Development and Testing of an Automatic Mixing Test Device for Water Jet Abrasive Under Confining Pressure

In response to the casing deformation issues encountered during the development of shale gas in southern Sichuan, this paper conducts relevant research on abrasive perforation testing to more accurately simulate the hydraulic sandblasting perforation state of small-diameter nozzles under confining pressure conditions. For this purpose, a specialized experimental setup was designed, which includes a high-pressure water jet test system, an abrasive supply system, a 3D PIV control system, and a simulated downhole confining pressure test system. The experimental results indicate that this setup can automatically mix and dispense abrasives, with an abrasive concentration control accuracy of ±1% and a control range covering 0% to 20%. Meanwhile, the equipment achieves precise control over the target confining pressure, with the fluctuation range of confining pressure controlled within ±0.05 MPa. It can effectively conduct abrasive perforation tests on casings in a submerged state and within a confining pressure range of 10 MPa. Further experimental tests have shown that under a target distance of 10 mm, the perforation speed is basically unaffected by the confining pressure, and the casing can be penetrated within 10 min under all test conditions. This lays the foundation for subsequent experimental research on casing perforation using small-diameter nozzles under different parameters. The application of this device will help optimize on-site perforation parameters, improve the consistency of perforation capability, enhance the safety and economy of casing perforation operations, and provide theoretical support for field operations.