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Subject Keyword PETROLEUM ♦ GULF OF MEXICO ♦ PETROLEUM DEPOSITS ♦ LOUISIANA ♦ MISSISSIPPI ♦ SOURCE ROCKS ♦ MATURATION ♦ CRETACEOUS PERIOD ♦ GEOLOGIC FORMATIONS ♦ GEOLOGIC HISTORY ♦ QUATERNARY PERIOD ♦ TERTIARY PERIOD ♦ ATLANTIC OCEAN ♦ CARIBBEAN SEA ♦ CENOZOIC ERA ♦ FEDERAL REGION IV ♦ FEDERAL REGION VI ♦ GEOLOGIC AGES ♦ GEOLOGIC DEPOSITS ♦ MESOZOIC ERA ♦ MINERAL RESOURCES ♦ NORTH AMERICA ♦ RESOURCES ♦ SEAS ♦ SURFACE WATERS ♦ USA 020200* -- Petroleum-- Reserves, Geology, & Exploration
Abstract The Lower Tertiary Sparta Formation, Wilcox Group, and the Midway Group in southern Louisiana include organic-rich source facies that generate crude oil at relatively high thermal maturities. The Wilcox Group is an important source of Wilcox crude oil, and regional kerogen variations explain two crude oil subfamilies. Wilcox crude oils in downdip areas of southern Louisiana migrated short distances, but long-range lateral migration (about 150 km) best explains Wilcox crude oils far updip from mature source rocks. Crude oils in Oligocene and younger reservoirs in southern Louisiana migrated vertically from deep lower Tertiary source rocks. Some crude oils in Upper Cretaceous Tuscaloosa reservoirs were emplaced by long-range lateral migration from Tuscaloosa source rocks. Given little evidence of upper Tertiary source rocks and the overmaturity problems of Mesozoic source rocks, most crude oils in upper Tertiary and Pleistocene reservoirs of the Gulf continental shelf are best explained by vertical migration from deep lower Tertiary source rocks. Even so, it is simplistic to assume an exclusive lower Tertiary origin. Many Tertiary and Pleistocene crude oils of this study probably include an overprint of high-maturity hydrocarbons from Mesozoic sources. 12 figs., 7 tabs.
ISSN 01491423
Educational Use Research
Learning Resource Type Article
Publisher Date 1990-06-01
Publisher Place United States
Journal AAPG Bulletin
Volume Number 74
Issue Number 6


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