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James W. Clarke

Publications and source records attributed to James W. Clarke.

7 recordsLinked to original sources
USGS1983

Petroleum geology and resources of the Volga-Ural province, U.S.S.R.

The Volga-Ural petroleum province is, in general, coincident with the Volga-Ural regional high, a broad upwarp of the east-central part of the Russian (East European) Platform. The central part of the province is occupied by the Tatar arch, which contains the major share of the oilfields of the province. The Komi-Perm arch forms the northeastern part of the regional high, and the Zhigulevsko-Pugachev and Orenburg arches make up the southern part. These arches are separated from one another by elongate downwarps. The platform cover overlies an Archean crystalline basement and consists of seven main sedimentation cycles. (1) Riphean (lower Bavly) continental sandstone, shale, and conglomerate beds, from 500 to 5,000 m thick, were deposited in aulacogens. (2) Vendian (upper Bavly) continental and marine shale and sandstone are up to 3,000 m thick. (3) Middle Devonian-Tournaisian transgressive deposits, which are sandstone, siltstone, and shale in the lower part and carbonates and abundant reefs in the upper part, range from 300 to 1,000 m in thickness. The upper carbonate part includes the Kamsko-Kinel trough system, which consists of narrow, interconnected, deepwater troughs. (4) The Visean-Namurian-Bashkirian cycle began with deposition of Visean clastic deposits, which draped over reefs of the previous cycle and filled in an erosional relief that had formed in some places on the sediments of the previous cycle. The Visean clastic deposits are overlain by marine carbonate beds. The cycle is from 50 to 800 m thick. (5) The lower Moscovian-Lower Permian cycle consists of 1,000 to 3,000 m of terrigenous clastic deposits and marine carbonate beds. (6) The upper Lower Permian-Upper Permian cycle reflects the maximum growth of the Ural Mountains and the associated Ural foredeep. Evaporite deposits were first laid down, followed by marine limestones and dolomites, which intertongue eastward with clastic sediments from the Ural Mountains. (7) Continental red beds of Triassic age and mixed continental and marine clastic beds of Jurassic and Cretaceous age were deposited on the western, southwestern, and northern margins of the Russian Platform; they are generally absent in the Volga-Ural province, however. Approximately 600 oilfields and gasfields and 2,000 pools have been found in the Volga-Ural province. Nine productive sequences are recognized; these are, in general, the same as the sedimentation cycles, although some subdivisions have been added. The clastic section of Middle and early Late Devonian age contains the major recoverable oil accumulations, including the supergiant Romashkino field. Cumulative production to 1980 is estimated at 30 to 35 billion barrels of oil equivalent, identified reserves at about 10 billion barrels of oil equivalent, and undiscovered resources at about 7 billion barrels of oil equivalent. Identified reserves of natural gas are estimated at 100 trillion cubic feet and undiscovered resources at 63 trillion cubic feet.

Circular↗
USGS1983

Geology of the Volga-Ural petroleum province and detailed description of the Ramashkino and Arlan oil fields

The Volga-Ural petroleum province is in general coincident with the Volga-Ural regional high, a broad upwarp of the east-central part of the Russian (East European) platform. The central part of the province is occupied by the Tatar arch, which contains the major share of the oil fields of the province. The Perm-Bashkir arch forms the northeastern part of the regional high, and the Zhigulevsko-Orenburg arch makes up the southern part. These arches are separated from one another by elongate downwarps. The platform cover overlies an Archean crystalline basement and consists of seven main sedimentation cycles as follows: 1) Riphean (lower Bavly) continental sandstone, shale, and conglomerate beds from 500 to 5,000 m thick deposited in aulacogens. 2) Vendian (upper Bavly) continental and marine shale and sandstone up to 3,000 m thick. 3) Middle Devonian-Tournaisian transgressive deposits, which are sandstone, siltstone, and shale in the lower part and carbonates with abundant reefs in the upper; thickness is 300-1,000 m. In the upper carbonate part is the Kamsko-Kinel trough system, which consists of narrow interconnected deep-water troughs. 4) The Visean-Namurian-Bashkirian cycle, which began with deposition of Visean clastics that draped over reefs of the previous cycle and filled in an erosional relief that had formed in some places on the sediments of the previous cycle. The Visean clastics are overlain by marine carbonates. Thickness of the cycle is 50-800 m. 5) Early Moscovian-Early Permian terrigenous clastic deposits and marine carbonate beds 1,000-3,000 m thick. 6) The late Early Permian-Late Permian cycle, which reflects maximum growth of the Ural Mountains and associated Ural foredeep. Evaporites were first deposited, then marine limestones and dolomites, which intertongue eastward with clastic sediments from the Ural Mountains. 7) Continental redbeds of Triassic age and mixed continental and marine elastic beds of Jurassic and Cretaceous age, which were deposited on the southern, southwestern, and northern margins of the Russian platform; they are generally absent in the Volga-Ural province, however. The Volga-Ural oil and gas basin is a single artesian system that contains seven aquifers separated by seals. The areas of greatest hydraulic head are in the eastern parts of the basin near areas where the aquifers crop out on the western slopes of the Ural Mountains. The Peri-Caspian basin is the principal drainage area of the artesian system. Approximately 600 oil and gas fields and 2,000 pools have been found in the Volga-Ural province. Nine productive sequences are recognized as follows: 1) Upper Proterozoic (Bavly beds), which are promising but not yet commercial. 2) Clastic Devonian, which contains the major reserves and includes the main pays of the super-giant Romashkino field. 3) Carbonate Upper Devonian and lowermost Carboniferous, which is one of the main reef-bearing intervals. 4) Visean (Lower Carboniferous) elastics, which are the main pays in the super-giant Arian field. 5) Carbonate Lower and Middle Carboniferous. 6) Clastic Middle Carboniferous Moscovian. 7) Carbonate Middle and Upper Carboniferous. 8) Carbonate-evaporite Lower Permian, which contains the major gas reserves and the lower part of the Melekess tar deposits. 9) Clastic-carbonate Upper Permian, which contains the major part of the Melekess tar deposits. The Volga-Ural province is divided into several productive regions on a basis of differences in structure, distribution of reservoir and source-rock facies, and general composition of the petroleum accumulations. These regions are the Tatar arch, Birsk saddle, Upper Kama depression, Perm-Bashkir arch, Ufa-Orenburg monocline, Melekess-Sernovodsko-Abdulino basin, Zhligulevsko-Orenburg arch, Ural foredeep, and north borders of the Peri-Casplan depression. Exploration activity has declined in recent years; however, interest remains high in several parts of the province, particula

Open-File Report↗
USGS1980

Salym: potential W. Siberian oil giant

SALYM oil field is on the Lempa high of the Salym uplift in the eastern part of the Khanty-Mansiysk depression in the Middle Ob region of West Siberia. The Salym uplift is about 50 km long and 45 km wide and trends north. The Lempa high is 25 km long and 16 km wide; closure is 150 m. The Salym field is about 275 km west of the giant Samotlor field. Stratigraphy. The sedimentary cover overlying the Paleozoic Hercynide basement in the Middle Ob region consists of Jurassic, Lower and Upper Cretaceous, Paleogene, and Quaternary marine and continental sediments.

Salym, Siberia↗