The use of supercritical carbon dioxide (SC-CO₂) for the fracturing of coal bodies has excellent development prospects and practicability. It alters the fissure structure of coal bodies and achieves CO₂ geological sequestration. This process, which involves the mutual interaction of coal, fissures, supercritical fluid, and gas, can be subdivided into fluid-induced and phase change-induced fracturing stages. Numerical simulation of the SC-CO₂ fracturing was carried out in a stagewise manner to characterize each stage's fracturing performance quantitatively. The effects exerted on the crack propagation behavior by such factors as the ground stress deviation, the permeability coefficient of coal bodies, fracturing fluid injection rate and temperature, was studied in detail for each stage. The crack morphology, length, and width of cracks induced in each stage in proportion to the total crack length and width values were determined and analyzed. The research results show that the crack length ratio of the SC-CO₂ fluid-induced fracturing stage to the total crack length was 80–90%, with the remaining 10–20% corresponding to the CO₂ phase change-induced fracturing stage. This indicates that cracks propagation primarily occurred at the former stage. Meanwhile, the crack width ratios were nearly the same: 40–55% for the former stage versus 45–60% for the latter stage. Thus, the crack width increased dramatically at both stages of the SC-CO₂ fracturing in the coal bodies. The research findings refined the insight into the SC-CO₂ fracturing mechanism in coal bodies.

利用超临界二氧化碳（SC-CO ₂）压裂煤体具有良好的发展前景和实用性。改变煤体裂隙结构，实现CO ₂地质封存。该过程涉及煤、裂缝、超临界流体和气体的相互作用，可细分为流体诱导压裂和相变诱导压裂阶段。SC-CO _{2 的}数值模拟压裂分阶段进行，定量表征每个阶段的压裂性能。详细研究了地应力偏差、煤体渗透系数、压裂液注入速度和温度等因素对裂缝扩展行为的影响。确定并分析了与总裂纹长度和宽度值成比例的在每个阶段引起的裂纹的裂纹形态、长度和宽度。研究结果表明，SC-CO ₂流体压裂阶段裂缝长度占总裂缝长度的比例为80%~90%，其余10%~20%对应于CO ₂相变诱导压裂阶段。这表明裂纹扩展主要发生在前一阶段。同时，裂纹宽度比几乎相同：前一阶段为 40-55%，而后一阶段为 45-60%。因此，煤体中SC-CO ₂压裂的两个阶段的裂缝宽度都急剧增加。研究结果完善了对煤体中SC-CO ₂压裂机制的洞察。