1. Gullfaks Sør, N1/N0 og Gullfaksfeltet
Tampen area

2. Gullfaks Satelitter Prosjektforslag til Gullfaks Landsbyen Bruk av multilaterale brønner på 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 )
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)

5. Development of GFS Statfjord reserves
drilled
G-3 drilled
DIACS / MLT

6. 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.

7. 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

8. Production profile one vs. multiple branches
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.

9. Gullfaks Satelitter Innfasing av to små satelittfelt
Prosjektforslag til Gullfaks Landsbyen 2006
Innfasing av to små satelittfelt

10. Situation in year 2001:
The SRI team also matured the Gulltopp (Dolly) discovery to PDO level in 2003
Rimfaks Brent:
Production start year 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 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.)
Skinfaks/Rimfaks IOR. RES/PRO-seminar, November 2005.

11. 11 variants of concept ’SRI to GFC via L/M’ (re)evaluated:
DG1 team establ.
Scr. ph. 1
Screen.phase 2
Scr. ph. 3
Scr. Ph. 4
Scr. Ph. 5
33/12-8S
Feasibility study phase
DG1
(BoK)
DG2
(BoV)
DG3
(BoG)
PDO
del.
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.)
To L/M
Recommendation from Project, February 2004:
Optimise concept ’2SX’ (1 template, 1 satellite, 2 flowlines) further towards DG2.
As we now know, concept for Gulltopp was in next screening round changed to paltform well.
’Basis’ well
’Upside’ well
Skinfaks/Rimfaks IOR. RES/PRO-seminar, November 2005.

12. Økt utvinning
Innfasing av segment N0 & N1

13. N0 og N1

14. Innfasing av N0 og N1 Reserver, produksjonsprofiler
Antall brønner, produksjonsutfordringer
Usikkerheter, økonomi

15. Gullfaks Satelitter Prosjektforslag til Gullfaks Landsbyen Gel for WC reduksjon i GF produsenter
Metodikk

16. Gelling reaction in water phase only

17. Flømming med vann / viskøst vann

18. Gel system - an intermediate system between ’weak’ and ’blocking’
Polymers emulsion blocking

19. Gelation time versus formation temperature
Injection of 130 m3 at
injection rate of 0.9 m3/min
means gelation time > 2.5 hours

20. A-16 before/after DPR

21. 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

22. Oppgave - stikkord Typer gel Tilbakeproduksjon/miljø
WC, perm, sonevis Lagdelte reservoarer
Injeksjonsvolum
Ønsket plassering
Finne egnet brønn på GF