Source quality variations tied to sequence development: Integration of physical and chemical aspects, Lower to Middle Triassic, western Barents Sea

Conference · Fri Mar 01 00:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:6006705

Bohacs, K M; Isaksen, G H ^[1]

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1. Exxon Production Research Co., Houston, TX (United States)

Triassic mudrocks from the Barents Sea area demonstrate to covariance of physical and chemical properties of mudrocks deposited in shelfal environments and the aspect of depositional sequences in distal settings. The tie of physical parameters to chemical character within a detailed sequence-stratigraphic framework enables the construction of depositional-facies models to predict organic-matter content and quality. This allows the explorer to more closely constrain and predict the nature of potential source rocks using seismic and well-log data. Changes in lithology, bedding geometry, sedimentary structures, body and trace-fossil assemblages, and inorganic, bulk-organic, and molecular geochemistry revealed the detailed depositional environments. The depositional environments stack predictably, according to their position in the depositional sequence: from aerobic lower-shoreface--offshore transition environments in lowstand systems tracts to dysaerobic-anaerobic distal open-marine-shelf environment in transgressive and early highstand systems tracts. Quantitative molecular geochemistry also revealed variations within this distal setting and strong covariance with sequence position. Input of organic matter from terrigenous higher plants dominates the lowstands whereas marine-algal organic matter is most prevalent within transgressive and highstand systems tracts. Specifically, the abundance of C{sub 30} steranes, total steranes, and moretane reflected development of the sequences.

• OSTI ID: 6006705
• Report Number(s): CONF-910403-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:3; Conference: Annual meeting of the American Association of Petroleum Geologists (AAPG), Dallas, TX (United States), 7-10 Apr 1991; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
58 GEOSCIENCES
CONTINENTAL SHELF
PETROLEUM DEPOSITS
STRATIGRAPHY
NORWAY
SOURCE ROCKS
GEOCHEMISTRY
LITHOLOGY
CHEMICAL PROPERTIES
DEPOSITION
EXPLORATION
OFFSHORE SITES
PHYSICAL PROPERTIES
SHALES
TRIASSIC PERIOD
CHEMISTRY
CONTINENTAL MARGIN
DEVELOPED COUNTRIES
EUROPE
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
MESOZOIC ERA
MINERAL RESOURCES
RESOURCES
ROCKS
SCANDINAVIA
SEDIMENTARY ROCKS
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences