Abstract: High-resolution porosity modeling integrating core, log and 3-D seismic data in Jurassic grain shoals, Gulf of Mexico, U.S.A.

PORTER, M. L., C. S. CALVERT, S. J. HELWICK, R. S. HUBBARD, V. KHARE, E. J. OSWALD, L. A. WAHRMUND

A integrated study of cores, logs and 3-D seismic attributes developed a fine-scale, high-resolution reservoir model of Jurassic grain shoals in the Gulf of Mexico. A new seismic attribute analysis technique resulted in a optimal prediction of vertical porosity information over the reservoir interval. These seismic attributes were calibrated to porosity values derived from log and core data in a 3-D calibration model. Geostatistical techniques integrated this calibration model with well data to build the final high-resolution porosity model of the grain shoals.

Previous studies and successful drilling results had relied heavily on seismic amplitude values at the top of the reservoir as an indicator of porosity. Thus development drilling was targeted at areas of porosity development in the upper portion of the reservoir. Our seismic attribute analysis technique preserved inherent porosity variations over the entire thickness of the reservoir. As a result, this study identified significant, previously unrecognized porosity development in the lower third of the reservoir. This overlooked porosity is contained within older carbonate grain shoals not imaged on conventional seismic attribute maps or targeted in field development plans.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria