Historical-geological modeling of hydrocarbon generation in the Mesozoic–Cenozoic sedimentary basin of the Kara Sea (basin modeling)

Abstract

Numerical models are developed to predict the generation, accumulation, and escape of hydrocarbons at the time of sediment accumulation (basin modeling) in the West Siberian geosyneclise during the Jurassic, Cretaceous, and Cenozoic. A theoretical framework for such computer models is presented with a special emphasis on modeling of gas generation during early catagenesis. The study provides a description of the algorithm used for interpretation of simulation results and considers the stages of formation of a shale cap rock during lithogenesis. Peak oil generation began in the Aptian and continued for about 80 Myr until Eocene–Miocene times; gas generation in the late catagenetic window took place from the Valanginian to the Maastrichtian. Numerical simulations show that the major oil-prone source rocks in the South Kara kitchen area were, in the decreasing order of potential, the Bazhenovo (Yanov Stan), Kiterbyut, and Malyshevka Formations. The Upper Jurassic regional rock unit generated over 60% of liquid hydrocarbons and heterocyclic compounds (oils). The major gas-prone source rocks in the area were, in the decreasing order of potential, the Kiterbyut, Malyshevka, Alym, and Bazhenovo (Yanov Stan) Formations. The Lower and Middle Jurassic regional rock units generated about 65% of hydrocarbon gases. Results are presented to quantify the amount of hydrocarbons dissipated due to either the absence or poor effectiveness of confining seals and to explore the role of Cenozoic tectonic processes in the formation of petroleum accumulations in the basin.

History of anticlinal traps and oil and gas fields in Jurassic reservoirs in the northern West Siberian basin

“…The paleotectonic approach allowed Kontorovich (1975Kontorovich ( , 2013 to interpret most of oil and gas generation within the Middle Ob reaches in terms of regional- scale Early Cenozoic uplifting. Kirov (1964) used this approach, with reference to confining pressure and reservoir properties, to estimate that traps in the zone J 1 of the North Vasyugan and Myldzha fields were filled in the Aptian-Albian.…”

“…We consider the history of anticlinal traps in Jurassic sediments in the context of oil and gas generation, according to the models of Kontorovich et al (2013). The Bazhenov Formation shale is the principal source of oil in the basin and, at the same time, the largest reservoir and a regional-scale cap which confines gas released from organic matter in Jurassic sediments.…”

“…Oil fields in the Middle Ob area formed during Early Cenozoic tectonic activity. (Kontorovich et al, 2013) Basin modeling (history of generation, migration, and storage of hydrocarbons) for the case of South Kara reservoirs showing that generation of oil and gas in northern West Siberia occurred in the Late Cretaceous and especially in the Cenozoic. Most of existing models predict that oil and gas accumulations in the region formed between the Late Cretaceous and the Present, mainly in the Cenozoic.…”

Tectonic evolution of the Arctic onshore and offshore regions of the West Siberian petroleum province

“…At present, one of the key research challenges facing Russian petroleum geologists and geophysicists is the study of the geologic framework of the Russian Arctic, including West Siberia and Kara shelf, considering their high potential for hydrocarbons (Bochkarev et al, 2010;Kazanenkov et al, 2014;Kontorovich et al, 2013).…”

Structure and Source Potential of the Bazhenov Formation in the Central Part of Western Siberia

“…Качество нефтематеринских пород характеризуется типом ОВ, его содержанием в породе и генерационным потенциалом. Многие специалисты [4,7,8,10] относят исходное органическое вещество пород баженовской свиты к типу II. И. В. Гончаров при изучении юго-восточных районов Западной Сибири [3] отнес породы баженовской (марьяновской) свиты к нефтегенери-рующим толщам с органическим веществом пограничного (между I и II) типа.…”