Study on distribution features and main control factors of coalbed methane in Wulunshan Minefield

In order to find out the main control geological factors of the seam gas content, the mathematical statistics and geological analysis and other method were applied to analyze the relativity of the structure, seam depth, roof lithology, hydrogeologic condition and other factors with the gas content. The study results showed that the gas content of No. 8 seam was high generally and would have a distribution feature with "a high gas content in the middle part, a high gas content at the syncline axis of Shuigong River and a low gas content at the Jiaga anticline axis. The geological structure and hydrogeologic conditions would be main geological factors of the gas content. The syncline axis part of Shuigong River and the groundwater collected area would have good occurrence conditions and the seam gas content would be high. The small fault near the cutting seam would have a poor sealing, easy released coalbed methane and low gas content. The seam gas content had a poor relativity with the seam depth, roof lithology and thickness. But near Shuigong River syncline axis part, the gas content would be increased with the depth increased and would have the syncline gas control features. In the study area, the roof thickness generally would be higher than 5 m, the roof sealing would be good, the sealing and covered performances of the developed mudstone false roof would be more better and the seam gas content would be higher.