Vareganskoe field

VAREGANSKOE GAS-PETROLEUM FIELD (RU: Варъеганское газонефтяное месторождение) is situated within the Tyumen province of the Russian Federation, at the distance of 20 kilometres to the north-east of the Surgut city. The field belongs to the West Siberian petroleum-gas-bearing province. The reservoir of gas has been discovered during the 1967, the reservoir of petroleum has been discovered during the 1968; the field is being developed since the 1974. The field is confined to the local uplift with the meridional strike, within the limits of the southern part of the Vareganskij embankment. The amplitude of the uplift is 250 metres. There have been identified 13 reservoirs, including the reservoirs with the gas condensate within the layers of the Upper Jurassic (2), and of the Lower Cretaceous (2); the petroleum reservoirs within the depositions of the Valanginian (6), and the gas reservoirs within the layers of the Cenomanian (3), at the depths of 800-2500 metres. The reservoirs are layered, vaulted, and lithologically shielded. The collectors are porous (the sandstones with the interlayers of the clays, argillites, and aleurolites), with the porosity of 23-24%, and with the permeability of 274-331 millidarcies. The gas-petroleum contact within the Cenomanian reservoir is at the depth of 755 metres, the water-petroleum contact for the Jurassic reservoir is at the depth of 2450 metres. The initial reservoir pressure is from 71 to 25.7 megapascals, the temperature is from 32 to 87 degrees Celsius. The gas factor is from 89 to 4563 cubic metres per cubic metre, the pressure of the gas saturation is 161 megapascals. The density of the petroleum is 760-860 kilograms per cubic metre. The method for the operation is the peripheral flooding. The centre of the field is the Nizhnevartovsk city.