Casing DrillingCasing Drilling--Recent Advances for Drilling ChallengesRecent Advances for Drilling Challenges

SPE Gulf Coast SectionSPE Gulf Coast SectionJanuary 10, 2001January 10, 2001

Allen Sinor Allen Sinor Hughes ChristensenHughes Christensen-- A Baker Hughes CompanyA Baker Hughes Company

The Woodlands, TexasThe Woodlands, Texas

Casing Drilling Isn’t New…..Casing Drilling Isn’t New…..•• Mid 20’sMid 20’s-- Retractable Bits in Poland/France (Retractable Bits in Poland/France (GelfgatGelfgat))•• Mid 70’sMid 70’s-- Retractable Bits in Siberia (Retractable Bits in Siberia (GelfgatGelfgat))•• Early 80’sEarly 80’s-- California Heavy Oil Sands California Heavy Oil Sands •• Mid 80’sMid 80’s-- West Texas West Texas InfillInfill Drilling (Weaver)Drilling (Weaver)•• Late 80’sLate 80’s-- High Speed Coring/Drilling (High Speed Coring/Drilling (MillheimMillheim))•• 90’s90’s

•• Unsaturated / InUnsaturated / In--Situ (LongSitu (Long-- DOE Yucca DOE Yucca MtnMtn.).)•• Depleted Reservoir Sections (Sinor, Depleted Reservoir Sections (Sinor, VogtVogt))•• Unstable Formations / Ocean Drilling (O.D.P.)Unstable Formations / Ocean Drilling (O.D.P.)•• Well Cost Reduction (Well Cost Reduction (TessariTessari, Warren), Warren)

Casing Drilling HistoryCasing Drilling History

Drilling ChallengesDrilling Challenges

Why Casing Drilling?Why Casing Drilling?

•• Getting Casing / Liner to Total DepthGetting Casing / Liner to Total Depth

•• Running Casing / Liner into Depleted Running Casing / Liner into Depleted

Pay with Weak Matrix StrengthPay with Weak Matrix Strength

•• Minimizing Flat TimeMinimizing Flat Time

•• Extending the Length of Open Extending the Length of Open WellboresWellbores

•• Mitigating Shallow Gas / Water HazardsMitigating Shallow Gas / Water Hazards

•• Rubble Zones Above / Below Salt DomesRubble Zones Above / Below Salt Domes

Getting Casing / Liner to Total DepthGetting Casing / Liner to Total Depth

Bestline Bestline Liner SystemsLiner Systems

Liner Drilling in Heavy Oil ApplicationLiner Drilling in Heavy Oil Application

Evolutionary Process……• Bridges While TIH With Liner• Drilling Liner to Remove Obstacles• Drilling Liner Underbalanced• Drilling Liner and Gravel Packing

Successes• 2000 Liner Drilling Completions Since 1981• 260+ in 1998, 100+ in 2000• Three Sizes

•8-1/2” bit (or 7”x15” UR) with 7” liner for 9-5/8” casing•7-7/8” bit (or 7”x15” UR) with 6-5/8” liner for 8-5/8” casing•Same for 5-1/2” liner for 8-5/8” casing•6-1/8” bit (or 6”x13” UR) with 5-1/2” liner for 7” casing

• Texaco, Chevron, Aera Energy LLC + independents• INCREASED PRODUCTION

DRILL PIPE

BOP

DRILL IN NIPPLE

UNDERREAMER

CASING

CASING SHOE

BIT

PILOT HOLE

ROTATING HEAD

DIRECTION OF CIRCULATION

LINER

DIVERTER LINE

Procedure• Run Liner to Casing Shoe• Establish Foam Rate and Pressure• Establish Shoulder for Underreaming• Begin Foam Drilling• Take Returns Through Diverter Line

ONE STEP Completion System• Drill and Underream Liner• Gravel Pack Liner• Release Liner• All Steps Completed in One Trip

DRILL PIPE

BOP

SLOTTED LINER

UNDEREAMER

CASING

CASING SHOE

BIT

GRAVEL PACK VALVE

DIVERTER LINE

DIRECTION OF CIRCULATION

CASINGVALVE

ROTATING HEAD

• At TD, Circulate Foam Until Clean• Switch Returns to Casing Valve• Close Hydril • Drop Ball Down Drillpipe, Opening

