Diverse super-giant petroleum deposits in the West Siberian oil-gas basin

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

OSTI ID:6762760

Clarke, J W; Peterson, J A ^[1]

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1. Geological Survey, Reston, VA (USA)

The West Siberian sedimentary basin is a relatively uncomplicated basin where deposition has continued with little significant interruption during the almost 200 m.y. since the beginning of the Pliensbachian Age in the Early Jurassic. The petroleum deposits, however, are diverse, as exemplified by the Salym Samotlor, and Urengoy fields. During the Volgian Age, in the latest Jurassic, bituminous siliceous clays were deposited during a tectonic calm in an anoxic basin. These clays, now the cherty shale of the Bazhenov Formation were enriched in sapropelic organic matter and became source rock reservoir rock, and seal for the oil of Salym field. The oil occurs along fractures generated by the hydraulic effect of the generating oil. No significant water or gas accompanies the oil. Following the tectonic calm progradational deltaic deposits began to fill the sedimentary basin during the Early Cretaceous. Deltaic sands deposited on a mid-basin high were winnowed by currents that carried the finer material farther west. These sands became reservoirs whose source beds were either the distal pelitic facies to the west or the underlying bituminous Bazhenov Formation. The oil pools of Samotlor field which accounts for about 5% of the world production, are in these progradational sandstones. Deposition of sandy facies continued with little interruption through the Cenomanian after which clay was deposited during the Turonian in an anoxic environment similar to that of the Bazhenov. Urengoy field, probably the largest gas deposit in the world, occurs in the sandstones beneath the Turonian clays. The gas is almost pure methane and was sourced probably by both the humic organic matter in the rocks beneath and adjacent to the pool and by organic matter in the overlying Turonian bituminous clays. The source beds of the West Siberian basin are presently at those depths favorable for petroleum generation.

• OSTI ID: 6762760
• 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
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ASIA
DIAGENESIS
EASTERN EUROPE
EUROPE
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGY
MATURATION
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NATURAL GAS FIELDS
OIL FIELDS
ORIGIN
PERMEABILITY
PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SIBERIA
SOURCE ROCKS
USSR