Gas Generation and Its Carbon Isotopic Composition during Pyrite-Catalyzed Pyrolysis of Shale with Different Maturities

In this study, two shale samples with different maturities, from Geniai, Lithuania (Ro = 0.7%), and Wenjiaba, China 2.7%), were selected for open-system pyrolysis experiments at 400 °C 500 °C, respectively. The generation of isotopic gases the shales maturities was investigated, effects pyrite catalysis on carbon compositions also studied. It found that CO2, CH4 their main gaseous products both shales, more hydrocarbon generated low-maturity Geniai shale. δ13C1 values fluctuated −40‰ to −38‰, δ13C2 showed higher (−38‰~−34‰) addition, its δ13CCO2 ranged −28‰ −26‰. Compared shale, lower (−43‰~−42‰) (−19‰~−14‰) detected Wenjiaba As temperature increased, became isotopically lighter C2H6 heavier, which changes due mass-induced reaction rates 12C 13C radicals. Furthermore, made kinetic isotope effect stronger thus especially °C.