Research on fracturing performance evaluation of coalbed methane well in Qinshui Basin

In order to evaluate productivity after fracturing of coal-bed methane wells, closure stress of coalbed fracture was predicted with Function Curve G, squa re root of time curve, double logarithmic function curve and in-situ stress model of coal was established based on the coalbed methane wells of Qinshui Basin. Accordin g to in-situ stress model, net pressure, fracture friction and production were contrasted. Then a model to evaluate the productivity after fracturing was established with fil tting the correlations between net pressure, fracture friction with productivity. The results showed that the error of the predicted stress and well testing result was 0.75 MPa. There were good relevance between the productivity with net pressure and friction. The higher net pressure and fracture friction were, the more complexity the fra cture would be and the more difficulty the fracture propagation would be. Then the productivity of coalbed methane wells would be low. The methods could provide the r eferences to in-situ stress and production prediction after fracturing of coalbed methane wells.