Breakthrough Horizontal Drilling Performance in Pre-Khuff Strata with

Steerable Turbines

Mike Simpson, Shaohua Zhou, Dave Treece, Carlos Rondon, Tom Emmons, Saudi Aramco; Craig Martin Sii-Neyrfor and

Mohammad Tahir, Diamant Drilling Services

SPE 90376

Outline

Introduction

Economic Importance of Pre-Khuff Reservoirs

Pre-Khuff Geology

Turbo-drilling Experience in Saudi Arabia

Breakthrough Horizontal Drilling Performance

Turbo-drill Runs in Potassium Formate Brines

Conclusions

Introduction

Saudi Aramco Produces 8.1 mmbopd, 6.9 bscfd non-associated Gas &1 mmbpd NGL’s

Introduction

It operates 49 Land and Offshore Drilling & Workover Rigs consisting of:

25 Onshore Oil Rigs

3 Offshore Oil Rigs

21 Land Gas Rigs, 2000 hp or larger

Economic Importance of Pre-Khuff Reservoirs

25% Gas Prod. f/Pre-Khuff – Mostly UnzyUnzy’s Most Abrasive & Problematic to DrillGas Demand will inc. to 12 bscfd by 202550-55% of this must come from the Pre-Khuff Currently Drlg. 47 Gas Wells/year w/18 RigsUtilizes three Workover Rigs & one Snub. U.Unzy Well Design Changed to Horz. in 2003 to meet demand

Pre-Khuff Geology

Pre-Khuff – Formations of Lower Permian Age or older deposited before the Khuff

Include the Unayzah, Jauf, Tawil, Sharawra, Qusaiba, Sarah, Qasim and Saq

Mainly hard and ultra abrasive sandstones interbedded with siltstones and shales

Shales often unstable requiring 1500 psi overbalance to mitigate tight hole

Unayzah A, B & C

Unzy-A has 3000

to 9000 psi UCS (PDC Drillable)

Unzy-B (7000-27,000 on this RMA) Too hard & Abrasive for PDC’s – TCI’s & Impregs Only

Unzy-C 9000-22,000 UCS

Unayzah-A Core from Tinat-6

•Abrasive

• Not as Hard as UNZY-B

•Friable

Internal friction angle (phi): Unayzah reservoir core rock mechanics lab test result

40

45

50

55

60

65

0 2 4 6 8 10 12 14

porosity (%)

inte

rnal

fri

ctio

n a

ng

le (

deg

)

phi (WDYH-1)

phi (GHZL-2)

phi (GHZL-3)

Unayzah Porosity vs. Abrasivity from Offset Core

Unayzah Angle of Internal Friction typically ranges between 42 and 63° for the A, B and C.

BHA: 3 BHA TYPE : VerticalDATE: WELL : TINAT #3

JOB N° : RIG: SF 162 ARAMCOGRAPHIC DESCRIPTION OD (in)ID (in) LENGTH ( ft )SERIAL N°

8 3/8" Hughes Christensen S279G8-3/8" -- 1.17 1.17)

CUSTOMER :

15 x HWDP

2 x Drill Collars

5" 3" 452.41970.82ARAMCO

Jars

6-1/2" 59.45518.41 ARAMCO

Cross-Over 6-1/2” 1.49 458.96ARAMCO

Flex Joint 457.47ARAMCO

12 x Drill Collars

6-1/2” 1.50 426.81ARAMCO

6-1/2"

2-13/16"367.27425.31 ARAMCO

Roller Reamer 6-1/2" 2-7/8" 6.30 58.04 ARAMCO

8 3/8"

Circulating Sub 2 " 1.80 51.74 ARAMCO

Turbine Section 1 6-5/8" -- 17.61 49.94

Turbine Section 2 -- 16.96 32.33

8-516"

Turbine Bearing Section6-5/8" 12.40 15.37

Bit-Box-Stabilizer 3" 0.95 2.12 NEYRFOR

64010

6-5/8"

