--> Abstract: Geologic and Seismic Modeling of a West African Deep-Water Reservoir Analog (Black’s Beach, La Jolla, Ca.), by Lisa Stright, Jonathan Stewart, Mike Farrell, and Kirt Campion; #90078 (2008)

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Geologic and Seismic Modeling of a West African Deep-Water Reservoir Analog (Black’s Beach, La Jolla, Ca.)

Lisa Stright1, Jonathan Stewart2, Mike Farrell2, and Kirt Campion2
1Graduate Program in Earth, Energy and Environmental Sciences, School of Earth Sciences, Stanford University, Stanford, CA
2Upstream Research Company, ExxonMobil, Houston, TX

Exploration of offshore West Africa has yielded many discoveries of deep-water confined channel reservoirs. The geologic complexities of these reservoirs are being revealed by production and 4D seismic data. Although many of these fields are imaged by very high quality seismic data, particularly when compared to other basins, the scale of features controlling reservoir distribution and connectivity appears to be close to or below the resolution of the seismic data. In this study, geologic and seismic models from a detailed stratigraphic description of a deep-water reservoir outcrop analog are used to better understand how such stratigraphic complexity is expressed in seismic data.

The Middle Eocene Scripps and Ardath Formations, exposed at Black’s Beach in La Jolla, California, provide a spectacular seismic-scale exposure of a deep-water confined channel system. The geometry and scale of the channels and the range of lithofacies observed at the outcrop are directly analogous to those seen in the subsurface of offshore West Africa. A detailed 2D lithofacies model of the outcrop was built using measured sections and surfaces correlated on photo panoramas. The model was populated with typical elastic rock properties and forward seismic models were generated at various frequencies and angles. The resulting seismic datasets were inverted for rock properties and the predicted lithofacies were compared to the outcrop model. The detailed stratigraphy of the outcrop was not recovered after inversion but important features for reservoir definition and connectivity were still resolved.

 

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas