Geodynamic Aspects of Geological Development of the Terek-Caspian Trough: A Study of Oil- and-Gas Potential

The Terek-Caspian trough is a tectonic unit at the junction of two structural elements of different age and composition. This is a megatrough with promising oil-generating properties, which has attracted academic and commercial interest since the century before last. The uniqueness of this higher-order structure lies in the fact that its constituent elements of the second order have different basement age, geomorphology, lithology, facies composition, phase composition of hydrocarbons, while remaining a single geostructural element. This article is aimed at identifying new foci of oil and gas formation and accumulation of hydrocarbons. The main method was the geodynamic approach to interpreting the available geological and geophysical data. In particular, it has been established for sure nowadays that most of the world’s hydrocarbon accumulations are associated, firstly, with zones of convergent and divergent boundaries of tectonic plates, and, secondly, with sedimentary-rocks basins developed within the above boundaries. These are exemplified by back-arc troughs, pre-arc foredeep troughs, and inter-arc sedimentation basins formed during the development of the Terek-Caspian segment of the Alpine-Himalayan folded belt. At the same time, the Terek-Caspian trough is an integral part of the Black Sea-Caspian region, a highly productive object of hydrocarbon accumulations. These structures provide a comprehensive range of all geological situations that can contribute to the formation and accumulation of hydrocarbons. The article presents a stratigraphic refinement of some geological and structural units based on the analysis of the chemical composition of volcanites, determines the petrographic composition of rocks by the propagation velocities of seismic waves and substantiates the sources of oil and gas formation and accumulations of hydrocarbons based on the geodynamic model of the region. Innovative methods are proposed in the search and exploration of hydrocarbons, based both on an iterative approach to the forecast of oil and gas potential, and on a methodological one. The probability of detecting unconventional accumulations of hydrocarbons is substantiated due to favorable geological conditions for their formation during the development of this region and the presence of precedents in certain areas (volcanogenic rocks, positive magnetic anomalies, etc.). The obtained data are of practical importance for theoretical geologists, oil geologists, prospectors and developers.