4D Ocean Bottom Seismic technology: an innovative tool for improved hydrocarbon recovery at Gullfaks

Abstract

The GullfaksOilFieldislocated inthe Norwegiansector ofthe Northern NorthSea.Time-lapse(4D) seismic datah aveb eenu sed atGullfakss ince 1995a ndh avec ontributed significantly to the reservoir management ofthe field.Permanent fieldinstallations limitthe area wherenewmarinestreamersurveys canbe acquired;thisrestriction affects in25%ofthe field.In2001 anOceanBottom Seismic (OBS)pilot surveywas acquired aroundthe GullfaksC(GFC)p latform,to test whethert he OBS technologycouldc overt he 'shadow zones' aroundthe permanent installations. The results from the 2001 OBS surveyclearly show thatthe OBS data coverthe 'shadow zone'andprovide new4D information aroundthe GFC platform. Withinthe OBS area two newwells havebeensuccessfully drilled based on updated 4D information comparingstreamerdatafrom 1999 andOBS datafrom 2001. Based on the experience from the 2001 surveyanewOBS surveywasacquired in2003 to coverthe areasaroundthe GFA andGFB platforms.