CAREW, WAYNE, and PAUL F. OSTENDORF, Exxon Company, U.S.A., New Orleans, LA, and GLENN K. KRUM, Exxon Exploration Company, Houston, TX
ABSTRACT: 3-D Seismic and Reservoir Modeling, Ram Prospect, Viosca Knoll Block 912, Offshore Gulf of Mexico
Ram prospect is a large stratigraphic trap located in Viosca Knoll Blocks 912/956/957, offshore Alabama in 3500-ft water depth. Reservoirs are Pliocene and Miocene gas- and oil-bearing deep-water sands deposited as fan complexes in an intraslope basin. The field has been proved by a total of 12 well penetrations and is nearing the development stage. In an effort to predict reservoir performance and recovery efficiencies, we constructed three-dimensional (3-D) reservoir models Exxon's in-house 3-D modeling program (geoset). Reservoir simulation studies will be based upon these 3-D geological models.
We used 3-D seismic data to map seismic attributes around the prospect and well control to calibrate the seismic attributes based on known reservoir characteristics, thereby deriving a facies map for the entire field.
Top/base structure, gross isopach, facies polygons, porosity, and Vshale were input into geoset to define the overall reservoir container and fill. The paucity of well data was compensated by using the 3-D-seismic based facies as a guide to filling polygons and by creating "pseudowells" from the real well data. These pseudowells aided in correlating within and between polygons.
The resulting 3-D models (total porosity, effective porosity, Vsand) faithfully reflect the heterogeneity inferred from both 3-D seismic data and well control and provide an excellent visualization of reservoir continuity much better than models derived from well data alone. The models serve as a framework within which one can perform reservoir simulations and run various sensitivities. Additionally, the geoset porosity models can provide an alternative reservoir volume calculation.
AAPG Search and Discovery Article #90989©1993 GCAGS and Gulf Coast SEPM 43rd Annual Meeting, Shreveport, Louisiana, October 20-22, 1993.