Gullfaks Sør, N1/N0 og Gullfaksfeltet Tampen area

Gullfaks Satelitter Prosjektforslag til Gullfaks Landsbyen 2006 Bruk av multilaterale brønner på GFS Statfjord,

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

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)

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

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.

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

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.

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

Situation in year 2001: The SRI team also matured the Gulltopp (Dolly) discovery to PDO level in 2003 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.) Skinfaks/Rimfaks IOR. RES/PRO-seminar, 23.-24.November 2005.

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, 23.-24.November 2005.

Økt utvinning Innfasing av segment N0 & N1

N0 og N1

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 produsenter Metodikk

Gelling reaction in water phase only

Flømming med vann / viskøst vann

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

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

A-16 before/after DPR

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

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