To ensure the continuous and stable exhaust process of coalbed methane wells, prevent coal fines from lowering the guidance ability of seepage channel, and solve the problem of stuck pump and submerged pump caused by gathering of coal fines, taking Hancheng block as the experimental area, this paper analyses on the source of the coal fines, and divides it into two categories of original coal fines and secondary coal fines. Based on the characteristics of coal petrography, coal structure, coal seam and engineering factors, we make analysis of their factor on the output of coal fines, and we conclude that the characteristics of coal petrography are the foundation, and the engineering is the precipitating factor, but the development of deformed coal is the primary factor. The study on the division of types of coal fines and output factors can provide a guidance for reasonable coal-fines-control measures.

According to the 2012s workover treatment statistic in the Hancheng block, the eastern Ordos gas field, the workover caused by pulverized coal accounts for 41.8% of the total, which has seriously affected the continuous and stable drainage. This is one of the main factors which constraint coalbed methane production yield. In this paper, geological factors including the composition of coal petrography, the mechanical strength of coal petrography and coalbody structure destruction and engineering factors including drilling, fracturing and drainage were analyzed to study on the controlling factors on the output of pulverized coal. We conclude that the determinant on output of pulverized coal is the nature of coal seam, however engineering factors cause the output of pulverized coal directly. The root-mean-square amplitude attribute analysis was first used to display the mechanical strength of coal seam. Based on the result, we made the prediction about the possibility of the output of pulverized coal and divided the studying area into four grades. The research on the controlling factors and the prediction of the output of pulverized coal could provide the basis for the prevention and comprehensive treatment of pulverized coal.