Directional Drilling – Technology, Developments and Achievements

Martin Cox CEng FIMMM Aberdeen Drilling Management (ADM)

8th December 2016

Outline• Early oil industry drilling (1885 – 1930’s)• Early Survey practice • Oil & gas drilling/surveying developments (up to late 1970’s)• Improvements in drilling/surveying technology• Oil & Gas industry developing deviated drilling (1980’s & 90’s)• Refining deviated drilling technology for he 21st Century: Extended Reach Drilling (ERD) Ultra Extended Reach Drilling/UERD

Early Oil Industry Drilling• Small scale shallow drilling water/salt/oil recorded for centuries.• Oil from seepages – many areas mainly for lamp fuel.• 19th Century whaling industry for lamp fuel. Oil industry competes with and replaces by end 19th century).• Oil industry begins 1859, Titusville, Pennsylvania . USA.•‘Colonel’ Edwin L Drake (former railroad conductor). • Attempts to mine near oil seeps – floods.• Adapts technique for salt drilling using iron ‘drive pipes’ to drive through shale to oil deposit.• Discovers oil at 69 ½ ft – 400 gallons (approx 10 bbls)• Oil boom in Western Pennsylvania – production up to thousands of barrels a day (oil price collapses)

Oil drilling expansion into 20th Century• Spindletop, Beaumont, Texas strikes oil 10th January 1901.• Identified as an area with high oil potential by sulphur springs & bubbling gas• Utilises rotary drilling & use of drilling mud to drill deeper (1,139ft/347m).• 1st well comes in at 100,000 bbl/day (35 Imp gal/bbl 42 us gal/bbl)•Spindletop boom results in 600 companies formed by 1902 with 285 wells in the field (Founding of Amoco, Chevron, Exxon, Mobil, Texaco)• US becomes world major oil producer• Overcapacity in US market - drinking water 5 cents/drink ($1/gal) - Oil 3 cents/bbl (0.1 cents/gal)• Peak production 1927 @ 21 million bbls/day.• Spindletop productive to 1956 and then mined for sulphur to 1975.

Early Oil Industry drilling • Early drilling in areas with history of seepage• Percussive drilling initially utilised (e.g. Titusville 69 ½ ft)• Deeper /more productive wells – rotary drilling establishes its

self (to present day) (Spindletop >1,000ft)• Oil often found (in NA) when looking for water for agriculture• Rotary drilling includes use of mud (fluid) in the well at all

times. Cutting removal/hole stability/cooling/formation fluid containment

• Surveying – Limited to depth (Measured Depth)

Route to Directional Drilling - Surveying 1920’s to 70’s

• Several lawsuits allege wells may not all be vertical – deliberate or otherwise crossing lease/reservoir boundary

• Small diameter tools developed to survey wells

• Survey requires: 3 components measured at a given point: - Depth (Measured Depth) - Inclination - Magnetic Azimuth (problematic due to metal in well)

• Azimuth solution from (gyroscopic compass) creates first survey company ‘Sperry Sun’ - Sperry Corporation – aero navigation industry - Sunoil – Involved in several lawsuits ‘Slant Drilling Scandal – East Texas Oilfield’. (Deeper wells >3,000ft)

• Surveying - Run during trip, later deployed by cable - Continual innovation 1930 – 70’s (acid etching / pendulum / photographic single and multi shot)

Route to Directional Drilling 1920’s to 70’s

• Rotary drilling establishes principles for equipment configuration of Bottom Hole Assembly (BHA)

- Prone to dill a crooked hole from the vertical - Prone to bring a crooked hole closer to the vertical

• 1934 John Eastman innovation to reliably ‘kick off’ from the vertical using a whipstock.

• Combined BHA designs and ability to survey makes directional drilling possible but considered arcane/specialist operation (e.g. Drilling relief well for a blow out)

• Industry prefers to find new areas to exploit with vertical/conventional wells - 1950’s Industry exploratory rate 900 bbls/ft drilled where no previous oil/gas production

- 1960’s Industry exploratory rate 200 bbls/ft drilled where no previous oil/gas production

Directional Drilling Developments 1980’s & 1990’s

Drivers• Need to increase recovery efficiency Increase exposed section length

through reservoir by drilling at angle through the reservoir.