Gravel Pack Valve Inside Liner• Foam Down Drillpipe, Out Through

Liner Slots and Casing Valve

ROTATING HEAD

DRILL PIPE

BOP

SLOTTED LINER

UNDERREAMER

CASING

BIT

GRAVEL PACK VALVE

CASING SHOE

DIVERTER LINE

DIRECTION OF CIRCULATION

CASINGVALVE

Begin Gravel Packing• Reverse Foam Down Casing, Liner

Slots and Gravel Pack Valve• Begin Adding Gravel to Foam • Continue at Slow Rate Until Liner Has

Packed Off• Bleed Off Pressure, Drop Release Ball• Circulate to Remove Sand from Liner

Top• Pull Tools and Tailpipe Out of the Hole

Running Casing / Liner into Depleted Pay Running Casing / Liner into Depleted Pay

with Weak Matrix Strengthwith Weak Matrix Strength

Baker Hughes Inc.Baker Hughes Inc.

North Sea- Valhall• 10 Wells Drilled Rotating the Liner• 7 Wells Drilled with a Drill-in Liner• Liner Sizes of 5”, 7”, 7-5/8” and 9-5/8”• Liner Lengths up to 4,472’ / Inclination up to 67°• Successful Drilling into Severely Depleted Pay (∆ 7 ppge• Significant Well Cost Savings (~$2MM/well)

Offshore Indonesia- Arun Field• 9 Wells Drilled with a Drill-in Liner• Liner Sizes of 7” and 9-5/8”• Liner Lengths up to 6,872’ / Inclination up to 67°

Liner Drilling SuccessesLiner Drilling Successes

North SeaNorth Sea-- ValhallValhall Field (BP Amoco)Field (BP Amoco)

Valhall Field

Depleted Oil Reservoir

• Lista Top Formation 14.7 ppg, Tor Payzone 7,0 ppg• Top of Reservoir ca. 2400 - 2500 m• Sea Level ca. 200 m

9 5/8” Liner• Used for New Drills

7” and 7 5/8” Liner• Used for Reentry (Sidetrack) Wells

• Sidetrack off Whipstock• Directionally Drill Section

Mobil Indonesia / North SumatraMobil Indonesia / North Sumatra-- Arun Arun FieldField

Depleted Gas Reservoir• Top of Reservoir ca. 2900 - 3200 m• Shale 14,7 ppg, Limestone 2.5 ppg

7” Tools: Reentry Application• Section Milling• Whipstock• Perforate & Squeeze or no Cementing

North Sea North Sea Valhall Valhall Challenges:Challenges:High porosity / low matrix permeabilityHigh porosity / low matrix permeabilityResult: weak matrix reservoir Result: weak matrix reservoir

Production ChallengesProduction Challenges•• Solids productionSolids production•• Reservoir compactionReservoir compaction•• SubsidenceSubsidence

Drilling ChallengesDrilling Challenges•• Reservoir compaction (9 ft)Reservoir compaction (9 ft)•• Reservoir depletion (up to 8Reservoir depletion (up to 8 ppgeppge))•• Lista Lista shale (overburden) fracturingshale (overburden) fracturing

Depleted Pay With Weak Matrix StrengthDepleted Pay With Weak Matrix Strength

•• Drillable PDC Bit ShoeDrillable PDC Bit Shoe•• Float CollarFloat Collar•• Landing CollarLanding Collar•• PackerPacker-- optionaloptional•• LinerLiner•• Liner Hanger / PBR PackerLiner Hanger / PBR Packer•• Rotating Liner Hanger Running ToolRotating Liner Hanger Running Tool•• HWDPHWDP•• DrillpipeDrillpipe to surfaceto surface

Rotary MethodRotary Method

•• PDC orPDC or RollerconeRollercone PilotPilot•• UnderreamerUnderreamer-- optionaloptional•• Core ShoeCore Shoe•• Mud MotorMud Motor•• Drill CollarsDrill Collars•• Thruster / Bumper SubThruster / Bumper Sub•• Liner Hanger Running ToolLiner Hanger Running Tool•• DrillpipeDrillpipe to surfaceto surface