6-1/2"

Cross-Over 2-13/16"

66039

66042

2-13/16"15.33

8-516"

ARAMCO442.14

6-1/2"2-13/16"15.33

2-13/16"

2-13/16"

BIT-STUCK BHA: TINAT #3

8/30/97

--

Bearing Shaft(Box-End)

6-1/2"

6-5/8"

--

-- 0.85 2.97 NEYRFOR

The 1st Vertical Turbo-drill run was made with a Two Stage conventional turbine and Imprenated diamond Bit from 16,143 to 16,149’.

Attempted to pick up off bottom for connection, bit stuck on bottom on 8/30/97.

Back-reamed and jarred fish up to 16,144’.

Spotted Diesel, Pipe-Lax and 15% HCl, No Success.

Finally string-shot/backed off @ 14,674’ & again @ 15,736’ leaving 430’ of fish (Bit / turbine / CS / NBRR / 12 DC’s) in hole.

Lost time: 12 days

Stuck Pipe/Fishing Cost: $560,000

Turbo-drilling Experience in Saudi Arabia – 1st Run

Drilling Report

BHA: 2 BHA TYPE:VerticalDATE: WELL :

JOB N° : RIG:NAD-117 ARAMCOGRAPHICDESCRIPTIONOD (in)ID (in)LENGTH ( ft )SERIAL N°

CUSTOMER :9/21/97QTIF-150

BIT-STUCK BHA: QATIF #150

15 HWDP 3-1/2"2-1/16"458.84980.22ARAMCO

Jars

4-3/4"2-1/4"62.43521.388ARAMCO

2 x Drill Collars

12 x Drill Collars4-3/4"2-1/4"

28.36458.59ARAMCO

Roller Reamer4-3/4”2-1/4"5.2956.10ARAMCO

5-7/8"

Cross-Over 2 1/4"1.0750.81ARAMCO

5-13/16"Turbine Section 14-3/4"-- 18.2149.7446114

5-13/16"Turbine Section 24-3/4"-- 17.3231.5346115

5-13/16"Turbine Bearing Section4-3/4"-- 12.21514.212

(Box-End) Bearing Shaft

0.782.00

5 7/8"-- 1.221.225-7/8” Impreg Bit (Pin-Up

4-3/4"

4-3/4"

374.49 ARAMCO430.59

4-3/4"2-1/4"

--

Drilled 5-7/8” Hole with T-2 Turbine and 5-7/8” STC-K35TX Impreg Bit from 16,135 to 16,147’ (12’). Picked up to make connection and stuck pipe 7’ off bottom on 9/20/97.

Spotted 40 bbl Grease pill - jarred and worked on pipe, no success.

Spotted 1100 gal of HF acid & two 40 bbl EZ-Spot Pills & Worked pipe.

String Shot Backed off @ 15,866’ leaving 274’ of fish (7 DC, NBR, XO, Turbine & Bit) in hole.

Worked on fish a total of 11 days then decided to ST.

Spent another 13 days sidetracking back to 16,147’.

Total Time lost: 23 days

Total Stuck Pipe/Fishing Cost: $690,000

Turbo-drilling Experience in Saudi Arabia - 2nd Run

Drilling Report

BHA:2 BHA TYPE:

VerticalDATE: WELL:

JOB N° : RIG:SF 174 ARAMCOGRAPHICDESCRIPTIONOD (in)ID (in)LENGTH ( ft )SERIAL N°

32 x 3-1/2" HWDP3-1/2"2-1/16"986.671549.9ARAMCO

3 x Spiral Drill Collars4-3/4"2-1/4"92.94563.22ARAMCO

Jars 4-3/4"2-1/4"31.35470.28ARAMCO

10 x Spiral Drill Collars4-3/4"2-1/4"310.73438.93ARAMCO

5-13/16"String Stabilizer-- 2-1/4"5.76128.20ARAMCO

2 x Spiral Drill Collars4-3/4"2-1/4"62.18122.44ARAMCO

Bit Sub w/ Float Valve4-3/4"2" 3.1560.26ARAMCO

Cross Over Double Pin.4-1/2"1-3/8"1.4457.11ARAMCO

5-13/16"String Stabilizer-- 2-1/4"5.7755.67ARAMCO

5-13/16"Turbine Section 14-3/4"-- 18.2049.9046143

5-13/16"Turbine Section 24-3/4"-- 17.3031.7046122

5-13/16"Turbine Bearing Section4-3/4"-- 12.1914.40Bearing Shaft (Pin-End) Safety Sub 5" 1-3/16"0.901.90 5-7/8"-- 1.001.005-7/8” Impreg bit (Box-Up / T.F.A: =1.00in²)

CUSTOMER:

BIT STUCK – HRDH-642

HRDH-642 12/28/99

4-3/4"-- 0.312.21

Drilled 5-7/8” Hole with T-2 Turbine and 5-7/8” STC-KGRCETPX Impreg Bit from 13,975 to 14,057’ in the Unayzah-B. Picked up to check 9’ Drilling Break f/5-25 fph – Pipe Stuck.

Spotted 50 bbl Hi-Vis and Grease pills & jarred with 25K, no success.

Jarred out of Neyrfor Bit Safety Sub with 60K. Left bottom half of Safety Sub and Impreg bit on bottom (1.57’).

Milled and worked on fish with 5-7/8” Burn shoes, Cobra Mills, Taper Taps and Jars for 21 days and finally broke through.

Total Time lost: 23 days

Total Stuck Pipe/Fishing Cost: $842,000

Turbo-drilling Experience in Saudi Arabia - 3rd RunDrilling Report

Primary Cause of Bit StickingRadial Hole Deformation

elastic hole deformation(E = 2.8 Mpsi, v = 0.3, Biot = 0.8, TVD = 14050 ft

Sv = 1.05 psi/ft, Shmax = 1.27 psi/ft, Shmin = 0.82 psi/ftPp = 90 pcf, MW = 100 pcf)

0.900

0.925

0.950

0.975

1.000

1.025

1.050

05 10 15 20 25

3035

4045

5055

606570

7580

85

90

95

100105

110115

120125

130135

140145

150155160165170175

180185190195200205

210215

220225

230235

240245

250

255260

265

270

275

280285

290295

300305

310315

320325

330335340345350355

For 8 3/8" bithole size reduction = 0.0684 (in)hole enlargement = 0.3936 (in)

For 5 7/8" bithole size reduction = 0.0476 (in)hole enlargement = 0.2761 (in)

roller cone bit drills hole usually1/16" (0.0625 in) larger than bit size

Shmax

Shmin

initial hole size

after elastic deformationdue to high in-situ stresses

initial breakout zone

Radial Hole Deformation and breakout in the near wellbore region due to High Insitu Stresses

Equivalent to 1/16” in 8-3/8” hole and 1/32” in 5-7/8” hole

Radial Hole Deformation

Excessive Breakouts normally occurred across Sandstones, as shown in this Image Log from HWYH-950

Secondary Cause of Bit Sticking – Unstabilized Rotating Length

Bit Box Stab

Pin Up Bit Box Down ShaftLower Brg Stab Turbine Body

2.97 ft

2.00 ft

Turbine BodyLower Brg StabBox Down ShaftPin Up Bit

2.21 ft

Turbine BodyLower Brg StabPin Down Shaft

Box Up Bit

TINAT-38 3/8”

Bit Sticking

QATIF 1505 7/8”

Bit Sticking

Haradh 6425 7/8”

Bit StickingBit Safety Sub

1.43

Box Up Bit

Pin Down Shaft

Lower Brg Stab

Turbine Body

HWYH 9618 3/8”

