check each cell with a hydrometer (cost, about USD 5). The hydrometer measures the specific gravity of the electrolyte in each of the six cells. A low specific gravity indicates that the proportion of water to acid is too high. This means that the battery needs to be charged more to turn the lead sulfate into sulfuric acid and thereby restore the proper water-to-acid ratio in the electrolyte. If the specific gravity is still low after a 24-hour charge from a battery charger, the battery is probably worn out (the plates are sulfated). Take the battery to a qualified battery shop to have the battery tested.

A worn-out battery can still indicate 12.5 V with no electrical load on it. Turn on three or four cabin lights for about 15 minutes, and then turn them off and recheck the battery voltage. If the battery voltage has decreased to below 12 V, the battery is probably worn out. If the specific gravity in one cell is low but normal in the others, it indicates a problem with that cell (sulfated or damaged plates), and you probably need to replace the battery. Take it to a qualified battery shop and have the battery tested (Fig. 4-12).

Figure 4-12. Battery Hydrometer

Batteries are rated in amp-hours, cold cranking amps (CCA), marine cranking amps (MCA), and reserve-minute (res/min) amp-hours.

A rating of 100 A.h means that a battery can deliver a steady 5 A for a period of 20 hours (5 X 20 = 100 A.h) or 10 A for 10 hours before the battery voltage drops to 10.5 V. This testing method is used to compare batteries:

CCA: The number of amps a battery can deliver for 30 seconds at 0 degF before the battery voltage drops to 7.2 V. This is an automotive rating.

MCA: The same as CCA but measured at 32 degF. It is always higher because a warm battery always delivers more power than a cold one.

Res/min: A rating of 180 means that the battery can supply a steady 25 A for 180 minutes (3 hours), before the battery voltage drops to 10.5 V. This also means that it can supply a load (i.e., two cabin lights and a stereo) of 5 A (1/5 of 25 A) five times longer, or 15 hours. The voltage rating is the same for all batteries, whether the battery is a deep cycle, a starting, or a car battery. The only thing that varies is the amperage ratings.

Schlumberger units may have more than one battery system to supply power to different portions of the unit and to keep one system from affecting the other. For example, one batch of batteries would supply the data-acquisition portion of a unit, and a second batch of batteries would supply the basic starting and work lights system.

In many cases, a system may be required to deliver more electrical energy than one battery can provide. At Schlumberger, unit batteries are usually connected in parallel to provide 12 V and a higher current capacity. These batteries have all positive terminals connected and all negative terminals connected.

•

•

•

•


In contrast, batteries connected in series (connected end to end or positive to negative) are additive, providing a higher voltage than the current capacity of a single battery (Fig. 4-13).

Figure 4-13. Voltmeter

Battery maintenance

To ensure that plenty of power is available when needed, proper battery maintenance is essential. Keep batteries fully charged at all times. If there is a drop or lack of power when starting, charge a battery to its full capacity when possible.

Use this checklist for routine secondary (rechargeable lead/acid) battery maintenance:

Check the fluid levels in the battery periodically, and use distilled water to replenish the fluid.

•

Warning:Wear safety glasses when working with a battery. The electrolyte in a battery is a mixture of sulfuric acid and water that can damage vehicle paint and burn your skin or eyes if spilled. A battery also vents explosive hydrogen gas, especially when charging. Keep all sparks and flames away from a battery. Remove metallic watches, rings, and necklaces or chains to avoid contact with battery terminals and possible electrical arcing. Use tools with insulated handles when servicing a battery.

Keep the battery terminals clean and clear of buildup that can corrode the cables.

Check to ensure that terminal connections are tight.

Check the condition of the entire cable, not just the area near the battery, to verify that there are no exposed wires or cracks in the insulation.

Protect the battery from extreme temperatures.

Do not overcharge a battery.

Do not let two-way radio and computer batteries run down completely.

Frequently charge and discharge nickel cadmium (NiCd) batteries to prevent memory effect. This effect is a condition in which the batteries do not recharge above the level of their first recharge, which could be below their full capacity.

To check an automobile battery, turn on the lights and start the engine. If the lights go out or dim excessively, the battery may be weak and

•

•

•

•

•

•

•


in need of a charge. There also could be loose connections.

Jumping a dead battery

If an automotive battery fails to provide adequate power and requires jumping (Fig. 4-14), follow this procedure:

STEP 01 Put on rubber gloves and goggles.

STEP 02 Connect the positive terminal of the charged battery to the positive terminal of the dead battery. The positive terminal usually has a red wire on it. Check the color code or embossed plus (+) and minus (-) signs.

STEP 03 Connect the negative terminal of the charged battery to a grounding point on the vehicle with the dead battery. The negative terminal has a black wire on it. Make this connection far enough from the battery so that a spark will not ignite the hydrogen gas generated by the lead/acid battery.

STEP 04 Do not stand near the battery when the engine is cranked.

STEP 05 After jumping the battery, disconnect the cables. First, remove the cable from the negative terminal, which is connected far enough from the battery so that a spark cannot ignite the hydrogen gas generated by the lead/acid battery. Never make a spark close to this type of battery because an explosion could occur.

Figure 4-14. Jumping

4.9 Generators and alternatorsAutomobiles have an electrical system that powers the headlights, cooling fans, radio, etc. The source of the power is the fuel. The link from the fuel tank to the battery is the alternator. The alternator converts the power from the fuel to electrical energy.

Generators

Before about 1970, most cars and marine engines were equipped with a generator that produced direct current (DC). A generator uses magnetism to produce electricity. A generator or alternator consists of a loop of wires placed so that the loop can be rotated in a stationary magnetic field (stator) to cause an induced current in the loop. This loop contains a multitude of wires (rotor). In a generator, a commutator and brushes are used to connect the loop of wires to an external circuit.

A generator can be compared to an electric pump. The faster it turns, the greater is its output in terms of voltage (electrical pressure) and, thus, current. At idle speed, the earlier generator produced barely enough voltage to


prevent the red generator warning light on the vehicle’s dashboard from turning on.

If you connected a generator directly to a battery, it would become a motor, just like the starter motor. Electric cars use that principle. When the accelerator pedal is depressed, the battery powers the DC motor; when the pedal is released, the motor becomes a generator and recharges the batteries.

In an alternator, slip rings and brushes are used to connect the loop to an external circuit. In a generator, a commutator and brushes are used to connect the loop to an external circuit.

Alternators

In the 1970s, with the advent of the semiconductor and solid state electronics, the alternator displaced the generator because it could produce more power at low rotational speeds. It was also smaller, lighter, and more powerful than the generator. An alternator initially produces alternating current (AC) (Fig. 4-15). Before this AC current can be used by a marine or land-based electrical system, it must go through a rectifier and a voltage regulator. Unlike DC, which has a constant polarity, AC has a polarity that continually reverses itself (alternates).

Figure 4-15. Alternator

The center part of the alternator (the rotor) contains electromagnets with north and south poles on each magnet (positive and negative). The stator surrounding the rotor contains coils of wire. As the rotor turns inside the stator, both the north and south poles of the electromagnets are induced alternately, first a positive and then a negative voltage, thus the alternating current in the stator coils.

Because AC cannot be used by the electrical system, it must go through a rectifier, where it is changed into DC (Fig. 4-16). This DC is not pure like battery power; rather, it is a slightly rough DC form acceptable to the electrical system. The rectifier contains diodes, which are electrical one-way valves that allow current to flow only if the current has the proper polarity. This converts the negative phase of the AC into a positive phase. The result is a rapidly pulsating (rough) DC, rather than pure battery DC power.

