4D seismic interpretation plays a key role in the reservoir management of the Draugen Field, situated offshore Norway. Time lapse seismic surveys of exceptional quality conducted in 1990, 1998, 2001 and 2004 have all shown outstanding areal and vertical definition of the water movement towards the producing wells.

Excellent reservoir properties with relatively few high rate wells and an expected recovery factor exceeding 60 percent make Draugen one of the best performing fields offshore Norway. The field has a simple geology, however, the reservoir structure is relatively uncertain due to the low number of well penetrations for calibrating the structure. Fortunately, the 4D seismic interpretations have largely compensated for this shortcoming by providing improved lateral control for refining the reservoir simulation models.

All of the 4D interpretations conducted so far have indicated the need for simulation model changes such as modified reservoir volumes in certain areas, revised fault transmissibilities, and the need for improved relative permeability characteristics. Integration of the 4D interpretation results has greatly improved the various Draugen reservoir simulation models enabling improved forecast and reserve estimates as well as better business decisions. Effects on the field reservoir management have included revising the water injection strategy, converting a producer to injector, re-positioning a development well and drilling an appraisal well.

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