Gullfaks fieldRune Instefjord

Project leader, Gullfaks IOR

• Location: northern North Sea

• Discovered: 1978

Key data for GF main field

• Start production: 1986

• Base reserves: 356 Mill. Sm3

• Produced to date: 327 Mill. Sm3

• Expected recovery: 61 %

GullfaksGullfaks

• Location: northern North Sea

• Discovered: 1978

• Start production: 1986

• Base oil reserves: 356 Mill. Sm3

• Produced to date: 327 Mill. Sm3

• Expected recovery: 61 %

– Recovery pr. 2006: 56%

• Initial pressure: 310-320 bar at 1850 m TVD

MHN

• Bubble point pressure: ~200-240 bar at 1850 m

TVD MHN

• GOR: ~ 100 Sm³/Sm³

• Viscosity: ~ 0.5 – 1 cp

• Dip angel in western part: 12-15 deg0

500

1 000

1 500

2 000

2 500

3 000

3 500

1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020

Ra

te 1

00

0 S

m3

/mo

nth

Basis Water IOR Water Basis OIL IOR Oil Start prognosis

• Complex fault system– Main fault system trending

north-south: large faults (50 – 250 m throw)

– Secondary fault system east-west (10 – 100 m throw)

– Three structual areas

• A major challenge to realise the IOR potential, is a continuous improvement of the structural description by

– frequent seismic surveillances (conventional time lapse and Ocean Bottom Seismics)

– Use of advanced geological and reservoir simulation models

Gullfaks Field-Structural setting and reservoir performance, Gullfaks Field

A

C

BA

CB

Structural Depth Map, top Statfjord Fm. View from south.Vertical scale 4x horisontal

4000 m

3000 m

5000 m

msl

1000 m

2000 m

Statfj. Fm.

Brent Gr.

Post-Jurassic sediments

Intra-Teist refl.

7000 m

6000 m

8000 m

5 km

Basement

Low-angle detachment

Tordis break-away fault

Domino System HorstAccom-modation

Structural interpretation

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1200 14001000800600CDP 400

Statfjord Fm.

Intra-Lomvi reflector

Brent Group

Base Cretaceous unconformity

Cretaceous/Tertiary sediments

W E

DOMINO SYSTEM

ACCOMODATION

HORST COMPLEX

Line 736

Reservoir Quality• Reservoirs: Brent, Cook,

Statfjord & Lunde

• Complex reservoir, very faulted

• Porosity: 25-35 %

• Permeability:– Tarbert, Etive, good Ness, good

Statfjord and Cook- 3 >1D

– Rannoch, poor Ness, poor Statfjord, Cook-2 and Lunde : 100 mD – 1 D

• Moderate-to-High Reservoir

Quality

• Contrasting layers

• Weak formations

DRAINAGE STRATEGY (primary)

• Aquifer support

• Water injection

• Reservoir pressure over bubble point

• Injectors in the water zone

• Producers high on structure

Drainage strategy (continues)

Secondary:• Gas injection, up-dip• WAG injection

Secondary:• Gas injection, up-dip• WAG injection

• Horizontal wells

Secondary:• Gas injection, up-dip• WAG injection

• Horizontal wells

• Reservoir pressure under bubble point

Secondary:• Gas injection, up-dip• WAG injection

• Horizontal wells

• Reservoir pressure under bubble point

• Commingle production

Secondary:• Gas injection, up-dip• WAG injection

Horizontal wells

• Reservoir pressure under bubble point

• Commingle production

Why?

• Avoid production reduction when gas export is at its maximum

• Reduce storage costs and CO2 tax

• Produce attic oil

• Reduce residual oil saturation

• Reach areas difficult to reach with water injection, ex. Ness by LB injection

Why?• Avoid production reduction when gas export is at its

maximum• Reduce storage costs and CO2 tax• Produce attic oil• Reduce residual oil saturation• Reach areas difficult to reach with water injection, ex. Ness by LB

injection

• Get uniform drainage, decrease sand production• Drain by-passed oil

Why?• Avoid production reduction when gas export is at its

maximum• Reduce storage costs and CO2 tax• Produce attic oil• Reduce residual oil saturation• Reach areas difficult to reach with water injection, ex. Ness by LB

injection

• Get uniform drainage, decrease sand production• Drain by-passed oil

• Create gas lift, save drilling costs

Why?• Avoid production reduction when gas export is at its

maximum• Reduce storage costs and CO2 tax• Produce attic oil• Reduce residual oil saturation• Reach areas difficult to reach with water injection, ex. Ness by LB

injection

• Get uniform drainage, decrease sand production• Drain by-passed oil

• Create gas lift, save drilling costs

• Accelerate production

Why?• Avoid production reduction when gas export is at its

maximum• Reduce storage costs and CO2 tax• Produce attic oil• Reach areas difficult to reach with water injection, ex.