Figure 4-16. DC and AC Current Flow

After the output has been rectified, it goes through the solid state (no spring or contacts) voltage regulator, which performs the same functions as the generator voltage regulator.

The ends of the rotor are connected to the slip rings, which rotate with the armature. Brushes ride against the slip rings to pick up the


electricity generated in the armature and carry it to an external circuit.

Alternators like the ones used in most cars to maintain battery charge are smaller units that provide output at slower speeds.

The following is a checklist of the tasks required to keep an automotive alternator performing smoothly. These checks are generally performed by maintenance personnel:

Check for the proper drive belt condition and tension.

Keep connections clean, tight, and protected from heat.

Check the output voltage to make sure a positive output is maintained.

4.10 Regulators, breakers, and fusesThe voltage from an alternator can be varied by changing the speed of the prime mover. The internal resistance of the generator windings (the coils of wire) also causes the output voltage to vary with the load. Under many circumstances, these voltage changes are undesirable; therefore, a voltage regulator is used.

Circuit breaker

A circuit breaker is a circuit control device that is designed to open the circuit if the current exceeds a predetermined value (Fig. 4-17). The two types of circuit breakers are magnetic and thermal.

In magnetic circuit breakers, the current is sensed by a coil that forms an electromagnet. When the current is excessive, the electromagnet actuates a small armature that pulls the trip mechanism to open the circuit breaker. In thermal-type circuit breakers, the current heats a bi-metallic strip. The two different metals in the strip expand at different

•

•

•

rates, causing the strip to bend and allowing the trip mechanism to operate.

Figure 4-17. Circuit Breakers

Most circuit breakers require a manual reset. When tripped, they must be manually closed. For most applications, the magnetic circuit breaker is superior because the trip point does not change after many cycles. The thermal circuit breaker’s trip point changes as a result of metal fatigue.

Fuses

The simplest protective device is a fuse. All fuses are rated according to the amount of current that is safely carried by the fuse element at a rated voltage (Fig. 4-18).

Fuses are components that use special metals with very low resistance values and low melting points. They are designed to melt and thus open the circuit when the current exceeds the fuse’s rated value. When the power consumed by a fuse raises the temperature of the metal too high, the metal melts and the fuse blows.


Figure 4-18. Typical Household AC Fuses

The two types of fuses in use today are conventional fuses and slow-blowing fuses. Conventional fuses blow immediately when the circuit is overloaded. Slow-blowing fuses can accept momentary overloads without blowing, but if the overload continues, the circuit will open. Slow-blowing fuses are used in circuits that have a sudden rush of high current when turned on, such as motors and some appliances.

Warning:Always remember to disconnect a power source before you change a fuse!

Fuses must be replaced with the proper type, current, and voltage rating (Fig. 4-19).

Figure 4-19. Fuses of Varying Type

4.11 ApplicationsAt Schlumberger, electricity is used to power starter motors, lighting systems, instruments, data acquisition systems, ignition systems, and even valves in hydraulic systems. An overpressure shutdown device is one example of where Schlumberger uses electrical circuits.

An overpressure shutdown device is an electrical circuit that responds to excessive pressure in a hydraulic system, such as a triplex pump. A Martin Decker gauge monitors system pressure. It is preset to disengage the clutch and bring the engine to idle speed.

System pressure passes through the gauge saver to the Martin Decker gauge, which is set to close the circuit when it reaches a certain level. A needle on the gauge responds to system pressure, and when the needle makes contact with the preset contact, the circuit closes.

When the circuit closes, the engine drops to idle speed and the clutch is disengaged. The reset junction box requires a manual reset of the system after the pressure drops below the set point (Fig. 4-20).


Figure 4-20. Overpressure Shutdown

Truck over-pressure relay Deck over-pressure relay

Power

Signal

Alarm

RatePressure

4.12 SafetyAlways follow these safety procedures when you work with electrical systems:

De-energize all circuits before servicing.

Use LOTO (lockout/tag-out).

Never wear rings or watches.

Never short terminals or connections with tools.

Never allow flames or sparks around batteries.

Always wear chemical goggles and rubber gloves when handling batteries.

Always maintain adequate ventilation around batteries.

When in doubt, consult your supervisor or field service manager. Leave the repairs to the experts.

•

•

•

•

•

•

•

•




5.0 Basic Hydraulic Systems

Hydraulics, the study of the behavior of liquids, explains how forces are created and how the tremendous potential of fluid power can be effectively applied.

Pascal’s law states, “Pressure applied on a confined fluid is transmitted undiminished in all directions, and acts with equal force on equal areas, and at right angles to them.” Keeping Pascal’s law in mind, what would you expect to happen if a piston was forced into a bottle that was completely filled to the rim with water? The bottle would break because the liquid is practically incompressible and transmits the force applied at the piston throughout the container. This is a simple example of hydraulic force (Fig. 5-1).

Figure 5-1. Hydraulic Force in a Bottle

5.1 Why use hydraulic power?Schlumberger uses hydraulic power for tasks such as mixing, proportioning, and agitating in cement mixers and liquid- and dry-additive systems. These are auxiliary circuits or systems that support downhole operations.

Hydraulic devices are used for these applications because they offer a number of advantages:

produce high power output but are light and small

require minimum day-to-day maintenance because the same hydraulic fluid used to drive the system is also used to lubricate the parts inside the hydraulic system

are simple to operate

can be operated at varying speeds

are reversible

can be stalled without damage when overloaded and will start up immediately when the load is reduced

can be hooked up in a variety of configurations as needed for the most efficient operating.

Hydraulic systems are significantly less efficient than direct-drive systems because of internal friction that produces heat. They also tend to leak internally. However, they require less day-to-day maintenance than direct-drive systems, though they require a qualified technician for major repairs. Nevertheless, for a coiled tubing unit and its spatial restrictions and power transfer requirements, hydraulic devices provide the best load distribution and packaging available (Fig. 5-2).

•

•

•

•

•

•

•

48 | Basic Hydraulic Systems

Figure 5-2. Hydraulic Hoses

5.2 Maintenance of hydraulic components

The maintenance of hydraulic equipment (Fig. 5-3) is important to eliminate or reduce failures.

Figure 5-3. Hydraulic System in a POD Blender Skid

Common causes of failure are

high contamination levels

wrong oil viscosity

high-temperature operation

cavitation

faulty circuit-protection devices.

•

•

•

•

•

Over the years, the performance, sophistication, and operating pressures of hydraulic equipment have increased significantly. These changes are particularly true in mobile hydraulic equipment. As a result, not only is the more modern hydraulic equipment more expensive to fix when it breaks, but proactive maintenance is required to maximize service life and minimize operating costs. It is not realistic to expect (as many equipment owners do) to run hydraulic devices for many hours without checking anything more than the fluid level and not have problems.

At a minimum, follow these six guidelines to minimize the chances that a hydraulic component will suffer expensive, premature component failure and unscheduled downtime:

Keep fluids clean.

Keep the fluid temperature and viscosity within optimum limits.

Keep hydraulic system settings to the manufacturer’s specifications.

Schedule change-outs before components fail.

Follow correct commissioning procedures.

Conduct failure analyses.

Implementing an effective, proactive maintenance program requires time, effort, and some expense. However, the investment is quickly recovered through savings in costs as a result of improved equipment performance, increased component life, increased fluid life, reduced downtime, and fewer repairs.

5.3 Stem I auxiliary posttrip inspectionThe auxiliary posttrip inspection is a comprehensive inspection that identifies any auxiliary defects. This inspection determines the repairs required to make a unit operationally ready for the next service job.

•

•

•

•

•

•


Highlighted items (in red on the 587-2H form) are to be reported to the maintenance staff by the last person operating a unit.

