Influence of High-rank Coal Reservoir Sensitivity on Coalbed Methane Wells Production

In order to realize the efficient exploitation of coalbed methane in high- rank coal reservoir, the velocity sensitivity and stress sensitivity of Sihe No. 3 co al seam were experimented and analyzed. Based on the engineering, the influence of high- rank coal reservoir sensitivity on coalbed methane wells production was ana lyzed. The experimental results showed that, high- rank coal reservoir had the feature of velocity sensitivity, the permeability could reduce to 50% of initial value to the maximum extent, directional flooding would also reduce permeabilit, the minimum reduce to 62. 1% of initial value, the higher the clay content of the reservoir was, the lower the permeability decreasing amplitude would be. The high- rank coal reservoir had a strong stress sensitivity and existed apparent irreversibility; when the net con fining pressure increased from 2 MPa to 5 MPa, the permeability decreased as 20% ~ 50% of the initial permeability, after the buck boost, the permeability could not res ume to the initial level, the maximum of irreversible damage rate was more than 50%，the lower the reservoir permeability was, the stronger the stress sensitivity would be. The coalbed methane wells production process should follow continuous, slow and stable principle, especially in initial stage.