1

Gullfaks Sør, N1/N0 og Gullfaksfeltet

Tampen area

Gullfaks Satelitter Prosjektforslag til Gullfaks Landsbyen 2006

Bruk av multilaterale brønnerpå GFS Statfjord,

3

Gullfaks Sør Statfjord Formation

Discovered in 1979, and part of the Gullfaks Satellites – tie in to Gullfaks field – 10 km

Statfjord formation consist of 134 m oil zone, and gas cap

Statfjord formation

Production start: April 1999

Reservoir depth: 3300 m

Pressure, initial: 476 bar

Temp. @ 3300 m: 128 oC

4

GFS Statfjord Challenge:

• Complex reservoir with low recovery, goal +18% (LTP 2003-2008)

• PDO – 12.6 MSm3. Today 5.4 MSm3

• Increasing GOR -> reduces the oil rates.

Aggressive search to increase recovery factor:

EXTENDING THE LIMITS - STEP BY STEPS

• Additional perforation of G-2 H and F-4 H in lower Statfjord (summer 2003)

• G –1 H with RMC (2003/2004)

• G –2 YH MLT with RMC (2004)

• F –2 YH MLT with RMC (2004)

454000 455000 456000 457000 458000 459000 460000 461000

6778000

6777000

6776000

6775000

6774000

6773000

6772000

6771000

6770000

461000460000459000458000457000456000455000454000

6770000

6771000

6772000

6773000

6774000

6775000

6776000

6777000

6778000

KILOMETERS 0 1 2 KILOMETERS1:30000

D

E

FGLM

2

16

21

3875

30

32Aô

33

G-2T3H

L-3H

L-4H

3302

G-3HT2

E-4H

F4AHT3

G-1H

G-2Y2H

A3

A2

A1

A4

A6

A5

3 50 0

0

065

3

0

9

04 04

51

2

21

3875

3300

L-4H

3343

F-2Y1H

F-2Y2H

FS1

FS2

FS2.1

FS2.5

FS2.3

FS2.3

FS3

FS3.7

FS3.3

FS3.2FS3.1

FS3.4

FS3.5

FS4

FS4.2

FS4.4

FS4.3

FS4.6

FS4.5

FS4.1

FS5.1

FS8

FS8.2FS9 FS8.1

FS8

FS7

FS2.2

FS3

FS5

FS_North_bound

G-3 Y2H

G-3 Y3HG-3 Y3HT2

G-3 Y3HT3 OW

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Development of GFS Statfjord reservesGullfaks Sør Statfjord

0

5

10

15

20

25

30

35

40

45

PDO 1997 1998 1999 2000 2001 2002 2003 2004

Date

ST

OO

IP+c

on

d (

MS

m3)

0

5

10

15

20

25

30

35

40

45

Rec

ove

ry F

acto

r (%

)

STOOIP Oil reserves Recovery Factor

F-4 / G-2

drilledDIACS / MLTG-3 drilled

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Why MLT and Remote Monitoring & Control?

• Poor reservoir communication and structural complexity More drainage points reduces

the uncertainty.

– The need for more drainage point is clearly based on the STOOIP and estimated volume pr.

well.

– A smart well and MLT well will be more robust for the geologic complexity and uncertainty

in the reservoir.

• More drainage points

– will increase the estimated production pr well

– expose more of the reservoir:

• minimize the drawdown

• extra reservoir penetrations also allows access to reserves that otherwise would be likely

to be left behind.

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Why MLT and Remote Monitoring & Control?• Production experience.

– Want to keep old wellbore

– Verify contribution from each branch

– Optimize, if possible, the contribution from each branch, different drawdown and GOR

– Adjust production from different zones by surface operated valves.

– Clean-up of well easier with RMC

– More flexibility when co-producing with the other wells

– Natural gas lift

• Limited number of slots

• Aquire more data about pressure communication in the reservoir.

• Smart well technology is an insurance and it provides more data.

• Reduces the need for expensive well interventions

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Production profile one vs. multiple branches

Extra production each year

-200000.00

0.00

200000.00

400000.00

600000.00

800000.00

1000000.00

2003 2004 2005 2006 2007 2008 2009 2010

Year

Oil

pro

du

ctio

n S

m3

F-2 H North F-2 H South F-2 H Mlt

F-2 H North cum Cum .F-2 H South Cum. F-2 H Mlt

• Eclipse simulations used for justification of MLT

• Decision tree, evaluating well concept used.

