Northern West Siberian–South Kara Composite Tectono-Sedimentary Element, Siberian Arctic

Abstract

The Northern West Siberian-South Kara Composite Tectono-Sedimentary Element (NWSSK CTSE) occupies over 1 mln. km2 of the northern West Siberian Basin and the South Kara Basin. It formed as a result of the latest Permian - earliest Triassic crustal extension following thermal subsidence. The Early Triassic palaeorifts are buried under 10-12 km-thick post-rift Middle Triassic - Quaternary siliciclastic sediments. In the Tithonian - Early Berriasian period, a deep-water anoxic depression formed in the West Siberian Basin and accumulated organic-rich carbonate-siliceous Bazhenov shales, that are the main source of hydrocarbons.The West Siberian Basin, including the NWSSK CTSE, is one of the major petroleum provinces worldwide. Oil and gas deposits have been identified in Paleozoic carbonate basement rocks, Triassic, Jurassic, and Cretaceous reservoirs. The main gas reserves are concentrated in the Lower Aptian-Cenomanian play. Significant gas and oil reserves are located in the Berriasian - lowest Aptian and Jurassic plays.The CTSE comprises 18-20% of the world known gas reserves and provides approximately 90% of the total Russian natural gas, which is 22% of the world gas extraction. In this chapter we provide a summary of the CTSE geology and petroleum geology based on bulk results mainly published in the Russian literature.

Assessment of Oil and Gas Potential in Vychegda Trough in Connection with the Identification of Potential Petroleum Systems

“…The Early Cretaceous period corresponded to the regressive phase of the Late Jurassic basin not only in many large basins of the world [57][58][59], but also in the Vychegda Trough. Clastic sediments represented by siltstones and sands were accumulated in marginalmarine conditions.…”