The Gulf of Mexico Basin: New Science and Emerging/Re-emerging Deepwater Plays
John Snedden
University of Texas at Austin
Abstract
The Gulf of Mexico (GOM) basin is one of the richest hydrocarbon basins of the world, with estimated hydrocarbon endowment exceeding 140 BBOE. The foundation of such a rich endowment is the unique confluence of sedimentary processes, ranging from a continental-scale drainage system network, robust depositional systems, unusual extrabasinal perturbations, and long-lived salt tectonics. This combination of factors has allowed the GOM to continue to "reinvent itself", generating new exploration plays both onshore and offshore, suprasalt to subsalt, fluvial to deep-water, conventional and unconventional reservoirs. The surprising emergence of several new exploration plays and new ideas on the basin history demonstrates that we have much more to learn and harvest from this natural laboratory of sedimentary processes.
New ideas are leading to a reevaluation of the framework history, including how the Chixculub impact event at the end of the Cretaceous altered the deep Gulf of Mexico seascape and set up subsequent deep-water deposition. New models have been formulated for the timing and distribution of salt deposition and sea floor spreading. Our understanding of the interaction of sediment and salt since the Mesozoic continues to evolve. The GOM has also provided dramatic improvements in the Neogene chronostratigraphy resulting from interpretation of new biostratigraphic data from deepwater wells.
Wells drilled in the deep subsalt province have altered our view of the Mesozoic source to sink depositional pathways, leading us to question older North American paleogeographic maps. A recent reported hydrocarbon discovery at El Perdido, located in the Mexican deep-water, has increased the Paleogene (Wilcox) play extent to the south.
Onshore, exploitation of Type II source rocks as shale gas plays in the Jurassic Haynesvilleand Cretaceous Eagle Ford have generated significant drilling activity and this in turn has stimulated a reevaluation of interpreted Mesozoic source rock distributions, including offshore areas of the Gulf of Mexico. Our perspective on the eastern Gulf of Mexico potential is likely to change as well, given new and ongoing deep crustal imaging work in this area.
AAPG Search and Discovery Article #90200 © AAPG Geoscience Technology Workshop, Fifth Annual AAPG-SPE Deepwater Reservoir, January 28-29, 2014, Houston, Texas