Ness by LB injection

• Get uniform drainage, decrease sand production• Drain by-passed oil

• Create gas lift, save drilling costs

• Accelerate production

230240

211210230

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538522

560574 579 588585 581582587582581582

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Historie Basis profil Reserver STOOIP

STOOIP (3,6 billion bbl)

RESERVES

PRODUCED

BASE PROFILE

Gullfaks reserves estimates through time

2,2 billion bbls

Remaining oil

Sammenligning av prognoser for basis oljeproduksjonGullfaks hovedfelt

0

5

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35

1986

1988

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mill

Sm

3 pr.

år

Produsert 88 Rev PUD 93 Høst 94 Høst RSP 96

RSP 00 RSP 02 RSP 03 RSP 04

In additon, tie-in of satellite fields has increased the oil and gas sales from the field (1994 Tordis, 1998 GF Satellites Phase 1, 2001 GF Satellites Phase 2.

Present prognosis for economical lifetime: Year 2018. Ambition: Year 2030

Reserves Growth GullfaksM

ill.

Sm

3 p

er

year

IOR at Gullfaks Main reasons for improved recovery

• Continuous focus on reservoir description and monitoring

• An increased no. of drainage points / wells and the use of superinjectors for

water injection

• Supplementary gas injection (WAG) in selected reservoir segments

• Increased process capacities where necessary both for water (prod/inj), liquid, oil

and gas

• Reduced inlet separator pressure

• Use of time-lapse (4D) seismic to map remaining hydrocarbons

Ambitions in Long Range Plan

• Produce 400 Mill. Sm³ oil in the field life time. Corresponding to around 70%

recovery factor on the main field.

• Cost reductions and an active IOR implementation is the most important

instrument to reach the ambition.

• Lengthening the field life time with several years.

• Third parts processing.

Gullfaks Main Field – oil rate prognosis

0

5

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30

351986

1990

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2018

2022

2026

Mil

lio

ns

Olj

ep

rod

uksjo

n (

Sm

3/å

r)

Basis Basis+ØOU Ambisjon

Gullfaks ”IOR ambition” project• Duration: 2006-2008.• Main goal: mature the undefined IOR ambition volumes (and more?) to RC 5.

– Identify specific measures and demonstrate that they may be economical feasible.

Mill Sm³Basis profil 0-3 Gullfaks 356,7 Senfase trykkavlastning Cook 7A Cook 1,0 Infill Cook 4A Cook 0,2 Lavtrykk Cook 7A Cook 1,1 Forbedret sweep i Cook ved økt vanninjeksjon 4A Cook 0,2 Nye IOR-brønner i Brent 4A Brent 10,6 Massiv vannsirkulering i Brent 4A Brent 7,0 Statfjord IOR 7A Statfjord 0,2 Massiv vannsirkulering Statfjord 4A Statfjord 1,3 Krans/Kyrre IOR 7A Krans 0,5 Lunde IOR 7A Lunde 2,1 CO2 prosjekt 6 Brent - Ambisjonsprofil 7A Gullfaks 17,4 Lunde IOR 0,4<Sw<0,6 7F Lunde 1,7 Sum all IOR Measures Sum All 43,3

Gullfaks Hovedfelt

Gullfaks Main Field. Improved oil recovery.

Implemented:

• Water injection from start

• Upgrading of water injection capacities

• Sand control (screens) in most wells

• ”Designer wells” (horisontal, 3D)

• Extended reach drilling (9 km drilled, 10 km well is beeing

drilled)

• Extensive exploration activity within drilling reach from

platforms => new volumes

• Hydraulic fracturing in low perm reservoirs

• WAG (Water alternating gas) injection

• ”Huff and puff” gas injection

• Monobore completions

• ”Intelligent wells”, remotely operated zone isolation valves

Implemented (continued):

• Multilateral wells

• Coiled Tubing drilling

• Through tubing drilling

• Rig assisted snubbing

• Underbalanced drilling

• Expandable liners

• 4D seismic

Studied, but discarded:

• Surfactant injection (pilot)

• Gel blocking (pilot)

• CO2 miscible injection

Under evaluation:

• MIOR (Microbiological IOR)

Water circulation

• Main mechanism for IOR at Gullfaks.

• Done a simulation study with extended

water injection.

• Maximum use of platform capacity for all

phases.

• Residual oil saturation down to 5% from

lab experiments.

• Drilling infill wells, both injectors and

producers.

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0,9

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Water Saturation

Rel

. Per

m.

Krw - Referanse Krw - Sor = 0.2

Kro - ReferanseKro - Sor =0.2

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0,01

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0,6 0,65 0,7 0,75 0,8 0,85 0,9 0,95 1

Water Saturation

Rel. P

erm

.

Water circulation, results

• Most important mechanism is the

creeping relative permeability and long

tail production from each well.

• One well has historically produced with oil

rate < 100 Sm³ and wct > 0,9 for 7 years.

• H2S is a problem, but nitrate injection

seems to control it.

• Water production may be an

environmental challenge.

Added use of today’s medicine

gives the highest contribution

to the future recovery.

