Basalt formations are potentially attractive targets for carbon capture and sequestration (CCS) on the basis of favorable CO₂-water-rock reactions, which result in permanent CO₂ isolation through mineral trapping. Recent pilot-scale experiments in Iceland and Washington state, USA, provide promising results that indicate rapid carbon mineralization occurs within basalt reservoirs. Nevertheless, transitioning these pilot-scale results to large-scale industrial CCS operations is fraught with uncertainty because fluid flow in basalt formations is governed by fracture-controlled hydraulic properties that are highly heterogeneous and difficult to map in situ. This uncertainty is exacerbated by feedbacks between multi-phase fluid dynamics (CO₂ and water) and fluid-rock reactions, which may result in a reinforcing feedback comprising CO₂ mineralization, permeability alteration, and fluid mobility. To begin to understand the feedbacks between multi-phase fluid flow and mineralization in fractured basalt, this study uses reactive transport simulation methods to model CO₂ infiltrating a meter-scale, synthetic basalt fracture overlying a storage reservoir while accounting for porosity change due to mineralization and its corresponding effect on permeability and fluid mobility. Results show that (i) carbonate and clay mineralization tends to occur downgradient of a fracture intersection, (ii) mineralization reduces porosity, which leads to permeability reduction and slows free-phase CO₂ migration, (iii) stronger porosity-permeability coupling increases the proportion of mineralized carbon while reducing CO₂ mass that can enter fracture, which may lead to self-sealing behavior as fluid mobility approaches nil, and (iv) errors caused by unknown porosity-permeability relationships are small in comparison to errors that arise by omitting mineralization-induced permeability reduction when simulating CO₂ sequestration scenarios in basalt reservoirs.

基于有利的 CO _{2 -}水-岩反应，玄武岩地层是碳捕获和封存 (CCS) 的潜在有吸引力的目标，这导致通过矿物捕获实现永久的 CO ₂隔离。最近在冰岛和美国华盛顿州进行的中试规模试验提供了有希望的结果，表明玄武岩储层中发生了快速的碳矿化。然而，将这些中试结果转化为大规模工业 CCS 操作充满不确定性，因为玄武岩地层中的流体流动受裂缝控制的水力特性控制，这些特性高度异质且难以原位绘制。多相流体动力学 (CO ₂和水）和流体-岩石反应，这可能会导致增强反馈，包括 CO ₂矿化、渗透率改变和流体流动性。为了开始了解裂隙玄武岩中多相流体流动与矿化之间的反馈，本研究使用反应输运模拟方法模拟 CO ₂渗入覆盖储层的米级合成玄武岩裂缝，同时考虑到矿化引起的孔隙度变化及其对渗透率和流体流动性的相应影响。结果表明，(i) 碳酸盐和粘土矿化趋向于在裂缝交叉点的下坡处发生，(ii) 矿化降低孔隙度，导致渗透率降低并减缓自由相 CO ₂迁移，(iii) 更强的孔隙度-渗透率耦合增加了矿化碳的比例，同时减少了可以进入裂缝的CO ₂质量，当流体流动性接近零时，这可能导致自密封行为，以及 (iv) 未知孔隙度引起的误差 -与模拟玄武岩储层中CO ₂封存情景时忽略矿化引起的渗透率降低而产生的误差相比，渗透率关系很小。