One potential risk in CO₂ sequestration is the leakage of carbon dioxide, which can result in contamination of underground water, creating potential threats to existing ecosystems. The common leakage pathway is through the pre-existing fractures or discontinuities within cement in the wellbore, incurred by the environmental conditions imposed on the cement. Injecting nanoparticles into pre-existing cracks is one of the most recently proposed ideas for mitigating fracture propagation in cement CO₂ sequestration. To demonstrate the feasibility of this new technology, a numerical approach was taken in this work, as it is challenging to investigate it in a laboratory setting. We proposed a coupled ALE (Arbitrary Lagrangian–Eulerian)–DEM (Discrete Element Method)–peridynamic modeling strategy within the LS-Dyna package to investigate the intertwined interaction among the CO₂ fluid flow, native fluid (e.g., brine), particle clusters, and cracks within the cement. The numerical results demonstrate that injected nanoparticles can effectively reduce the pressure exerted on the crack surface. Accordingly, the potential fracture propagation at the crack tip would be reduced compared to corresponding cases without nanoparticels as pressurized by fluid flow. This result verifies the effectiveness of proposed nanoparticle injection technology. Finally, using this established modeling strategy, the effect of filling particles on the fracture mitigation for different crack geometries (e.g. particle cluster patterns, aspect ratio of crack aperture and length) and CO₂ reservoir pressure are examined. The result shows that injected particles successfully reduce the fracture propagation in these scenarios.

隔离CO _2的潜在风险之一是二氧化碳的泄漏，这可能导致地下水污染，对现有生态系统构成潜在威胁。常见的泄漏途径是由于施加在水泥上的环境条件引起的，井眼中水泥中预先存在的裂缝或不连续性。将纳米颗粒注入预先存在的裂缝中是缓解水泥CO _2中裂缝扩展的最新提议之一隔离。为了证明这项新技术的可行性，在这项工作中采用了一种数值方法，因为在实验室环境中对其进行研究具有挑战性。我们在LS-Dyna软件包中提出了耦合ALE（任意拉格朗日–欧拉）–DEM（离散元素方法）–蠕动建模策略，以研究CO ₂之间的相互作用水泥浆中的流体流动，天然流体（例如盐水），颗粒团簇和裂缝。数值结果表明，注入的纳米粒子可以有效降低施加在裂纹表面的压力。因此，与没有纳米颗粒的相应情况相比，在裂纹尖端处潜在的裂纹扩展将被减少，而纳米颗粒不会受到流体流动的压力。该结果验证了所提出的纳米粒子注射技术的有效性。最后，使用这种既定的建模策略，填充颗粒对不同裂缝几何形状（例如，颗粒团簇模式，裂缝孔径和长度的长宽比）和CO ₂对缓解裂缝的影响检查油藏压力。结果表明，在这些情况下，注入的颗粒成功地减少了裂缝的扩展。