In this study, the effect of argon as a co-contaminant in a CO₂ stream on interfacial tension, diffusion coefficients and storage capacity was experimentally determined under conditions relevant to carbon sequestration, using the pendant drop method. Interfacial properties affect primary capillary trapping mechanisms when CO₂ is injected since they set a limit to storage capacity in a geological formation. A strong increase in the isothermal interfacial tension at 45 °C and up to 20 MPa was observed with an increase in Ar co-contamination from 5 vol.% up to 100 vol.%. Since Ar content is present in small concentrations in most injected CO₂ streams, we focused on measuring brine-CO₂ interfacial tension and brine mixture (CO₂ and Ar) interfacial tension, with 5 vol.% and 10 vol.% of argon content at pressures from 7.5 MPa up to 40 MPa and in the temperature range from 40 °C to 80 °C, which has not previously been investigated and can be considered more oriented to real-world conditions for carbon sequestration. It was found that storage capacity decreased significantly from a scenario where pure CO₂ was injected, down to a scenario where 5 vol.% and 10 vol.% Ar were co-injected into the CO₂ stream. Additionally, the effect of other common impurities in CO₂ streams on interfacial properties and storage capacity is discussed.

In order to evaluate the risk of CO₂ diffusion loss through a cap rock, we measured the diffusion coefficients of geological water in the injected fluid. It was found that the diffusion coefficients of water in Ar are higher in comparison to those of water in CO₂. Small quantities of salt in water had a minor effect on the diffusion coefficients of brine in supercritical CO₂. Experimentally obtained diffusion coefficients (D_ab) were correlated to obtain the effective diffusion coefficient (D_eff). It was found that, in the case of co-injection of Ar with CO₂, the diffusive gas breakthrough could be enhanced.

在这项研究中，使用悬滴法，在与碳固存相关的条件下，通过实验确定了氩气作为CO ₂物流中的共污染物对界面张力，扩散系数和储存容量的影响。注入CO ₂时，界面性质会影响主要的毛细管捕集机制，因为它们限制了地质构造中的储存能力。观察到等温界面张力在45°C时高达20 MPa的强烈增加，而Ar共同污染从5％（体积）增加到100％（vol。％）。由于大多数注入的CO ₂流中的Ar含量都较低，因此我们专注于测量盐水-CO ₂界面张力和盐水混合物（CO₂和Ar）的界面张力，在7.5 MPa至40 MPa的压力下以及40°C至80°C的温度范围内，氩含量分别为5％和10％。可以认为更适合现实世界中的碳封存条件。已经发现，从注入纯CO ₂的情形到将5vol。％和10vol。％的Ar共同注入到CO ₂流中的情形，存储容量显着降低。此外，还讨论了CO ₂物流中其他常见杂质对界面性质和存储容量的影响。

为了评估CO ₂通过盖岩扩散损失的风险，我们测量了地质流体在注入流体中的扩散系数。发现与Ar _2中的水相比，Ar中的水的扩散系数更高。水中少量的盐对盐水在超临界CO _2中的扩散系数影响较小。将实验获得的扩散系数（D _ab）进行关联，以获得有效扩散系数（D _eff）。已经发现，在Ar和CO ₂共同注入的情况下，扩散气体的穿透可以增强。