AAPG Bulletin; April 2008; v. 92; no. 4;
p. 417-442; DOI: 10.1306/11140707076
© 2008 American Association of Petroleum Geologists (AAPG)
Upper Jurassic updip stratigraphic trap and associated Smackover microbial and nearshore carbonate facies, eastern Gulf coastal plain
Ernest A. Mancini1,
William C. Parcell2,
Wayne M. Ahr3,
Victor O. Ramirez4,
Juan Carlos Llinás5 and
Milo Cameron6
1 Department of Geological Sciences and Center for Sedimentary Basin Studies, P.O. Box 870338, University of Alabama, Tuscaloosa, Alabama 35487; emancini{at}geo.ua.edu
2 Department of Geology and Geography, Wichita State University, Wichita, Kansas 67260; william.parcell{at}wichita.edu
3 Department of Geology, Texas A&M University, 3115 College Station, Texas 77843-3115; ahr{at}tamu.edu
4 Department of Geological Sciences, Box 870338, University of Alabama, Tuscaloosa, Alabama 35487; present address: Ecopetrol, Bogotá, Colombia; victor.ramirez{at}ecopetrol.com.co
5 Gulf of Mexico Exploration, Anadarko Petroleum Corporation, Lake Robbins Dr. 1201, The Woodlands, Texas 77380; juan.llinas{at}anadarko.com
6 Department of Geological Sciences, Box 870338, University of Alabama, Tuscaloosa, Alabama 35487; mlcameron{at}bama.ua.edu
Ernest A. Mancini is a Distinguished Research Professor in petroleum geology and stratigraphy in the Department of Geological Sciences and the director of the Center for Sedimentary Basin Studies at the University of Alabama. His research focus is on sequence stratigraphy, sedimentary basin analysis, petroleum system studies, and reservoir characterization and modeling.
William C. Parcell is an associate professor in the Department of Geology and Geography at Wichita State University. His research focus includes stratigraphic modeling, geoinformatics, reservoir characterization, and sedimentary basin analysis.
Wayne M. Ahr is a professor of geology with a joint appointment in petroleum engineering at Texas A&M University. His research concentrates on the geology of carbonate reservoirs, with emphasis on the origin and distribution of porosity, permeability, and petrophysical characteristics.
Victor O. Ramirez is an exploration geologist with Ecopetrol in Colombia. He obtained a B.A. degree in geology from the National University of Colombia in 1993 and an M.S. degree from the University of Alabama in 2007. His work and research have focused on sequence and seismic stratigraphy and petroleum systems as applied to hydrocarbon exploration in Colombia.
Juan C. Llinás obtained a B.A. degree in geology from the National University of Colombia. He received his M.S. degree and his Ph.D. in geology from the University of Alabama. His dissertation focused on oil fields associated with microbial reef buildups and genetically related depositional facies using well and seismic data. He is presently working as a petrophysicist for Anadarko Petroleum Corporation.
Milo Cameron obtained a B.S. degree in mathematics from the University of Alabama, Huntsville, and an M.S. degree in geology from the University of Tennessee. He is presently working on a Ph.D. in geology at the University of Alabama. His dissertation research is on the formation of metamorphic core complexes and sea-floor spreading in the Woodlark Basin, Papua New Guinea.
ABSTRACT
The development of Little Cedar Creek field in the eastern Gulf coastal plain of the United States has shown that the current exploration strategy used to find hydrocarbon-productive microbial and high-energy, nearshore carbonate facies in the Upper Jurassic Smackover Formation requires refinement to increase the probability of identifying and delineating these potential reservoir facies. In this field, the petroleum trap is a stratigraphic trap characterized by microbial boundstone and packstone and nearshore grainstone and packstone reservoirs that are underlain and overlain by lime mudstone and dolomudstone to wackestone and that grade into lime mudstone and dolomudstone near the depositional updip limit of the Smackover Formation. Reservoir rocks trend from southwest to northeast in the field area. The grainstone and packstone reservoir is thickest in the central part of the field. The boundstone reservoir is thickest in local buildups that are composed of thrombolites in the southern part of the field and is absent along the northern margin. These reservoir facies are interpreted to have accumulated in water depths of approximately 3 m (10 ft) and in 5 km (3 mi) of the paleoshoreline. In contrast to most other thrombolites identified in the Gulf coastal plain, these buildups did not grow directly on paleohighs associated with Paleozoic crystalline rocks. The characterization and modeling of the petroleum trap and reservoirs at Little Cedar Creek field provide new information for use in the formulation of strategies for exploration of other Upper Jurassic hydrocarbon productive microbial and related facies associated with stratigraphic traps in the Gulf coastal plain.
Copyright © 2009 by American Association of Petroleum Geologists (AAPG)