The Perdido fold belt, northwestern deep Gulf of Mexico, part 2: Seismic stratigraphy and petroleum systems

Analysis of 12,000 km of two-dimensional multifold seismic data shows a thi ck succession of Mesozoic and Cenozoic deep-water strata in the Perdido fol d belt, northwestern deep Gulf of Mexico, These strata differ in seismic fa cies, areal distribution, and reservoir/petroleum potential. Mesozoic strat a are interpreted as dominantly fine-grained carbonates and show minor thic kness changes, Cenozoic strata are largely mud-dominated siliciclastic turb idite deposits and vary considerably in thickness across the fold belt, The se changes reflect the shifting position of Cenozoic marginal-marine depoce nters. Mesozoic reservoir potential consists of fractured Upper Jurassic and Creta ceous deep-water carbonates. Cenozoic reservoir potential consists of silic iclastic deep-water turbidites. Portions of the Paleocene to lower Eocene s trata are sand-prone and are the downdip equivalents of the lower and upper Wilcox shallow-marine depocenters,These strata are all incorporated within the folds. Lower to middle Oligocene strata coincide with the main growth phase of the fold belt. Potentially sand-prone middle Oligocene to lower Mi ocene strata are the downdip equivalents of the Vicksburg (early Oligocene) , Frio (Oligocene), and Oakville (early Miocene) shallow-water depocenters, These strata form potential stratigraphic traps against the folds. Mesozoic source potential was modeled assuming Oxfordian, Tithonian, Barrem ian, and Turonian source beds. One-dimensional thermal maturation modeling showed these sources reached peak oil generation between 51 and 39 hla, 33 and 8 Ma, 32 and 2 hla, and 26 and 8 Ma, respectively Cenozoic source poten tial was modeled using an Eocene source, Modeling showed this source reache d only early oil generation in the basinward half of the fold belt. Thermal maturation was reached by source beds at different times in different loca tions due to changes in burial depth, amount of structural uplift, and unde rlying thickness of autochthonous salt, hll of these factors indicate that seal and reservoir carry significant risk, but that the potential exists fo r large petroleum accumulations.