• Increased production and accelerated effect.

• Possible to produce from areas of low productivity which otherwise would be left behind.

• Limited reservoir communication, need for more drainage points.

• Mitigate gas breakthrough.

Gullfaks SatelitterProsjektforslag til Gullfaks Landsbyen 2006

Innfasing av to små satelittfelt

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Skinfaks/Rimfaks IOR. RES/PRO-seminar, 23.-24.November 2005.

Situation in year 2001:

Rimfaks Brent: Production start year 2000. Spring 2001: IOR possibility documented, 2 infill wells + extra gas handling capacity gives 2.1 MSm3 of extra oil.

GF Sør L+M templates, prod.start Sept.2001. 3 flowlines to GFC for GF Sør Brent gas production. Extra capacity and tie-in possibility at L/M for upsides in GF Sør Field.

Prospects defined in the Brent Gp. and Statfjord Fm. in the Ole, Dole and Doffen (ODD) segments. (Later named Skinfaks.)

The SRI team also matured the Gulltopp (Dolly) discovery to PDO level in 2003

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RF Lunde

J RF Cook

Skinfaks/Rimfaks IOR. RES/PRO-seminar, 23.-24.November 2005.

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D

2002 2003 2004

DG1(BoK)

DG2(BoV)

DG3(BoG)

PDOdel.

33/12-8SDG1 team establ. Scr.

ph. 1

11 variants of concept ’SRI to GFC via L/M’ (re)evaluated: - 1 or 2 templates, + 1 or 2 satellites, 1 or 2 flowlines.

- Further optimising of subsea wellhead locations and subsea/pipeline cost.- Increased volumes (3.RF well, Skinfaks N1 segment, Skinfaks gas lift)

-Upside volumes quantified, value (risked) calculated.-Selection criteria: NPV (and then IRR and NPV/CAPEX disc.)

Screen.phase 2

Scr. ph. 3

Scr. Ph. 4

To L/M

Recommendation from Project, February 2004: Optimise concept ’2SX’ (1 template, 1 satellite, 2 flowlines) further towards DG2.

’Basis’ well ’Upside’ well

Scr. Ph. 5Feasibility study phase

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Økt utvinning

• Innfasing av

segment N0 & N1

29/3-1

29/3

33/12

N1 Ness

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N0 og N1

Geosnitt fra sør mot nord

N0b

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Innfasing av N0 og N1

•Reserver, produksjonsprofiler

•Antall brønner, produksjonsutfordringer

•Usikkerheter, økonomi

Gullfaks Satelitter Prosjektforslag til Gullfaks Landsbyen 2006

Gel for WC reduksjon i GF produsenterMetodikk

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Gelling reaction in water phase only

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Flømming med vann / viskøst vann

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Gel system- an intermediate system between ’weak’ and ’blocking’

1,E+00

1,E+01

1,E+02

1,E+03

1,E+04

0 0,2 0,4 0,6 0,8 1Saturation

RR

FRRFw RRFo

Polymers ------ emulsion ----------blocking

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Gelation time versus formation temperature

Gel viscosity at 90°C

0

50

100

150

200

250

300

0 1 2 3 4 5Time (hours)

Vis

co

sit

y (

cp

)

E:250/30

E:250/40

E:250/50

E:250/60

Injection of 130 m3 at injection rate of 0.9 m3/minmeans gelation time > 2.5 hours

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A-16 before/after DPR

0

20

40

60

80

100

120

140

160

180

200

23-apr-04 12-jun-04 1-aug-04 20-sep-04 9-nov-04 29-des-04

Oil

rate

[S

m³/

sd

], P

I [S

m³/

d/b

ar]

, WH

P

[ba

r]

0

400

800

1200

1600

2000

2400

2800

3200

3600

4000

Wa

ter

rate

[m

³/s

d]

Oil rate [Sm³/sd]

PI [Sm³/d/bar]

WHP [bar]

Water rate [m³/cd]

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Methods for reducing sand production

•A gel will act as glue between sand grains

– Consolidation of loose sand

– Some permeability reduction

– Permeability reduction can be controlled (minimum reduction in

water permeability)

– Increased sand free production rate

•As a result – increased production rate with the potential of reduced

water-cut

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Oppgave - stikkord

•Typer gel

•Tilbakeproduksjon/miljø

•WC, perm, sonevis

Lagdelte reservoarer

• Injeksjonsvolum

•Ønsket plassering

•Finne egnet brønn på GF