• Need to access reservoir/area of reservoir with limited or no vertical access

Onshore – access limited by physical or environmental constraint

Offshore – platform access to all areas of reservoir or adjacent reservoir

• Reduce environmental impact and cost of surface facilities to handle production

• Requirements not limited to oil & gas

Innovations• Downhole Motor Development of turbo drill concept mud

flow moves turbine which rotates bit with drill pipe stationary. (Frank Whittle – 1st Directional well 1950’s Gainsborough).

Downhole Motor + Bent Sub enables Slide Drilling. (Ability to change angle without placing whipstock).

• MWD (Measurement While Drilling) + Mud Pulse/EM Telemetry.

Continuous well survey measurements taken downhole and transmitted to surface.

• Straight Hole Applications, e.g.

Freeze Hole Drilling e.g. Selby project

To drill holes to tighter tolerance

Directional Drilling - Where?

Freezing Agent

Pumped Down Each

Well

“Perfect”Vertical Wells

Equally Spaced

1970’s Directional Drilling BHATwo modes of operation:

•Sliding (steering) - Drillstring is non-rotating and bend is oriented in plane of directional change

Early 1970’s POOH and change out to straight rotary assembly once angle built•Drilling ahead - Drillstring and motor body are rotated by late 70’s•Survey by cable deployed wireline tool. Late 70’s early survey transmission by mud pulse.•Trip out of well for change of bend (angle)

1980’s Directional Drilling BHA80’s Directional Assembly:Bent housing motor – changeout at surfaceMajor advancement - Could rotate or slideMWD – for survey measurementsCould survey in minutes (Higher data transmission rates – more information)Tools powered by lithium batteries

Introduction of Evaluation Tools-Gamma Ray-Resistivity-Early Porosity Tools (Density & Neutron)-Acoustic Calipers

1990’s DD BHA

• Bent Sub adjustable at surface (AKO).• Can drill in rotary or sliding to change angle.• Continuous MWD survey data stream.• Higher accuracy survey measurements Reduced survey ellipse of uncertainty.

• Full set of evaluation logs available Multiple Resistivity, Porosity (Density, Neutron, Sonic), Acoustic Caliper, fracture imaging pressures

• Ability to Geosteer in reservoir• Continuous data stream to surface Mud pulse or EM telemetry at up to 200 bps (theoretical), usually 30-70 bps range, <10bps @10km• Downhole Positive Displacement Motors/Turbines in BHA Greater reliability

• New generation of bit technology for directional drilling activities Design & Materials technology

Directional well design & surveying

Directional Survey• Measured Depth (MD)• Angle (from vertical)• Azimuth

• True Vertical Depth (TVD)• Vertical Section – displacement from

surface location

• Trajectory

• Directional Terms• Build Rate – how fast angle is

increased• Tangent – section of well where

angle is constant• Drop Rate – how fast angle is

decreased• Walk rate – natural turn in a well

path• Dog Leg Severity – measure of rate of

change of angle• Rotate Vs. Slide – drilling term• Ellipse of uncertainty

Ellipse of Uncertainty

Potential location of the wellbore when the Accuracy of the survey methods are applied To the well path.

“Cone” represents range of wellbore locations .If directional survey errors are applied.

Brent Field1970’s

4 platforms

NEIMME - Tyneside

NEIMME – N-U-T CS

1980’s field developmentDirectional Drilling enables greater reservoir access

Extending the reach

BP Wytch Farm – South Coast UK (Dorset)

1990’s Towards ERD

• Wytch farm near to shore development of 200mm bbl field• World record well set late 90’s at 10.1km (now exceeded)• Further development of Direction Drilling Technology• Identification of future industry requirement for ERD/UERD

drilling - Field development with less surface disturbance - Cost & environmental impact reduction at acceptable risk level• Oil and gas industry sets out requirement to be able to

directionally drill in rotary – The Rotary Steerable System

ERD and on to Ultra Extended reach Drilling

Rotary Steerable – Push the Bit

Rotary Steerable – Point the Bit

Directional Drilling in the 21st Century – Rotary Steerable Systems

• Directional Drilling while rotating the pipe• More time on bottom making hole• Continuous survey data transmission • Faster ROP / Better hole cleaning along reach• Smoother wellbore (eases completion phase)• Operational Cost $30K - $40K/day• Cost around $3m per assembly• Wells exceeding 15km have been drilled• Wells of up to 18km are planned

How far can we go?

Reach limited by• Torque – limited by

strength of tubulars and tool joints and is directly related to length of hole.

• Power to the bit – deeper depths or longer step outs require more power to pump mud that distance and remove cuttings from the hole.

20km by 2015?