Experimental Studies On Particle Production From Coalbed Methane Wells

Coal-bed Methane Production is usually a drainage gas recovery process, in the process of mining, since coal is brittle, fragile, easily collapse, coal powder and other coal seam particles will flow as the flow of fluid migration. Transport of pulverized coal will clog seam cracks, reduce permeability, affect the production of coal-bed methane wells and reduces the production rate of coalbed methane. So the research output of pulverized coal bed methane drainage and gas law in the process of actual production has a very important significance.Firstly, this paper analyzes the causes and mechanism of pulverized coal in coal-bed methane wells, and then build coal-rock model, measuring physical parameters of the physical model, analysis of coal rocks in stress sensitivity characteristics, then set up our own experimental apparatus, by measuring permeability changes in the different experimental models of pulverized coal under different flow rates, changes in the quality of output of pulverized coal and gas well production capacity, analysis of output liquid and particle size under various flow rates with laser particle size analyzer. The latter using a vertical pipe flow devices, analog settlement law of pulverized coal in a vertical wellbore, then conclusion:At lower speeds drainage, coal output is very little, almost no powder, when the flow rate is gradually increased, the amount of pulverized coal output increases with increasing flow rate, but coal powder will be reduced with the extension of the drainage; when the productivity velocity close to the critical velocity, coal powder will be drived to significant migration by coal-seam fluid, coal particle output in large quantities, coal particles can cause blockage flow channel, which led to the rapid decline in coal seam permeability, resulting in speed-sensitive phenomenon, specifically in the actual production of coal-bed methane production is the sharp decline; as the flow rate continues to increase, the output liquid coal particle size gradually increases until it is completely clogged pores. Evaluated by the ratio of pulverized coal output after pulverized coal permeability can be determined the extent of the impact of the reservoir, and to determine the percentage decline in production. CBM wells in the normal production process, when the pressure is not produced within the wellbore fluid migration although part of pulverized coal to bring out the wellhead, but always have some around the inner wall of the wellbore in a reciprocating motion of pulverized coal, they can not be discharged wellhead. Research for the development of scientific and rational row mining speed, reducing pulverized coal output to provide evidence.