Geological characteristics and latest progress in exploration and development of Russian shale oil

Abstract

© 2019, OIL & GAS GEOLOGY Editorial Board. All right reserved. Russia is rich in unconventional shale oil resources, covering almost all sedimentary basins ranging from Cambrian to Neogene in age. The major areas of prospecting potential in Russia are the Bazhenov Formation of the Western Siberian platform and the Domanik formations in the Eastern European platform. Bazhenov Formation is the Upper Jurassic-Lower Cretaceous in age. Its main lithology is siliceous shale, with a thickness of 30 m and TOC of 7% on average. Its TOC is generally above 4%, mainly falling on kerogens TypeⅠ-Ⅱ domain, with the maturity ranging from 0.5% to 1.1%. While Domanik formations, also called "Domanik facies" or "Domanik deposits" from the Paleozoic Upper Devonian (Russian stage-D3 fr2) to Lower Carboniferous (Tournaisian-C1t) in age, in the Volga-Urals and Timan-Pecher oil and gas provinces, are dark siliceous-clayey-bituminous limestones falling on kerogens TypeⅠ-Ⅱ domain, with an overall thickness of 100-600 m, TOC of 0.5-24%, and maturity ranging from 0.5% to 1.5% in the north-central part of Volga-Ural Basin. However, their gas production is mainly concentrated on the southern part of Caspian sea. Despite of the unfavorable impact due to the low international oil prices, the exploration and development of shale oil resources in Russia have never been stopped: 146 vertical wells in the Bazhenov Formation were tested in 2016, with an average daily production rate of 10.8 t during the active days; meanwhile 36 horizontal wells were tested with an average daily production rate of 7.5 t during the active days. The Bazhenov technology center, set up by Gazprom in 2018, has cut down the time of hydraulic fracturing to 50%, and unit production cost to 40% in the development of Bazhenov oil. Moreover, the deve-lopment of shale oil resources in Russia can enjoy preferential policies like zero tax rate for mineral exploitations. Together with its existing favorable conditions, including abundant geological data for most oil fields, relatively short distances among these oil fields, and perfect infrastructures, the expectation is very positive for the future commercial development of shale oil in Russia.