Oil-source rock correlation using carbon isotope data and biological marker compounds, Cook Inlet-Alaska Peninsula, Alaska

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6667010

Magoon, L B ^[1]; Anders, D E ^[2]

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1. Geological Survey, Menlo Park, CA (USA)
2. Geological Survey, Denver, CO (USA)

Rock and oil samples from the Cook Inlet-Alaska Peninsula area were analyzed to determine the source of the commercial hydrocarbons produced in the Cook Inlet basin from lower Tertiary nonmarine sandstone reservoirs. Rock-Eval (hydrogen index) analysis and organic carbon content were used to identify the most favorable rock samples for solvent extraction and carbon isotope, gas-chromatographic (GC), and gas-chromatrographic/mass-spectrometric (GCMS) analyses. On the basis of organic-matter richness, five nonmarine Tertiary coal and shale samples and 12 marine Mesozoic (Upper Triassic and Middle Jurassic) shale samples were selected. A total of 28 oil and condensate samples from producing wells, oil-stem tests, field separators, and seeps were used for oil-oil and oil-source rock correlation. On the basis of biomarker and carbon isotope data, four of the shallower oils and condensates are from nonmarine source rocks, and 24 of the deeper oils are sourced from marine shales. Geochemical and regional geologic considerations indicate the following conclusions. The upper Tertiary nonmarine oils and condensates associated with commercial microbial gas accumulations are geochemically similar to the immature organic matter in the Tertiary nonmarine rocks. In the upper Cook Inlet, marine oils in lower Tertiary nonmarine reservoirs originated from Middle Jurassic rocks that matured during the Pliocene to Holocene; in the lower Cook Inlet-Alaska Peninsula area, oils migrated from both Upper Triassic and Middle Jurassic source rocks during the Late Cretaceous to early Tertiary. Although three petroleum systems are identified, this study on the petroleum potential in a convergent-margin setting indicates that only one of these three systems was responsible for the 1.2 billion bbl of recoverable oil in the lower Tertiary nonmarine reservoirs.

• OSTI ID: 6667010
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ALASKA
CENOZOIC ERA
CHEMICAL REACTIONS
CHEMISTRY
COAL DEPOSITS
CRETACEOUS PERIOD
DECOMPOSITION
FEDERAL REGION X
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
JURASSIC PERIOD
MATURATION
MESOZOIC ERA
MINERAL RESOURCES
NORTH AMERICA
PETROLEUM DEPOSITS
PYROLYSIS
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SHALES
SOURCE ROCKS
TERTIARY PERIOD
THERMOCHEMICAL PROCESSES
TRIASSIC PERIOD
USA