EXPERIMENTAL STUDY OF INFLUENCES FOR WATER CONTENT IN COALBED GAS RESERVOIRS ON METHANE SEEPAGE

The studied specimen was briquettes molded by coal from 3# coalbed of Zhaozhuang coal factory,Jincheng Coal Industrial Company.An experimental plan was designed to test the influence of water content on methane permeability.By using self-developed "coal containing gas thermal-hydrological-mechanical(THM) coupling experimental equipment",the change rule of water content effects permeance of coalbed methane was studied.The research results showed that:under the conditions of constant temperature and effective stress but different water contents,the methane effective permeability increased with the decreasing of water content in coal.In the range of water content tested in this experiment,the relationship between water content of coal and methane effective permeability could be expressed by a linear function.The water in coalbed gas reservoirs occupies space of permeance pores in coal seams and decreases methane transportation passages which makes the transportation difficulty.According to the analysis of experimental results,it is theoretically proven that to wet the coal by pouring water could be used as a measure to prevent coal and gas outburst.