3D seismic characterization and prospect assessment of the upper miocene interval, virgo block, offshore Louisiana, Gulf of Mexico

The Virgo Block has been proven as one of the highest hydrocarbon potential and low operational risk regions in the Gulf of Mexico (GOM) basin. Despite the northeastern region of the Virgo Block not fitting into the typically recognized exploration plays on the continental shelf, the southwestern region on the upper continental slope is characterized by suitable properties comparable with the generally accepted deeper exploration plays found in the GOM basin. In this study, the main structural setting in the Virgo Block, offshore Louisiana, was interpreted using 262 km2 of 3D seismic data, biostratigraphic tops, and well log data. The main seismic reflectors, the tops of Cretaceous and Miocene, were picked across the interest area for assessing the main structure. The dominant structural features in the interest area comprise growth faults and accompanying synthetic and antithetic faults, and salt diapirs. These faults fractured mostly the middle and upper section of the Miocene while the salt diapirs served as migration pathways between the Cretaceous and the Miocene. Two seismic amplitude anomalies associated with middle and upper Miocene sandstones were assessed. These amplitudes may represent direct hydrocarbon indicators linked to gas saturated sandstones. The type of traps interpreted includes three-way dip closure against multiple faults, and four-way dip structural closure associated with deepwater fan systems (turbiditic fan lobes) deposited on a regional slope and base-of-slope environments. The two top-ranked prospects represent fan lobes partially overlapped and could contain ~111 billion cubic feet of gas. The chance of geologic success for these two prospects is about 66% and 52%, respectively