Delineation of the Cenozoic Petroleum plays in the Main Pass area, North Eastern Gulf of Mexico, United States of America

Abstract

This study was undertaken in the Main Pass area, north eastern Gulf of Mexico Basin with the aim of delineating the Cenozoic petroleum plays. The study involved the grouping of the structural and stratigraphic traps into plays as interpreted using a post-stacked 3D seismic dataset. Seismic data interpretation was guided by extracting seismic attributes, mainly variance, instantaneous phase, Root Mean Square (RMS), and average envelope to enhance the interpretation of structural and stratigraphic traps. Based on interpreted shared source rock, shared tectonic setting and common trap type, eight (8) distinct structural and stratigraphic plays were mapped out in the study area. The structural plays in the Main Pass area include the salt diapiric play consisting of salt diapiric traps found in most of the downdip Cenozoic strata where adjacent strata truncates against the salt body; titled fault play made of tilted fault traps dominating the up-dip Upper and Middle Miocene sediments; an anticlinal play consisting of the anticline traps in the downdip Upper and Middle Miocene Formations; positive flower structure play consisting of the positive flower traps in the up-dip Miocene to Pliocene strata; salt cored anticline plays made of salt cored anticline traps in the Middle Miocene Formation; and salt rollover play consisting of salt roller anticline traps in the downdip Middle Miocene strata. The stratigraphic plays of the Main Pass area are pinch-out play made of the pinch-out traps in the Miocene Formation and the dominant sand lens play consisting of the sand lens traps in the Miocene to Pliocene Formation. The sand lens play formed due to scour of original sand deposits as the delta advanced during the Miocene to Pliocene periods forming sand patches. The Cenozoic plays are charged by the Mesozoic source rocks of Oxfordian, Tithonian, and Turonian. Hydrocarbons migrated vertically through faults, collapsed salt stocks, and laterally to a lesser extent. The study has provided an opportunity to group the Cenozoic petroleum traps of the Main Pass area into plays which offer an opportunity for analog exploration within and outside the Gulf of Mexico basin. The study has also provided an opportunity to group the prospects that helps in risk management and selection of appropriate technologies for drilling. This reduces both technical and financial risk during exploration in the area.