The output mechanism and control measures of the pulverized coal in coalbed methane development

Pulverized coal is the key factor restricting continuous stable coalbed methane production. Taking Hancheng coalbed methane block as the research area, adopting the research methods of the field monitoring, experiment test and analyses, physical simulation experiment, the engineering application, from the aspects of the reasons and influence factors of the pulverized coal, the pulverized coal output laws and control measures, the research on output mechanism and control measures of pulverized coal were conducted systematically. The results show that the influence factors of pulverized coal output are divided into static geologic factors of coal reservoir and dynamic engineering factors of coalbed methane development. The different coal body structure has different orientation and characteristics of pulverized coal. The pulverized coal concentration of granulated coal and scaled coal output is high, the yield is large. Pulverized coal is mainly composed of inorganic minerals and vitrinite. The concentration and particle size of the pulverized coal have distinct stages change in the different coalbed methane production stage. Based on the output mechanism research of the pulverized coal, combined with the production practice of the coalbed methane well, the control measures system of the pulverized coal is put forward from the geological prevention, reservoir reconstruction, equipment selection, early warning, drainage controlling and process treatment. The control measures have been applied to the CBM wells in Hancheng block. The good results have been achieved.