Structural Design and Analysis of Hydraulic Sandblasting Perforation Device

The coalbed methane reservoirs in China are mostly low-permeability reservoirs, which face many difficulties in mining, such as complex fractures, susceptibility to sand blockage, and low support rate. This article designs a new type of hydraulic sandblasting perforation device that integrates hydraulic sandblasting and perforation technology. It adopts a modular structure and includes guiding, adjusting, fixing, perforation, and stabilizing mechanisms. It is suitable for a well diameter of 139.7mm, a maximum outer diameter of 110mm, an inner diameter of 45mm, a total length of 450mm, a nozzle outlet diameter of 6mm, and a pressure bearing capacity of 90MPa. The fixed mechanism uses threaded rods and other components to achieve stable fixation, and the sandblasting perforator of the perforation system consists of a gun body, a protective cover, and a nozzle. According to static analysis, the maximum deformation value of the perforator is 0.015602mm, and the maximum stress is 235.31MPa, which is less than the allowable stress of 715MPa for the material, and the strength meets the requirements. Modal characteristic analysis shows that its first six natural frequencies are all above 3377Hz, much higher than the normal operating frequency of 100Hz, and it will not resonate during operation. This device can ensure the accuracy of sandblasting perforation, reduce the risk of accidents, and provide technical support for efficient exploitation of coalbed methane.