Acid Diversion Technique and Perforation Job Design ... · Acid Diversion Technique and Perforation Job Design Improves Injection Profile in Carbonate Reservoir ... Matrix Acidizing

Schlu

mberg

er

Confidential

2011 Middle East and North Africa Perforating

Symposium - MENAPS

Acid Diversion Technique and Perforation Job Design

Improves Injection Profile in Carbonate Reservoir

Jamal M.A Al-Gub, Tsuneo Horikoshi, and Kazutoshi Ichikawa, Bunduq Co., Ltd., Alan

Salsman SPE, Fardin Ali Neyaei SPE, and Fidias Vasquez SPE, Schlumberger.

Presenter: Fardin M. Ali Neyaei

2

Carbonate Reservoir

• Continuous reservoir

• Four layers

• Limestone – Dolomite mix

• Significant permeability

variations

Perf

Interval

Top Bottom Length

(ft)

Perm

(md)

1 x776 x798 22 9.5

2 x798 x828 30 44.7

3 x828 x882 54 16

4 x892 x912 20 3.6

Volumes10

PU/division

3

Gas Injection Profile in 2005

9 5/8” casing shot with 2” Deep Penetration Guns

Flow

Spin

Temp

4

2009 Workover

• Convert dual water string water injector into single string

gas injector

• Cement 7” liner inside existing 9 5/8” casing

• Remove completion and squeeze perfs

• Re-perforate same intervals and stimulate

• Effort made to improve injection profile

5

Perforation Design

New 7” Casing Completion inside 9 5/8”

Perforating System #1, 7.3 g

60º Phasing, 6.00 spf

Pore Pressure: 4200 psi

Vertical Stress: 8284 psi

Rock UCS: 8000 psi

Rock Type: Limestone

Formation

MR Scanner Measure Depth

Cement

Cement

Brine

0 deg

0

0

5

5

10

10

15

15

20

20

Angle Clearance Total Pen Form Pen Form Dia Csg EH Dia(deg) (in) (in) (in) (in) (in)

0 4.28 6.93 3.94 0.15 0.10/0.07

60 2.60 8.20 5.21 0.21 0.13/0.10

120 0.46 11.72 8.73 0.32 0.21/0.16

180 0.00 11.70 8.71 0.34 0.22/0.17

240 0.46 11.72 8.73 0.32 0.21/0.16

300 2.60 8.20 5.21 0.21 0.13/0.10

Average 1.74 9.74 6.76 0.28 0.17/0.13

AOF (in²/ft) 0.08 at 6.00 spf

API: Pen 21.80 in, EH Dia 0.22 in, 19B 1st Ed.

Company: Bunduq Well: EB-48

Results are based on API and other test data of Schlumberger perforating systems as well as computermodeling of perforated completions. Results are provided in good faith without warranty

File: C:\Program Files\Schlu...nduq EB 48 paper Arab D2.SP8SPAN Version 8.0l© Copyright 2009 Schlumberger

Perforating System #2, 38.8 g

72º Phasing, 5.00 spf

Pore Pressure: 4200 psi

Vertical Stress: 8284 psi

Rock UCS: 8000 psi

Rock Type: Limestone

Formation

MR Scanner Measure Depth

Cement

Cement

Brine

0 deg

0

0

5

5

10

10

15

15

20

20

Angle Clearance Total Pen Form Pen Form Dia Csg EH Dia(deg) (in) (in) (in) (in) (in)

0 1.78 22.55 19.56 0.67 0.37/0.33

72 1.05 24.47 21.49 0.80 0.44/0.40

144 0.13 24.93 21.95 0.74 0.41/0.37

216 0.13 24.93 21.95 0.74 0.41/0.37

288 1.05 24.47 21.49 0.80 0.44/0.40

Average 0.82 24.27 21.29 0.75 0.42/0.37

AOF (in²/ft) 0.55 at 5.00 spf

API: Pen 59.20 in, EH Dia 0.43 in, 19B 1st Ed.

Company: Bunduq Well: EB-48

Results are based on API and other test data of Schlumberger perforating systems as well as computermodeling of perforated completions. Results are provided in good faith without warranty

File: C:\Program Files\Schlu...nduq EB 48 paper Arab D2.SP8SPAN Version 8.0l© Copyright 2009 Schlumberger

2” gun, 6 spf

Pen – 6.8”, avg EH – 0.17/0.13 4.5” gun, 5 spf

Pen – 21.3”, avg EH – 0.42/0.37

6

Inject Index (II) Modeled

• Predict II for each layer with each perforation option

• More consistent II with 2” gun in Layer 2 • 4 ½” gun in layers 1, 3 and 4

7

Matrix Acidizing Design

• Considered 3 different acid scenarios • 15% HCl

• 15% HCl + 5% Self Diverting Acid

• 28% Emulsified Acid + 5% Self Diverting Acid

•+15% HCl post flush

• 15% HCl typical in this area

• Modeled using proprietary PC based modeling software

• Acid and diverter placed with coiled tubing • Assists with diversion requirement

