Miocene chronostratigraphy, paleogeography, and play framework of the Burgos Basin, southern Gulf of Mexico

Abstract

This study characterizes Miocene chronostratigraphy and plays in the Burgos Basin and adjacent south Texas within an area of approximately 39,700 km2 (15,300 mi2), onshore and offshore (to the 500-m [1640-ft] isobath). Using greater than 40,000 linear kilometers (25,000 mi) of two-dimensional seismic lines, 115 onshore wells, 9 offshore wells, and paleontological data, we established a correlation framework of 9 key surfaces (upper Oligocene to lower Pliocene) representing major (probably third-order) sequence boundaries and maximum flooding surfaces throughout the basin. Five of the Burgos Miocene surfaces coincide with regional chronostratigraphic surfaces from the Veracruz and Laguna Madre-Tuxpan basins, thus establishing a consistent correlation framework throughout much of the Mexican Gulf Coast Basin. Twenty Miocene plays are defined by four age divisions (lower Miocene, middle Miocene, upper Miocene_1, and upper Miocene_2) and four paleogeographic settings (unexpanded and expanded shelf, proximal slope, and distal slope). Because of proven high productivity in salt-bounded basins in the northern Gulf of Mexico, the onlap of strata onto diapirs in the eastern Burgos salt province was evaluated as a fifth setting. The paleogeographic provinces and onlap areas exhibit characteristic seismic facies, stratal geometries, and structural relations; a characterization of each one of these being key to the overall play evaluation. This play framework provides the means for continuing exploration of Miocene strata and evaluation of key play elements (reservoir presence and quality, seal, trap, source, and migration and timing) in this structurally complex, underexplored basin. The relative importance of these play elements varies systematically for each play, especially between the onshore shelf plays and the offshore deep-water plays, where fault complexity and stratigraphic variability are greater.