Deepwater Reservoir Termination against Topography: Integrating Subsurface and Outcrop Data in Seismic Forward Modelling

In many deepwater settings, the style and distribution of reservoir facies reflects deposition adjacent to topography. The presence of topography during deposition imparts a complexity on the reservoir distribution and quality that can be difficult to assess from seismic data. In particular, reservoir termination against topography, in terms of facies and geometry, is crucial to understand, as these terminations may form stratigraphic traps or leak points. The Gres d’Annot Formation, cropping out in southeast France, is a well-studied deepwater system that reflects deposition adjacent to topography. The outcrops are considered as a partial (process) analogue for complex reservoir distribution and character observed in the Gulf of Mexico, the Jurassic of the Central North Sea and offshore Brazil. End-member termination styles including both sand-prone and heterolithic successions are identified. These termination styles, together with outcrop data including sedimentological logs, gamma-logs and LIDAR scans, have been integrated with subsurface properties (well log data) from selected reservoirs to construct forward seismic models. The resulting seismic stratigraphic termination models give insight to end-member detectability and characteristics at different seismic resolutions and burial depths. This enables higher confidence predictions of complex Deepwater termination geometries adjacent to topographic highs in areas of poor seismic resolution and well control, and enables the more accurate assessment of future exploration prospects.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California