Research on pull-out drilling technology of coal mine gas geology

During the process of mine gas geological drilling,only to pressurize the drilling will not be sufficient to solve the drilling depth and drilling diameter.It is necessary base on the imbalanced drilling theory to study the pull-out drilling technology for mine gas geology and to systematically study different accidents,tension proof drilling rods and right and left directional integrated bits for the drilling bore- holes.Therefore a new drilling and exploration technique system can be established.In order to perfectly have the drilling and implement drilling system with a large diameter and medium drilling depth,depth and diameter of the hole,the paper stated the pull-out drilling technology of the mine gas geology according to the study and practical experiments in the recent years.This theory has been successfully applied to some coal mines.