Organic Matter in the Middle Devonian–lower Frasnian Deposits in the Izhma–pechora Depression Based on Pyrolytic and Organic Petrographic Studies

The Middle Devonian–lower Frasnian terrigenous complex of the Izhma–Pechora depression within the Timan–Pechora petroleum province includes rocks with a fair hydrocarbon potential. We present the results of organic-petrography analysis, including RVto determination, Py–GC and Py–GC–MS studies, FTIR spectroscopy, and study of the kinetics of hydrocarbon formation using the Rock-Eval method. The main hydrocarbon-generating maceral groups in the rocks are alginite and liptinite (represented by sporinite). Despite the relatively low hydrogen index and the results of organic-petrography studies, the kinetic characteristics and chemical structure of the fossil organic matter resemble Type I kerogen. The organic matter of the rocks of the Middle Devonian–lower Frasnian deposits is enriched in n-alkyl structures and converts its hydrocarbon potential into highly paraffinic oil at late stages of thermal maturity corresponding to the EASY%Ro and EASY%RoDL values of ca. 1.2%.