Structure, formation conditions, oil and gas potential of Domanicoid high-carbon formation in the Central and South-Eastern Parts of the Volga-Ural basin

Abstract

The article discusses the structure and formation conditions of the domanicoid high-carbon formation (VUF) within the central and southeastern parts of the Volga-Ural basin. The presented results of the analysis of the structure, conditions of formation and oil and gas content of domanicoid deposits are a generalization of the accumulated knowledge obtained during the research of the authors in certain regions and areas. The regional geological model of the formation of the domanicoid complex was created based on the results of seismostratigraphic and cyclostratigraphic analyzes. In the structure of the Middle Frasnian – Tournaisian domanicoid deposits, three different areas are distinguished, differing in composition, structure, thickness, and formation conditions –the carbonate platform, the intrashelf depression and its slopes. The revealed cyclicity in the structure of the complex showed that the section consists of 4 large cyclites, the accumulation of which occurred at the stage of changes in the relative sea level. An analysis of the material composition of the deposits made it possible to identify various sedimentation environments and their characteristic strata, which unite lithological units, within each large cyclite. Geochemical and petrophysical studies of the rocks of the domanicoid VUF made it possible to assess the oil and gas potential, identify the intervals containing the largest amount of organic matter, and intervals of reservoir rocks in the context of the studied deposits.