DrillDrill--in Methodin Method

Drill Pipeto Surface

Liner HangerPackerRunning Tool

Drill Pipe (inner string)

Thruster Motor

Landing Sub Standard Lower BHA

Rotating Core Shoe / Pilot Bit

Step 1:Step 1:Drill aboveDrill aboveproblem zoneproblem zone

Step 2:Step 2:Drill Liner into zoneDrill Liner into zoneRotary or Motor MethodRotary or Motor Method

Step 3:Step 3:Isolate CasingIsolate CasingCement / PackersCement / Packers

Liner Drilling ProcedureLiner Drilling Procedure

DrillDrill--in Liner Procedurein Liner Procedure

DL_Movie.exe

Liner Example: Well 2/8Liner Example: Well 2/8--AA--2A2A

Depth(m)

ROP(m/hr)

WOB(klbs)

RPM Flow(gpm)

P(psi)

3,157 9.0 5.5 75 210 12803,158 11.9 6.5 90 150 8403,159 8.7 7.5 90 150 8303,160 13.5 7.5 90 150 8403,161 14.3 7.5 90 145 8703,162 7.7 10.5 90 145 9003,163 6.3 6.5 90 145 9233,164 7.0 8.5 90 145 9003,165 7.1 12.0 90 140 10503,166 4.9 11.5 90 145 8503,167 2.8 7.5 90 140 6803,171 2.0 4.0 80 180 260

Well 2/8Well 2/8--AA--2A2A

Results:Results:•• Drilled 15.6m in 3.2 hours, 4.9 m/hrDrilled 15.6m in 3.2 hours, 4.9 m/hr•• Drilled 7.6m of depleted TORDrilled 7.6m of depleted TOR•• Total losses of 14.6Total losses of 14.6 ppgppg mud was 1,350mud was 1,350 bblsbbls•• Annulus kept full with 69Annulus kept full with 69 bblsbbls of 6.8of 6.8 ppgppg base oilbase oil•• Mill drilled landing/float collar, shoe in 65 min.Mill drilled landing/float collar, shoe in 65 min.•• Reduced rig time from 33.8 days to 15.6 daysReduced rig time from 33.8 days to 15.6 days•• Estimated savings of $1.82MM ($100k/day)Estimated savings of $1.82MM ($100k/day)

Liner Shoe ImprovementsLiner Shoe Improvements

Well 2/8Well 2/8--AA--3B3BWell 2/8Well 2/8--AA--2A2A

• Anti-whirl features• Four blades• Shorter PDC cutters (cone)• Lower cone angle• Thicker base plate

• Carbide Cutters• Two blades

Carbide CuttersSaw Cuts forImproved Milling

Well 2/8Well 2/8--AA--8A(T2)8A(T2)

• Anti-whirl features• Two blades• Bicenter design• PDC cutters• Larger nozzles

TimeTime

Liner Drilled WellsLiner Drilled Wells

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A-1A A-2A A-8A A-3B F6

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track

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edril

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l 1

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Well 312.1 days

Well 1Baseline33.8 days

Well 215.6 days

$2.2MM$2.2MMSavingsSavings

$1.8MM$1.8MMSavingsSavings

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elin

e

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WellName

Year HoleAngle(deg)

LinerSize(in)

LinerLength

(ft)

LengthDrilled

(ft)

DrillTime(hrs)

Comments

A-1A 1993 0 5.00 568 899 29.0 F.H. 6” PDC bitHod A-7B * 1995 40 11.75 5335 89 2.5 Bit, UR, PDM, SpearA-2A 1995 7 7.00 3346 49 6.5 Rotary / PDC shoeA-8A 1996 5 7.00 1640 7 2.5 Rotary / PDC shoeA-8A(T2) 1996 5 7.00 1640 28 1.5 Rotary / PDC shoeA-3B 1996 2 7.00 3960 31 2.5 Rotary / PDC shoeF6 1996 60 9.63 4472 3 1.0 Rotary / PDC ShoeA-9A ** 1997 12 7.63 2789 64 12.0 Rotary / PDC ShoeA-5B 1997 60 7.63 433 66 2.5 Rotary / PDC ShoeA-22A 1999 64 9.63 801 Motor then Rotary buA3D 2000 67 9.63 24 Rotary / PDC

