To investigate the mechanisms of fluid migration during shale gas extraction under microwave irradiation, we developed a coupled Electromagnetic-Thermal-Hydraulic-Mechanical (ETHM) model. This model accounts for changes in fracture permeability due to variations in temperature, gas pressure, and methane desorption. The impact of microwave power on both gas production and the alteration of reservoir geological properties under microwave stimulation was investigated. Simulation results revealed that with a microwave injection power of 4,000 W, cumulative gas production increased by 45 %, reaching 64.9 million cubic meters. Additionally, the influence of initial water saturation and the diffusion damping coefficient on both gas and water production was examined. The findings show that cumulative water production was 33 % higher when microwave heating was applied compared to scenarios without microwave stimulation. An increase in initial water saturation led to a decrease in daily gas production during the early stages of extraction. Under microwave irradiation, the methane adsorption capacity at data acquisition point MP2 decreased to 0.0075 m/kg, representing a 69 % reduction compared to conditions without microwave stimulation. Our analysis also found that daily gas production is highly sensitive to the diffusion damping coefficient. The diffusion attenuation effect had a notably negative impact on improving the recovery rate of shale gas reservoirs. In a word, this research holds significant implications for understanding the trends in gas and water production as well as the sensitivity of geological parameters during microwave-assisted thermal recovery of shale gas.

中文翻译：

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模拟微波加热以提高页岩气采收率：可变形储层中传热和电磁的完全耦合两相流

为了研究微波辐射下页岩气开采过程中的流体运移机制，我们开发了电磁-热-液压-机械耦合（ETHM）模型。该模型考虑了由于温度、气压和甲烷解吸的变化而导致的裂缝渗透率的变化。研究了微波功率对微波刺激下天然气产量和储层地质性质变化的影响。模拟结果显示，微波注入功率为4000W时，累计产气量增加45%，达到6490万立方米。此外，还考察了初始含水饱和度和扩散阻尼系数对产气和产水的影响。研究结果表明，与没有微波刺激的情况相比，应用微波加热时的累积产水量高出 33%。初始含水饱和度的增加导致开采早期阶段日产气量下降。在微波照射下，数据采集点MP2处的甲烷吸附量下降至0.0075 m/kg，与没有微波刺激的条件相比减少了69%。我们的分析还发现，日产气量对扩散阻尼系数高度敏感。扩散衰减效应对提高页岩气藏采收率具有显着的负面影响。总之，这项研究对于了解页岩气微波辅助热采过程中天然气和水产量的趋势以及地质参数的敏感性具有重要意义。