Currently, reserves replacement issues are of particular interest for Tatneft and generally for the Republic of Tatarstan. Reserves replacement due to discovery of new fields in conventional oil plays does not enable 100% replenishment of current oil production. For intrinsic geological reasons, newly discovered fields are small and very small. In light of the above, following US “shale revolution” the Company has turned its focus toward the Domanic deposits (Zavozhskian through Sargaevskian), widely spread across the Republic of Tatarstan and generally in the Volga-Ural petroleum province. Since 2013, Tatneft has been conducting extensive research of domanikites. To date, a series of studies on refinement of geological structure of the Domanic sediments has been performed, petroleum potential has been determined, a series of scientific research and issue-related studies has been conducted. Each year, technologies and methods for stimulation of poor-quality reservoirs are developed and implemented, in that number horizontal drilling technologies, non-damaging acid treatments and multi-zone fracturing. The paper considers the lessons learned from the study and pilot oil production operations conducted by Tatneft in the Domanic sediments. Results of scientific research of the Domanic sediments conducted in cooperation with Moscow State University, Oil and Gas Institute of the Russian Academy of Sciences, All-Russian Geological Research and Development Oil Institute, Kazan (Volga region) Federal University, and Arbuzov Institute of Organic and Physical Chemistry are provided. The first-priority production targets are the Domanic deposits of the Semilukskian/Mendymskian horizons. These are tight low-permeability rocks, containing considerable amounts of organic matter, and exhibiting both oil-producing and petroleum containment properties. Oil production from Domanic deposits requires stimulation of productive formations. Well stimulation techniques applied in promising intervals identified from extended well logging data comprise massive bottom-hole treatments, hydrochloric acid injection, hydraulic fracturing and acid fracturing. The paper reviews the details of field trials (in intervals with various petroleum mobility characteristics): well selection workflow is provided; conducted field operations are highlighted as well as success rate by production targets. Necessity and challenges of polygon creation are discussed. Prospects and suggested way forward on the development of Domanic deposits are summarized.
1Minnikhanov R.N., Maganov N.U., Khisamov R.S., On creation of research and testing facilities to promote study of nonconventional oil reserves in Tatarstan (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 8, pp. 60–62.