Carbon dioxide (CO) emissions are being reduced using the technique known as CCUS (Carbon Capture, Utilization, and Storage). At present, cementing cement paste based on ordinary silicate cement (OPC) and compounded with CO corrosion-resistant materials are often used in CCUS wells. CAC cement is characterised by low alkaline hydration content and its study in CCUS wells has rarely been reported. Therefore, CAC cement will be a new cement material for CCUS wells. In this study, we have developed an experimental device to simulate the working conditions of CCUS based on the actual well conditions of CCUS and investigated the effects of stress-coupled CO corrosion environment on the performance of CAC cement. According to the experimental findings, CAC cement's compressive strength degraded at a rate of 30.6% after 60 days of CO corrosion, which was lower than that of OPC cement (38.3%). When compared to OPC cement, the peak strain and stress of CAC cement increased by 57.2% and 7.85%, respectively. Furthermore, compared to OPC cement sheath, the CAC cement sheath's bearing capacity increased by 8 MPa after stress corrosion, and the crack area of the CAC cement sheath after failure was considerably smaller at 275 mm than at 735 mm. Additionally, after being subjected to stress-coupled CO corrosion, the integrity of the CAC cement sheath was much superior to that of the OPC cement sheath, offering a fresh viewpoint for building CCUS cement slurry systems.

中文翻译：

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增强CCUS水泥环完整性的新型材料：铝酸钙水泥的探索与应用

使用 CCUS（碳捕获、利用和储存）技术可以减少二氧化碳 (CO) 排放。目前CCUS井多采用以普通硅酸盐水泥（OPC）为主，复合耐CO腐蚀材料的固井水泥浆。 CAC水泥具有碱性水化含量低的特点，其在CCUS井中的研究鲜有报道。因此，CAC水泥将成为CCUS井的新型水泥材料。本研究基于CCUS实际井况，研制了模拟CCUS工况的实验装置，研究了应力耦合CO腐蚀环境对CAC水泥性能的影响。根据实验结果，CO腐蚀60天后，CAC水泥的抗压强度下降率为30.6%，低于OPC水泥的抗压强度（38.3%）。与OPC水泥相比，CAC水泥的峰值应变和应力分别增加了57.2%和7.85%。此外，与OPC水泥环相比，应力腐蚀后CAC水泥环的承载力提高了8 MPa，并且CAC水泥环破坏后的裂纹面积在275 mm处比在735 mm处要小得多。此外，在遭受应力耦合CO腐蚀后，CAC水泥环的完整性大大优于OPC水泥环，为构建CCUS水泥浆体系提供了新的视角。