Study on reconstruction of inefficient well of coalbed methane in southern Shizhuang Block of Qingshui Basin

The present situation of massive inefficient wells had become an important factor that restricting the CMB output in the southern Shizhuang Block of Qinshui Basin. In order to improve the production of single well, it was necessary to reconstruct the inefficient well. Based on the prediction model of reservoir pressure,reservoir dynamic permeability,fracture dynamic permeability and fracture length, we studied the reconstruction of Well TS-001 and used numerical simulation method to predict the reconstruction effect of the well. The results showed that the reservoir permeability of this well decreased first and then increased, and now reached the initial level of production; the initial fracturing effect was good, but later the effective stress effected invalidated the crack and led to the recent decline of gas production; the gas production of the well gradually increased after reconstruction, but the well couldn't reach high yield in the short time due to low yield for a long time which led to homogeneous-distribution of reservoir water, so it needed to take some time to re-drainage.