Rotary Liner Drilled WellsRotary Liner Drilled Wells

* Bit and underreamer, inner string motor and casing spear** Drilled in three attempts due to casing failure at window

Changed from 3.6° exit angle to 2.1° on whipstock

# Date Customer Field Liner Liner Measured Depth Drilling Incl. DLS Remark finalLocation Well length OD / ID weight in out Distance Time Result

1 Jun.1995 Mobil Arun 493 m 7" 35 ppf 3240 m 3264 m 24 m 9 hrs 56° 7°/30 m No hanger used Successful

Indonesia C-I-16 1616 ft 5.879" 10626 ft 10707 ft 80 ft 7°/100 ft Releasing tool problems

2 Sep.1995 Mobil Arun 912 m 7" 35 ppf 3212 m 3236 m 25 m 16 hrs 53° 8°/30 m Problems start drilling Successful

Indonesia C-II-8B 2992 ft 5.879" 10534 ft 10615 ft 81 ft 8° / 100 ft Releasing tool problems

3 Dec.1995 Mobil Arun 1024 m 7" 35 ppf 3402 m 3462 m 60 m 33 hrs 51° 8°/30 m Releasing tool problems Successful

Indonesia C-I-12 3360 ft 5.879" 11157 ft 11355 ft 198 ft 8°/100 ft

4 Oct.1997 Mobil Arun 915 m 7" 35 ppf 3049 m 3062 m 12.8 m 9 hrs 38° 2°/30 m Meptec & BOT involved Successful

Indonesia C-II-6 3000 ft 5.879" 10000 ft 10042 ft 42 ft 2°/100 ft No problems

5 Nov.1997 Amoco Valhall 2080 m 9 5/8" 53.4 ppf 3551 m 3570 m 19 m 1.5 hrs 67° 2°/30 m Only sliding Mode SuccessfulNorway 2/8-F17 6822 ft 8.5" 11646 ft 11709 ft 62 ft 2°/100 ft No problems

6 Dec.1997 Mobil Arun 808 m 7" 35 ppf 3264 m 3265 m 0.76 m 1.5 hrs 43° 2°/30 m No problems Successful

Indonesia C-IV-9 2650 ft 5.879" 10705 ft 10707.5 ft 2.5 ft 2°/100 ft

7 Jan.1998 Amoco Valhall 1445 m 9 5/8" 53.4 ppf 2652 m 2669 m 17 m 3 hrs 63° n/a Only sliding mode Successful

Norway 2/8-F11 4674 ft 8.5" 8698 ft 8756 ft 56 ft n/a No problems

8 Jan.1998 Mobil Arun 806 m 7" 35 ppf 3021 m 3027 m 5.8 m 15.5 hrs 36° 3.3°/30 m Differential - Successful

Indonesia C-II-3B 2642 ft 5.879" 9908 ft 9927 ft 19 ft 3.3°/100 ft Sticking problems

9 Feb.1998 Amoco Valhall 1600 m 7 5/8" 39 ppf 4295 m 4302 m 7 m 3 hrs. 60° 1.5°/30 m Only sliding Mode, stalling Successful

Norway 2/8-A-19A 5277 ft 6.5" 14087 ft 14110 ft 23 ft 1.5°/100 ft problems, Nodeco Hanger

10 Mar.1998 Mobil Arun 837 m 7" 35 ppf 3192 3202 m 10.4 m n/a 39° n/a got stuck on the first trial, Succesful

Indonesia C-1-8 2747 ft 5.879" 10469 ft 10503 ft 34 ft n/a fishing required, roller reamer

11 May.1998 Amoco Valhall 1352 m 9 5/8" 53,4 ppf 2563 m 2575 12 m 2 hrs. 3° 2.5°/100 ft slow drilling Succesful

Norway 2/8-F14 4434 ft 8,5" 8406 ft 8445 ft 39 ft 2.5°/30 m DL set 10 m into reservoir

