Petroleum geology of Cook Inlet Basin: an exploration model

Journal Article · Mon Jun 01 04:00:00 EDT 1981 · Am. Assoc. Pet. Geol. Bull.; (United States)

OSTI ID:6150255

Magoon, L B ^[1]; Claypool, G E

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1. Geological Survey, Menlo Park, CA

The potential of Cook Inlet for oil, evaluated with respect to the reservoir rocks encountered in the COST well and the relation of west-flank fields to the oil system, is discussed. The hydrocarbon potential is highest where Tertiary or Cretaceous reservoir rocks truncate Middle Jurassic source rocks. Several lines of evidence suggest that Middle Jurassic rocks are a possible source of all the commercially important oil in the Cook Inlet basin. Nonmarine Tertiary rocks are tentatively eliminated as possible oil source rocks because they are thermally immature and because they contain a coaly type of organic matter that does not yield liquid hydrocarbons efficiently upon pyrolysis. Cretaceous rocks are also tentatively eliminated as possible source rocks because of their inadequate organic richness and thermal immaturity. Only Middle Jurassic rocks contain adequate amounts of thermally mature, oil-prone organic matter and extractable hydrocarbons that both chemically and isotopically resemble Cook Inlet oil. The petroleum in west-flank oil fields first concentrated in a large stratigraphic trap in Tertiary rocks at the end of Miocene time. Pliocene and Pleistocene deformation caused secondary migration of this oil into present structural accumulations. (JMT)

• OSTI ID: 6150255
• Journal Information: Am. Assoc. Pet. Geol. Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol. Bull.; (United States) Vol. 65:6; ISSN AAPGB
• Country of Publication: United States
• Language: English

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