Geneza gazu ziemnego akumulowanego w utworach karbonu i czerwonego spągowca w nadbałtyckiej części Pomorza Zachodniego

Maciej J. Kotarba, Jędrzej Pokorski, Cezary Grelowski, Paweł Kosakowski


Origin of natural gases accumulated in Carboniferous and Rotliegend strata on the Baltic part of the Western Pomerania.
S u m m a r y. Origin of natural gas of Gorzysław, Białogard and Daszewo fields from Lower and Upper Carboniferous, and Rotliegend reservoirs on the Baltic part of the Western Pomerania was characterized by means of geochemical methods. The results of molecular analyses as well as stable carbon isotope analyses of methane, ethane, propane and carbon dioxide, stable hydrogen isotope analyses of methane and stable nitrogen isotope analyses of gaseous nitrogen enabled the determination of gas origin. Gaseous hydrocarbons and carbon dioxide originated from thermogenic processes from type III kerogen with small component of type II kerogen. At least two phases of gas generation took place: the first one at the stage of 0.6 to 0.8%, and the other one at the stage of 1.4 to 1.8% maturity of source rocks in the vitrinite reflectance scale. Gaseous hydrocarbons generated from source rocks within the Upper Carboniferous (Wesphalian) and Lower Carboniferous (Visean) strata. Nitrogen probably originated during thermocatalytic processes of organic matter transformation and partly in abiogenic processes.

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