Many wells become abandoned with the depletion of oil and gas reservoirs, and low-enthalpy geothermal energy could be extracted from these abandoned wells. CO₂ has been proposed and studied as the working fluid for mining such geothermal energy sources, owing to its favorable thermodynamic properties. The objective of this study is to develop an uncertainty-based simulation-optimization approach to analyze the techno-economic feasibility of CO₂-circulated geothermal production in a closed reservoir system. In doing so, we address the particular geothermal reservoir conditions found in North Oman`s foreland basin where several large oil/gas fields are located. The geothermal reservoir conditions in this area can be characterized by inclined and thin layers, partially to fully fault-blocked, and relatively homogeneous and low permeable formations. Such conditions have not been investigated in the context of CO₂-circulated geothermal production. Another key novelty of this work is to analyze a triplet horizontal well placement designed particularly for such thinly-bedded fully-closed reservoirs. The main building blocks of the proposed methodology are the application of a non-isothermal, multi-phase, multi-component numerical reservoir simulator, a neural network-based metamodel, Monte Carlo simulations, and genetic algorithm. The findings suggest the proposed well pattern is technically feasible and economically viable to harvest low-enthalpy geothermal energy from the type of depleted reservoirs found in North Oman region.

随着油气藏的枯竭，许多井被废弃，这些废弃的井可以提取低焓地热能。由于其良好的热力学性质，CO ₂已被提议和研究作为开采此类地热能源的工作流体。本研究的目的是开发一种基于不确定性的模拟优化方法来分析 CO ₂的技术经济可行性- 封闭储层系统中的循环地热生产。在此过程中，我们解决了在北阿曼前陆盆地发现的特定地热储层条件，那里有几个大型油气田。该地区地热储层条件具有倾斜薄层、部分至完全断层阻断、相对均质和低渗透地层的特征。尚未在 CO ₂的背景下研究此类条件- 循环地热生产。这项工作的另一个关键创新点是分析专为这种薄层全封闭油藏设计的三重水平井布置。所提出方法的主要构建模块是非等温、多相、多组分数值油藏模拟器、基于神经网络的元模型、蒙特卡罗模拟和遗传算法的应用。研究结果表明，拟议的井网在技术上和经济上都是可行的，可以从阿曼北部地区发现的枯竭型储层中获取低焓地热能。