WCT vs cumulative oil, history and prediction

Drilling history at Gullfaks

• 3 platforms with 42, 42 and 52 slots.

• Started with vertical wells (less than 60 deg) and 6 sub sea wells.

• After 4-5 years drilled horizontal wells.

• Water breakthrough gave sand problems:

– Gravel packed wells, screen,

– Fractured wells with proppants.

• Last 5 years

– Sidetracks.

– Through Tubing Drilling.

– Multilateral incl. DIACS in the well junction.

Sand handling project

0 2 4 6 8 10 12

Tid (timer etter bunn opp på ny rate)

01020

3040

506070

8090

100

Sand

i sa

ndfe

lle (g

ram

/tim

e)

Kurve for MSR-testing

Assumption:

Most wells on Gullfaks has sand production. Wells classified after probability for erosion. Allow higher sand production rate in the cases with low erosion risk. Monitoring erosion progress. Started at Gullfaks A in 2003 after a pilot at GFA on 3 wells in 2002. Installed at all 3 platforms in 2004. Both accelerate and increase oil recovery.

•Cumulative gain for ASR in 2003: 216 000 Sm³ which gives a daily rate of around 590 Sm3/d

Shadow area

Seismic acquisition on Gullfaks

Surface seismic 1985, 1996, 1999, 2003

OBS acquired in 2001

OBS acquired In 2003

Based on 4D/4C seismic…

XPotential new well location cancelled

After 1996 survey:

After 1999 survey:

After 2001 survey:

After 2003 survey:

Well B-4A successfully drilled in 1999

Well C-26AT2 drilled in 2003

Well C-15C drilled 2003

Well A-29A successfully drilled in 2003

Well B-15AT4 successfully drilled 2003

Well C-44A successfully drilled early 2001

Well A-21A successfully drilled early 2000

Well B-41A successfully drilled late 2000

Well C-43 under drilling

Well A-46T2 drilled mid-2000

Status 4D

• Based on 4D seismic we have drilled more than 10 wells with success.

• Top Brent (Tarbert), top Etive, top Cook and top Statfjord are the formations

where 4D has been most valuable.

• Ness, Rannoch and lower part of Statfjord is more difficult.

• Have seen 4D effects in areas around injectors were the pressure is significance

higher than initial pressure.

• All wells have hit their target and most of them produced more than expected in

the ‘Recommendation To Drill’.

Flooding map

Structural framework

Sedimentology, detailed stratigraphy

Reservoir description and initial volume

Well position, and perforation levelsProduction, injection

rates, RST and PLT

Top reservoir

OWC OWC

1985

Top reservoir

1999

Time-lapse seismic

Simulation models

Reservoir monitoring and management

Flooding map

Oil producer

Future producer

WAG injector

Water injector

Gas injector

Vannflømmet

Oljefylt

Gasskappe

Usikker vannflømming

Usikker gassflømming

Usikker gassflømming i delvis vannflømmet område

Delvis vannflømmet

Delvis gassflømmet

Delvis vann- og gass-flømmet

Usikker vann- og gass-flømming

A-XX

Prospekt

Usikker gassflømming i vannflømmet område

Delvis gassflømming i vannflømmet område

OljeprodusentVanninjektorGassinjektorVAG injektor

Syklisk prod./gassinj.Mulig injeksjonMulig produksjonØOU mål

3041

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2201

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2171

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2141

2131

2121

2111

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2091

2081

2071

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0 1 2 Km

1:32500

7

6 0

6

7

07

8

81

0

2

18

01

06

8

0

0

0

08

0

00

91

1

0

1

0

2

9

0

9

1

1

1

40

9

1

1

1

6

1

1

08

91

19

1

20

00

0

2

2

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02

2

2

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2

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0

0

06

02

60

08

02

8

001

12

0

0

21

20

2

612

12

08

06

03 32

A

B

C

A-181864

A-20

1866

A-20A

1860

A-24

1973

A-24A

1893

A-25

1985A-25A

1921

A-27

1868

A-27A

1898

A-28

1856

A-29

1899

A-32A

1894

A-32B

1826

A-45

1773

B-1

1846

B-12

1946

B-13

1902

B-16

2035

B-18

1981

B-22

1905 B-22A

1882B-23

1811

B-26

1932

B-29

1966

B-29A

2002

B-29BT2

1958

B-3

1867

B-30

1817

B-35

2037

B-36

1878

B-36AT2

1879

B-8

1876

C-171995

C-27(3)

1895

C-36A(2)

1922

C-36AT3(3)

1912

C-36AT3(2)

1923

5

1871

B-41A

1912

A-111771

A-12

1778

A-15

1851

A-161789

A-16A1791

A-19

1772

A-21A

1864

A-22

1787

A-23

1810

A-26

1778

A-301771

A-31

1790

A-33

1777

A-42(1)

1821

A-42(2)

1856

A-44

1782

A-6A

1771

A-8

1780

A-9H

1820

B-13AT2

1860

B-14

1839

B-14A

1845

B-15

1822

B-15T2

1820

B-17

1851

B-20

1832

B-21

1816

B-23(1)