The tools required are

a flashlight

a shop towel

pliers

a screwdriver.

The auxiliary posttrip inspection involves these 25 areas:

all fluid levels

all belts

air filter indicator

engine and transmission power take-offs

batteries and cables

exhaust system

instrumentation

clutch operation

hydraulic system

drain air tanks

mixing systems

chemical additive systems

suction/discharge piping

centrifugal pumps

high-pressure pumps

bulk systems

displacement tanks

safety systems

dome lids

tank test date

placarding

blinds/caps

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

radiation papers and decals

densitometer lock

posttrip inspector signature.

5.3.1 All fluid levelsCheck all fluid levels and bring them to the full level. Also, confirm that all filter caps are in place (Fig. 5-4).

Figure 5-4. Checking Fluid Level

5.3.2 All beltsCheck all belts for proper tension and condition (Fig. 5-5).

Figure 5-5. Checking Belts

•

•

•


5.3.3 Air filter indicator

Check to ensure that the air filter indicator is in the normal operating range (Fig. 5-6).

Figure 5-6. Air Filter Indicator

5.3.4 Engine and transmission power take-offs

For the engine and transmission power take-offs, check the following (Fig. 5-7):

engine performance

coolant and oil leaks

mounting for loose bolts and cracks

proper operation of the neutral safety switch.

•

•

•

•

Figure 5-7. Power Take-Offs

5.3.5 Batteries and cables

Check batteries for terminal and cable condition. Ensure that the battery and cover are properly secured (Fig. 5-8).

Figure 5-8. Batteries


5.3.6 Exhaust systemFor the exhaust system, do the following (Fig. 5-9):

Inspect for leaks, loose fittings, and damaged pipe.

Ensure that hoses and electrical wires do not contact the exhaust system.

Check the condition of the muffler and its mounting.

Figure 5-9. Exhaust System

5.3.7 InstrumentationVerify that all gauges operate properly and can be clearly read (Fig. 5-10).

Figure 5-10. Gauge Panel

•

•

•

5.3.8 Clutch operationCheck the clutch for proper operation, and make sure there is clutch pedal clearance.

5.3.9 Hydraulic systemFor the hydraulic system, check the following (Fig. 5-11):

system performance

hydraulic components

condition of hoses

tank mounting for missing bolts, cracks, or missing brackets

filter indicator.

Figure 5-11. Hydraulic System

•

•

•

•

•


5.3.10 Air tanksDrain moisture from the air tanks (Fig. 5-12).

Figure 5-12. Draining Moisture

5.3.11 Mixing systems

Verify that all mixing systems are functioning properly (Fig. 5-13). Ensure that there are no leaks in piping or valves.

Figure 5-13. Mixing System

5.3.12 Chemical additive systemsCheck to ensure that

all chemical additive systems are functioning properly.

•

all lines are clean and free of debris and obstructions.

all valves are operating properly.

5.3.13 Suction/discharge pipingConfirm that

piping or valves are not leaking (Fig. 5-14).

all lines are clean and free of debris and obstructions.

all valves are operating properly.

Figure 5-14. Piping in Truck

5.3.14 Centrifugal pumpsFor the centrifugal pumps, sometimes called C-pumps, check to ensure that

mounting brackets are secured and all bolts are in place.

no loss of suction or discharge pressure has occurred.

there is no unnecessary noise or vibration.

nothing is leaking (Fig. 5-15).

•

•

•

•

•

•

•

•

•


Figure 5-15. Centrifugal Pump

5.3.15 High-pressure triplex pumpsFor the high-pressure triplex pumps, check that

the fluid-end is functioning properly with no leaks.

the fluid-end is securely mounted with all nuts and bolts in place.

clamps are on plungers.

the power-end is working properly, with no unusual noises, vibrations, or oil leaks (Fig. 5-16).

Figure 5-16. Triplex Pump

•

•

•

•

5.3.16 Bulk cement transportCheck that the bulk cement transport pressures up with no leaks and that it unloads material properly (Fig. 5-17).

Figure 5-17. Bulk Cement Transport

5.3.17 Displacement tanksCheck that displacement tanks are clean and free of debris (Fig. 5-18). Check for missing barrel indicators.

Figure 5-18. Displacement Tanks


5.3.18 Safety systemsCheck safety systems to ensure that

the emergency kills and over-pressure trips are functioning properly.

the relief and cycle valves are operating properly.

the burst disc is in place.

5.3.19 Dome lidsOn the dome lids, check the condition of

the gasket

the latches

the roll-over vent valve.

5.3.20 Tank test dateCheck that there is a current, legible test date on the tank.

5.3.21 PlacardingCheck that the placards are securely mounted and in good condition (Fig. 5-19). Check that the correct placard is in place for the load (Fig. 5-20).

Figure 5-19. Placarding

•

•

•

•

•

•

5.3.22 Blinds/capsCheck to ensure that all required blinds and caps are in place on tanks and piping.

Figure 5-20. Caps

5.3.23 Radiation papers and decalsCheck that all radiation papers and decals are in place (Fig. 5-21).

Figure 5-21. Radiation Decal


5.3.24 Densitometer lockCheck that the densitometer is in the OFF position and is locked (Fig. 5-22).

Figure 5-22. Densitometer Lock

5.3.25 Auxiliary posttrip inspector signature

The signature on the auxiliary posttrip portion of the driver’s trip report (form found in Stem I Inspection Guidelines For Well Services Land Operations, InTouch Content ID# 2024129) verifies that

the safety inspection has been performed.

any repairs necessary to make the unit safe and operationally ready for the next service job have been identified.

5.4 Stem I repair processThe STEM I repair process is identified by each district. Therefore, each district should develop a plan that identifies the specific person who will be responsible for repairs to unit components.

•

•




6.0 Stem I Diesel Engine

There are many different sizes of diesel engines found on Schlumberger equipment. All of them play a vital role in the completion of a failure-free job.

Completing the STEM I Report before and after every job is a key factor in keeping these engines in optimum working condition. Follow the steps below to complete the STEM I inspections:

Before a job and before starting the engine, do the following:

STEP 01 Make sure the power source is in LOTO (lock-out/tag-out) before performing these tasks. Refer to WS Safety Standard 5: Pressure Pumping and Location Safety, InTouch Content ID# 3313681, for details.

STEP 02 Check the previous STEM I inspection to make sure that earlier problems have been repaired.

STEP 03 Inspect the oil level. It should be up to the full mark. Add as needed. If the oil looks gritty, watery, diluted (diesel in oil) or milky, check with a mechanic; a STEM II inspection may be required. When adding oil, make sure to use the correct type and viscosity. Do not mix these, if possible, and do not overfill the oil level. Ensure that the correct dipstick is being used for a particular engine; the wrong dipstick can make a big difference.

Note:For two-stroke Detroit diesel engines, use SAE 30W or 40W oil. For CAT and Detroit diesel four-stroke engines, use 15W to 40W oil.

STEP 04 Inspect the coolant level. It should be 50 mm [2 in] below the radiator neck. Add as needed. Inspect the hoses for leaks, wear, splits, and cracking. Inspect the clamps and fittings for tightness and wear. If coolant is needed, alert the field service manager or a mechanic to the problem. Do not mix different coolants. Use the same type of coolant if at all possible.

STEP 05 Inspect the fuel system. Inspect the filters, hoses, and lines for leaks, rubbing, chafing, and loose connections. Fill the tank to within 50 mm [2 in] of the top (90% capacity) to allow for fuel expansion. In cold environments, use winter-grade diesel fuel. Ordinary fuel may cloud and clog the fuel filters.

