Е. А. Danilova, Ya. D. Shibanov

Shear dislocations of the Buzuluk depression and Pugachev arch junction zone in the Volga-Ural oil and gas province based on the 3D common depth point method seismic survey data

Abstract. Gravimetric data allowed mapping a northeastern left-lateral strike-slip in the junction zone of the Buzuluk depression, Pugachev arch, Orlyanskoye-Ivanovskoye protrusion, and Sernovodsk-Abdulino aulakogen in the Volga-Ural oil and gas province. It has an amplitude of about 50 km and a length of over 300 km. A chain of low-amplitude disturbances stretches along the strike-slip. The gravitational field transformations calculations confirm the disturbance. The strike-slip is likely to impact on hydrocarbon deposits localization in the region. The paper aims to study the structure of the Buzuluk depression, Pugachev arch, Orlyanskoye-Ivanovskoye protrusion, and Sernovodsk-Abdulino aulakogen junction zone from the 3D common depth point method seismic survey data in the Zalesskaya area, its oil and gas potential, and “reconstruction” of possible strike-slip events. The study demonstrates that the region is likely to have northwestern left-lateral horizontal strike-slips with an amplitude of up to 5 km. Their strike coincides with the radial fault of the Sverdlovsk ring megastructure and strike-slip identified by gravimetric data. The “reconstruction” results in an expected strike-slip fault zone of a “jagged” type crossing the Zalesskaya area. Its direction coincides with annular faults of the megastructure. Most hydrocarbon deposits and promising structures of the Zalesskaya area are concluded to be associated with lines of expected disturbances of the strike-slip fault zone and their intersections.

Keywords: Eastern European platform, left-lateral, gravimetric data, Sverdlovsk ring megastructure, hydrocarbon deposits, geophysical methods