1809

B-24(1)

1850

B-28(2)

1880

B-32

1795

B-34

1798

B-4A

1785

B-5AT21809

B-6

1801

B-9

1830

C-10

1878

C-15A(4)

1826

C-15A(3)

1825

C-15AT21827

C-27(2)1861

C-30(2)1803

C-31

1822

C-36A(3)

1907

C-38

1852

3

1867

34

1972

8

1797

B-21A

1818

B-41T3

1919

B-41A

1921

C-44

1889

C-44A

1894

A-21(F)

A-32(F)

A-42(F)

A-45(F)

A-7A(F)

B-29B(F1)

B-29BT2(F1)B-29BT3(F2)

B-29BT3(F1)

B-29BT3(F4)

B-29BT3(F3)

C-36(F)

C-36A(F)C-36AT3(F)

6(F)

A-1H

1756

A-17

1778A-17AT21788

A-2AH

1753

A-34/A

1752

A-35

1813

A-36

1745

A-39

1765

A-39A

1764

A-39A(2)1760

A-39A(3)1761

A-4H

1749

A-41

1808

B-10

1772B-10A

1765

B-19

1794

B-19A

1798

B-19T2

1799

B-25

1756

B-31(2)

1790

B-38

1758

B-39T2

1758

B-5

1810

B-7

1774

C-111791

C-12

1773

C-22

1800

C-23(5)

1938

C-26

1817

C-28

1777

C-35

1767

C-38

1924

C-5

1761

41795

B-4

1767

C-19(2)

1971

C-30

1783

A-41A

1792

A-10

1761

A-13

1783

A-14

1779

A-38

1765

A-3H

1758

A-5H

1762

B-11

1821

B-2

1806

B-271857

B-28

1836

B-33

1789

B-5

1810

C-15

1814

C-15A1824

C-15A

1814

C-19

1858

19121905

19101915

C-23

1853

C-23(2)

1860

C-23(3)

1867

C-23(4)

1879

C-23A

1855

C-25

1842

C-27

1823

C-3

1804

C-33

1835

C-38(2)

1951

1

1757

14

1889

9

1808

D3

D5

E1

E2

E3

E4

F1

F2

F3

F4

F5

F6

F7

G1

G2

G3

G4

G5

G6

G7

H1

H2

H4

H5

H6A

H6B

H7

I1

I2A

I2C

I3B

I4

I5A

I5B

U1

D4B

D4A

H3

A

B

C

B-35

B-16

B-12

B-17

B-9

B-21B

B-13AT2

A-23

A-16A

A-32B

A-8R2

A-28

A-29A-24A

A-22

A-46T2

A-15

A-30

A-21A

A-27A

A-25A

A-31

A-26

A-19

A-11A-20A

PBTE41

B-29BT3

PBTD31

B-29BT3

B-29BT3

PATF31

A-42

PATD11

PATE11

PBTF71

PBTD41

PBTG62

A-7A

PBTG63

34/10 GullfaksVann og gassflømming i Tarbertformasjonen

Topp Tarbert dybdekart

B-24

B-37 (F)

A-33

A-6A

B-4A

B-6

B-34

B-23 (1)

B-23 (3)

B-36AT2

B-1

B-3

B-30

B-15

B-32

B-20

PBTH53 C-30 (2)

C-31

B-14AB-26

B-18

C-27 (2)

C-27 (3)

