Study on the Mechanism of High-Efficiency Rock Breaking by Hydraulic Jet Based on Explicit Dynamics

High-efficiency rock breaking by hydraulic jetting is the key to radial horizontal drilling technology. In order improve efficiency of jet in wells, based on LS-Dyna display dynamics, a numerical simulation model single-nozzle was established analyze influence different nozzle parameters rock-breaking effect. Then, spin multi-nozzle bit established, and rotation speeds effect analyzed. Finally, characteristics conventional were compared The results show that when impacts surface, larger inclination angle is, width formed is. smaller dip angle, greater depth. When than 60°, it difficult meet needs reaming. depth gradually increase with diameter. diameter 1.3 mm, growth rate begins decrease. optimum mm. v = 50 m/s, damage caused surface very small, because condition fracture not reached this velocity. This shows there critical value water impact velocity, only velocity reached, will break. 150 200 250 300 breaks. At same time, higher speed, degree fracture, depth, area, better tangential increases shear tensile failure sample, improves jet, which has certain guiding significance for improving well drilling.