Hydrogeology of the Pre-Devonian deposits in the north-eastern parts of the Volga-Ural Oil and Gas Province and the adjacent areas

AbstractThe article reviews hydrogeology of the Pre-Devonian deposits in the north-eastern parts of the Volga-Ural Oil and Gas. The integrated analysis of the unique data on the thermal properties of the section, fluid composition and properties were the estimation basis for the most basic hydrogeological regularities of the Pre-Devonian sequence. Certain community of the hydrogeochemical features of the Riphean-Vendian hydrogeological sequence with the Devonian terrigenous deposits within the Kama-Belsk aulacogen was established alongwith favorable hydrogeological conditions of the hydrocarbon deposits preservation.
Materials and methods
Systematization of the hydrogeological data related to the wells, statistical and graphicalmethods of the hydrogeochemical and thermal data analysis.
Results
It has been established that the Riphean-Vendian hydrogeological sequence and the Devonian terrigenous deposits form a single hydrochemical system. A modern thermodynamic mode of the Riphean-Vendian deposits corresponds withthe hydrostatic indicators. It is anticipated that the deep vertical mass transport along the local fi sure zone plays a signifi ant role. Formation brines of the Pre-Devonian deposits can be assigned to the bromine and iodine-bromine industrial waters.
Conclusions
Forming a single hydrogeochemical system in the Riphean-Vendian and Devonian deposits isan important sign of the hydrocarbon saturation in the section, and it shall be considered when building conceptual geomigration models.The most permeable beds and zones of highly permeable faults in the Vendian deposits can serve as production zones of brine extraction in order to extract industrially valuable components. Organized hydrogeological information can be used to design new deep parametric wells within the Riphean-Vendian deposits.