A case study of predicting net reservoirs within J2 unit of the Tyumen formation of polyfacial genesis in the territory of the Uvat project

On the periphery of the West Siberian Basin, up to 30 % of J 2-4 reservoirs within the Malyshev horizon of the Tyumen formation cannot be predicted correctly. The reasons include the low exploration degree of the territories by deep wells, which is why the net reservoirs are predicted based on 3D seismic data, and poor seismic resolution against the size of traps in the Tyumen formation. The article presents a case study of the application of geological and geophysical, seismic materials related to the Uvat area in the south of Tyumen region. The aim is to describe the lessons learned when addressing the reservoir forecasting issue associated with one of the Tyumen formation reservoirs (J 2 ) of complex (coastal-transitional and continental) genesis. The article describes the technologies applied by the Tyumen Petroleum Research Center LLC to estimate net pays based on 3D seismic data. A complex of main geological and seismic factors that control the forecasts of thin terrigenous reservoirs based on seismic data is considered. These include the structure of the J 2 unit (vertical features of net reservoir evolution), the effect of carbon content, the issues of separating net-reservoir and non-reservoir rock by petroelastic properties, etc. The results of the analysis presented in this article are employed actively in the context of geological exploration and the identification of priority traps in the Tyumen formation within the territory of the Uvat project.