NO Bit Sticking

Turbo-drilling Experience in Saudi Arabia – 4th Run

4th Vertical Run on HWHY-961:

8-3/8” IADC M842 Impreg bit with Box-up Connection

Turbine Sleeve with Back-reaming Feature

Prismatic Link Release Mechanism (120,000 lbf)

Turbo-drilling Experience in Saudi Arabia – 4th Run

Run on HWYH-961

Made 242’ in 23.5 hrs @ 10.3 fph with cost of $443/ft

Figure 11: Caliper Log over Turbo-Drilled Interval (100 pcf MW) (No undergauge hole across Unayzah or Jauf)

7.250

7.625

8.000

8.375

8.750

9.125

9.500

9.875

10.250

10.625

11.000

11.375

11.750

12.125

12.500

13690

13700

13710

13720

13730

13740

13750

13760

13770

13780

13790

13800

13810

13820

13830

13840

13850

13860

13870

13880

13890

13900

13910

13920

13930

13940

Depth (feet)

Cal

iper

(in

ches

)

0

20

40

60

80

100

120

140

GR

(ap

i)

CALX (in)

CALY (in)

GR (api)

Khuff -D

Anhydr i teUnayzah Jauf

HWYH-961 – No Undergauge hole across Unayzah or Jauf

Fourth Turbodrill Run – No Undergauge hole

Horizontal Vs. Vertical Well Productivity

Horizontal Wells showed substantial increase in productivity over Vertical Wells without Fracking

GH

ZL-3

GH

ZL-8

GHZL-4

GHZL-11(H)GHZL-10 GHZL-5 GHZL-7(H)

GHZL-2

GHZL-9(DL)

GHZL-6(H)GHZL-1

Unayzah even tougher to drill horizontally

Diminished bit performance in 5-7/8” vs. 8-3/8” bits

Diminished bit performance in Horizontal vs. Vertical Hole

Requirement that all bit runs be made on PDM’s at much higher RPM’s than on rotary

Diminished bit performance in the target reservoir - the Unayzah-B

Abrasive Wear/Lost Cones – PDC/Impreg Wear Major Problems in Unayzah-B

Two 5-7/8” IADC 627Y TCI’s lost all three cones while drilling Unayzah-B on WDHY-1

HSE concern over tripping frequency with TCI’s (every 14 hrs) in desert climate with daytime temp ≥120°F

Lost Cones – PDC/Impreg Wear Major Problems in Unayzah-B

RR Impreg 100% Worn after drilling 22’ in 8.5 hours

Run on Low-Speed PDM

ROP: 2.6 fph

WOB: 13,000 lbf

RPM: 190Dull: 8-8-RO-G-X1/16

Lost Cones – PDC/Impreg Wear Major Problems in Unayzah Formation

PDC completely cored out after Drilling 219’ in 26.5 hours

Run on Low-Speed PDM

ROP: 8.2 fph

WOB: 18,000 lbf

RPM: 240Dull: 8-7-RO-M-X-IN-CR&BT-PR&DMF

Horizontal Solution to Radial Hole DeformationDrill Paralell to Maximum Horz. Stress Axis

Horizontal Wellbore Drilled Due East or West in Ghawar Area(Parallel to Shmax)

•Shmax

ShmaxShmax

Vertical WellHole diameter reduction causing ”bit sticking”

Slight Hole diameter enlargement providing stable hole & drilling

conditions “no sticking”

Shmax

Solution to hole spiraling – One Stage 4-3/4” Steerable Turbine & Box-Up bit (Min. Rot. Length)

One Power Section

99 Pressure Profile Turbine Blade Sections

Flexible Titanium Drive Shaft with1° integral bend

Use of Box-up bit with Turbine-Sleeve

Breakthrough Horizontal Drilling Performance on WDHY-1

1st Horizontal Run: 5-7/8” IADC M842 Box-up 12 blade Impregnated diamond bit run on advanced steerable turbodrillDrilled 737’ averaging 5.5 fph in 134 rotating hours with cost of $402/ft. Graded 3-3-WT-A-X-I