STEP 06 Inspect the belts. Also inspect the shrouds and guards. Belts should yield 12 mm to 19 mm [1/2 in to 3/4 in] under thumb pressure. Inspect the belts for cracking and fraying. Check the condition of the pulley for loose bearings. A belt that is too tight is destructive to the bearings of the driven part. A loose belt will slip.

STEP 07 Operate and reset the emergency kill mechanism.

58 | Stem I Diesel Engine

Note:The emergency kill latch must be spring loaded to prevent it from accidentally tripping during a job. If it does not work, the flapper shaft has probably seized. If the flapper has seized, make sure the engine cannot be accidentally started, and then spray a little penetrating oil around the pin and trip mechanisms. Make sure the flapper has a good reset handle or pin. Be careful not to drop any items down the air intake.

STEP 08 Inspect the batteries. Inspect the fluid level in each of the cells. The fluid should be 10 mm [3/8 in] above the plates. If additional fluid is required, add distilled water only. Battery fluid is a solution of sulfuric acid. The acid strength can be measured by determining its weight with a hydrometer. The fluid in a fully charged battery will weigh 1.260 SGU at 26.6 degC [80 degF]. The weaker the battery, the lower the fluid weight will be. Make sure the battery terminals are tight, the cables are in good condition, and excessive corrosion is not noticeable on the terminals.

Use water and baking soda applied with a wire brush to remove terminal corrosion. A light coating of petroleum jelly can prevent future terminal corrosion. Make sure the top of the battery is wiped clean and dry to prevent accidental discharge. Make sure the cover fits tightly. Commonly used maintenance-free batteries do not need to be checked for fluid level. Simply look into the hydrometer eye and note the color. Green means the battery is >65% charged; black or clear means that it is <65% charged.

Caution:Use care to avoid shorting with a wrench or screwdriver. The current generated by these batteries is enough to cause very serious burns.

Hydrogen gas is produced in the normal operation of a battery. To prevent a dangerous explosion, keep all flames and sparks away from vent openings in a battery. Follow the guidelines in Safety Standard 4: Facilities and Workshops, InTouch Content ID# 3313678, concerning safe procedures to follow when charging, jumping, hooking up, or storing batteries.

STEP 09 Inspect the air filter. Look for obstructions and dirt buildup. Check the external filter restriction indicator, and ensure that it works. Make sure no dirt can enter the engine through the air intake. Filter elements should be removed from their housing only when they are being changed. More dirt is induced into the engine when the filter is being changed or checked than would be allowed by the dirty filter itself. Oil bath-type air filters should not be used because they offer very low engine protection during low engine rpm’s.

A blower forces air into the cylinders to sweep the exhaust gases out through the exhaust valves, leaving the cylinders filled with fresh air. This air also helps cool internal engine parts, particularly exhaust valves. Therefore, a restricted air flow can cause an engine to starve for air. This lack of air will result in the incomplete burning of the fuel and cause the engine to send black smoke out of the exhaust.

STEP 10 Inspect the hydraulics. If the unit has a hydraulic system, check the hydraulic fluid level. In warm climates, it should be 50 mm [2 in] from the top of the reservoir. In warm


climates, 3 to 4 in from the top for expansion may be needed. Inspect the hose condition for pinching, cracks, wearing, and cutting.

Note:If hydraulic fluid must be added regularly, check the seals on the motors and C-pumps, the hydraulic pumps and gear-boxes, and the cylinder rams. A problem may exist that needs immediate attention.

STEP 11 Power take-off (PTO) operation, grease bearings (if the unit drives a PTO). The PTO is a means of disconnect between the engine and, in this case, the compressor. Sometimes the PTO is directly mounted to a gear reduction case. If so, always check the oil level in the gear case. Grease the throw-out bearing and clevis lever shaft. Inspect clutch operation; ensure that the clutch will click in and out when engaged. The force to engage the clutch should be 50 lbf. Note any fluid additions or abnormalities on the STEM I checklist.

Note:Any fluid additions should be made with a clean container used for one type of fluid. Contamination and/or buildup can occur if fluid mixing takes place inside the engine or cooling system!

STEP 12 Inspect the transmission fluid. If the unit drives a transmission, check the fluid level by using the dipstick. Check it twice for consistency. If an automatic transmission is used, the level will need to be rechecked when the engine is running. The correct level can be ensured only when the transmission temperature is at a normal operating temperature, above 160 degF.

STEP 13 Inspect engine mountings. Make sure all components are securely fastened to the frame. Both the front and the rear engine and transmission mounts must be inspected. Inspect under and around the unit for oil and coolant leaks, drips, and puddles.

After starting the engine with partial throttle, follow this procedure:

STEP 01 Look at all the gauges.

a. Check the oil pressure. Ensure that it is within the operating range for the engine used: 20 psi to 55 psi for a Detroit diesel and 30 psi to 90 psi for a Caterpillar.

b. Make sure the tachometer is working by throttling the engine a couple of times. If an hour meter is incorporated into the tachometer, make sure it is working.

c. Check the engine temperature. Make sure it is within the operating range for the engine used: 160 degF to 190 degF for a Detroit diesel and 160 degF to 210 degF. for a Caterpillar.

d. Make sure the alternator is keeping the battery charged. The battery voltage range is from 12.5 V to 15.0 V DC. If the charging system is working correctly, the voltage will increase when the engine rpm’s are increased after starting.

STEP 02 If the unit is clutch driven, engage the PTO and confirm that the connected unit is operating. It should take about 50 ft/lbf to engage the handle. If the clutch is too loose, damage can occur during job.

STEP 03 Inspect the hydraulic system. If hydraulics are installed, check for leaks while they are in use. Bypass valves, relief valves, pumps, and motors should be traced for leaks, vibrations, and loose components. Confirm that


the hydraulic pressure is within the operating range of the system. All valves should be fully open or fully closed during operation.

STEP 04 Inspect the exhaust system. Look for leaks and excessive noise. Look for leaks around the exhaust manifold gaskets, muffler, and muffler piping. If the engine has not been used in a long time, drain any accumulation of fluid from the exhaust manifold. Avoid excessive idling. Prolonged engine idling will result in the temperature of the engine coolant falling below the specified operating range. A low operating engine temperature causes incomplete combustion of fuel in the cylinders. Incomplete combustion may cause lacquer or gummy deposits to form on the valves, pistons, and rings. It also causes rapid accumulation of sludge within the engine. When prolonged engine idling is necessary, keep the engine running at a minimum of 900 rpm.

STEP 05 Inspect the automatic transmission fluid level. If necessary, run through the gears with the unit on level ground, and then read the fluid level on the dipstick. The unit should be at a normal operating temperature.

Note:Disengage the drive mechanism (transmission or PTO), and allow the engine to idle for 5 minutes before shutting down.

During a job, do the following:

STEP 01 Check the gauges:

a. Make sure the coolant temperature remains in the operating range for the engine.

b. Check the oil pressure as often as possible during the job. If the oil pressure gauge shows a large drop in oil pressure, possible engine failure may be imminent. Let the field supervisor or field engineer in charge know immediately, and then switch to an alternate power source if available.

STEP 02 Check how the unit is operating. Continuously check the unit for unusual noises, vibrations, leaks, or smoke. Note any operating problems on the STEM I inspection form or Driver’s Trip Report. Remember to idle the engine for 5 minutes before shutting the engine down. Doing this allows the internal components to cool, which can prevent serious internal damage.

After the job, do the following:

STEP 01 Inspect the oil level. Wait until the engine has cooled, and check the oil level and condition. Top off the oil if necessary. Use the appropriate type of oil with the correct viscosity. Be sure the engine oil level has not risen during the job. An increase in the level could indicate contamination by fuel, water, or coolant.

