Oil-saturated deposits of the Vereyian horizon at the Tatarstan Republic

Abstract

The article discusses the structure of multilayer oil deposits of the Vereyian horizon in the territory of the Tatarstan Republic. It is shown that in the sections the reservoir rocks are different facies of limestones (mostly grainstone), sandstones and siltstones. The reservoir rocks were formed in the regressive stage of the development of the marine sedimentation basin. Oil deposits of the Vereyian horizon have experienced flooding processes with formation edgewater. The penetration of groundwater into reservoir rocks led to uneven oxidation of oils in oil-producing structures. With weak waterflooding, dolomite and pyrite were formed in the reservoir rocks, with strong waterflooding, anhydrite aggregates appear.

Reasons for the low productivity of the Bashkirian stage oil deposits on the southwestern slope of the South Tatar arch

“…Geological exploration drilling in other areas of the structure yielded more modest results in oil production. Recently, oil companies have focused on the southwestern slope of the arch, where numerous small-sized dome uplifts have been identified [7]. Some of them are oil-producing, while others, despite the presence of oil intervals in core, do not produce oil inflows.…”