Breakthrough Horizontal Drilling Performance on WDHY-1

2nd Horizontal Run: 5-7/8” IADC M842 Box-up 12 blade Impregnated diamond bit run on advanced steerable turbodrill, drilled 852’ averaging 7.0 fph in 122 rotating hours with cost of $330/ft. Graded 3-3-WT-A-X-I

Turbo-drill Operating Parameters

WDYH-1(re): turbine drilling parameters (SA5.4)

0

5

10

15

20

25

30

35

40

1585

0

1590

0

1595

0

1600

0

1605

0

1610

0

1615

0

1620

0

1625

0

1630

0

1635

0

1640

0

1645

0

1650

0

1655

0

1660

0

1665

0

1670

0

1675

0

measured depth, ft

RO

P /

WO

B /

Cir

c M

nt

0

500

1000

1500

2000

2500

3000

3500

4000

RP

M /

GP

M /

PS

I

Circ Mntaver WOBROP FT/HRturbine RPMPress PSIFlow GPM

WOB: 4,000 lbf

RPM: 1,400

ROP: 7.0 fph

P. Press: 2900 psi

Circ. Rate: 220 gpm

Breakthrough Horizontal Drilling Performance on WDHY-1

100 200 300 400 500 600 700 800 900

SA5.2 WDYH-4

XR40YODPDWDYH-4

KRG50CETPXXWDYH-1

SA5.4 WDYH-1

FOOTAGE DRILLED

TURBINE

TURBINE

PDM

PDM

FORMATION DRILLED

Unayzah –B –Siltstone/ Sandstone

100 200 300 400 500 600 700 800 900

SA5.2 WDYH-4

XR40YODPDWDYH-4

KRG50CETPXXWDYH-1

SA5.4 WDYH-1

FOOTAGE DRILLED

TURBINE

TURBINE

PDM

PDM

FORMATION DRILLED

Unayzah –B –Siltstone/ Sandstone

Breakthrough Horizontal Drilling Performance on WDHY-1

14000

14500

15000

15500

16000

16500

17000

17500

MD

(Fee

t)

8/3/2003 8/10/2003 8/17/2003 8/24/2003 8/31/2003 9/7/2003 9/14/2003

WDYH-1 first lateral, 5-7/8" bit record

SA5.4

KRG50OETPXX

MILL

XTG48PX

SL63DGKPR

XSD57D

DSX143D

XR40YOD

R4

Impreg/Turbine Runs

58% of Total Footage

TCI, PDC, IMPREG/PDM RUNS

TCI/PDM RUNS

AVERAGE 5-7/8" BIT PERFORMANCE IN UNAYZAH-B For WDHY-1 & 4

BIT TYPE # RUN

AverageFOOTAGE

AverageHOURS

Avg. ROP

Avg.$/FT

DULL GRADET- B

TSP/PDM 1 13 7 1.9 4608 3---3

IMPREG/PDM 7 82 23 3.6 2219 8---8

IMPREG/TURB 2 794 128 6.2 366 3---3

PDC/PDM 14 152 28 5.5 1233 6---5

TCI/PDM 49 124 12 10.6 545 5---8

TSP/PDMIMPREG/PDM

IMPREG/TURB.PDC/PDM

TCI/PDM

4608

13

2219

82

366

794

1233

152

545

1240

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Fo

ota

ge

Co

st,

$/F

T

$/FT FOOTAGE

Turbo-drill Runs in Potassium Formate Brines

Clear “solids free” Liquid the can be used as drilling, spotting, workover or completion fluids

Sodium Formate – up to 85 pcf Potassium Formate up to 98 pcf Cesium Formate up to 144 pcf Used in over 400 wells since introduced by