B-41A

PCTH63

C-17

C-44A

Vannflømmet

Oljefylt

Gasskappe

Usikker vannflømming

Usikker gassflømming

Usikker gassflømming i delvis vannflømmet område

Delvis vannflømmet

Delvis gassflømmet

Delvis vann- og gass-flømmet

Usikker vann- og gass-flømming

A-XX

Prospekt

Usikker gassflømming i vannflømmet område

Delvis gassflømming i vannflømmet område

OljeprodusentVanninjektorGassinjektorVAG injektor

Syklisk prod./gassinj.Mulig injeksjonMulig produksjonØOU mål

3041

3031

3021

3011

3001

2991

2981

2971

2961

2951

2941

2931

2921

2911

2901

2891

2881

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2851

2841

2831

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2811

2801

2791

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2711

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2411

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2381

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2351

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2331

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2301

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2281

2271

2261

2251

2241

2231

2221

2211

2201

2191

2181

2171

2161

2151

2141

2131

2121

2111

2101

2091

2081

2071

3060

3050

3040

3030

3020

3010

3000

2990

2980

2970

2960

2950

2940

2930

2920

2910

2900

2890

2880

2870

2860

2850

2840

2830

2820

2810

2800

2790

2780

2770

2760

2750

2740

2730

2720

2710

2700

2690

2680

2670

2660

2650

2640

2630

2620

2610

2600

2590

2580

2570

2560

2550

2540

2530

2520

2510

2500

2490

2480

2470

2460

2450

2440

2430

2420

2410

2400

2390

2380

2370

2360

2350

2340

2330

2320

0 1 2 Km

1:32500

7

6 0

6

7

07

8

81

0

2

18

01

06

8

0

0

0

08

0

00

91

1

0

1

0

2

9

0

9

1

1

1

40

9

1

1

1

6

1

1

08

91

19

1

20

00

0

2

2

0

02

2

2

0

2

2

04

0

0

06

02

60

08

02

8

001

12

0

0

21

20

2

612

12

08

06

03 32

A

B

C

A-181864

A-20

1866

A-20A

1860

A-24

1973

A-24A

1893

A-25

1985A-25A

1921

A-27

1868

A-27A

1898

A-28

1856

A-29

1899

A-32A

1894

A-32B

1826

A-45

1773

B-1

1846

B-12

1946

B-13

1902

B-16

2035

B-18

1981

B-22

1905 B-22A

1882B-23

1811

B-26

1932

B-29

1966

B-29A

2002

B-29BT2

1958

B-3

1867

B-30

1817

B-35

2037

B-36

1878

B-36AT2

1879

B-8

1876

C-171995

C-27(3)

1895

C-36A(2)

1922

C-36AT3(3)

1912

C-36AT3(2)

1923

5

1871

B-41A

1912

A-111771

A-12

1778

A-15

1851

A-161789

A-16A1791

A-19

1772

A-21A

1864

A-22

1787

A-23

1810

A-26

1778

A-301771

A-31

1790

A-33

1777

A-42(1)

1821

A-42(2)

1856

A-44

1782

A-6A

1771

A-8

1780

A-9H

1820

B-13AT2

1860

B-14

1839

B-14A

1845

B-15

1822

B-15T2

1820

B-17

1851

B-20

1832

B-21

1816

B-23(1)

1809

B-24(1)

1850

B-28(2)

1880

B-32

1795

B-34

1798

B-4A

1785

B-5AT21809

B-6

1801

B-9

1830

C-10

1878

C-15A(4)

1826

C-15A(3)

1825

C-15AT21827

C-27(2)1861

C-30(2)1803

C-31

1822

C-36A(3)

1907

C-38

1852

3

1867

34

1972

8

1797

B-21A

1818

B-41T3

1919

B-41A

1921

C-44

1889

C-44A

1894

A-21(F)

A-32(F)

A-42(F)

A-45(F)

A-7A(F)

B-29B(F1)

B-29BT2(F1)B-29BT3(F2)

B-29BT3(F1)

B-29BT3(F4)

B-29BT3(F3)

C-36(F)

C-36A(F)C-36AT3(F)

6(F)

A-1H

1756

A-17

1778A-17AT21788

A-2AH

1753

A-34/A

1752

A-35

1813

A-36

1745

A-39

1765

A-39A

1764

A-39A(2)1760

A-39A(3)1761

A-4H

1749

A-41

1808

B-10

1772B-10A

1765

B-19

1794

B-19A

1798

B-19T2

1799

B-25

1756

B-31(2)

1790

B-38

1758

B-39T2

1758

B-5

1810

B-7

1774

C-111791

C-12

1773

C-22

1800

C-23(5)

1938

C-26

1817

C-28

1777

C-35

1767

C-38

1924

C-5

1761

41795

B-4

1767

C-19(2)

1971

C-30

1783

A-41A

1792

A-10

1761

A-13

1783

A-14

1779

A-38

1765

A-3H

1758

A-5H

1762

B-11

1821

B-2

1806

B-271857

B-28

1836

B-33

1789

B-5

1810

C-15

1814

C-15A1824

C-15A

1814

C-19

1858

19121905

19101915

C-23

1853

C-23(2)

1860

C-23(3)

1867

C-23(4)

1879

C-23A

1855

C-25

1842

C-27

1823

C-3

1804

C-33

1835

C-38(2)

