The paper provides general information on the gas content and productivity of low-permeable gas reservoirs of the Berezovskaya formation. The Berezovskaya reservoir testing practices in directional and horizontal wells at the fields of Rosneft and Gazprom companies are described. The paper also considers the procedure of cased wells testing in the Berezovskaya formation developed to improve the operational success taking into account the unique properties of the target. The productivity of terrigenous reservoirs of the Upper Berezovskaya sub-formation depends on the rock grain size, the higher the grain size, the higher the reservoir quality and thus the gas rates. Commercial gas rates can be achieved even without hydraulic fracturing. The productivity of clay silicites of the Lower Berezovskaya sub-formation is an order of magnitude lower. The reservoir quality is defined by the pore space structure, the pore size, and the presence of natural rock fracturing. The best reservoirs are characterized by needle-shaped pore space and pore size of 200–500 nm. In fields with spongy pore space and pore size of up to 60 nm, formation tests without hydraulic fracturing were unsuccessful. Increased gas rates were obtained in wells located near tectonic faults (here is the maximum fracturing intensity), in tentative corridors above strike-slip faults, and at structural inflections. Hydraulic fracturing in silicite reservoirs provides a 3,8 to 47 times increase in gas rates reaching post-fracturing rates proportionate to the terrigenous reservoir of the Upper Berezovskaya sub-formation. The productivity potential of the Berezovskaya reservoir, based on the results of hydraulic fracturing tests in directional wells, amounted to up to 90 thousand m3/day. The economic efficiency of the Lower Berezovskaya sub-formation development can be achieved by drilling horizontal wells with multistage hydraulic fracturing. The initial rates of horizontal wells with multi-stage hydraulic fracturing reach up to 170 thousand m3/day. The well test results show the advantages of horizontal wells drilled across the maximum stress. The lessons learned by companies in studying and testing the Berezovskaya reservoir are insufficient for making decisions on the involvement of reserves into full-scale development. The production potential should be further investigated through pilot projects involving various well designs in areas with various types of natural fracturing.
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