Genetic suppositions of oil and gas formation and conditions of hydrocarbon deposits in Mesozoic-Cenozoic sediments in the Caspian Sea shelf

Source rocks are present in all the stratigraphic units of the Mesozoic-Cenozoic deposits of the Turkmen shelf in the Caspian Sea. The highest source rock potential is characteristic of I terrigenous and carbonate-terrigenous rocks of Middle Jurassic age, and the Aptian, Paleogene, Neogene and Apsheron stages of the Quaternary system. To reveal the formation conditions of hydrocarbon deposits within Southwestern Turkmenistan, the principle of chemical thermodynamics is primarily used via the calculation of the free energy of gaseous hydrocarbons. This showed that hydrocarbon deposits within the topmost depositional complex (the red-colored strata of the Middle Miocene at the Akchagyl and Apsheron stages) are syngenetic; their formation was due to lateral migration from even-aged deposits from depression zones neighboring the uplifts.