Regional thermal maturity modelling of hydrocarbons along the deep-water Yucatan margin, southern Gulf of Mexico

Abstract

Abstract The stratigraphy, structure and hydrocarbon potential of the deep-water Yucatan margin remains less understood than other margins of the Gulf of Mexico (GoM), as Yucatan has not been systematically mapped and has few well penetrations. Despite the presence of widespread oil slicks along the continent–ocean boundary, the maturity and distribution of source rock kitchen areas have not been well defined. This study uses a grid of 2D post-stack depth migration (PSDM) seismic profiles covering an area of approximately 120 000 km 2 to map the structure and stratigraphy, and to model thermal maturities of three potential Mesozoic source horizons. Thermal 1D modelling of six pseudo-wells, positioned along a dip profile, was performed using estimates of lithospheric thickness and thermal properties. Integrated 3D model results indicate that the principal Tithonian-age source rock reached the oil window within the diapiric salt province during the Oligocene–Miocene. Inherent model uncertainty was addressed using a range of thermal scenarios. The result of modelling was that deeply-buried, salt-related minibasins along the outer marginal trough are low risk and the uppermost slope is high risk for maturity. Large, salt-related structural traps are directly adjacent to oil kitchens within deeply-buried minibasins. Normal faults bounding minibasins provide effective vertical migration pathways as supported by the clustering of overlying oil slicks.