A fully coupled thermo-hydro-mechanical model in multiphase shale gas reservoirs is first developed and is then validated with analytical solutions and experimental result. Subsequently, the coupling responses are investigated to addressing mechanisms of gas recovery enhancement. Finally, a series of parameter sensitivity analyses are implemented to investigate the effect of parameters on gas recovery. The results indicate that gas production is strongly dependent on heating temperature, while the economic benefits should be evaluated further. The heating treatment for shale gas reservoirs not only rapidly desorbs the adsorbed gas, but also quickly evaporates the water in the pores within the shale, which removes the water lock effect and makes the desorbed gas produced smoothly. The parameters such as permeability, thermal conductivity, bottom-hole pressure, Langmuir volume, and entry capillary pressure also affect thermal recovery, which should be considered comprehensively to evaluate thermal recovery efficiency. Hydraulic fracturing enhances gas recovery at early-stage, and formation heat treatment can promote gas source supply at later-stage. Therefore, the combination of the two techniques can extend the life of shale gas wells and achieve effective and sustainable development of shale gas.

首先建立了多相页岩气储层的全热力-水力-力学模型，然后用解析解和实验结果对其进行了验证。随后，研究了耦合响应以解决气体采收率提高的机理。最后，进行了一系列参数敏感性分析，以研究参数对气体采收率的影响。结果表明，气体产量在很大程度上取决于加热温度，而经济效益应进一步评估。页岩气储集层的加热处理不仅使吸附的气体迅速解吸，而且使页岩气孔中的水迅速蒸发，消除了水锁作用，使解吸的气体顺畅产生。诸如渗透率，热导率，井底压力，Langmuir体积和入口毛细管压力也会影响热采收率，应综合考虑这些因素以评估热采收率。水力压裂可提高早期的天然气采收率，地层热处理可促进后期的气源供应。因此，两种技术的结合可以延长页岩气井的使用寿命，实现页岩气的有效，可持续发展。