Characteristics of source rocks and features of petroleum systems of the South Caspian basin

To assess the generation potential of oil and gas source strata of the South Caspian Basin (SCB) of the Cenozoic age, pyrolytic studies were carried out using the Rock-Eval-6 pyrolysis method from VINCI Technologies.In the SCB with a complex geological structure and geodynamic development, there are very difficult conditions for the development and distribution of generationaccumulation hydrocarbon systems.During the evolution of the basin, unique conditions were created for the formation of hydrocarbon systems that differed significantly from the classical ones.The paper examines the rates of sedimentation and subsidence, as well as the regional geo-temperature background influencing the catagenetic evolution of organic matter.In the SCB there is a unique natural phenomenon -the Miocene-Pliocene generation-migration-accumulation hydrocarbon megasystem with a reservoir in the productive strata (PS), the oil and gas content of which is formed due to the migration of hydrocarbons from several oil and gas source strata -mainly from the Oligocene-Miocene (Maykop) and Miocene (Tarkhan Chokrakian and diatom) age, partly from the Eocene and the PS (Productive Series) itself, mainly its lower section, both according to classical migration patterns and according to systems of mud volcanoes, widespread in the SCB.Along with the above megasystem, shale hydrocarbon systems were formed within the SCB: diatomaceous shale hydrocarbon system, Oligocene-Miocene shale hydrocarbon system and Eocene shale hydrocarbon system, which are combined unconventional oil and gas systems with hydrocarbons, partially emigrated from oil and gas source strata and partially preserved (not displaced).