A coupled THMC (thermal-hydrological-mechanical-chemical) model is developed and applied to explore the potential feasibility of using scCO₂ (supercritical carbon dioxide) as a working fluid in geothermal reservoirs. This is achieved by examining the evolution of the kinetics of mineral precipitation-dissolution and its associated impact on the evolution of the rock permeability and porosity. The pH of the reservoir rapidly reduces from 7 to ∼4.5–5 due to the fast dissolution of calcite. Chemical reactions and mineral dissolution and precipitation near the injector are suppressed by the plug-flow penetration of anhydrous scCO₂ displacing the original pore fluid. A conceptual three-zone model is proposed to illustrate the kinetic process of feldspar dissolution and precipitation depending on timing. The initial high concentration of K⁺ prompts feldspar to precipitate in the first stage by consuming K⁺ until 1y, Feldspar were dissolved into precipitations of illite, smectite, and siderite at 1-6y, with albite, muscovite and kaolinite mostly precipitated in the last stage 6–10y. The precipitations of secondary clay minerals and quartz serve to maintain the integrity of caprock sealing. Continuous scCO₂ injection under fully coupled THMC model shows a 1.4-times enhancement of fracture permeability and 1.2-times enhancement of matrix permeability dominated by chemical dissolution and thermal unloading process. The pronounced thermal drawdown is the principal factor in enhancing permeability and porosity near injection well. Furthermore, the expansive capability of CO₂ provides extra benefits in enhancing formation pressure to ensure consistent high flow rates, while achieving a higher thermal energy extraction efficiency and preventing scaling issues in wellbore. The mass concentration of scCO2 in the production well increased to 0.82 after 1.2 × 10⁸s also leads to the enhancement of fluid enthalpy up to 6.5 × 10⁵ J/kg, due to the high heat capacity of scCO₂. The injected CO₂ are sequestered at ∼2 × 10⁷ kg at t = 2 × 10⁸s (6.34y) as the solubility trapping mechanism.

开发并应用耦合 THMC（热-水文-机械-化学）模型来探索使用 scCO ₂ （超临界二氧化碳）作为地热储层工作流体的潜在可行性。这是通过检查矿物沉淀溶解动力学的演变及其对岩石渗透率和孔隙度演变的相关影响来实现的。由于方解石的快速溶解，储层的 pH 值从 7 迅速降低到 4.5-5 。注入器附近的化学反应和矿物溶解和沉淀受到无水 scCO ₂的活塞流渗透取代原始孔隙流体的抑制. 提出了一个概念性的三区模型来说明长石溶解和沉淀随时间变化的动力学过程。K ⁺的初始高浓度促使长石在第一阶段通过消耗 K ⁺沉淀直到 1 y ，长石在 1-6 y 时溶解为伊利石、蒙脱石和菱铁矿的沉淀，其中钠长石、白云母和高岭石主要沉淀在最后阶段6-10 ÿ。次生粘土矿物和石英的沉淀有助于维持盖层封闭的完整性。连续 scCO ₂全耦合 THMC 模型下的注入显示裂缝渗透率提高 1.4 倍，基质渗透率提高 1.2 倍，主要是化学溶解和热卸载过程。显着的热压降是提高注入井附近渗透率和孔隙度的主要因素。此外，CO ₂的膨胀能力在提高地层压力以确保一致的高流速方面提供了额外的好处，同时实现了更高的热能提取效率并防止井筒中的结垢问题。生产井中 scCO2 的质量浓度在 1.2 × 10 ⁸ s后增加到 0.82也导致流体焓提高到 6.5 × 10 ⁵ J/kg，由于 scCO _{2 的}高热容量。注入的 CO ₂ 在 t = 2 × 10 ⁸ s (6.34 y ) 时被隔离在 ~2 × 10 ⁷ kg作为溶解度捕获机制。