1.School of Energy, China University of Geosciences (Beijing), Beijing , China;2.MOE Key Lab of Marine Reservoir Evolution and Enrichment Mechanism, Beijing , China;3.Beijing Key Lab of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing , China

In order to study a poor gas production effect cause of partial coalbed methane high potential wells in Southern Shizhuang Block, with the analysis on the coal structure and the roof and floor characteristics of the seam, in combination with the analysis on the hydraulic fracturing effect and in comparison with the gas drainage system of the high production well, the paper analyzed and summarized the low production causes of the typical well. The results showed that the hydraulic fracturing effect would directly affect to the production capacity of the coalbed methane well and could improve the permeability of the coal reservoir, also would connect with the aquifer and could cause the low production of the coalbed methane well. During the single-phase water drainage stage and the gas-liquid two-phase flow gas production rising stage at the gas drainage initial period, irrational gas drainage system would be an important cause of the low production for the high production potential well. During the two stages, a rational control of the gas drainage system would have the influences to the future whole gas production process. The control of the cracking height and the fracturing scale to eliminate the penetration of the aquifer could maximally make the cracking far expanded in the seam. Also the rational gas drainage system would be the key of a long term high efficient development after the second fracturing reconstruction of the coalbed methane production improved potential well.