Carbon isotopes fractionation of oil shale organic matter under artificial maturation in an autoclave in the presence of water

The initial results of the experimental isotope studies of organic matter rich deposits are presented. The experiments on the artificial maturation of the Upper Jurassic oil shale (Sysola region) and Upper Devonian bituminous shale (Ukhta region) in an autoclave in the presence of water are carried out. The carbon isotopic composition of kerogen, bitumen and its fractions, termobitumen and its fractions were studied. It is shown that changes in carbon isotopic composition characteristic of Jurassic and Devonian shales are different. The direction of these changes is given by a complex of factors including the composition of the initial organic matter, geochemical conditions of sedimentation and, ultimately, the chemical structure of kerogen.