Relationship between the methane carbon isotope and gas-bearing properties of coal reservoir

被引：0

作者：

Meng, Zhao-Ping ^{[1
,2
]}

Zhang, Ji-Xing ^{[1
]}

Liu, He ^{[1
]}

Liu, Shan-Shan ^{[1
]}

机构：

[1] College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing

[2] Key Laboratory of Geological Hazards on Three Gorges Reservoir Area, Ministry of Education, China Three Gorges University, Yichang

来源：

Meitan Xuebao/Journal of the China Coal Society | 2014年 / 39卷 / 08期

关键词：

Coal reservoir; Control mechanism; Gas-bearing properties; Methane carbon isotope;

D O I：

10.13225/j.cnki.jccs.2014.9031

中图分类号：

学科分类号：

摘要：

Coalbed methane carbon isotope is an effective parameter to reflect the coal-bed gas origin and occurrence conditions. Through the analysis of the measured data of coalbed methane carbon isotope (δ13C1) in the Qinnan-East block of Qinshui Basin and its coal reservoir gas-bearing properties, the distribution property of methane carbon isotope (δ13C1) in No. 3 coal seam was analyzed, then the correlations and their models among the coalbed methane carbon isotope (δ13C1) and vitrinite reflectance, burial depth and gas-bearing properties of coal reservoir were established respectively, and its controlling mechanism of coalbed methane carbon isotope distribution was finally revealed. The research results show that the δ13C1 value of naturally desorbed gas of No. 3 coal seam is from -28.89‰ to -53.27‰ and the average value is -36.48‰ in this area. The δ13C1 value is heavier compared with the same evolution degree coalbed methane in other parts of China and shows that the coal seam has a good preservation condition. The δ13C1 value of No. 3 coal seam and vitrinite reflectance, burial depth have a non-linear Logarithmic function relationships, and increases with the increasing of the vitrinite reflectance and burial depth of coal seam, which is suited to the national statistical regularity. Coalbed methane carbon isotope in this area is mainly controlled by the isotopic differentiation effect under the thermodynamical mechanism and the fractionation effect in the process of the coalbed methane desorption-diffusion-migration. Coalbed methane carbon isotope (δ13C1) also has a good correlation with gas-bearing properties of coal reservoir. The δ13C1 value of No. 3 coal seam becomes heavier with increasing of the coalbed methane content, coal reservoir pressure and gas saturation, which best fits the logarithmic relation. And the control factors of gas-bearing properties in coal reservoir are consistent with that of its methane carbon isotope (δ13C1).

引用

页码：1683 / 1690

页数：7