ALBERT

Description: This integrated study provides a geological and geochemical framework for upper Miocene and Pliocene siliciclastic gas plays in the Macuspana Basin. Structural controls for the plays are deep-seated faults that tap Mesozoic thermogenic gas sources, areas of intense shale diapirism and folding, and areas with structural inversion that could enhance trapping and reservoir productivity. Early Neogene thrusting south of the basin triggered evacuation of Oligocene shale along northwest-dipping listric faults in the eastern and southeastern basin margin. These faults are associated with large-scale rollover structures and thick (〉500 m) upper Miocene shoreface and wave-dominated deltaic complexes. A second phase of extension in the early Pliocene formed a set of broad, southeast-dipping listric faults in the western basin, controlling thick accumulations of stacked Pliocene shoreface deposits. Trap formation and enhancement in the southern basin margin are linked to late Miocene to Pliocene inversion. The primary stratigraphic controls on play occurrence in the upper Miocene in the onshore part of the basin are the regional facies distribution of northwest-prograding shoreface and wave-dominated deltaic systems. There was a shift in Pliocene sedimentation from the southeast to the west and northwest parts of the basin, where thick successions of aggradational shoreface and wave-dominated deltaic deposits accumulated in depocenters defined by shale evacuation along growth faults. Valley-fill deposits in both the upper Miocene and Pliocene resulted from shortlived periods of base-level change induced by either uplift on the southern basin margin or eustasy. The offshore part of the basin is inferred to consist of deep-water turbidite deposits that formed downdip (westward) of a hypothesized mixed clastic-carbonate prograding complex from the Yucatan platform. Three petroleum systems (Mesozoic, Paleogene–lower Neogene, and upper Miocene–Pliocene) contributed to the hydrocarbon accumulations and hydrocarbon generation and migration in the basin. Principal Upper Jurassic/Lower Cretaceous source rocks generated wet thermogenic gases and oil. Secondary lower Tertiary source rocks generated dominantly dry biogenic gases. Mixtures of the two gas types are common. Numerous deep-seated growth faults and faults serve as pathways for Mesozoic-sourced hydrocarbons. Surface seeps and abundant gas shows suggest that hydrocarbons are being generated today. William A. Ambrose is a stratigrapher specializing in clastic sedimentology. He received an M.A. degree from the University of Texas at Austin in 1983. He worked for Research Planning Institute, Texas from 1984 to 1986 and has been with the Bureau of Economic Geology since 1987, working on a variety of international and Gulf Coast reservoir-characterization and basin-analysis projects.Tim F. Wawrzyniec is a structural geologist specializing in kinematic analysis and geophysics. He received his Ph.D. from the University of New Mexico (UNM) in 1999 and worked for Vastar and the Bureau of Economic Geology. In 2002, he started GWN Consulting, where he works with the Bureau of Economic Geology on Gulf Coast basin-analysis projects. He recently accepted a senior research scientist position at UNM. Khaled Fouad has been a senior seismic interpreter at the Bureau of Economic Geology since 1997. He has more than 17 years experience as a seismic interpreter with various major oil companies. He received his B.Sc. degree in 1982 from Alexandria University, Egypt. He received his Diploma of higher studies in 1984 with honors from the same university. His experience includes the Gulf of Mexico, Maracaibo Basin, Vienna Basin, and Gulf of Suez. Suhas C. Talukdar is a geologist-geochemist with 35 years of professional experience in industry, research, and teaching. He received a Ph.D. in 1973 from Rice University, Houston. His expertise is in petroleum geochemistry, basin modeling, petroleum system analysis, and hydrocarbon-charge assessment. He is presently a consultant with the Bureau of Economic Geology and BaselineDGSI at Woodlands, Texas. Rebecca H. Jones received her M.S. degree from the University of Wyoming in 1999 and her A.B. degree from Dartmouth College in 1996, both in geology. She worked for ExxonMobil from 1999 to 2001 before joining the Bureau of Economic Geology in 2001. She performs stratigraphic and seismic interpretation in basin-analysis and reservoir-characterization studies. David Jennette has 15 years of industry experience in nonmarine and shelf- and deep-water reservoir prediction and characterization for ExxonMobil Upstream Research; since going to the Bureau of Economic Geology, he has been involved in high-resolution digital outcrop capture and interpretation and play assessment and characterization of Pemex's turbidite-dominated Veracruz Basin. Mark H. Holtz is a reservoir engineer with more than 16 years of reservoir characterization experience at the Bureau of Economic Geology. His expertise focuses on integration of geology and engineering in both carbonate and sandstone oil and gas reservoirs. Mark has been involved in primary and secondary oil and gas projects in Texas, Australia, Venezuela, Argentina, Mexico, and Austria. Shinichi Sakurai is a petrophysicist and was employed by ARCO Technology & Operation Services before joining the Bureau of Economic Geology in July 2001. He also worked for Core Laboratories and BP. He has served the Society of Professional Well Log Analysts as a distinguished speaker, a technology committee member, and a symposium-organizing committee member. Shirley P. Dutton is a senior research scientist at the Bureau of Economic Geology with research interests in sedimentology, reservoir characterization, sedimentary petrology, and clastic digenesis. She received a B.A. degree from the University of Rochester and an M.A. degree and her Ph.D. from the University of Texas at Austin, all in geology. 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 and has been employed by the Bureau of Economic Geology since that time. He has worked on many international and domestic projects, focusing on subsurface mapping, modeling, and data management. Edgar H. Guevara is a research scientist at the Bureau of Economic Geology; he previously worked in the Venezuelan petroleum industry. He holds geological degrees from Universidad Central Venezuela and the University of Texas, Austin (M.A. degree and Ph.D.). He has more than 35 years experience in geological studies/project coordination, particularly depositional systems/stratigraphy applications to petroleum exploration, reservoir characterization, and geoenvironmental studies. Javier Meneses-Rocha received degrees in geology and geological engineering from the Universidad Nacional Autónoma de México and University of Texas at Austin. His work with Pemex includes regional studies, planning and analysis of exploration projects, and evaluation of reserves and resources. He is currently head of the Pemex exploration group in the deep Gulf of Mexico Basin. Jorge E. Lugo received a bachelor's degree from Escuela Superior de Ciencias Marinas, Universidad Autónoma de Baja California and an M.A. degree from the University of Texas at Austin. In 2002, after 32 years of work mostly in biostratigraphy, he retired from Pemex as a specialist in project coordination. He is currently a consultant working in play analysis with Pemex. Leonardo Aguilera is an engineer and geologist specializing in integrated reservoir-characterization studies. He has recently been involved in several field studies with Pemex in southeastern México, where results from combined petrophysical, pet