The increasing demand for clean energy with minimum environmental impact motivates development of geothermal energy. Simulating a geothermal reservoir is complex and time consuming, mainly because of the systems spatial and temporal non-isothermal nature and the enormous size of the domain/reservoir. Simulations become even more complex when representing Enhanced Geothermal Systems (EGS), where wells in a hot, low permeability reservoir are interconnected by hydraulic fracturing to provide pathways for injection of cold water, in situ heating, and consequent production of hot water. In this study, various issues related to simulation of enhanced geothermal systems are investigated and practical solutions are proposed. A comprehensive study was conducted to show the effect of different grid systems on predictions of the transient temperature of the produced water. It is shown that the performance of an EGS is affected by the transmissivity (product of permeability and width of the fracture) of the fracture more so than by the values of permeability and width of the fracture considered individually. A simplified model (downscaled model) reduces the simulation times significantly (by 1.5–14.5 times) without compromising the accuracy of the results. In the proposed model, only two simulations - capturing small portions of the top and bottom of a reservoir with two active hydraulic fractures is used to evaluate performance of the entire reservoir. The proposed model is proved to be robust when exposed to different scenarios created by varying the inclination of the wells with respect to horizontal, spacing of the hydraulic factures, and spacing between the injection and producing wells. Value of R2 close to unity (0.96–1.0) and smaller value of MAPE (Mean Absolute Percentage Error), less than 3% in comparison to the entire reservoir simulations, indicate the utility of proposed model.

中文翻译：

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用于模拟多裂缝增强型地热系统 (EGS) 的高效工作流程

对环境影响最小的清洁能源日益增长的需求推动了地热能的发展。模拟地热储层既复杂又耗时，主要是因为系统空间和时间的非等温性质以及域/储层的巨大规模。在表示增强型地热系统 (EGS) 时，模拟变得更加复杂，其中热的低渗透性储层中的井通过水力压裂相互连接，为注入冷水、原位加热和随后的热水生产提供路径。在这项研究中，研究了与增强地热系统模拟相关的各种问题，并提出了实用的解决方案。进行了一项综合研究，以显示不同网格系统对采出水瞬态温度预测的影响。结果表明，EGS 的性能受裂缝渗透率（渗透率和裂缝宽度的乘积）的影响比单独考虑的渗透率和裂缝宽度值的影响更大。简化模型（缩小模型）可显着减少仿真时间（减少 1.5-14.5 倍），而不会影响结果的准确性。在所提出的模型中，仅使用两个模拟 - 捕获具有两个活动水力裂缝的油藏顶部和底部的一小部分来评估整个油藏的性能。当暴露于通过改变井相对于水平面的倾斜度、水力压裂的间距以及注入井和生产井之间的间距而产生的不同场景时，所提出的模型被证明是稳健的。R2 值接近 1 (0.96–1.0) 和 MAPE（平均绝对百分比误差）的较小值，与整个储层模拟相比小于 3%，表明所提出模型的实用性。