Abstract: Origin of High-Sulfur Oils, Gulf of Mexico Continental Slope

Roger Sassen, A. G. Requejo, Tom McDonald, Mahlon Kennicutt, II, James Brooks

Oils of the Gulf of Mexico slope typically show higher sulfur contents, higher metal contents, and lower API gravities than do oils of the Gulf shelf. These properties result in increased costs of production, transportation, and refining, thereby diminishing their value. In contrast to shelf oils, many of which are derived from lower Tertiary shale source rocks, the sources of slope oils are thought to be of Mesozoic age. Since deeply buried source rocks have not been encountered during drilling on the slope, we focus on detailed geochemical characterization of the slope oils to infer their origin. Biomarkers suggest variable clastic-starved source facies containing marine kerogen, such as marls and carbonates. Higher sulfur contents and lower API gravities are thought to correlate wi h increasing carbonate content of the source facies and milder thermal maturity histories. Carbonate-sourced oils from the Upper Jurassic Smackover and Lower Cretaceous Sunniland trends show some similarities but are not strong analogs.

AAPG Search and Discovery Article #90983©1994 GCAGS and Gulf Coast SEPM 44th Annual Meeting, Austin, Texas, October 6-7, 1994