1951

1

1757

14

1889

9

1808

D3

D5

E1

E2

E3

E4

F1

F2

F3

F4

F5

F6

F7

G1

G2

G3

G4

G5

G6

G7

H1

H2

H4

H5

H6A

H6B

H7

I1

I2A

I2C

I3B

I4

I5A

I5B

U1

D4B

D4A

H3

A

B

C

B-35

B-16

B-12

B-17

B-9

B-21B

B-13AT2

A-23

A-16A

A-32B

A-8R2

A-28

A-29A-24A

A-22

A-46T2

A-15

A-30

A-21A

A-27A

A-25A

A-31

A-26

A-19

A-11A-20A

PBTE41

B-29BT3

PBTD31

B-29BT3

B-29BT3

PATF31

A-42

PATD11

PATE11

PBTF71

PBTD41

PBTG62

A-7A

PBTG63

34/10 GullfaksVann og gassflømming i Tarbertformasjonen

Topp Tarbert dybdekart

B-24

Vannflømmet

Oljefylt

Gasskappe

Usikker vannflømming

Usikker gassflømming

Usikker gassflømming i delvis vannflømmet område

Delvis vannflømmet

Delvis gassflømmet

Delvis vann- og gass-flømmet

Usikker vann- og gass-flømming

A-XX

Prospekt

Usikker gassflømming i vannflømmet område

Delvis gassflømming i vannflømmet område

OljeprodusentVanninjektorGassinjektorVAG injektor

Syklisk prod./gassinj.Mulig injeksjonMulig produksjonØOU mål

3041

3031

3021

3011

3001

2991

2981

2971

2961

2951

2941

2931

2921

2911

2901

2891

2881

2871

2861

2851

2841

2831

2821

2811

2801

2791

2781

2771

2761

2751

2741

2731

2721

2711

2701

2691

2681

2671

2661

2651

2641

2631

2621

2611

2601

2591

2581

2571

2561

2551

2541

2531

2521

2511

2501

2491

2481

2471

2461

2451

2441

2431

2421

2411

2401

2391

2381

2371

2361

2351

2341

2331

2321

2311

2301

2291

2281

2271

2261

2251

2241

2231

2221

2211

2201

2191

2181

2171

2161

2151

2141

2131

2121

2111

2101

2091

2081

2071

3060

3050

3040

3030

3020

3010

3000

2990

2980

2970

2960

2950

2940

2930

2920

2910

2900

2890

2880

2870

2860

2850

2840

2830

2820

2810

2800

2790

2780

2770

2760

2750

2740

2730

2720

2710

2700

2690

2680

2670

2660

2650

2640

2630

2620

2610

2600

2590

2580

2570

2560

2550

2540

2530

2520

2510

2500

2490

2480

2470

2460

2450

2440

2430

2420

2410

2400

2390

2380

2370

2360

2350

2340

2330

2320

0 1 2 Km

1:32500

7

6 0

6

7

07

8

81

0

2

18

01

06

8

0

0

0

08

0

00

91

1

0

1

0

2

9

0

9

1

1

1

40

9

1

1

1

6

1

1

08

91

19

1

20

00

0

2

2

0

02

2

2

0

2

2

04

0

0

06

02

60

08

02

8

001

12

0

0

21

20

2

612

12

08

06

03 32

A

B

C

A-181864

A-20

1866

A-20A

1860

A-24

1973

A-24A

1893

A-25

1985A-25A

1921

A-27

1868

A-27A

1898

A-28

1856

A-29

1899

A-32A

1894

A-32B

1826

A-45

1773

B-1

1846

B-12

1946

B-13

1902

B-16

2035

B-18

1981

B-22

1905 B-22A

1882B-23

1811

B-26

1932

B-29

1966

B-29A

2002

B-29BT2

1958

B-3

1867

B-30

1817

B-35

2037

B-36

1878

B-36AT2

1879

B-8

1876

C-171995

C-27(3)

1895

C-36A(2)

1922

C-36AT3(3)

1912

C-36AT3(2)

1923

5

1871

B-41A

1912

A-111771

A-12

1778

A-15

1851

A-161789

A-16A1791

A-19

1772

A-21A

1864

A-22

1787

A-23

1810

A-26

1778

A-301771

A-31

1790

A-33

1777

A-42(1)

1821

A-42(2)

1856

A-44

1782

A-6A

1771

A-8

1780

A-9H

1820

B-13AT2

1860

B-14

1839

B-14A

1845

B-15

1822

B-15T2

1820

B-17

1851

B-20

1832

B-21

1816

B-23(1)

1809

B-24(1)

1850

B-28(2)

1880

B-32

1795

B-34

1798

B-4A

1785

B-5AT21809

B-6

1801

B-9

1830

C-10

1878

C-15A(4)

1826

C-15A(3)

1825

C-15AT21827

C-27(2)1861

C-30(2)1803

C-31

1822

C-36A(3)

1907

C-38

1852

3

1867

34

1972

8

1797

B-21A

1818

B-41T3

1919

B-41A

1921

C-44

1889

C-44A

1894

A-21(F)

A-32(F)

A-42(F)

A-45(F)

A-7A(F)

B-29B(F1)

B-29BT2(F1)B-29BT3(F2)

B-29BT3(F1)

B-29BT3(F4)

B-29BT3(F3)

C-36(F)

C-36A(F)C-36AT3(F)

6(F)

A-1H

1756

A-17

1778A-17AT21788

A-2AH

1753

A-34/A

1752

A-35

1813

A-36

1745

A-39

1765

A-39A

1764

A-39A(2)1760

A-39A(3)1761

A-4H

1749

A-41

1808

B-10

1772B-10A

1765

B-19

1794

B-19A

1798

B-19T2

1799

B-25

1756

B-31(2)

1790

B-38

1758

B-39T2

1758

B-5

1810

B-7

1774

C-111791

C-12

1773

C-22

1800

C-23(5)

1938

C-26

1817

C-28

1777

C-35

1767

C-38

1924

C-5

1761

41795

B-4

1767

C-19(2)

