Influence on velocity sensitivity effect of coal reservoir to production law of pulverized coal and gas productivity

The velocity sensitivity effect of coalbed methane would be directly affected to the gas production effect of coalbed methane well.In development process of the well,the variation of fine coal production content would be presented in a certain degree. Based on the division of the“five stage and three pressure' in the coalbed meth ane development,the paper analyzed the production tendency and fine coal production quantity variation of over 70 wells within Fanzhuang Block of Qinshui Basin and disc ussed the response features between the velocity sensitivity effect of coal reservoir and coalbed methane well production capacity.The results showed that the velocity sen sitivity effect during the water drainage period was mainly affected by the dropping rate of the dynamic liquid level.When the dynamic liquid level initially dropped to the loc ation near the seam,there would be a high fine coal occurred period. In the gas and water phase flow stage,the fine coal settling rate would be faster than the water draina ge stage and the migration distance would be relatively shorter.In the stable production period,the gas flow would cause the fine coal in vibration locally,the velocity sensiti vity influence effect would be weak generally and coal matrix shrinking would increase seam permeability improvment.