Distribution of zones of decompression of the Earth's crust as an indicator of the oil prospects of the territory of the Caspian region

The issues of the structure of the earth's crust of the Caspian basin and the associated deep origin of hydrocarbons are considered. The main mobilist ideas about the role of tectonic forces in the formation of the modern appearance of the Caspian region, which were developed in theoretical conclusions arising from the “concept of the fluid regime in the upper crust”, based on the crustal waveguide hypothesis (Karakin, 2001), are reviewed. It is shown that waveguides can be considered as elements of the section structure in which accumulation of fluids migrating from deeper horizons is possible. Based on regional seismic observation data presented by velocity levels, a non-trivial method for constructing 3D models of the distribution of decompression zones in the upper part of the earth's crust is proposed. The calculation results made it possible to develop a 3D model of the distribution of density heterogeneities, in which the leading role is given to zones of low velocity (density). It is shown that the decompaction zones
are not randomly located. Their distribution is in good qualitative agreement with the known scheme of oil and gas potential prospects for the Caspian Sea. The preliminary results obtained give reason to assume that the decompression zones identified from experimental data objectively reflect the pattern of fluid flow direction and hydrocarbon accumulation. The revealed patterns in the distribution of decompression zones, in combination with other geophysical data, can serve as an additional criterion when assessing the oil potential of the territory and carrying out exploration work in the Caspian region. And the method of identifying them can be applied when studying other oil-promising regions