STEP 02 Inspect the coolant level. When the engine has cooled, check the coolant level and refill it if necessary. Inspect the hoses, cap, and fittings for looseness and wear. The radiator operates under pressure at a normal operating temperature. Wait until the engine has cooled before removing the radiator filter cap. Never use a flame (match, cigarette lighter) when checking the coolant level.


STEP 03 Refuel the tank. Fill the fuel tank with clean diesel. Leave a 50-mm [2-in] space at the top of the tank for fuel expansion.

STEP 04 Inspect the belts. Also inspect the shroud and guard. Vibrations from unit operation can loosen the guard bolts and shroud fasteners. Inspect the pulleys and check for worn or loose bearings.

STEP 05 Check the hydraulic fluid level. If necessary, fill as required. Inspect the hoses and fittings for wear, cracks, pinches, and leaks.

STEP 06. Inspect the unit visually. Inspect the engine and under the unit for unusual drips or puddles. Record the engine hours and any maintenance that needs to be performed on the STEM I inspection form or Driver’s Trip Report.




7.0 Stem I Compressor

The compressors in use with Schlumberger auxiliary equipment vary in type, manufacturer, and size. However, they all perform the same basic function: they supply air to operate the controls and transfer bulk material and/or acid.

The following steps outline the STEM I inspection procedure for the compressors used with Schlumberger auxiliary equipment. For a complete overview of pneumatic systems, refer to JET 6, Bulk System.

Before a job and before starting the engine, do the following:

STEP 01 Check the previous STEM I inspection report.

STEP 02 Do the STEM I diesel engine inspection.

STEP 03 Check the hydrostarter system. If the engine uses a hydrostarter instead of an air- or electric-powered starter, follow these steps:

Inspect the operation of the hydrostarter pump and the condition of the pressure gauge. The pump should have resistance in both directions. Ensure that a rubber boot is in place.

Check that the oil level in the hydrostarter reservoir is 3/4 full, with no pressure on the system. After charging the system, the screen on the bottom of the tank should be covered with fluid (C3 or SAE 10W oil). Some manufacturers

a.

b.

recommend a 50/50 mix of diesel and motor oil.

After the system is charged, the hydrostarter requires the following pressures to start the engine: 1,500 psi above 4 degC [40 degF] 2,500 psi at -17 to 4 degC [0 to 40 degF] (use starting aid) 3,300 psi below -17 degC [0 degF] (use starting aid)

STEP 04 If the system is water cooled, complete the same inspections for the compressor coolant system and level as for the engine.

STEP 05 Inspect the compressor belts guard if the drive is not direct. The belts should give about 13 to 19 mm [1/2 to 3/4 in]. If a belt is frayed or damaged in any way, replace the complete set of belts. Also inspect belt guards for damage.

STEP 06 With air-cooled compressors, inspect the cooling fins to make sure they are free of dirt and oil buildup. Also inspect the cooling fan and belts if applicable.

STEP 07 Inspect the compressor oil level. Some Gardner-Denver models have a dipstick located on the crankcase. The Leroy models and some Gardner-Denver models can be checked by sight glass. The proper level is in the middle of the sight glass. In rotary-type compressors such as the Ingersol-Rand, the reservoirs are in the air-oil separator. These usually require a special oil. Drum or Europer

c.

64 | Stem I Compressor

STEP 08 Inspect the pilot unloader control lines. These lines run from each compressor piston. Check for cracks and leaks.

Note:These lines control the maximum and minimum pressures by opening the individual suction valves on each piston. If a valve fails, it can affect the safe operating limits of the system.

STEP 09 Drain moisture from the reservoir.

STEP 10 Inspect the unloader and relief valves. The compressor should also have its own pressure-regulating system (unloader).

This system may be a brass pilot control valve on the compressor reservoir tank. This valve should be set to cut out at 32 psi and cut in at 27 psi. The differential should be approximately 15% of pounds per square inch. Verify that the lines and fittings are tight, with no apparent wear or cracks.

Unloader and pressure relief valves must be inspected periodically in accordance with WS Safety Standard 27: Inspection and Testing of Pressure Relief Valves and Gauges, InTouch Content ID# 3313707. Pressure relief valves must be inspected for proper operation for every job, as well as every month and every year, as required by WS Safety Standard 27. The valves should be green-tagged with the test date noted on the tag. A pressure relief valve should also be in place on the reservoir tank. It should be set at 35 psi, unless otherwise noted on the pressure vessel plate.

Make sure the pressure relief valve is working for every job. Lubricate the spring and plungers of the relief valve with light oil. Verify that the valve has been green-tagged, with the last test

date displayed. Always check the specification plate on the pressure vessel for pressure relief valve settings. If a valve is not working properly, it must be replaced. If it needs to be repaired, the repair must be done by a qualified person.

It must also be properly reset and bench-tested before being reinstalled. Doing this requires the aid of a qualified mechanic and is required by WS Safety Standard 27.

Note:Cement surge cans have a lower psi setting. For details, refer to WS Safety Standard 27, Maintenance Bulletin 625E, and Technical Alert 98-03.

STEP 11 Inspect the discharge plumbing, including the valves, check valves, and gauges. Check that they are properly installed and are operating correctly.

STEP 12 Inspect the air filters. Look for dirt, dust, and oil accumulation. Repair or replace them if necessary. Make sure the filter retaining studs in the centers of the filters are tight.

STEP 13 Check the STEM backup compressor. If a backup compressor is available, connect it in line with the primary compressor so that it is ready, if necessary, for a quick changeover during the job.


After starting the engine, do the following:

STEP 01 Perform the STEM I inspection on the diesel engine.

STEP 02 Check the compressor oil pressure. The pressure should be about 5 to

10 psi.

STEP 03 Verify unloader operation. Shut in the discharge of the compressor to ensure that the unloader is operating correctly. It should actuate at 30 to 32 psi, preventing further pressure buildup. It should reload at 15% UNDER unload pressure.

During a Job, do the following:

STEP 01 Check the gauges. Look at the engine oil pressure, compressor oil pressure, and temperature and ammeter or voltmeter functions.

STEP 02 Check unit operation. Check air pressure and safety devices continuously. If problems occur, quickly change to the backup compressor, if available.

STEP 03 Document all problems noticed during the job.

After a job, do the following:

STEP 01 Do the postjob STEM I inspection on the diesel engine as outlined in Section 8 of this manual.

STEP 02 Inspect the compressor oil level. Add SAE 30W oil if necessary.

STEP 03 Drain the reservoir tank. Leave the valve open (either the drain cock or the discharge valve of the system). Note any

problems or maintenance that needs to be done on the STEM I inspection form or Driver’s Trip Report.

66 | Stem I Compressor



8.0 STEM I Acid Transport

When transporting hazardous materials, such as acid, the preventive maintenance must be done correctly to avoid regulatory (e.g., U.S. Department of Transportation) violations and to eliminate any chance of injury to Well Services personnel and others due to the dangerous nature of the hazardous materials.

Note:When working around any unit containing hazardous materials, wear and use the proper safety equipment listed in the MSDS for each chemical. Be careful!

Before a job

To do a STEM I inspection for acid transport, follow these steps:

STEP 01 Review the previous STEM I inspection report.

STEP 02 Perform the STEM I chassis inspection as noted in Section 9 of this manual.

STEP 03 If the unit has a hydraulic system, do the following inspections:

Inspect the hydraulic fluid level. The correct fluid level is 2 in below the top of the tank.

Inspect the hydraulic system. Inspect the pumps, hoses, and gauges for leaks, cracks, pinching, and excessive wear.

Verify PTO operation.

a.

b.

c.

