Research on directional drilling technology of air srew motor in soft coal seam

In view of the difficulty in accurately crossing the working face in soft coal mines,the soft coal air screw motor oriented drilling technology was first used to realize the coal seam gas control at the working face and coal roadway to be drilled,and formed a new model of efficient management of soft coal gas.It researched air screw motor,Electromagnetic Measurement While Drilling (EM MWD) systems,directional drilling technology in soft coal,soft coal directional drilling screen hole protection and other key technologies,then a feasibility test was conducted at a mine in Huainan,and a soft coal air screw motor directional drilling and hole forming technology was formed.At home and abroad,for the first time,12 wells with a depth of more than 200 m and a soft coal seam oriented long borehole have been successfully constructed under the coal mine,which under the full-hole screen,the maximum hole depth is 231 m,the amount of gas scavenged is 12.56 thousand square meters,and the concentration is more than 50%.And its drainage effect is 3～4 times of conventional drilling volume.This technology provided new ideas for efficient gas treatment of soft coal seams.