This paper presents a new comprehensive approach to model High Energy Gas Fracturing (HEGF) process. This coupled model consists of 6 sub-quantitative modules, including (1) loading build-up due to propellant deflagration, (2) gas-liquid interface displacement caused by killing liquid column movement, (3) stress distribution around the casing wellbore and the perforation holes, (4) fluid penetration through the perforation holes, (5) rate dependent critical pressure of fracture initiation and (6) hydro-mechanical coupled fracture propagation. The solution to the coupled model is obtained combining the analytical method and finite difference method, which solves the mass conservation equation and energy conservation equation with the subsystem pressure and temperature as the main variables. Subsequently, The single pulse and the multi-pulse HEGF processes are simulated. The dynamic changes of the loading built-up of propellant deflagration, the movement of killing liquid column as well as the dynamic propagation of fracture are further studied. Meanwhile, in-depth analysis has been applied on the affect sensitivity of the five key parameters to the single pulse HEGF results as well as the mechanism of multi-pulse HEGF. The results indicate that the final lengths of fractures generated by single pulse HEGF can be extended with the increase of the perforation density, the diameter of perforation holes, the thickness of propellant column and the total propellant quality. However, the effect of the height of killing liquid column is insignificant. It also demonstrates that the multi-pulse HEGF could bring multiplier fractures length by concatenating series propellants with different burning rates. This coupled model could add new dimensions to the understanding of the coupled mechanism of single pulse and multi-pulse HEGF. In addition, the model could be applied as a parameters quantitative design tool to assist the field implementation of these technologies.

本文提出了一种新的综合方法来对高能气体压裂（HEGF）过程进行建模。该耦合模型由6个子定量模块组成，包括（1）推进剂爆燃引起的载荷积累，（2）压井液柱运动引起的气液界面位移，（3）套管井眼周围的应力分布和射孔，（4）流体穿过射孔，（5）断裂速率与速率有关的临界临界压力，以及（6）液压机械耦合的裂缝扩展。结合解析法和有限差分法，得到了耦合模型的解，以子系统压力和温度为主要变量，求解了质量守恒方程和能量守恒方程。随后，模拟了单脉冲和多脉冲HEGF过程。进一步研究了推进剂爆燃载荷的动态变化，压裂液柱的运动以及裂缝的动态扩展。同时，对五个关键参数对单脉冲HEGF结果的影响敏感性以及多脉冲HEGF的机理进行了深入分析。结果表明，单脉冲HEGF产生的裂缝的最终长度可以随着射孔密度，射孔直径，推进剂柱厚度和总推进剂质量的增加而延长。但是，杀死液柱的高度的影响是微不足道的。这也表明，多脉冲HEGF通过将燃烧速率不同的系列推进剂串联在一起，可以使倍增断裂长度增加。该耦合模型可以为理解单脉冲和多脉冲HEGF的耦合机制增加新的维度。此外，该模型可以用作参数定量设计工具，以协助这些技术的现场实施。