BIOMARKER HYDROCARBONS AND CARBON ISOTOPES OF INDIVIDUAL N-ALKANES IN PARAFFIN OILS AND BITUMENS OF THE MIDDLE DEVONIAN-LOWER FRASNIAN TERRIGENOUS COMPLEX OF THE TIMAN-PECHORA BASIN
D.A. Bushnev1, A.A. Ilchenko1, L.V. Ogdanets2, N.S. Burdel’naya1
1Institute of Geology, Komi Science Center, Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
2Branch of Gazprom VNIIGAZ LLC, Ukhta, Russia
Keywords: Paraffin oil, bitumen, biomarker hydrocarbon, Middle Devonian-lower Frasnian petroliferous terrigenous complex, carbon isotope composition, Timan-Pechora basin
Abstract
The objects of study were bitumens of sedimentary rocks and paraffin oils of the Middle Devonian-lower Frasnian terrigenous complex of the Timan-Pechora basin. We studied the composition of biomarker hydrocarbons and the carbon isotope composition of individual n-alkanes of bitumens from the cores of the wells of the Omra-Lyzha saddle. The results were compared with similar data on the composition of paraffin oils from the south of the Pechora-Kozhva megaswell. The generation potential and thermal maturity of organic matter were studied by the Rock-Eval pyrolysis method. The maturity of organic matter in the rocks of the studied complex in the Omra-Lyzha saddle and the Pechora-Kozhva megaswell corresponds to the oil window. Data on the carbon isotopy of n-alkanes and on the composition of biomarker hydrocarbons do not contradict the possible genetic relationship between paraffin oils and the organic matter of the host sedimentary complex. Both the studied paraffin oils and the rock bitumens contain early eluting rearranged hopanes atypical of oils of other petroliferous complexes and show high contents of n-alkanes relative to iso-alkanes and polycyclic biomarkers. The content of 13C tends to decrease with an increase in the number of carbon atoms in the n-alkane molecule in both oils and bitumen rocks.
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