Shell in 1993 Extends Temperature Range of Conventional

Viscosifiers and Fluid Loss Agents from 240-340º F. Cesium Formate successful up to 429°F

Turbo-drill Runs in Potassium Formate Brines

3rd Horizontal Run: 5-7/8” IADC M842 12 Blade Impreg run on 4-3/4” Turbine in Unzy-B on HRDH-658Suffered Total Failure of Impreg Segment Cutting Structure

Turbo-drill Runs in Potassium Formate Brines

4th Horizontal Run: 5-7/8” IADC M842 8 Blade Impreg run on 4-3/4” Turbine in Unzy-B on HRDH-658Drilled 81’ in 24.5 hrs at 3.31 fph in 93 pcf K-Formate Brine Drilling Fluid

Turbo-drill Runs in Potassium Formate Brines

5th Horizontal Run:

5-7/8” IADC M842 12 Blade Impreg run on 4-3/4” Turbine in Unzy-B on HRDH-658

Drilled 60’ in 16 hrs at 3.75 fph in 102 pcf K-Formate Brine Drilling Fluid

Effect of Overbalance of Rock Confined Compressive Strength

Increased overbalance between formation and Drilling fluid increase confined compressive strength and impede drilling rates

18000

20000

22000

24000

26000

28000

30000

32000

34000

36000

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

confined pressure (overbalance) in psi

rock

co

mp

ress

ive

stre

ng

th (

psi

)

f = 40o

f = 45o

f = 50o

f = 55o

f = 60o

Potassium Formate Brine Performance HRDH-658

Use of a 102 pcf potassium Formate Brine with excess CaCO3 on HRDH-658:

Lowered Pump Pressures

Decreased Rotating Torque and Drag

Allowed a 11,649’ horizontal section to be drilled with 1500 psi overbalance without differentially sticking the drillstring

Turbo-drill Run in 90 pcf K-Formate Brine on Tinat-3

4-3/4” Steerable Turbo-drill prior to being RIH on Tinat-3

Setting Turbo-drill bearing section in Mouse-hole

Stabbing Power Section onto BearingSection & Making up same

Making up Turbine Sleeve Impreg Bit and checking bearing gap on Turbo-drill

RIH with Turbo-drill Assembly

Record Breaking ROP run in Tinat-3 Unayzah-A

6th Horizontal Run:

5-7/8” M834 Impreg drilled 360’ in 50 hrs @ 7.2 fph with avg cost of $402/ft.

Graded 3-4-WT-A-X-I

Run in 90 pcf Sodium/Potassium Formate drilling fluid

Average 5-7/8" Bit Performance on Tinat-3 in the Unayzah-A

BIT TYPE # RUN

AverageFOOTAGE

AverageHOURS

Avg. ROP

Avg.$/FT

DULL GRADET- B

IMPREG/TURB 1 360 50 7.2 410 1---0

PDC/PDM 3 320 35 9.3 320 5---5

TCI/PDM 2 118 13 8.9 472 2---1

IMPREG/TURB.PDC/PDM

TCI/PDM

410

360320320

472

118

0

100

200

300

400

500

Average Drilling Cost,

$/FT $/FT

FOOTAGE

Potassium Formate Brine Performance in Tinat-3

Lowered Pump Pressures from 4200 to 3400 psi at 220 gpmDecreased Rotating Torque from 9400 to 7600 ft-lbReduced hole drag from 25,000 to 10,000 lbf at the end of the horizontal section

Composition of formate-based drilling fluidComponent Function Concentration

Formate brine Density control

Lubricity

Polymer protection

Biocide

1 bbl

Xanthan Rheology control

Drag reducer

1 ppb

Modified starch and/or ULV PAC

Fluid loss control 4 –8 ppb

Sized calcium carbonate

Bridging agent 20 ppb

Potassium carbonate

pH and corrosion control

2 ppb

Typical properties of formate-based drilling fluid

Property Initial Hot rolling @285oF

Mud density (pcf) 90 90

PV (cp) 24 30

YP (lb/100 ft2) 22 29

Gel (lb/100 ft2) 4/5 7/9

API Filtrate (cc/30 min)

