Analysis on geological factors of coalbed methane distribution and production in Lu'an area

The dominant geological factors influencing the target coal seam's gas occurrence and production in Lu′an area are analyzed. Based on that the causes of low gas productivity and high water productivity in the study area are revealed. The reason for that is caused by lots of extensional faults and sandstone belts above No. 3 coal seam. On the whole, with underground water recharging from outcrops at the east of the area and discharging to Wenwangshan and Ergangshan fault zones, as well as the sandstone aquifer above No. 3 coal seam and No. 3 coal seam itself, a complete underground water system was formed, which communicates with the faults. Consequently, reservoir energy was released and coalbed methane was transformed and escaped, which resulted in the low reservoir pressure and the low coalbed methane productivity.