Global Petroleum Occurrences in Submarine Fans and Turbidite Systems

Abstract

Submarine fans and turbidite systems are major petroleum reservoirs in many sedimentary basins worldwide. More than 80 sedimentary basins contain major petroleum-producing submarine fan deposits, and these reservoirs produce from a variety of structural, stratigraphic, and combined traps. To characterize these reservoir occurrences, tables were constructed for each continent and basin showing reservoir age, formation name(s), tectonic setting, and a field example, if appropriate. In addition, 23 major turbidite reservoirs from eight basins are discussed to illustrate the variability in these kinds of reservoirs. Turbidite reservoirs occur primarily as submarine fan deposits, with some occurrences in debris aprons, canyon-related features, and carbonate deposits of mass transport origin. Submarine fans and turbidite systems can occur in any tectonic setting. Rift and passive margin settings contain both lacustrine and marine turbidite reservoirs. Major syn-rift lacustrine turbidite reservoirs occur in Tertiary basins in China and Hungary, and in the Lower Cretaceous basins of Brazil and west Africa. Syn-rift marine turbidite reservoirs are best developed in the Upper Jurassic-Lower Cretaceous of the North Sea. The Paleogene postrift intracratonic sag basins of the North Sea also contain major turbidite reservoirs that are mainly stratigraphic traps and compactional features over older structures. Passive margins contain turbidite reservoirs in a variety of structural styles. Salt diapiric and growth fault-influenced basins include the Neogene of the U.S. Gulf Coast and the Upper Cretaceous and Tertiary of Brazil. Reservoirs associated with shale diapirs occur in the Tertiary strata of the Canadian Beaufort Sea, Gulf Coast of Texas, and Nigeria continental margin. Convergent and transform margins contain forearc, foreland, and wrench-fault-related basins. Turbidite reservoirs in forearc basins produce from the Upper Cretaceous-Eocene strata of the Sacramento Basin (California) and from the Tertiary basins of Peru, Ecuador, and northern California. Forearc basin turbidites tend to be gas-prone because of low thermal maturity and lack of good oil source rocks. Foreland basin turbidites are productive in the Neogene Italian Apennine Mountains, Tertiary Alpine basins, Cretaceous Interior Seaway of the United States, Pennsylvanian Arkoma Basin, and Devonian strata of the Appalachian Mountains. The wrench-fault and successor basins associated with the Neogene transform margins of California include the giant oil fields of the Miocene San Joaquin, Mio-Pliocene Los Angeles, and Pliocene Ventura basins. Submarine canyons form in all of these tectonic settings and have two kinds of reservoirs: canyon fill and truncated strata against the canyon walls. Producing reservoirs from canyons include the Miocene and Eocene strata of offshore Brazil, Eocene strata of Mexico, Paleogene strata of Texas, and Paleocene-Eocene strata of the Sacramento Basin (California) and Gippsland Basin (Australia). Carbonate turbidite-related reservoirs occur as slope aprons, basinal debris-aprons, submarine fans, and resedimented chalks. Carbonate reservoirs include the Miocene of the Philippines, Paleocene-Upper Cretaceous of the central North Sea, Paleocene, Cretaceous, and Jurassic of Mexico, Permian of west Texas, and Devonian of western Canada.