Study on Main Control Factors of Gas Drainage in Coalbed Methane Well of Tunliu Minefield

In order to improve the production capacity of a coalbed methane well, the paper analyzed the coalbed methane drainage mechanism and gas drainage stage. From a geological structure, roof and floor lithology, fracturing liquid, well net layout and other aspects, the paper discussed the main factors affected to the coal bed methane drainage in Tunliu Minefield. The study held that the fold would highly be affected to the drainage effect of the coalbed methane well and the breaking of t he roof and floor would be certainly affected to the coalbed methane drainage. The fracturing technology was applied to the intensified reconstruction of the coal reserv oir, the assistant drainage effect of the activated water + nitrogen gas fracturing liquid system was better than the activated water fracturing and the assistance drainag e effect of the clean fracturing liquid was the worst. The coal reservoir features of the study zone determined that the coalbed methane well within Tunliu Minefield woul d be hard to have a high production, but could have a long production time. The study held that the well net of the coalbed methane wells in the study zone could be sm all well net structure with an inter-row distance of 200 m x 250 m and the layout of well position should be parallel to the extension direction ( northeast direction) of the main fracture.