12 July.1998 Amoco Valhall # 7 5/8" 39 ppf # # # # # # Tool failed at the rig site due abandoned

Norway 2/8 A-6A # 5.879 # # # # # # to wrong handling pocedure DL Job

13 Oct. 98 Mobil Arun 655 m 7" 35 ppf 3529 m 3556 m 27,4 m 37,8 hrs 63° 2,9°/100 ft no problems, first MOI DL Successful

Indonesia C-II-21 2148 ft 5.879" 11574 ft 11664 ft 90 ft 2.9°/30 m Whipstock Sidetrack

14 Nov-98 Mobil Arun 758 m 7" 35 ppf 3296 m 3325 m 29 m 6 hrs. 38° n/a not stuck, finiched drilling Succesful

Indonesia C-IV-4 ST 2487 ft 5,879" 10810 ft 10905 ft 95 ft when set 61 ft into reservoir

DrillDrill--in Liner Wellsin Liner Wells

Minimizing Flat Time Minimizing Flat Time

Improving Drilling Efficiency with Casing DrillingImproving Drilling Efficiency with Casing Drilling

Tesco Tesco CorporationCorporation

Casing Drilling Successes• Two Horizontal Test Wells• 18 Commercial Wells Drilled

• 16 Land• Two Offshore

• Directional up to Horizontal (7” casing) • Casing Sizes Drilled

• 4-1/2” • 7”• 9-5/8”

Casing Used for Drillstring

Uniform, Reduced Volume Annulus

Retrievable Bottom Hole Assembly- Drill lock assembly- Directional tools, if needed - Under reamer or drilling shoe- Pilot Bit

Operation:- Casing rotated- No drill string tripping - Almost continuous circulation- Casing on bottom at all times

Casing Clamp

Extend

Clamp(9-5/8” - 3-1/2”)

Four Wells• 800 ft Surface Holes• Drilled 12-1/4” Hole• Cemented 9-5/8” Casing

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Wyoming

PDCRollercone

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Wyoming- Wamsutter FieldFive Surface Holes Drilled to 1200’ (7” Casing)

Two 12-1/4” Holes Drilled with 9-5/8” Casing Depths of 3200 & 3800 ft

A - 14 A - 13A - 12

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75.5 hrs

Offshore Gulf of Mexico

January 2001• Surface Hole

– 8-1/2” hole drilled with 7” casing to 1200 ft– Tesco Underreamer and Hughes PDC pilot bit– Retrieve BHA & cemented (no plug)– 8 hr drilling time - 12.5 hr total time

• Production hole– 6-1/4” hole drilled with 4-1/2” casing to 9,436 ft– BHA retrieved in good shape after 236 drilling hrs– Pay zone drilled underbalanced– Retrieved BHA with wireline & pumped cement float– Successful cement job including float holding pressure

Deepest Casing Drilled Well

Additional Activities…..Additional Activities…..

BETA• Drilled 500’ w/10-3/4” casing & 12-1/4” Rollercone• Rotary Speeds Up to 300 rpm

Gulf of Mexico• Extending the Reach

– ~30 Disposable Motor Runs Past Two Years– 5-7/8” & 6-1/4” Bits / 7-5/8” Casing / 4-3/4” Motors

• ~8 Large Diameter Casing Strings Drilled– 10” & 18-5/8” Casing– Water Depths of 300’ - 800’

Bit Bounce -- CoPilot Run 3, Trigger 5

DownholeTorque

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Surface IndicatedWeight

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BETA Well ComparisonBETA Well Comparison

10-3/4” Casing BHA12-1/4” Hole

Standard Packed BHA w/ 8” Drillcollars

SummarySummary

Continuing Advances in Liner / Casing Drilling• Proven Successes

– Getting Casing / Liner to Total Depth– Running Casing / Liner into Depleted Pay with Weak Matrix

Strength– Minimizing Flat Time– Improving Drilling

• Opportunities– Flat Time Reduction with Large Diameter Surface Holes– Extending the Reach or Hole Section Limits– Shallow Water Flows