Performance analysis and mechanistic insights of penetrating crystalline self-healing cement (PCSHC) in dynamically sealing borehole cracks

The extraction efficiency of coalbed methane ( CBM ) poses a pressing concern for coal mining enterprises, necessitating urgent attention. This study delves into the performance analysis and underlying mechanisms of Penetrating Crystalline Self-Healing Cement ( PCSHC ), formulated with ultra-absorbent, alkali-stimulated materials, hydration retardants, and auxiliary self-healing components. Through meticulous single-factor and multi-factor analyses focusing on flow properties, setting characteristics, water absorption, and permeability coefficients, the material composition of PCSHC was optimized. Advanced techniques, including SEM, XRD, and FTIR, were employed to unravel the sealing mechanisms of PCSHC . The findings reveal a notable 28% reduction in the permeability coefficient of the optimized PCSHC , accompanied by a substantial decrease in internal air leakage channels. After 28 days of curing, a substantial amount of C–S–H crystals formed, with a decrease in hydration-participating components like C 2 S and C 3 S , indicating ongoing hydration reactions post-setting. This study demonstrates the potential for achieving dynamic sealing of borehole cracks, thereby enhancing CBM extraction efficiency.