8

Radial Penetration Prediction

0 2 4 6 8

Radial Penetration (ft)

8700

8750

8800

8850

8900

8950

Zon

e M

D (ft)

HCl 15%

StimCADE*

*Mark of Schlumberger

Radial Penetration Plot

1-2 HCL ONLY02-16-2009

• 15% HCl

9.5 md

44.7 md

3.6 md

16 md

9


• 15% HCl + 5% self diverting acid

0 2 4 6


8700

8750

8800

8850

8900

8950

Zone

MD

(ft)

HCl 15%

Self Diverting Acid 5%

StimCADE*



1-2-hcl-sda02-16-2009

10


• 28% Emulsified Acid + 5% Self Diverting Acid +15% HCl

0 1 2 3 4 5


8700

8750

8800

8850

8900

8950

Zone

MD

(ft)

Emuslified Acid 28%

Sef Diverting Acid 5%

HCl 15%

StimCADE*



1-2 sda5% with 15%HCL post flush02-16-2009

11

Wormhole Length Prediction

• 15% HCl

0 50 100 150 200 250 300

Volume (bbl)

0

0.5

1.0

1.5

2.0

2.5

3.0

Wor

mho

le L

engt

h (ft)

Zone 1

Zone 2

Zone 3

Zone 4

1

--- Treatment Fluids --- 1 - HCl 15%

StimCADE*


Acid Placement: Wormhole length vs. Volume by Zone

1-2 HCL ONLY02-16-2009

12

0 50 100 150 200 250 300

Volume (bbl)

0

0.5

1.0

1.5

2.0

2.5

3.0

Wor

mho

le L

engt

h (ft)

Zone 1

Zone 2

Zone 3

Zone 4

1 2 1 2 1 2 1 2 1

--- Treatment Fluids --- 1 - HCl 15% 2 - 5% Self Diverting Acid

StimCADE*



1-2-hcl-sda02-16-2009


• 15% HCl, 5% Self Diverting Acid

13


• 28% emulsified acid, 15% HCl, 5% self diverting acid

0 50 100 150 200 250 300

Volume (bbl)

0

0.5

1.0

1.5

2.0

2.5

3.0

Wor

mho

le L

engt

h (ft)

Zone 1

Zone 2

Zone 3

Zone 4

1 2 1 2 1 2 1 2 1 3

--- Treatment Fluids --- 1 - 28% Emuslion Acid 2 - 5% Self Diverting Acid 3 - HCl 15%

StimCADE*



1-2 sda5% with 15%HCL post flush02-16-2009

14

Final Stimulation Design

28% emulsified acid, 5% self diverting acid, 15% HCl

•What happens in each stage?

15

Execution- Pumping Record

02:15:16 03:21:56 04:28:36 05:35:16 06:41:56

Time - hh:mm:ss

0

125

250

375

500

625

750

875

1000

Pre

ssu

res -

ps

i

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

To

tal P

um

p R

ate

- bb

l/min

8750

8775

8800

8825

8850

8875

8900

8925

8950

CT

Dep

th -

ft

WH Press.

Total Pump Rate

CT Depth

Diversion deltaP

CCAT*

© Schlumberger 1994-2006

Pressure and Rate

BUNDUQEB4809-April-2009

Figure-13: Execution chart; pumping rate, CT depth and wellhead pressure versus operational time

x950

x925

x900

x875

x850

x825

x800

x775

x750

Diversion Delta P

16

Immediate Results: Injectivity test

0

350

700

1050

1400

1750

2100

0 200 400 600 800 1000 1200 1400 1600 1800

Time

Well

Head

Pre

ssu

re (

Psi)

0.00

1.00

2.00

3.00

4.00

5.00

6.00

Rate

(b

pm

)

WHP-1 WHP-2 RATE-1 RATE-2

Injectivity test before and after the job, 1 being before and 2 being after the job

17

RESULTS

PRODUCTION RUN LOGS RUN IN 2005

AND 2009 DURING WATER PUMP-IN TEST

PLT - 2009 PLT - 2005

18

Well Injection Results

• Injection profile improved

• Injection rate maintained

• Injection effect seen in nearby well

• Initial increase in oil production

19

Conclusions

• Unique situation where 2 completion strategies could be

evaluated on the same interval

• Combination of the tailored perforating program + the acid

matrix stimulation improved the injection profile

• Improve bottom zone with additional perforating or Dynamic

Underbalance clean-up

• Good set of well data + a team approach to planning and

execution = successful job

20

Questions?

Documents

Acid Diversion Technique and Perforation Job Design ... · Acid Diversion Technique and Perforation Job Design Improves Injection Profile in Carbonate Reservoir ... Matrix Acidizing