Abstract

The Tithonian petroleum source-rock in the Mississippi Canyon and northern Atwater Valley protraction areas of the northern deepwater Gulf of Mexico were modeled to evaluate the timing of generation and migration in relation to the age of reservoirs and timing of trap development. Source rocks include the Oxfordian, Tithonian, and Lower Cretaceous intervals. Basin modeling results indicate that the source rocks began to generate large volumes of oil during the middle Miocene (15 Ma). Today, about one-half of the source rocks are within the oil window. The upper to middle slope regions are in the dry and wet gas windows, respectively, and a small part of the abyssal plain reside sin the microbial gas window. The study area includes 84 fields and discoveries, 15 of which are subsalt.

The results indicate that most of the reservoir sands 50 fields were deposited after oil generation had begun for the Tithonian source rock, as well as most of the traps for 53 fields. The fields are primarily in the central and western part of the study area, where thick overburden is present and where extensive deformation of the allochthonous salt occurred. Most of the remaining fields are found in the eastern part of the study area, where the overburden is thinner (later oil generation), and fewer structures are present. These overall trends are controlled by the evolution of the Neogene depocenters, which migrated northwest to southeast through time, differentially loading the allochthonous salt systems.