Note:The indicator light on the PTO switch in the cab should signify correct operation. Repair or replace the fuse, if necessary.

STEP 04 If the unit has centrifugal (C-) pumps, check the following:

Inspect the C-pump lube tank level. Make sure the pump is properly lubricated.

Operate the C-pump to check for any unusual noises, vibrations, and leaks. When pumping acids and solvents, the seals cause most of the C-pump failures. Inspect these thoroughly.

STEP 05 Inspect the valves. Check that the suction and discharge valves operate and are positioned correctly. The tank discharge valves must be closed during transport.

Note:Certain fluids (for example, certain solvents) can soften and swell the seats in Weco butterfly valves. This swelling can make opening and closing the valves very difficult and can contribute to leaks.

a.

b.

68 | Stem I Acid Transport

STEP 06 Cover the ports with caps. Make sure they are secured with safety chains.

STEP 07 Inspect the dome lid arrangement. Verify valve condition, cam locks, and adjustment. Inspect the lid gasket and the dome guard drain hose.

Note:Maintenance Bulletin VII-691-B outlines the safety requirements for Well Services transport manhole covers, tanks, and inspections.

STEP 08 Inspect the tank gauges. They should be legible and mounted securely.

STEP 09 Check the placarding. Placards must be clearly legible.

Note:The correct hazard class and ID number for placarding each of Schlumberger’s hazardous materials should be available in each location. This information should also be noted on the Loading Sheet for each unit.

To simplify and meet the U.S. Department of Transportation Acid Transport Placard Requirements for North American operations, do the following:

For a multicompartmented transport (Schlumberger 5,000 galUS transport), the ID number and class of each product must be displayed on the sides of each compartment.

If the product is both flammable and corrosive, display “Flammable” on the ends. When hazardous materials are not being transported, display the original placards. When the empty tank has been triple-rinsed with water, display the “Drive safely” slogan.

Always check for proper paper work and placarding, and reference your Hazardous Material Pocket Handbook. More information is available from Maintenance Bulletin 1109 MUST DO, InTouch Content ID# 3036784, on the placarding of transports.

STEP 10 If an air lance is installed, check the condition of the system, including the

Note:Ensure that the lance can be operated only with the parking brake set.

STEP 11 Visually inspect the unit. Inspect under and around the unit for leaks from the tanks, C-pumps, and hydraulic lines. Note any discrepancies on the STEM I inspection form or Driver’s Trip Report.

During a job, check the following:

STEP 01 Check unit operation. Confirm valve operation, hydraulic operation, and C-pump operation (especially the seals).

STEP 02 Check the hydraulic gauges.

STEP 03 Check for leaks. Inspect the manifolds for leaks and corrosion.


Note:If leaks occur under pressure, take precautions to safely contain any spills. Leaking corrosive or flammable materials can be extremely dangerous.


STEP 01 Drain the tanks. Ensure that the tanks are properly drained and flushed in accordance with all state and federal/country regulations and that the contents are disposed of correctly. Review the MSDS manual for disposal guidelines.

STEP 02 Inspect the hydraulic system. If applicable, fill to 2 in below the cap in the reservoir, if needed. Look for leaks or wet spots.

STEP 03 Inspect the C-pumps. If applicable, look around the centrifugal system for drips and/or wear.

STEP 04 Refill the centrifugal lube tank. If required, fill it with clean 80W/90W oil.

STEP 05 Grease the centrifugal bearings if applicable.

STEP 06 Check that the dome lids and blanking caps are in place and are securely fastened.

STEP 07 Check the placards and correct them, as needed, for the trip back to the district. Note any maintenance that is required on the STEM I inspection form or Driver’s Trip Report. Remember that chassis and brake posttrip inspections are also required.

70 | Stem I Acid Transport


9.0 Stem I Cement Bulk Equipment

The quality of a cement job is only as good as the bulk cement delivery to the mixer. Therefore, it is very important for the bulk system operator to understand how his equipment works and how to keep it maintained so that it works well on every job.

Here are the general configurations of pressurized and gravity silos. The following steps will ensure that the bulk system being used (gravity surge can, pressurized silo, pressurized bulk truck) are in good operating condition when a job begins.

Note:Make sure the equipment has received the proper STEM I inspection, and confirm that the correct bulk equipment is being taken to location. Double-check the loading tickets and/or service order, the STEM I checklists, and the unit’s number to ensure that the correct piece of equipment is being dispatched to the job.

When working around cement pressure vessels, the operator must wear the following PPE (and have the minimum safety equipment):

goggles

dust mask.

Cement dust is very abrasive to the eyes, nose, throat, and lungs. Because it is caustic, it can burn the skin if handled improperly. Use it carefully.

•

•

Before a job and before applying air to a vessel, do the following:


STEP 02 Perform the STEM I chassis inspection, if applicable.

STEP 03 Make sure the maximum working pressure is stenciled on the tank.

STEP 04 Make sure the tanks are labeled correctly.

Note:Improper labeling of bulk tanks can cause an operating failure by mixing cement from the wrong tank during a job.

STEP 05 Inspect the check valves, relief valves, and gauges. Ensure that the check valve(s) and pressure-relief valve(s) are present and free of corrosion or dirt. Verify the test date on the pressure-relief valves. Inspect the pressure gauges. The recommended pressures are 0 to 60 psi, fluid filled, with a 6.5-cm [2.5-in] face.

Pressure-relief valves must be inspected every month and every year for every job, as specified in WS Safety Standard 27: Inspection and Testing of Pressure Relief Valves and Gauges, InTouch Content ID# 3313707. The valves should be green-tagged, with the test date noted on the tag.

72 | Stem I Cement Bulk Equipment

STEP 06 Verify that the butterfly valves work. Make sure they are in the correct position before air is introduced into the system.

STEP 07 All open 4-in ports must be covered by a two-piece cap/union.

STEP 08 Inspect the ball valves, hoses, and connections. Inspect the ball valves on the manifold for ease of use. Check the hoses and fittings for wear, cracking, and looseness, where applicable. Inspect the check valves for correct operation.

STEP 09 Inspect the frame and the skid for cracks and structural damage.

STEP 10 Perform a STEM I inspection on the air supply system (compressor) as outlined in Section 7 of this manual. Soft hoses are the only type of hose allowed on bulk fill, discharge, and vent lines.

While applying air to a vessel, do the following:

STEP 01 Inspect the compressor.

STEP 02 Inspect for leaks. Inspect hoses, caps, manifolds, and manhole covers. If leaks are found, bleed pressure completely from the tanks and then repair the equipment.

STEP 03 Check the pressurized system (bulk truck, pressurized silo, and pressurized surge can):

a. Pressurize the empty tank to 5, 10, and 15 psi. Record how long it takes to pressure up. If the compressor is cycling in and out, the compressor is keeping up with the delivery of the product. If the air pressure is dropping on the product tank and the compressor is cycling, there is a restriction in the air lines or pads.

b. Test the tank to 15 psi. Record any drop in pressure. If there is a drop, repairs are needed.

Note:If it is necessary to enter the tank for repairs or an inspection, follow the guidelines in QHSE Standard 12 (Permit to Work System).

To enter cement bulk equipment, do the following:

STEP 01 Obtain a safe work permit before any vessel is entered.

STEP 02 Isolate the tanks by blinding or disconnecting and completely cleaning them before entering.

STEP 03 Use a combustible gas detector. Analyze the O2 in the air.

STEP 04 Use PPE as necessary.

STEP 05 Use an air mover to change air out frequently.

STEP 06 Do not block the entry or exit while a person is inside a tank.

STEP 07 Shut down and lock any power-driven equipment (compressors) before entry.


