ABSTRACT

Burial history and thermal maturation analyses have been performed for strata of the Mississippi Interior Salt Basin. The tectonic and depositional histories form the foundation for the modeling. Five regional cross sections consisting of 48 wells, structural maps, and isopach maps comprise the basis for this study. Information interpreted from well samples, cross sections, and subsurface maps include biostratigraphic, paleoenviron-mental, lithologies and stratigraphic thickness of the units, com-paction, sediment accumulation and subsidence rates, uncon-formities and faulting. Basin modeling indicates that variation in sediment accumulation rate is related to lithology, unit thickness, and dura-tion of deposition. The highest mean sediment accumulation and tectonic subsidence rates were recorded for Late Jurassic and Early Cretaceous strata.

Thermal maturity modeling was accomplished utilizing vitrinite reflectance, thermal alteration index, T_max, bottom hole temperature, type of kerogen and total organic carbon data. Maturity modeling indicates that Upper Jurassic carbonate mud-stones (rich in algal kerogen) were effective regional source rocks throughout the basin. Oil generation commenced from these carbonate mudstones in the Early to Late Cretaceous and continued into the Paleogene. Upper Cretaceous black shales (rich in herbaceous kerogen) were effective local source rocks in the area of the Perry sub-basin. Oil generation was initiated from these shales in the Paleogene. Lower Cretaceous shales are possible local source rocks in the Perry sub-basin area. The burial and thermal histories of Paleogene shales were not conducive for the generation of hydrocarbons in this basin.