1971

C-30

1783

A-41A

1792

A-10

1761

A-13

1783

A-14

1779

A-38

1765

A-3H

1758

A-5H

1762

B-11

1821

B-2

1806

B-271857

B-28

1836

B-33

1789

B-5

1810

C-15

1814

C-15A1824

C-15A

1814

C-19

1858

19121905

19101915

C-23

1853

C-23(2)

1860

C-23(3)

1867

C-23(4)

1879

C-23A

1855

C-25

1842

C-27

1823

C-3

1804

C-33

1835

C-38(2)

1951

1

1757

14

1889

9

1808

D3

D5

E1

E2

E3

E4

F1

F2

F3

F4

F5

F6

F7

G1

G2

G3

G4

G5

G6

G7

H1

H2

H4

H5

H6A

H6B

H7

I1

I2A

I2C

I3B

I4

I5A

I5B

U1

D4B

D4A

H3

A

B

C

3041

3031

3021

3011

3001

2991

2981

2971

2961

2951

2941

2931

2921

2911

2901

2891

2881

2871

2861

2851

2841

2831

2821

2811

2801

2791

2781

2771

2761

2751

2741

2731

2721

2711

2701

2691

2681

2671

2661

2651

2641

2631

2621

2611

2601

2591

2581

2571

2561

2551

2541

2531

2521

2511

2501

2491

2481

2471

2461

2451

2441

2431

2421

2411

2401

2391

2381

2371

2361

2351

2341

2331

2321

2311

2301

2291

2281

2271

2261

2251

2241

2231

2221

2211

2201

2191

2181

2171

2161

2151

2141

2131

2121

2111

2101

2091

2081

2071

3060

3050

3040

3030

3020

3010

3000

2990

2980

2970

2960

2950

2940

2930

2920

2910

2900

2890

2880

2870

2860

2850

2840

2830

2820

2810

2800

2790

2780

2770

2760

2750

2740

2730

2720

2710

2700

2690

2680

2670

2660

2650

2640

2630

2620

2610

2600

2590

2580

2570

2560

2550

2540

2530

2520

2510

2500

2490

2480

2470

2460

2450

2440

2430

2420

2410

2400

2390

2380

2370

2360

2350

2340

2330

2320

0 1 2 Km

1:32500

7

6 0

6

7

07

8

81

0

2

18

01

06

8

0

0

0

08

0

00

91

1

0

1

0

2

9

0

9

1

1

1

40

9

1

1

1

6

1

1

08

91

19

1

20

00

0

2

2

0

02

2

2

0

2

2

04

0

0

06

02

60

08

02

8

001

12

0

0

21

20

2

612

12

08

06

03 32

A

B

C

A-181864

A-20

1866

A-20A

1860

A-24

1973

A-24A

1893

A-25

1985A-25A

1921

A-27

1868

A-27A

1898

A-28

1856

A-29

1899

A-32A

1894

A-32B

1826

A-45

1773

B-1

1846

B-12

1946

B-13

1902

B-16

2035

B-18

1981

B-22

1905 B-22A

1882B-23

1811

B-26

1932

B-29

1966

B-29A

2002

B-29BT2

1958

B-3

1867

B-30

1817

B-35

2037

B-36

1878

B-36AT2

1879

B-8

1876

C-171995

C-27(3)

1895

C-36A(2)

1922

C-36AT3(3)

1912

C-36AT3(2)

1923

5

1871

B-41A

1912

A-111771

A-12

1778

A-15

1851

A-161789

A-16A1791

A-19

1772

A-21A

1864

A-22

1787

A-23

1810

A-26

1778

A-301771

A-31

1790

A-33

1777

A-42(1)

1821

A-42(2)

1856

A-44

1782

A-6A

1771

A-8

1780

A-9H

1820

B-13AT2

1860

B-14

1839

B-14A

1845

B-15

1822

B-15T2

1820

B-17

1851

B-20

1832

B-21

1816

B-23(1)

1809

B-24(1)

1850

B-28(2)

1880

B-32

1795

B-34

1798

B-4A

1785

B-5AT21809

B-6

1801

B-9

1830

C-10

1878

C-15A(4)

1826

C-15A(3)

1825

C-15AT21827

C-27(2)1861

C-30(2)1803

C-31

1822

C-36A(3)

1907

C-38

1852

3

1867

34

1972

8

1797

B-21A

1818

B-41T3

1919

B-41A

1921

C-44

1889

C-44A

1894

A-21(F)

A-32(F)

A-42(F)

A-45(F)

A-7A(F)

B-29B(F1)

B-29BT2(F1)B-29BT3(F2)

B-29BT3(F1)

B-29BT3(F4)

B-29BT3(F3)

C-36(F)

C-36A(F)C-36AT3(F)

6(F)

A-1H

1756

A-17

1778A-17AT21788

A-2AH

1753

A-34/A

1752

A-35

1813

A-36

1745

A-39

1765

A-39A

1764

A-39A(2)1760

A-39A(3)1761

A-4H

1749

A-41

1808

B-10

1772B-10A

1765

B-19

1794

B-19A

1798

B-19T2

1799

B-25

1756

B-31(2)

1790

B-38

1758

B-39T2

1758

B-5

1810

B-7

1774

C-111791

C-12

1773

C-22

1800

C-23(5)

1938

C-26

1817

C-28

1777

C-35

1767

C-38

1924

C-5

1761

41795

B-4

1767

C-19(2)

1971

C-30

1783

A-41A

1792

A-10

1761

A-13

1783

A-14

1779

A-38

1765

A-3H

1758

A-5H

1762

B-11

1821

B-2

1806

B-271857

B-28

1836

B-33

1789

B-5

1810

C-15

1814

C-15A1824

C-15A

1814

C-19

1858

19121905

19101915

C-23

1853

C-23(2)

1860

C-23(3)

1867

C-23(4)

1879

C-23A

1855

C-25

1842

C-27

1823

C-3

1804

C-33

1835

C-38(2)

1951

1

1757

14

1889

9

1808

D3

D5

E1

E2

E3

E4

F1

F2

F3

F4

F5

F6

F7

G1

G2

G3

G4

G5

G6

G7

H1

H2

H4

H5

H6A

H6B

H7

I1

I2A

I2C

I3B

I4

I5A

I5B

U1

D4B

D4A

H3

A

B

C

B-35

B-16

B-12

B-17

B-9

B-21B

B-13AT2

A-23

A-16A

A-32B

A-8R2

A-28

A-29A-24A

A-22

A-46T2

A-15

A-30

A-21A

A-27A

A-25A

A-31

A-26

A-19

A-11A-20A

PBTE41

B-29BT3

PBTD31

B-29BT3

B-29BT3

PATF31

A-42

PATD11

PATE11

PBTF71

PBTD41

PBTG62

A-7A

PBTG63

34/10 GullfaksVann og gassflømming i Tarbertformasjonen

Topp Tarbert dybdekart

B-24

B-37 (F)

A-33

A-6A

B-4A

B-6

B-34

B-23 (1)

B-23 (3)

B-36AT2

B-1

B-3

B-30

B-15

B-32

B-20

PBTH53 C-30 (2)

C-31

B-14AB-26

B-18

C-27 (2)

C-27 (3)

B-41A

PCTH63

C-17

C-44A

Partly water flooded

Uncertain flooding

Water flooded

Gas flooded or originally in place

Oil filled

Alternative recovery methods

• Surfactant pilot in the early 1990’s. Full field project stopped due to:

– Chemical cost was too high relative too its efficiency.

– Remaining oil saturation after water flooding was lower than expected.

– Surfactant system efficiency was too little robust.

• CO2 MWAG Study last years

– Simulations done on Frontsim and Eclipse 300.

– Potential of 10-20 Mill. Sm³ oil identified.

– Too high cost totally and therefore a none economic project with to days

framework condition.

AMIOR

• Alternative project to reduce residual oil at Gullfaks.

• Add nitrate (doing already due to reduction of H2S), phosphate and oxygen to

the injection water.

• Reducing surface tension between oil and water and thereby mobilize oil.

BACTERIA + OIL + N + P + O2

MOBILISED RESIDUAL OIL ENHANCED SWEEP EFFICIENCY

AMIOR

• Pilot in well A-41B recommend.

• Closed area with steady-state conditions.

• Good reservoir understanding.

• Good spacing between injector and

producer.

• A-36 has an established water cut

growth.

• A-41B is perforated in the oil zone.

Prospects

• A wide range of prospects in the licence.

• Drill from the platforms where possible.

• Use existing infrastructure to produce

from the discoveries.

• Commercial solutions for prospects

across licence boundary.

• Coordinate exploration and production

drilling.

• Combine targets where possible.

Conclusions

• Recovery of 400 mill. Sm³ (app. 70% recovery factor).

• Lengthening the field life time.

• Water circulation is the main IOR method.

• Drilling of new and less expensive wells important.

• Alternative recovery methods may be a substantial part of the future.

• Exploration and third part processing contributes.

• Close collaboration between the different technical disciplines is an important

premise to reach the ambition.

Requirements to moving volumes from resource category 7a and 6 to 5a

Requirements to moving volumes from resource category 7a and 6 to 5a, cont…• Profitable measure• Assumptions regarding this evaluation are given in Appendix B• Likelihood of implementation equal to or greater than 30 %.

A way of calculating the likelihood of implementation is given in Appendix C.

• Prepare plan (studies, eventual technology qualification, manning, budget,) and timing for next phase (when is the right time to proceed). The level of detail of such a plan depends on the size of the project/measure.

• Documentation shall include; – Production effects (all HC phases) in the targeted reservoir(s)– Simple uncertainty estimation for production effects (low-medium-high)– Is the measure competing with other measures (yes/no – which ones)– Evaluate whether the measure has any consequence for process capacities[1] (yes/no – which ones)– Cost(Capex and OPEX) estimate for the measure (class A)– Economical evaluation– Plan and timing of next phase

•[1] If yes; will the measure displace other measures?