The damage of coal-rock reservoir completion fluid and the easy collapse of horizontal wells are the main factors limiting the output of coalbed methane horizontal wells in Qinshui area. In terms of the resulting problems of low horizontal well production and production reduction

the integrated technology of dual-tubing screen completion and production increasing is used to solve the problems of damage to coal seam caused by completion fluid of horizontal wells of coalbed methane and the instability of open hole wall of coal seam. Therefore

one-trip drilling of completion and flushing operation is realized

the outp

ut of single CBM well is improved

and the stable production cycle of a CBM well is extended. The dual tubing completion structure of a horizontal CBM well consists of an outer screen system and an inner flushing system. The outer screen system can realize the long time support of the shaft wall and prevent the collapse

while the inner flushing system can establish the completion fluid circulation channel

realize the function of hydraulic jet

pollution prevention

sand flushing and well cleaning

reduce the resistance encountered of screen pipe entering

and improve the success rate of screen pipe entering in just one-time. This process is the main method to develop horizontal wells in Qinshui CBM Block. A series of screen pipes and supporting tools with an outer diameter of 73 mm

89 mm and 110 mm have been developed

and this technology has been popularized and applied in 331 horizontal CBM wells. Compared with the open-hole horizontal wells developed in the year before 2014

the stable production cycle of the screen completion horizontal wells is increased by more than 5 times

and the single well production of the horizontal wells of 15# coal seam has exceeded 1 000 m

3

to the fundamentally solve technical difficulties in development. A new efficient development mode suitable for the horizontal wells in the refreshing water coalbed methane block is formed.