Optimization of a Perforator Nozzle Based on the Constant Velocity of Jet Core

Hydraulic sandblasting perforation plays a crucial role in the fracturing and reconstruction of unconventional oil and gas reservoirs. The jet nozzle is an essential part of the hydraulic perforation tool. Insufficient penetration depth, caused by excessive jet distances, presents challenges during the perforation process. To overcome this, an optimization design of the nozzle structure is required to enhance the perforation efficiency. In this paper, a computational fluid-dynamic model for conical-cylindrical nozzles has been elaborated. To further improve the rock-breaking efficiency of the jet nozzle, a fillet design is introduced at the nozzle inlet section. The SST k-ω model is employed to account for turbulent flow effects in submerged conditions. The results indicate that the nozzle’s geometric parameters greatly influence the flow characteristics. The orthogonal experimental method is employed to optimize the flow channel structure of the nozzle, taking the length of constant velocity core as the evaluation index. The following optimized geometric parameters for the conical-cylindrical nozzle have been determined accordingly: a cylindrical segment diameter of 3.2 mm, a contraction angle of 12°, a contraction segment length of 8 mm, a cylindrical segment length of 6.4 mm, and a fillet radius of 2 mm.