Bureau of Economic Geology, The University of Texas at Austin (www.beg.utexas.edu).
American Association of Petroleum Geologists Annual Meeting, Dallas, April 18-21, 2004
Miocene Depositional and Chronostratigraphic Framework: Relation to Potential Gas Exploration in the Burgos Basin, Northeastern Mexico
Tucker F. Hentz, Michael V. DeAngelo, Tim W. Wawrzyniec, L. F. Brown, Jr, Shinichi Sakurai, William A. Ambrose, Antonio Cuevas, and J. Javier Hernández Mendoza
Previous study of the Burgos Basin focused mostly on the Oligocene Frio/Vicksburg interval. As a result, little is known of the basic Miocene stratigraphic framework, paleogeography, and regional depositional trends in the basin. The Miocene succession of the Burgos Basin is underexplored and produces minimal gas; however, significant Oligocene production, structural complexity, and numerous seafloor seeps in the region suggest exploration potential in the Miocene interval.
The Bureau of Economic Geology and Pemex Exploración y Producción conducted a joint study of the Miocene chronostratigraphy, depositional fabric, structure, geochemistry, and plays in an area of approximately 32,500 km2, onshore and offshore (to 500 isobath) of the Burgos Basin and adjacent South Texas. Using a data set containing more than 15,000 linear kilometers of 2-D seismic lines, more than 90 onshore wells, and paleontological data, we correlated 15 low-order sequence boundaries and flooding surfaces. These include a subset correlated by previous BEG/Pemex play studies to the south along the shelf, thus providing a unified chronostratigraphic framework for most of the Mexican Gulf coast.
Sandstone-facies distribution within intrahorizon intervals indicates that the ancestral Rio Grande controlled primary sand distribution. The positions of Miocene shelf edges, sandy lowstand prograding complexes, and slope-fan intervals are associated with contiguous major growth faults within about 40 km north and south, and 15 to 30 km east, of the modern Rio Grande delta. Numerous postdepositional faults and mobilized shale/salt bodies within the lowstand depocenters and elsewhere form potential trap-producing structures.