Geochemistry of selected oils and rocks from the central portion of the West Siberian basin, Russia

Journal Article · Sat May 01 00:00:00 EDT 1993 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:6227950

Peters, K E; Huizinga, B J ^[1]; Kontorovich, A Eh; Andrusevich, V E ^[2]; Moldowan, J M ^[3]; Demaison, G J ^[4]; Stasova, O F ^[5]

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1. Chevron Overseas Petroleum Inc., San Ramon, CA (United States)
2. Inst. of Geology, Novosibirsk (Russian Federation)
3. Chevron Petroleum Technology Co., Richmond, CA (United States)
4. Petroscience Inc., Walnut Creek, CA (United States)
5. NPO SIBGEO, Novosibirsk (Russian Federation)

Six analyzed oils, produced from Middle jurassic to Upper Cretaceous strata in the Middle Ob region of the West Siberian basin, show biomarker and stable carbon isotope compositions indicating an origin from the Upper Jurassic Bazhenov Formation. The chemical compositions of these oils are representative of more than 85% of the reserves in West Siberia (Kontorovich et al., 1975). Bazhenov-sourced oil in Cenomanian strata in the Van-Egan field underwent biodegradation in the reservoir, resulting in a low API gravity, an altered homohopane distribution, and the appearance of 25-norhopanes without alteration of the steranes. High API gravity oil from the Salym field has surpassed the peak of the oil window, consistent with abnormally high temperatures and pressures in the Bazhenov source rock from which it is produced. The remaining oils are very similar, including samples from Valanginian and Bathonian-Callovian intervals in a sequence of stacked reservoirs in the Fedorov field. Bazhenov rock samples from the study area contain abundant oil-prone, marine organic matter preserved under anoxic conditions. While the Upper Jurassic Vasyugan Formation shows lower oil-regenerative potential than the Bazhenov Formation, it cannot be excluded as a source rock because insufficient sample was available for biomarker analysis. Core from the Lower to Middle Jurassic Tyumen Formation in the YemYegov 15 well was compared with the oils because it is thermally mature and shows TOC and HI values, indicating slightly more favorable oil-generative characteristics than the average for the formation (2.75 wt. % for 270 samples; 95 mg HC/g TOC for 25 samples). The core contains terrigenous, gas-prone organic matter that shows no relationship with the analyzed oils. 59 refs., 15 figs., 8 tabs.

• OSTI ID: 6227950
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 77:5; ISSN 0149-1423; ISSN AABUD2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
023000* -- Petroleum-- Properties & Composition
API GRAVITY
ASIA
BIODEGRADATION
CARBON
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DENSITY
EASTERN EUROPE
ELEMENTS
ENERGY SOURCES
EUROPE
FOSSIL FUELS
FUELS
GEOCHEMISTRY
NONMETALS
ORIGIN
PETROLEUM
PHYSICAL PROPERTIES
RESERVES
RESOURCE POTENTIAL
RESOURCES
RUSSIAN FEDERATION
SIBERIA
SOURCE ROCKS