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Strings to Remediate Annulus Gas Leak Problem

Mohamed El-Sayed Ibrahim , Ahmed Khalifa Al-Neaimi , Mohamed

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Mohamed El-Sayed Ibrahim , Ahmed Khalifa Al-Neaimi , Mohamed Abdelsalam Hassane , Abdul Salam Mohamed Al-Mansoori , Shanof

Mohamed , Omar Al-Mutwali , ADMA OPCO

Alan Salsman, Schlumberger

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Well Data

Slide 2

� Background

Well A was Drilled & completed in November

1994 to supply gas to complex/ auto gas inj.

Into other well

Tower – three gas producers , one gas

injector and two vacant slots

� Well “A” Casing Details

Sea Level

Sea Bed

30”(224’ TVD SS)

18 5/8” Csg (5816’TVD SS)Reservoir A

Formation 1

Annulus:

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� Well “A” Casing Details

30” conductor

18 5/8” casing

13 3/8” casing

9 5/8” casing

7” liner

7” liner tied back to surface with 7 5/8”casing

2/24/2013

13 3/8” Csg (8905’TVD SS)

9 5/8” Csg (12701’ TVD SS)

7” Csg (13895’ TVD SS)

9 5/8” DV (10171’ TVD SS)

13 3/8” DV (6505’ TVD SS)

Reservoir B

Reservoir C

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Problem & Consequences

Slide 3

� Well “A” HSE Problems

� Gas/Oil Bubbles at sea bed around the conductorpipe

� High Annulus Pressure in 18 5/8” x 13 3/8” – 2600 psi(max recorded)

� High Annulus Pressure in 13 3/8” x 9 5/8” – 900 psi(max recorded)

2620 psi 900 psi

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(max recorded)

� Risk rank No. 1 - Entire tower Unsafe.

� Consequences

� All the wells on tower shut in since Jan 2001 due tothe integrity problems with Well “A”

� Huge Loss in gas Production and Injection

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Objectives

� Identify Leaking Source.

� Restore Integrity – Cure Annuli pressures and eliminategas/oil bubbles

� Abandonment of Gas Well in line with InternationalStandards

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Standards

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Leak Source Identification

Slide 5

� Well Data & Operations Review

� Leak Rate Test

� Compositional Analysis

� Noise & Temperature Logs

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� Noise & Temperature Logs

� Multiple Bleed Downs

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2620 psi 900 psi

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6

13 3/8” ECP (@ 6720’, Th

III)

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Options to Cure Leaking Source

� Milling.

� Slicing.

� Perforations.

Slide 7P

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Innovative Option -Perforation

-Gun Selection , Deeper Penetration ( 4 ½”Premium Deep Penetration charge ).

-Used Orienting Adaptors to ensure effectivegun phasing

2620 psi 900 psi

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-Selected Proper Type of squeeze cement.

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Perforation Simulation & Real Test

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Orienting Adaptors

Perforation against 4 Casings

Gun Offset by 90 degrees with Orienting Adaptors

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Orienting Adaptors Provide Effective Phasing of 18 degree

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Cement Types

Property Class-G Fine Cement

Grain Size microns ~50 <5

No limitation with (35%

Selected proper type of cement to plug the source behind & between four casings

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TemperatureNo limitation with (35%

Silica flour)Up to 320F

Compressive Strength ~3000 ~2300

Acid Solubility <3% Yes

Use When InjectivityHigh

> 5 bpm

Very Low

< 1 bpm

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Remedial Against SourceRemedial Against Source� Perforated 3 ft below 18 5/8” shoe against A – 40 ft. (PJ, 12 spf)

� 2 runs to have 24 spf

� Injectivity after perf – 3.5 BPM

� Remedial:

� Bottom Perfs – 31 bbls fine cement

� Top Perfs – 53.2 bbls fine cement

� Pressure tested to 0.8 psi/ft –

Holding

� Perforated against 4 Casings top A – 20 ft (PJ, 5 spf, 2 runs)

� Orienting Adaptors for effective

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� Orienting Adaptors for effective phasing

� Improved injectivity to 3 BPM

� Remedial

� Squeezed 40 bbls fine cement

� Pressure tested to 0.8 psi/ft –

Holding

�Losses & Continuous return f/ 13 3/8” x 9 5/8”

05/12/2013

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Top Up Job

Slide 13

• Topped Up 18 5/8” x 13 5/8”

annulus with 42 bbls Class G

cement

• Topped Up 13 3/8” x 9 5/8”

annulus with 5 bbls Class G

30''@356'

CMT BTM at 2050'

PLUG

#: 9

CMT TOP at 1700'

TOP UP CEMENT JOB COUNSUMED 42

BBL CEMENT FOR 13 3/8" X 18 5/8 & 9

5/8 X 13 3/8" Annulus.

Zero PSI

Zero PSI

Zero PSI

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annulus with 5 bbls Class G

cement

Gun Perf. in Mishrif (4580 - 4600')

7 5/8"Tieback from

12312 to surface, 39

#, C-95, BDS

Burst - 10877 psi,

Collapse - 10007 psi,

Tensile - 915 kips.

CMT TOP @ 4250'

BP #3 set at 4200'

CMT BTM at 3860'

CMT TOP at 3390'

CMT BTM at 2050'

PLUG

#: 7

PLUG

#: 8

#: 9

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Slide 14

• Injectivity tests

• Cement Squeezed

• Losses into formations

Perforation Verifications

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Perforation Verification

• Losses into formations

• Fluid to surface

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#9 CMT Plug

#8 CMT Plug

Reservoir AReservoir A

#5 CMT Plug

#7 CMT Plug

#6 CMT Plug

#2 B. Plug

#3 B. Plug

� Isolated Reservoir D

� Isolated potential leaking points

� Cured Leaking Source

� Isolated Aquifer

� 9 cement plugs

� No annulus pressure build up

Reservoir MReservoir M

Slide 15

AquiferAquifer

Abandonment Operation

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#1 CMT Plug

#4 CMT Plug

#3 CMT Plug

#2 CMT Plug

#1 B. Plug

� No annulus pressure build up

is observed.

� Each cement plug Pressure tested for integrity check.

� Squeezed off Perforations pressure tested.

Reservoir DReservoir D

Pumped 1000 bbls of Cement

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Post Abandonment Evaluation

Slide 16

� Graph shows the Annuli pressure decreasing as operation progresses.� The pressure shown after rig release is trapped pressure.

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Objective Achieved & Tower Safe for Commissioning

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Results & BenefitsResults & Benefits

ORIGINALITY: (FIRST TIME)

Success of Perforation & Cementing behind Four Casings – First Time in OPCO’s

Successful Abandonment in line with International Standards

VALUES:

� Avoided Costly & Complication Options : 5 – 10 MM $ Saving

� Tower is Safe for production and injection ( 100 MMSCFD)

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� Tower is Safe for production and injection ( 100 MMSCFD)

� Tower Integral - Vacant slots can be utilized

COLLABORATION:

Project handled by Multidisciplinary Team within ADMA and Schlumberger.

PEOPLE:

� Excellent reference for all OPCOs, shareholders and International companies

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Acknowledgements

� Heart Felt Appreciation to the management of ADNOC and ADMA-OPCO for permission to publish the paper.

Slide 18P

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� Appreciation extended to Schlumberger personnel for their continuous support.

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Thank You / Questions

Slide 19P

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Tower

Well xx

Abandoned Well

1 2 3

Vacant SlotVacant Slot

� 3 Gas Producers

� 1 Gas Injector

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Well XXSGP Prod DataGas Rate: 20 MMscfdCondensate: 37 stb/MMscf

Well XX

SGI

Injection Rate

Gas Rate: 50 MM scfd

Well XXSGP Prod DataGas Rate: 20 MMscfdCondensate: 75 stb/MMscf

456

� 1 Gas Injector

� 2 Vacant Slots