Experiments and numerical investigation on rock-breaking enhancement mechanism of supercritical CO<SUB align="right">2 jet drilling

Supercritical CO2 (SC-CO2) jet drilling technology has been proposed to solve the problems of low rock-breaking efficiency and severe thermal wear of PDC cutters in high temperature formation. However, the rock-breaking enhancement mechanisms of SC-CO2 jet on PDC cutter are poorly understood. Therefore, in this paper, SC-CO2 jet-PDC cutter composite rock-breaking experiments and numerical simulation have been employed to study the fundamental factors of SC-CO2 jet enhanced rock-breaking and the influence of different working parameters on composite rock-breaking. The results indicated that the rock debris carrying, and impact effects of SC-CO2 jet are the fundamental causes of cutting force reduction. The main reason for the SC-CO2 jet cooling cutter is the heat absorption of gas expansion and phase transition. The research findings offer a theoretical basis for SC-CO2 jet-PDC cutter composite rock-breaking and could support gas drilling, hot dry rock drilling, and deep oil-gas development. [Received: 25 April 2024; Accepted: 24 June 2024]