Abstract:
The gas-bearing properties is an important parameter to determine the exploration and development of coalbed methane(CBM). The methane carbon isotope(
δ13C
1) can reflect the reservoir condition of CBM effectively. Based on the date of measured gas content from CBM well, the characteristic of gas content distribution in coalbed was analyzed, and the correlations and models of gas content, the burial depth of coalbed, geological structure were built. The characteristic of
δ13C
1 distribution was discussed and it had an indicative function to the distribution of gas-bearing properties. Findings show that, the gas content in the Xishan block is an average of 6.87 m
3/t, 8.4 m
3/t, 9.6 m
3/t in the No.2, 8 and 9 coalbed respectively. The gas content was mainly influenced by burial depth of coalbed and structural configuration. The
δ13C
1 value of the No.8 in the study area ranges from -65.33‰ to -40.94‰ and its average is -45.88‰, and there was a positive correlation between coalbed gas content and
δ13C
1.
δ13C
1 generally is getting heavy with increase of gas content.
δ13C
1 is mainly controlled by the coalbed methane desorption-diffusion-transport effect and hydrodynamic condition.