Important:When someone is working inside a closed vessel, an attendant must be stationed outside the entrance (manhole) to warn of external danger or to get help if necessary. A lifeline must be attached to the wrists of the employee inside the vessel.

c. Check the discharge pressure. Blow air through the discharge line to the tank to make sure the line is clear.

d. Fluff product through the pads, and note any pressure difference between that on the manifold gauge and that inside the tank. A pressure difference of 5 psi or greater will indicate partially plugged pads or jets. If no pressure is noted, a pad could be ripped, or there might be a large leak around the pads.

STEP 04 For gravity-feed systems (gravity silo, gravity surge can), do the following:

a. inspect for obstructions in the vent line. There should be no kinks in the hose.

b. If the vent is attached to a dust collector, make sure no more than 5 psi of back pressure exists on the system.

c. Look inside the tank and check that no excess cement is caked on the walls, pads, sight glass, or discharge valve.

d. Percolate air through the pads and make sure that air is exiting from the vent line. Improper labeling of bulk tanks can cause an operating failure.

e. Inspect the discharge valve. Check operation of the large discharge butterfly

valve on the bottom of the tank. Repair it if necessary.


STEP 01 Verify that the equipment operates. If the system is pressurized, watch for fluctuations in the air pressure of the tank.

STEP 02 Inspect the compressor. Do a STEM I inspection on the compressor and engine while it is running.


STEP 01 If the system is pressurized, bleed air from the unit, leaving the vent valve completely open. Use caution, and be aware of dust hazards.

STEP 02 Empty the vessel. Silos must be completely empty before transporting them. If any maintenance is required on the unit, note it on the STEM I inspection form or Driver’s Trip Report.

74 | Stem I Cement Bulk Equipment



10.0 Stem I Batch Mixers

The batch mixer requires regular and specific maintenance. This piece of equipment plays a very important role in the completion of a cement job. It must be maintained properly to avoid service incidents and operating failures. Many problems can be directly attributed to improper cleanup of the unit after a job.

Always take the time to properly clean up the batch mixer. It is much easier to wash up wet cement than to chip out set cement.

The following steps outline the basic STEM I inspection of the batch mixer. Though there are many different types of batch mixers in use, these steps are applicable to all of them.

Before a job and before starting an engine, do the following:


STEP 02 Do the STEM I diesel engine inspection.

STEP 03 Verify the C-pump lube tank level. Fill with clean 80W/90W oil if necessary.

STEP 04 Inspect the C-pumps. Inspect the housings and fittings of each C-pump. Ensure that the seal lubrication line is secure.

STEP 05 Inspect the tanks. Look inside the tanks for cement buildup. If you see excess cement, clean it out. Ensure that all access hatches have gratings in place. If the mixer has a closed top, make absolutely sure that there is no buildup of set cement in the upper corner

near the joint between the dished head and the cylindrical section.

If it is necessary to enter the tank, make sure the unit cannot be turned on by someone else. Review the lockout procedure for this.

STEP 06 Inspect the paddles and paddle shafts for looseness. Grease the bearings where required.

Some batch mixers may be chain driven through a gear drive. If so, make sure that the chain has a little slack in it and that the guards covering the chain are in good condition. The clutch operating the chain should be able to be greased through a nipple on the end of the shaft. If the shaft does not have a grease nipple, manual greasing is required.

There may also be a sight glass or dipstick to check the oil level in the paddle’s gearbox. Some gearboxes have a simple plug in the side to check the oil level. If in doubt, ask your supervisor. Top off the oil if necessary.

Note:Some gearboxes use specific oils, such as synthetics. Adding the wrong oil can cause failure almost immediately.

STEP 07 Inspect the piping. Look for cement buildup. Verify butterfly valve action. If the action is stiff or if you can see damage, repair the problem. Ensure that the blanking caps are secure on all 4-in openings.

76 | Stem I Batch Mixers

After starting the engine, do the following:

STEP 01 Do the STEM I inspection on the diesel engine, as noted on the STEM I inspection form.

STEP 02 Verify system operation. Run water through the system to check the C-pumps, paddles, and all circulating lines. If pressure gauges are not installed on the piping system, observe the flow rate and force of the returning water during testing.

If the flow is weak or if you see leaks around the C-pumps, refer to JET 3, Centrifugal Pumps , InTouch Content ID# 4127830, on repair of these pumps. Make sure the C-pumps are being lubricated and that the hydraulics operating the paddles are in good working order.

STEP 03 Inspect the air-actuated valves for proper operation. If a valve is inoperable, repair it or exchange it for an operational one.


STEP 01 Check the gauges, hydraulic operation, engine temperature, oil pressure, and ammeter operation.

STEP 02 Verify unit operation. Make sure all functions of the batch mixer are working correctly.


STEP 01 Wash up any remaining cement. Make sure a supply of water is available to clean up the batch mixer immediately after cementing is completed.

a. Clean out the dry cement piping with a hose.

b. Circulate clean water between the tanks using the C-pumps and paddles. Discharge the dirty water to the pit or other approved disposal area.

c. Flush more clean water through the individual manifolds on the unit.

Note:Make sure you know where the water is going as you flush the manifolds. This will ensure that the unit ends up being thoroughly cleaned.

d. Open the blanking caps and flush the water from each opening on the unit.

e. Drain all the water from the unit, including the drains on the C-pumps and all low points in the plumbing.

STEP 02 Do the postjob STEM I inspection on the diesel engine, as noted in Section 6 of this manual.

STEP 03 Refill the C-pump lube tank. Use clean 80W/90W oil.

STEP 04 Make sure the load is secure for the trip back to the district. Note any problems or maintenance requirements on the STEM I inspection form or Driver’s Trip Report.


11.0 Equipment Modifications

In accordance with Schlumberger standards, no modifications or equipment changes are permitted without approval. You must submit an equipment modification request (EMR) through InTouch. EMRs must be approved and signed off by the appropriate line manager and/or department supervisor before any work is carried out.

All such requests for equipment modification should be made in strict compliance with procedure 420 (Processing Request for Change). Any modifications or changes will be considered only when no practicable alternative is available. If there is equipment that meets the required specification, then this equipment must be used.

78 | Equipment Modifications

Figure 11-1. Equipment Modification Request Form


12.0 References

All Schlumberger employees must be familiar with the relevant safety regulations and precautions because of the many hazards involved in the oilfield industry. Be sure to know the relevant contents of the material data safety sheets (MSDSs) regarding required personal protective equipment (PPE) and handling procedures when handling chemicals.

JET manuals

JET Reference Page, InTouch Content ID# 4178854

Well Services safety standards

Safety Standard 4: Facilities and Workshops, InTouch Content ID# 3313678

Safety Standard 5: Pressure Pumping and Location Safety, InTouch Content ID# 3313681

Safety Standard 11: Pumping Nitrogen, InTouch Content ID# 3313684

Safety Standard 15: Lockout/Tagout, InTouch Content ID# 3313691

Safety Standard 17: Storage and Handling of Oxidizers, InTouch Content ID# 3313693

Safety Standard 18: HAZCOM, InTouch Content ID# 3313694

Safety Standard 22: Coiled Tubing Operations, InTouch Content ID# 3313710

Standard 25: Confined Space Entry, InTouch Content ID# 3313705

Safety Standard 26: Air Tanks and Receivers, InTouch Content ID# 3313706

Safety Standard 27: Inspection and Testing of Pressure Relief Valves and Gauges, InTouch Content ID# 3313707

Safety Standard 28: Pressure Management Operations, November, 2003, InTouch Content ID# 3313708

Safety Standard 30: Pumping Combustible and Flammable Fluids, InTouch Content ID# 3313709

