Distribution and formation conditions of major and large oil fields in Volga-Ural province

Regionally, the number of large and “gigantic” accumulations of oil (>50 million tons and >100 million tons of proved economic reserve, respectively) decreases progressively with decreasing age of their Paleozoic host. The apparent exceptions, in the Lower Carboniferous, are due to migrations of the Devonian pools into the Carboniferous traps. However, large accumulations of oil may develop also in several complexes, at intersections of the Devonian domes with the Lower Carboniferous Kama-Kinel trough. – IGR Staff.