Research on centrifugal mechanical cavitation and permeability improving mechanism for gas extraction hole and equipment development

Abstract

At present, most of the mature mechanical cavitation permeability improving devices in gas extraction need to use high-pressure water (gas), connecting rod or hydraulic cylinder as the power to drive the opening and closing of the knife arm, which requires higher power equipment in long boreholes. This paper develops a centrifugal mechanical knife which uses the centrifugal force generated by the rotation of the drill pipe as the opening power, and controls the opening angle of the tool arm by adjusting the rotation speed of the drill pipe. According to the preliminary test and mechanical numerical simulation analysis, the overall structure of the tool, internal rack, shaft pin, tool arm and other weak parts are optimized. The industrial test was carried out in the N1100 return air lane of a mine in Shanxi Province, and the construction time of mechanical cavitation and hydraulic cavitation and the pure amount of extraction were compared. The mechanical cavitation test hole achieved good cavitation and extraction effect, which verified the rationality and reliability of the centrifugal mechanical knife structure design. The equipment can reduce the dependence of cavitation reflection improvement on high pressure equipment, and the operation time of single hole is shortened by nearly 1/2, and the gas extraction amount is increased by 1.67 times compared with hydraulic cavitation.

Keywords

• gas extraction
• permeability improving technology
• mechanical cavitation
• centrifugal mechanical knife
• optimization design