528. 揭示SOx与NOx对CCS的影响：对注入能力、矿化作用及长期CO₂封存的意义

Unveiling the Impact of SOx and NOx in CCS: Implications on Injectivity, Mineralization, and Long-Term CO2 Storage 

本研究探讨了CO₂气流中SOx与NOx杂质对碳捕集与封存（CCS）关键环节的影响，包括注入能力、矿化作用以及长期封存行为。若在模拟中忽略这些杂质，将导致对储层动态的理解出现重大偏差，并可能低估地球化学及操作风险。研究旨在为设计能够适应含杂CO₂气流、同时确保安全高效封存的CCS系统提供可操作的见解。

研究采用CMG-GEM组分储层模拟器这一先进数值工具，模拟反应性运移过程，并刻画构造封存、残余封存、溶解封存及矿物封存等多种机制。模拟涵盖了酸液形成、矿物溶解与沉淀等关键地球化学过程，并考虑了多种操作情景。除基础案例（含5% SO₂与5% NO₂）外，还设置了两组对比案例：一组仅含10% SO₂，另一组仅含10% NO₂，以单独评估每种杂质的影响。

结果表明，SOx与NOx的存在改变了CO₂封存机制的相对贡献：含杂质情景下，溶解与残余封存比例下降，但结构封存能力增强，且矿物封存比例较纯CO₂注入提高约1%。其中，仅含NO₂的案例矿化程度高于仅含SO₂案例，而混合杂质情景（5% SO₂+5% NO₂）的矿物封存增幅最大。这主要归因于杂质引发的酸化作用加速了矿物溶解，并促进碳酸盐沉淀，从而实现更永久的CO₂固定。研究强调，若忽略杂质影响，将低估矿物封存潜力并误判长期封存行为；在CCS项目中对SOx与NOx进行显式建模，是准确评估封存容量、注入能力及安全性的关键。

Abstract

This study investigates the impacts of SOx and NOx impurities in CO₂ streams on key stages of Carbon Capture and Storage (CCS), including injection performance, mineralization, and long-term storage behavior. Excluding these impurities from simulations can lead to significant gaps in understanding reservoir dynamics and may underestimate geochemical and operational risks. This work aims to provide actionable insights for designing CCS systems that ensure safe and efficient storage while accommodating impure CO₂ streams.

Advanced numerical simulation tools, specifically CMG’s GEM compositional reservoir simulator, were employed to model reactive transport and simulate various trapping mechanisms, including structural, residual, solubility, and mineral trapping. The simulations captured key geochemical processes such as acid formation, mineral dissolution, and precipitation under a range of operational scenarios. In addition to the base case with 5% SO₂ and 5% NO₂ impurities, two additional cases were analyzed to isolate the effect of each impurity: one with 10% SO₂ and no NO₂, and another with 10% NO₂ and no SO₂.

The results demonstrate that the presence of SO_x and NO_x impurities alters the balance of CO₂ trapping mechanisms. Impurity-bearing scenarios showed reduced contributions from solubility and residual trapping but exhibited enhanced structural containment and an increase of approximately 1% in mineral trapping relative to pure CO₂ injection. Mineralization was greater in the NO₂-only case compared to the SO₂-only case; however, the mixed scenario (5% SO₂ + 5% NO₂) produced the highest overall increase. This enhancement is attributed to impurity-induced acidification, which accelerates mineral dissolution and promotes carbonate precipitation, leading to more permanent CO₂ immobilization. These findings highlight that overlooking impurities may underestimate the role of mineral trapping and misrepresent long-term storage behavior. The study underscores the importance of explicitly accounting for SO_x and NO_x when forecasting capacity, injectivity, and containment security in CCS projects.