BARRON, ERIC J. and GEORGE T. MOORE, Earth System Science Center, The Pennsylvania State University, University Park, PA

ABSTRACT: Late Jurassic to Mid-Cretaceous Source Rock, Reservoir, and Evaporitic Seal Distribution Derived from General Circulation Model Simulations

Multiple seasonal general circulation model (GCM) simulations of the Late Jurassic and mid-Cretaceous have been aggressively compared to the preserved biostratigraphic and lithostratigraphic record. From these comparisons we have determined that a Late Jurassic simulation with an elevated greenhouse gas concentration of 1120 ppm CO2 and a mid-Cretaceous simulation with 1120 ppm CO2 compare favorably with their respective geological records and published geochemical values for CO2. In these simulations we use the present-day orbital parameters of obliquity, eccentricity, and precession. This setting, while not representing potential orbital extremes, approximates average conditions through the 10 +/- m.y. intervals represented by the Kimmeridgian-Tithonian (Late Jurassic) and Albian-Ce omanian (Early-Late Cretaceous) stages.

Having completed these rigorous comparisons and selected a simulation for each time interval, we can then approach predictive lithostratigraphic studies of source rock distribution and kerogen type, siliclastic and carbonate reservoir rocks, and certain types of traps, particularly evaporities. With these two end member simulations and a knowledge of intermediate plate tectonic relationships, a synthetic stratigraphic section can be constructed for the intervening time interval. The modeled stages and interpolated interval approximates about 60 m.y. of geologic time. Combining simulation results with supplementary software programs, source rocks, reservoirs, and evaporitic seals can be predicted on a regional or basin scale for this interval. These results provide valuable information in reducing risk in frontier exploration and improving the knowledge of reservoir geometry at the basin and field scale.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.