Unconventional oil reservoirs in high-carbon carbonate-siliceous Domanik formations, Volga-Urals province: results of studies and future development trends

The paper discusses the features of architecture of unconventional oil reservoirs in the Domanik-type formations. The high-carbon shale-like carbonate-siliceous Domanik deposits common occurring within the Volga-Urals Petroleum Province are the most promising targets for future large-scale development. The Domanik deposits of the Volga-Urals Petroleum Province are found in the wide stratigraphic range from Upper Devonian Upper Frasnian substage to Famennian stage, and partially the Upper Carboniferous Tournaisian stage. The authors consider the Domanik depositional settings, the results of exploration and prospecting, and subsoil licensing in the current stage of oil pool development in the Domanik formations. Substantiation of variables used to estimate reserves, which were accepted in evaluation of resource potential using volumetric method is carried out. The results of estimation of the Domanik oil resources in the Volga-Urals Petroleum Province are presented (at least 12 billion tons of recoverable oil). It is shown that at the current level of exploration maturity and extent of the development, the recovery efficiency value is the most significant uncertainty in reserves and resources assessment in the Domanik-type rocks. The author takes a view at the prospects of unconventional oil reservoirs development in the Domanik-type formations. Development of unconventional oil accumulations in the Domanik-type formations will be economic with price about $40/bbl and higher