2.4 1.8

HTHP fluid loss (cc/30 min) @ 285oF

13.6 12

ph 10.5 11

Solids Control System for K-Formate Brine

Two Decanting Centrifuges

Two Linear Motion Shale Shakers w/180 & 200 Mesh Screens

Total Solids Content ~ 5%

Drill Solids ~ 0.45%

Potassium Formate Brine Liquor in Individual Bulk Containers (IBC’s)

Potassium Formate Powder in 25 kg sacks

Poor-Boy Brine Recovery System

Drain Lines from Rig Floor

Brine collected in IBC’s for Reuse

Expandable Sand Screen Completion

Well Completed with 1410’ of 4”/230 micron expandable Sand Screens

Run and expanded without major problems.

1

Successful Installation of 1410 ft of Expandable Sand Screens in TINT-3

7" Liner, 32 ppf@ 15191 ft MD

9-5/8" Casing, 58.4 ppf

7" Liner

Reservoir top

Running

4" ETC, 230 micron, 5-½" 15.5#Vam FJL Box x 4" ESS Pin

4" ESS 230 micron, 38ft, 4"ESS Box x Pin

Sand ControlCirculating Valve,4-½" Stub AcmeBox Up

4" EBC, 230 micron, 4" ESSBox x 4-½" Stub Acme Pin

6' EXY Tieback PBR, 5.625" OD 8TPI S.AcmeThreaded Down

7" x 5-½" EXP Deployment Hanger/Packer5.625" OD 8TPI S.Acme Thread Up x 5-½" 15.5 lb/ft Vam FJL Pin Down

M. Depth of 7" Liner Shoe : 15191 ftM.Depth/Length of 5-7/8" O.H. : 16747 ftTotal Length of O.H. : 1556 ft5-7/8" O.H. Max Inclination : 84.5 degMud : 90 pcf (Na/K/Formate)Total ESS Run Length : 1410 ft (37Jnts)

Top EXP @14482 ft

5-7/8" hole, TD@ 16747 ft

ESS Screenbottom at 1606 ft(131 ft from TD)

7" LinerHanger top @ 14181 ft

@ 14711 ft

Hanger top @ 13465 ft

Bridge Plug top @ 14014 ft

Whipstock top @ 13990 ft

7" Liner Shoe@ 15698 ft

Conclusions

Steerable turbo-drill/Impreg bit drilling has emerged as the most cost effective and HSE friendly manner to drill the Unayzah-B formation if the well can be drilled parallel to the maximum horizontal stress axis.

Trajectory control was improved with consistent reactive torque of 30-35° and a build rate of 0.3°/100’ in the rotating mode.

Conclusions, cont.

IADC 627-737 TCI bits are also cost effective when total revolutions are maintained in the 150,000 to 175,000 total revolutions range.

PDM/PDC drilling appears to be the cheapest way to drill the lower compressive strength Unayzah-A horizontally in the Tinat Area.

Conclusions, cont.

The 90 & 102 pcf potassium formate brines used in Tinat-3 & HRDH-658 provided lower pump pressures, torque and drag values and better bit performance than previously observed with conventional water base drilling fluids.

In HRDH-658 the 102 pcf K-Formate Brine allowed a 1649’ quasi-horizontal section to be drilled with 1500 psi overbalance without differential sticking.

Conclusions, cont.

Plans are to use Impreg/Turbo-drill assemblies over the entire Unayzah build and horizontal sections in conjunction with K-formate brines to further access their applicability and cost savings potential.

Breakthrough Horizontal Drilling Performance in Pre-Khuff Strata with

Steerable Turbines

Thank You! Questions?

SPE 90376