Coalbed gas geological characteristics of No.2 coal in Rujigou district, Ningxia

According to the data collected from different stages of coal exploration, coal mining, field investigation and laboratory measurements, the reservoir characteristics of No.2 coal are emphasized in this paper. The results show: a. No.2 coal seam is thick, laterally extensive, and high gas content, and that is the foundation for coalbed methane development; b. Although the coal rank is high, the matrix pores, cleats, and fractures are well-developed, therefore, the reservoir permeability is high; c. Perhaps the abnormal high reservoir pressure distributes regionally, as well as the adsorption isotherm showed that the coalbed gas can be quickly developed during depressurizing process. The conditions of coalbed gas ara more favorable for development in the Rujigou district than that in the Qinshui basin with the correlations of coal thickness, permeability, abnormal high pressure, and adsorption.