Experimental investigation on rock breaking performance of micro-abrasive slurry jet

This study investigates the effect of micro-abrasive slurry jet (MASJ) on reservoir rock to enhance rock-breaking performance. The influence of polyacrylamide (PAM) concentration, abrasive particle size, abrasive material on jet characteristics and rock breaking performance experiments were carried out. It was found that the optimal rock-breaking performance occurred with a PAM concentration between 0.06% and 0.12%, and an abrasive particle size range of 60.36–88.64 μm. Bivariate correlation technique analysis identified that abrasive bulk density > sphericity > hardness significantly influenced the rock-breaking effectiveness. PAM concentration of 0.09% and 240 mesh (D 50 of 60.36 μm) garnet abrasives for MASJ rock-breaking are recommended. Compared to pure water jet, MASJ increased erosion diameter by 32.05% and erosion volume by 1216.67%. Relative to abrasive water jet, MASJ achieved 75.43% of the diameter performance and 60.76% of the volumetric performance. MASJ produced more regular erosion patterns featuring smoother orifices and greater depth, attributable to higher kinetic energy enabling continuous micro-abrasive impacts. The rock-breaking mechanism is impacted by micro-abrasives in the pre-crushing stage, then in the accumulation and pressurization stage, finally is eroded and formed until the pressure relief stage. • The influences of different PAM concentrations, abrasive types and sizes on the rock breaking performance of MASJ were clarified. • PAM concentration of 0.09% and 240 mesh garnet for MASJ rock-breaking are recommended. • The erosion hole of MASJ is more regular with smooth orifices and greater depth.