Storing CO₂ in deep underground reservoirs is key to reducing emissions to the atmosphere and standing against climate change. However, the risk of CO₂ leakage from geological reservoirs to other rock formations requires a careful long-term analysis of the system. Mostly, oil well cement used for the operation must withstand the carbonation process that changes its poromechanical behavior over time, possibly affecting the system’s integrity.

This work focuses on the microstructure and mechanical behavior of cement modified with bacterial nanocellulose (BNC) cured at 90 °C, simulating temperature at the reservoir level. The chemo-hydro-mechanical (CHM) coupled behavior of the cement–rock interface is also investigated through numerical analyses.

Mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), ultrasonic wave velocity measurement, and unconfined compressive strength (UCS) tests were performed on cement samples subjected to a supercritical CO₂ environment. After carbonation, BNC samples show a lower mass gain and lower porosity compared to PC. Permeability based on MIP results indicate that the BNC reduces the permeability of the specimen. XRD quantification shows no substantial difference between the crystalline phases of the two samples. Samples with BNC have lower absolute strength but higher relative increase during carbonation.

The numerical study includes a homogenization of the medium considering the contribution of all components. CHM behavior of the cement with BNC is analyzed, and the results show the variations of the physical and chemical properties across the sample. The numerical study shows the advantage of using this type of tool to study realistic CO₂ injection scenarios in deep wells.

将 CO ₂储存在深层地下水库中是减少大气排放和抵御气候变化的关键。然而，CO ₂从地质储层泄漏到其他岩层的风险需要对系统进行仔细的长期分析。大多数情况下，用于作业的油井水泥必须能够承受随着时间的推移改变其孔隙力学行为的碳化过程，这可能会影响系统的完整性。

这项工作的重点是在 90 °C 下固化的细菌纳米纤维素 (BNC) 改性水泥的微观结构和力学行为，模拟储层水平的温度。还通过数值分析研究了水泥-岩石界面的化学-流体-机械 (CHM) 耦合行为。

_{对经受超临界CO 2}环境的水泥样品进行了压汞法(MIP)、X射线衍射(XRD)、超声波速度测量和无侧限抗压强度(UCS)测试。碳酸化后，与 PC 相比，BNC 样品显示出较低的质量增益和较低的孔隙率。基于 MIP 结果的渗透率表明 BNC 降低了试样的渗透率。XRD 量化显示两个样品的结晶相之间没有显着差异。具有 BNC 的样品具有较低的绝对强度，但在碳化过程中相对增加较高。

数值研究包括考虑所有组分的贡献的介质的均质化。分析了含有 BNC 的水泥的 CHM 行为，结果显示了整个样品的物理和化学性质的变化。数值研究显示了使用这种类型的工具来研究深井中实际的 CO _{2注入情景的优势。}