Abstract The Yuzhno Khilchuyu field, located in the Timan-Pechora Basin, has four stacked limestone and sandstone reservoirs ranging from Lower to Upper Permian. Reservoir depths range between 2150 and 1704 m subsea. The principal reservoir is a Lower Permian (Asselian-Sakmarian) limestone that has an oil-in-place estimate of 1584 million bbl (214 million t) approved in 1985 by the Russian Central Reserves Com mittee. In addition, a minor amount of oil (16 million bbl [2.2 million t]) with a gas cap is present in an overlying Lower Permian (Kungurian) sandstone. Overlying Upper Permian sandstones also contain minor amounts of free gas totaling about 27 bcf (763 million m 3 ) gas in place. Available data indicate that the Asselian-Sakmarian reservoir has high productivity in the central part of the accumulation, with somewhat lower productivity on the flanks. Development of the field will require water injection for pressure maintenance.

Abstract Several existing schemes for Carboniferous stratigraphy officially adopted in regions of the Russian Federation are summarized and discussed. These regions with different geological histories and distinct depositional settings include the Moscow Basin, the Urals, North Timan, Siberia, the Kuznetsk Basin and the Mongol–Okhotsk, Verkhoyansk–Okhotsk and Kolyma–Omolon regions. Broad correlations based on macro- and microfossils are possible between the regions, while all regional schemes are correlated to the official Russian General Stratigraphic Scheme for the Carboniferous, using zonations based on orthostratigraphic fossils. The Russian General Stratigraphic Scheme is correlated to the International Stratigraphic Scale using ammonoids, conodonts, foraminifers and palynomorphs.