The prospects of oil deposits of the Vereyian horizon of the marginal part of the Melekess-Abdulin oil and gas region of the Tatarstan Republic

The paper presents the results of a study of oil-bearing sections of the Vereyian horizon of low-amplitude uplifts in the western marginal part of the Melekess-Abdulin oil and gas region of Tatarstan. It has been established that the main reservoir rocks are algal-peloid packstones, fusulinide grainstones and greywacke fine-grained sandstones. Carbonate reservoirs of the lower part of the section of the Vereyian horizon and sandstones of the upper part of the section are watered to varying degrees, most of them are not promising for development. The productivity of the sections is associated with fusulinide grainstones and underlying algal-peloid packstones that have not experienced intensive waterflooding. As a rule, such lithotypes of carbonate reservoir rocks are in the middle parts of sections of Vereyian age. A feature of the fusulinide limestone layers is their areal inconsistency in thickness, which is due to the facies conditions of the sedimentation basin. Due to this, on some small oil-bearing structures they give good oil inflows, on others they show relatively small debits.