Conditions of oil and gas formation in the territory of the Eastern and Central Ciscaucasia

Abstract

The results of studies of hydrocarbon systems of the Eastern and Central Ciscaucasia are shown. The research area covers part of the Scythian platform, namely, the northern side of the Terek-Caspian foredeep, the north-eastern part of the East Kuban depression, the Tersko-Kum depression and the Stavropol arch. Based on the results of the work and basin modelling of hydrocarbons generation, emigration and accumulation processes, the reconstruction of the history of oil and gas formation and oil and gas accumulation in the sedimentary cover of the region was completed. The basin modelling of hydrocarbon formation processes in Central and Eastern Ciscaucasia was carried out using the PetroMod (Schlumberger) program complex. The obtained results made it possible to determine the dynamics of organic substance transformation processes, evolution of oil and gas formation zones, time and expected paths of hydrocarbon migration and phase composition and degree of hydrocarbon saturation of the section. The model reliability was corrected by comparing the values of benchmarks (modern reservoir temperatures measured in wells, with their calculated values obtained as a result of modelling). The location of possible foci of hydrocarbon generation in the sedimentary cover, the migration paths, the phase composition of hydrocarbons, the intensity of hydrocarbon saturation within individual tectonic zones and structures were determined. It has been established that the main foci of hydrocarbon generation in the southern part of the studied region are located in the Chechen depression (Tersko-Caspian deep), on the platform part–in the zone of the Manych deep and Nogai stage.