Catagenesis and Petroleum Reserves of the Jurassic and Prejurassic Sediments of the Krasnoleninskii Arch

Essential differences in organic matter alteration have been found in the Jurassic (gradation MK1 – MK4, Rυt0=0.5-1.5%) and Prejurassic (gradation AK1 – AK3, Rυt0=1.80-5.8%) sediments of the Krasnoleninskii Arch. The main petroleum reserves in the region under study is associated with the Tyumen Formation deposits in the terrains where organic matter occurs in the main zone of oil formation. High-grade catagenesis of the Prejurassic formations suggests that only small gas accumulations may be found in separate regions.