Pre-Jurassic basement of the Terek-Caspian basin in connection with the problem of deep oil and the formation of its accumulations

Abstract

Relevance. In recent decades, in the practice of geological exploration for oil and gas, there have been negative trends associated with an unfavorable ratio between the extraction of hydrocarbon raw materials and the increase in oil and gas reserves. As is known, for the stable development of oil and gas production, it is necessary that the pace of development of exploration ahead of the pace of hydrocarbon production. The above trends are associated not only with a decrease in the volume of exploration for oil and gas, but also with the obsolescence of the theoretical and methodological foundations of oil and gas prospecting and exploration, based mainly on sedimentary-migration and anticlinal theories. At present, experimental data and results of ultra-deep drilling in a number of regions of the world have proved the possibility of finding hydrocarbon deposits at depths of up to 9-11 km. In this regard, certain prospects for the oil and gas potential of the studied and other oil and gas regions can be associated with the basement and lower horizons of the sedimentary cover. Aim. Study the relationship between the fault-block structure of the basement, the structure of the sedimentary cover, the processes of oil and gas formation and the formation of hydrocarbon accumulations. Methods. To solve the problem, stock materials and published literature sources were used, a comprehensive analysis and generalization of geological and geophysical information (methods of the deep seismic sounding, CDP, seismic refraction, well drilling, etc.) was carried out on the pre-Jurassic basement and sedimentary cover. Results. The history of the development of views on the fault-block structure of the basement and the lower structural stage of the sedimentary cover and the oil and gas potential of the Eastern Ciscaucasia is covered. The results obtained by various methods are described - seismic exploration of the CDP, refraction correlation, deep seismic sounding, re-leveling, etc. The relationship between fault tectonics, processes of deep oil and gas formation and the formation of multilayer deposits within the Tereк-Caspian basin is established.