Consideration for influence of oil remigration history on fluid distributions

Abstract

Many fields reportedly have tilted oil water contacts (OWC). In the target carbonate reservoir of this paper, deeper OWCs, higher oil pressures, deeper free water levels (FWL) and larger transition zones were observed towards the direction of recent structure tilting while no difference in pressure was observed in the aquifer. From these observations and structure restoration and geochemical studies, it was considered that recent structure tilting after oil accumulation induced oil remigration and influenced the current fluid and pressure distributions of this reservoir. This idea was supported by the numerical experiments in which effects of capillary pressure hysteresis were considered.