One of the best practices for improving oil recovery in waterflood projects is horizontal drilling which involves construction of multifunctional horizontal wells as well as revitalization of marginal wells through sidetrack drilling, particularly horizontal sidetracking. The first attempts to implement horizontal drilling technology in Lower Carboniferous terrigenous and carbonate reservoirs, and in Domanic sediments of the Famennian stage and Upper Devonian Pashian reservoirs were made by geological surveys of Tatneft and Oil and Gas Production Department Bavlyneft. Oil fields operated by Bavlyneft comprise 29% of total count of horizontal wells drilled through the above mentioned reservoirs and 56% of horizontal wells drilled to produce from the Tournaisian production target.
Oil production rates obtained from horizontal wells in terrigenous reservoirs and low-permeability carbonates were estimated at 100 t/d and 10 t/d, respectively, at negligible water cut. In 2015, horizontal drilling was implemented in the Domanic sediments. These were brought into production using EOR methods and bottomhole assembly providing for division of a horizontal section into multiple isolated intervals with different reservoir properties.
Engineering design and well construction technology, as well as completion and operation of horizontal wells in Tatarstan have been brought to a relatively high level, which is confirmed by production and economic performance indicators that are comparable to those of the leading foreign and Russian energy companies.
