Abstract:

 The CO2 reducted to CH4 pathway is important to biogas generation in the geological historyThe Quaternary biogenic gas fields in Qaidam Basin of China belongs to the CO2/H2 reduction biogenic gasAccording to the theory of H2/CO2 reduction, we have carried out the biosimulation experiments with different occurrences and different initial carbon isotope values of carbon sourcesThe experimental results indicated that there is a positive correlation between the δ13Cmethane values and the δ13C values of the substrate in products, and that,  in response to the existence of excessive substrate, the occurrence of substrate has its effect on the δ13Cmethane valuesThe δ13Cmethane values from free CO2 reducted to CH4 is relatively lower than that coming from HCO-3 and CO2-3 ionsBy applying to the Quaternary biogenic gas filed in the east of Qaidam Basin, the source and occurrences of the main substrate CO2 are discussed, and these have import reference value for evaluating the biogas resources and searching for favorable exploration ares

Key words:

biogenic gas; CO2/H2 reduction; carbon isotope fractionation; Qaidam Basin; biogas resources