Evaluation on factors to influence production capacity differences of coalbed methane well group

In order to reveal the factors to influence the productivity difference of the coalbed methane well group, based on the gas production and water productio n features of a typical coalbed methane well group in the south part of Qinshui Basin, the paper discussed the difference of the four gas drainage feature parameters, in cluding the average water production, initial gas production time, initial gas pressure at the well bottom and accumulated water production at the initial gas production a nd the relationship between the difference and the gas production. The gray correlation analysis method was applied to quantitatively evaluate the importance of each p arameter to the productivity control. The results showed that the average water production value, initial gas time and accumulated water production value when initial g as occurred would have a good negative correlation with the gas well productivity and the initial gas pressure at the well bottom would have a positive correlation with t he gas well productivity. Among them, the gas pressure at the initial gas well bottom would be the max influence to the gas well productivity and analysis held that the V alue could reflect the well control coal bed methane resources volume and the gas saturation. In addition, the extraneous water refilling was the basic reason to cause t he long initial gas time of the gas well, high average water production, high accumulated water production when the initial gas producted and low productivity.