ALBERT

Description: The Miocene and Pliocene interval of the Veracruz Basin, southeast Mexico, experienced an evolving array of shortening, strike-slip, and volcanic forces in response to plate-scale interactions. The basin is divided into six structural domains that define regions of comparable timing and type of structural deformation, and the basin fill is separated into two long-term depositional phases, each of which can be tied to a waning and then waxing of major basin-bounding tectonic events. The first phase of deposition took place from the early to late Miocene and is tied to the waning effects of the Laramide orogeny. The Miocene basin inherited a tectonically steepened basin margin, across which deep canyons were carved and variably filled with mudstone and thin remnants of coarse sandstone and conglomerate. This zone of erosion and bypass grades into thick, sandstone-rich basin-floor fans. Later in phase I, subaqueous volcanoes, tied to distant plate subduction, developed offshore and formed a bathymetric barrier that prevented turbidity currents from entering the ancestral Gulf of Mexico. The volcanoes also served as immovable buttresses, around which intrabasinal thrust belts developed in response to regional shortening. The second depositional phase is tied to the onset of internal basin shortening and uplift of the north basin margin known as the trans-Mexican volcanic belt. This uplift caused a dramatic reconfiguration of the sediment-dispersal system, whereby large shelf clinoforms prograded from north to south across the basin. In contrast to the onlapping stacking pattern of phase I units, phase II units stack in a strongly offlapping pattern. Proven and postulated reservoir-trap combinations, ranging from four-way to three-way combination (stratigraphic), to pure stratigraphic traps are common. Four-way closures mapped from the two-dimensional and three-dimensional seismic data are large (P50: 5000 km2) and are covered with thick, lower Miocene fan sandstones. Traps that depend on a stratigraphic component are thinner and smaller in size (P50: 1000 km2), but more numerous than the four-way closures. Because many structures have experienced prolonged pulses of compression, top seal is considered an important geologic risk to the retention of substantial gas-column heights. David C. Jennette received a B.S degree from Allegheny College and an M.S. degree from the University of Cincinnati. He is currently a program director at the Bureau of Economic Geology, conducting a range of studies on siliciclastic basins, reservoirs, and outcrops. Previously, he was a senior research geologist at ExxonMobil's Upstream Research in their Deepwater Reservoirs Research Group. He maintains a research focus on multidisciplinary analyses of turbidite reservoir systems.Tim F. Wawrzyniec is a structural geologist specializing in kinematic analyses and geophysics. He earned his Ph.D. from the University of New Mexico in 1999 and joined the Bureau of Economic Geology in 2000. Tim is currently a senior research scientist at the University of New Mexico and continues to work with the Bureau of Economic Geology on several basin analysis projects. Khaled Fouad is a senior researcher responsible for seismic interpretation and visualization technology. Before joining the Bureau of Economic Geology in 1997, he worked over 14 years as a seismic interpreter with various major oil companies where he gained experience in the Gulf of Mexico, Maracaibo Basin, Vienna Basin, and Gulf of Suez basins. Khaled received his B.Sc. degree in 1982 from Alexandria University, Egypt, and a Diploma of Higher Studies in 1984. Dallas B. Dunlap is a geologist and database coordinator for the Bureau of Economic Geology. He received a B.S. degree from the University of Texas at Austin in 1997. He has worked on many international and domestic projects that focus on subsurface mapping, 3-D visualization, modeling, and data management. Javier J. Meneses-Rocha received a B.S. degree in geological engineering in 1976 and earned his M.A. degree and his Ph.D. in geology from the University of Texas at Austin in 1985 and 1991, respectively. Meneses-Rocha started with Pemex in an 1985 as field geologist and then worked on regional petroleum evaluation projects, planning, reserve evaluation, prospect evaluations, and structural and play analysis projects. He is now manager of Geological and Geophysical Integration and Interpretation for Pemex Exploración and Producción. He is the past president of the Asociación Mexicana de Geólogos Petroleros. Francisco is a geologist and petrophysicist presently developing prospects and interpreting drillwell data from northern Veracruz Basin. Rafael Munoz is a geophysical interpreter identifying prospects and drilling exploration wells in the northern Veracruz Basin. David Barrera received a geologist engineering degree from the Instituto Politecnico Nacional in 1982. He has worked in Pemex for 15 years conducting petroleum systems, play, and prospect analysis. He is currently the team leader of the southern Veracruz exploration project in the Activo Salina del Istmo. Carlos T. Williams-Rojas is a geologist working on stratigraphy, basin, and play analysis, and economic evaluation. He earned an M.S. degree from Universidad Nacional Autonoma de Mexico in 1995 and an M.S. degree from Colorado School of Mines in 2000. Carlos is currently a senior geologist working for Pemex in the Activo Salina del Istmo. Arturo Escamilla-Herrera is a geologist conducting seismic interpretation, basin, and play analysis, and formation evaluation. He earned a B.S. degree from Instituto Politecnico Nacional in 1985 and is candidate for an M.S. degree in the same institution. Arturo is currently a senior geologist working for Pemex in the Activo Salina del Istmo.