Synergistic Control of Electrohydraulic Fracturing: A Coupled Analysis of Shock Wave Attenuation and Damage Feedback

Summary This study elucidates the dynamics of rock fragmentation under high-voltage electrohydraulic pulse (HVEP) fracturing by employing a fully coupled electric-thermal-mechanical-damage model. Although increased energy input generally promotes fracture propagation, we identify a previously unrecognized mechanism: heterogeneity-induced nonlinear pressure attenuation. This mechanism gives rise to anomalously high local pressure peaks (5.064 MPa) under lower-voltage pulses (10 kV), surpassing those induced by higher-voltage pulses (4.098 MPa at 12/14 kV). Quantitative analysis reveals significant energy dissipation, with a 97.18% pressure drop occurring within 3.75 m for 10-kV pulses. Simulation results indicate that discharge voltage predominantly controls the extent of final damage—yielding a 31.5% larger damaged area at 14 kV than at 10 kV after five pulses—whereas the cumulative impact of repeated discharges increases the damaged area by 632% relative to a single pulse. Taken together, these findings establish a synergistic framework in which initial energy input, heterogeneity-modulated wave propagation, and stress-induced damage feedback loops jointly dictate fracture outcomes, offering crucial theoretical insights for optimizing HVEP operations in geologically complex formations.