A prototype finite element double porous Thermo-Hydro-Mechanical (THM) model that considers elastoplastic and damage evolution effects, is used to investigate deformability, fluid flow and heat transfer during injection of carbon dioxide (CO2) injection. The primary objective is to explore the feasibility of injecting CO2 at temperatures lower than the surrounding formation, including subzero conditions. This is done to enhance the energy efficiency of the CO2 storage process by eliminating the need to pre-heat the CO2 prior to injection. The numerical analysis investigates the impact of internal wellbore temperatures and pressures on the surrounding rock, using Stainton Sandstone as the reference material. Various internal wellbore temperatures and pressures are simulated to represent different CO2 injection scenarios. The results suggest that injecting CO2 at lower temperatures than the wellhead is feasible. However, the long-term integrity and lifespan of the wellbore may require further investigation. This study provides a novel approach to enhancing energy efficiency in CO2 storage by exploring subzero injection, potentially reducing operational costs. Additionally, it identifies critical challenges regarding wellbore integrity, which warrant further research to ensure the safety and durability of the storage site.

中文翻译：

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零下 CO2 注入下的热-水-机械 （THM） 井筒分析


考虑弹塑性和损伤演化效应的原型有限元双孔热-水-机械 （THM） 模型用于研究二氧化碳 （CO2） 注入过程中的变形能力、流体流动和传热。主要目标是探索在低于周围地层的温度（包括零度以下条件）注入 CO2 的可行性。这样做是为了提高 CO2 储存过程的能源效率，无需在注入前预热 CO2。数值分析以 Stainton Sandstone 为参考材料，研究了内部井筒温度和压力对围岩的影响。模拟各种内部井筒温度和压力，以表示不同的 CO2 注入场景。结果表明，在低于井口的温度下注入 CO2 是可行的。然而，井筒的长期完整性和使用寿命可能需要进一步调查。这项研究提供了一种通过探索零度以下注入来提高 CO2 储存能源效率的新方法，从而可能降低运营成本。此外，它还确定了井筒完整性方面的关键挑战，需要进一步研究以确保存储场地的安全性和持久性。