Hard-to-recover reserves of Yugra oil (West Siberia)

In 2017, the Yugra’s share of the all-Russian production was 43.0 %, it’s 235.3 million tons in absolute units. This is 3.9 million tons less than in 2016 and 43.1 million less than in 2007. The Neocom shelf sandstones are the main development object. 44 % of the expected resources of Russia in prospective D1 category reserves (resources of sediments and territories with proven oil) are concentrated in Yugra. The key challenge for the oil industry of Yugra is prevention of decline and the stabilization of oil production. It can be obtained by the active involving hard-to-recover reserves to the development. Criteria of hard-to-recover reserves, results and opportunities of their using for development in the conditions of Yugra fields are analyzed in the article. These are oil deposits with abnormal physical and chemical properties, under-gas-cap zone of deposits, sediments of the AB11–2 reservoir “Hazel Grouse” of type, Achimov Formation, Tyumen Formation, rocks of the Pre-Jurassic play and Bazhenov Formation. Increase in the oil production for only three plays (Achimov, Bazhenov-and-Abalak and Tyumen) was almost 4 million tons in 2017. This is comparable with the rate of decline in oil production for Yugra in general. Geological initial resources of the Bazhenov play are estimated at 11 billion tons, recoverable oil resources, at 3.1 billion tons. The primary source of the stabilization of oil production level in Yugra is involvement in the development of hard-to-recover reserves of Achimov and Tyumen plays. The production growth of the hard-to-recover reserves of the Pre-Jurassic play is possible. Now its annual production is 2—3 million tons. Resources of Bazhenov play will replenish the declining production trend by 2030.