Schlumberger QHSE standards

Standard S001: Journey Management and Driving, InTouch Content ID# 3051691

Standard S002: HSE Event Reporting and Management, InTouch Content ID# 3260257

Standard S003: Personal Protective Equipment, InTouch Content ID# 3260259

Standard S004: Business Continuity, Emergency, and Crisis Management InTouch Content ID# 3253244

Standard S013: Mechanical Lifting, InTouch Content ID# 3260276

80 | References

Other regulations

Maintenance Bulletin 1170 MUST DO - Important Update - Hydraulic Hose Inspection and Replacement, InTouch Content ID# 3880621

Maintenance Bulletin 1170 MUST DO, InTouch Content ID# 3036784

U.S. DOT Out-of-Service (OOS) Criteria for Drivers, Vehicles, and HAZMAT Cargo, InTouch Content ID# 3381268

13.0 Check Your Understanding

81JET 04- Basic Oilfield Equipment |

1. The global consistency of fuel is one of the advantages of using gasoline engines as a prime mover.A. trueB. false

2. Match each fuel system component with its description.Components___ A. shut-off valve ___ B. reservoir ___ C. fuel pump___ D. injectorsDescription1. holds and supplies fuel for use by the

engine2. transfers fuel from the tank to the

engine3. terminates the flow of fuel from the tank

to the engine4. calculates the right amount of fuel and

directs it into the cylinder under high pressure

3. In a two-stroke engine cycle, each down stroke is a power stroke.A. trueB. false

4. Which three of the following are functions of a diesel fuel management system? A. holds a supply of diesel fuelB. uses high pressure to inject fuel into the

cylinderC. meters the quantity of fuel required for

each cycle of the engineD. carries fuel to various components of

the engine through a network of hoses and pipes

E. controls the rate at which fuel is injected

5. Match each routine maintenance system with the corresponding routine maintenance.System___ A. air system___ B. fuel system___ C. oil system___ D. coolant system

Routine maintenance1. Check fluid level; check fan for damage;

check radiator for leaks.2. Ensure that pressure is maintained;

check for leaks in hoses and connections.

3. Check oil level and condition by looking at the dipstick.

4. Check coolant level; look for leaks in lines and connections; check filters to make sure they are not clogged.

82 | Check Your Understanding

6. Match each stroke with its description.Stroke___ A. power___ B. compression___ C. intake___ D. exhaust

Description1. The piston moves downward and draws

air into the cylinder.2. Both valves are closed and the piston

moves upward, squeezing the air into a tiny space until it becomes hot.

3. The piston moves upward to push out the burned gases.

4. The buildup of burning gases forces the piston down.

7. Which two of the following are true about clutches? A. The clutch is a driveline component.B. A clutch may be controlled by electrical,

mechanical, or pneumatic actuators.C. The pneumatic actuator is standard for

most clutches.D. The clutch connects and disconnects

engine power the transmission.E. The clutch is a type of flexile coupling.

8. Which of the following three statements are true about flexible couplings?A. They provide overload protection.B. Schlumberger uses them on many skid

units to drive centrifugal pumps.C. They provide universal joint flexibility.D. They permit axial and radial

misalignment.E. They require close proximity mounting.

9. Match each type of pneumatic system with its description.System___ A. High-pressure/low-volume___ B. Low-pressure/high-volume___ C. High-pressure/high-volume

Description1. Used only in liquid additives, or LAS,

applications, such as fracturing.2. Used to power brakes, horns, cab tilt

controls, and deck engines.3. Used to convey and fluff bulk material

such as sand and cement.

10. Match each part of a pneumatic system with its position on the diagram below.

Figure 13-1. Parts of Pneumatic System

1

5

2

3

6

4

1. ___ A. pressure release valve

2. ___ B. air tank3. ___ C. dryer4. ___ D. drain cock5. ___ E. check valve6. ___ F. compressor


11. When should drain cocks on pneumatic air tanks be opened for drainage? Select two correct answers.A. after each operation has startedB. before each operationC. neverD. after each operation

12. If the compressor fails, which of the following will happen?A. Nothing will happen.B. The check valve allows air to flow out

of the tank, which releases excess pressure.

C. The check valve seals the tank and prevents pressurized air from backing up.

D. The check valve releases accumulated moisture from the system.

13. Which of the following lubricates a mesh gear compressor?A. the engineB. the check valveC. the governorD. the dryer

14. How does the operator know when it is time to add oil to the lubricator?A. by following a schedule and always

adding oil at regular intervalsB. by looking at the level through a sight

glassC. by estimating when oil should be addedD. by using a dipstick to determine the oil

level

15. Which of the following should be performed when jumping a dead battery? Check three correct answers.A. Wear rubber gloves and goggles.B. Connect the positive terminal of the

charged battery to the positive terminal of the dead battery.

C. Connect the negative terminal of the charged battery to a grounding point on the vehicle with the dead battery. The connection should be made far enough away from the battery so that a spark could not ignite hydrogen gas from the battery.

D. Stand near the battery when the engine is cranked, ready to remove cables.

E. After jumping the battery, remove the cable from the positive terminal first.

16. Which of the following should be performed for routine lead/acid battery maintenance? Check three correct answers.A. Use tap water to replenish battery fluid

levels.B. Check the condition of the entire cable,

not just the area near the battery, to confirm that there are no exposed wires or cracked insulation.

C. Protect the battery from extreme temperatures.

D. Slightly overcharge the battery for extended use.

E. Check to ensure that terminal connections are tight.


17. Assuming a constant load, which of the following motor functions will be affected if the flow rate is increased or decreased?A. speedB. displacementC. available torqueD. operating pressure

18. Which of the following areas should be inspected during the auxiliary posttrip inspections? Select three correct answers.A. suspensionB. tank test dateC. bulk systemsD. tires, lugs, and clampsE. displacement tanksF. license plate

19. What should be done if hydraulic fluid is added regularly during STEM I diesel engine inspections?A. Check seals on motors, C-pumps,

hydraulic pumps and gearboxes, and cylinder rams.

B. Switch to a different type of hydraulic fluid.

C. Add stabilizer to the hydraulic fluid.D. Replace the hydraulic fluid filter.

20. During a STEM I compressor inspection, moisture should be drained from the reservoir after the engine is started.A. trueB. false

21. Which two of the following should be performed before starting the engine when conducting a STEM I Sand Chief inspection?A. Inspect the sand-conveying belt for

damage and tears.B. Open and close the sand gates to

ensure proper action.C. Ensure that all leftover proppant is

cleaned out of each compartment.D. Lower the pads to lift the Sand Chief to

its proper height.

22. When conducting a STEM I acid transport inspection, which three of the following should be performed after completing the job? Select all the correct answers:A. Verify the placarding.B. Verify the centrifugal pump operation.C. Inspect the dome lids.D. Refill the centrifugal lube tank.

23. Which three of the following should be performed during a STEM I cement bulk equipment inspection before starting a job?A. Ensure that check valves and pressure

relief valves are present.B. Verify the test date on the

pressure-relief valves.C. Bench test the gauges for accuracy

before each job.D. Ensure that check valves and

pressure-relief valves are free of corrosion and dirt.


24. As part of the STEM I inspection for batch mixers, which three of the following should be performed for paddles before a job? A. Grease the bearings where required.B. Grease the clutch on the chain drive.C. Ensure that there is no slack on the

chain drives.D. Check the oil level in the paddle

gearbox.



Documents

Basic Oilfield Equipment - Remote Desktop Webamusement21.com/testcdl/EO-Library/EOT-EO1 Folder/EOT-EO1 Jet... · JET 04 - Basic Oilfield Equipment| 9 2.0 Basic Engines and Transmissions