Impurity effects are an intricate issue in CO₂ geological storage, involving both pre-dissolved impurities in the geological medium and co-injected impurities. Numerical simulations were carried out in this study to investigate the coupling effects of pre-dissolved H₂S and different co-injected impurities (H₂S, CH₄ and N₂) on CO₂ sequestration in layered sour saline aquifers. The native H₂S would be exsolved out of the sour formation brine and pushed ahead by the injected plume. The exsolved H₂S reduced the concentrations of the injected gases at the two-phase interface. Particularly, when H₂S was co-injected with CO₂ into the sour saline aquifers, both dissolved CO₂ inventory and dissolved CO₂ ratio would reduce by nearly half compared with that in the regular saline aquifers without native H₂S. It was observed that the decrease of the dissolved CO₂ ratio due to the existence of the native H₂S was much compensated by the co-injection of CH₄ or N₂. Nevertheless, the native impurity seemed to have more profound effects on CO₂ sequestration than the co-injected impurities. The results should be considered in selecting appropriate sequestration sites and establishing risk assessment strategies.

杂质影响是CO ₂地质存储中的一个复杂问题，涉及地质介质中的预溶解杂质和共注入杂质。在这项研究中进行了数值模拟，以研究预溶解的H ₂ S和不同的共注入杂质（H ₂ S，CH ₄和N ₂）对层状酸性盐水层中CO ₂螯合的耦合作用。天然的H ₂ S将从酸性地层盐水中溶解出来，并被注入的羽流推动。溶解的H ₂ S降低了两相界面处注入气体的浓度。特别是当H ₂将S与CO ₂共同注入酸性盐水层中，与没有天然H ₂ S的普通盐水层相比，溶解的CO ₂存量和溶解的CO ₂比例将减少近一半。CH ₄或N ₂的共注入大大补偿了由于天然H ₂ S的存在而产生的溶解CO ₂比率。然而，天然杂质似乎比共注入杂质对CO ₂隔离具有更深远的影响。在选择合适的隔离地点并建立风险评估策略时应考虑结果。