We simulate two sets of dissolution experiments in which CO₂-saturated solutions are injected into calcite formations. We explore the impact of non-linear reaction kinetics and charge-coupled ion transport in systems representing different levels of flow and mineralogical complexity. First, we flow CO₂-saturated water and brine through cylindrical channels drilled through solid calcite cores and compare directly with experimental dissolution rates. We find that simulations using a linear saturation model match experimental results much better than the batch-reactor-derived non-linear saturation model. The use of a coupled diffusion model causes only a very small increase in the overall dissolution rate compared to a single diffusion coefficient, due to the increase in transport rates of reaction products, particularly the highly charged $C{a}^{2+}$ ion. We also determine the relative importance of the two calcite dissolution pathways, with H⁺ and H₂CO₃, and conclude that the H₂CO₃ – calcite reaction is by far the more dominant, in contrast with common assumptions in the literature. Then, we compare to the experiments of Menke et al. (2015) in which CO₂-saturated brine was injected into a microporous Ketton carbonate, and compare dissolution rates over time. We find that including non-linear saturation behaviour markedly changes the simulated dissolution rate, by up to a factor of 0.7 in the case of the experimentally derived saturation model of Anabaraonye et al. (2018), however neither case matches the experimental result which is several times slower than the simulation. Including the effects of coupled ion transport lead to virtually no change in overall dissolution rate due to the convection dominated behaviour. The model also shows differences in the trend of the dissolution rate over time observed in Menke et al, with an approximately linear relationship with time compared to the experimental square-root dependence on time. We conclude that the geochemical model may need to include other effects such as dissolution inside microporous regions.

我们模拟了两组溶解实验，其中将CO ₂饱和溶液注入方解石地层中。我们探讨了非线性反应动力学和电荷耦合离子输运在代表不同水平的流量和矿物学复杂性的系统中的影响。首先，我们流入CO ₂-通过固体方解石岩心钻出的圆柱形通道使饱和水和盐水饱和，并直接与实验溶出度进行比较。我们发现，使用线性饱和度模型进行的仿真与实验结果相匹配，比批处理反应器派生的非线性饱和度模型要好得多。与单个扩散系数相比，耦合扩散模型的使用只会使总溶解速率仅产生非常小的增加，这是因为反应产物（尤其是高电荷的）的传输速率增加了$C{\mathrm{一种}}^{\mathrm{2个}+}$离子。我们还确定了H ⁺和H ₂ CO ₃两种方解石溶解途径的相对重要性，并得出结论，与文献中的常见假设相比，H ₂ CO _3-方解石反应到目前为止更具优势。然后，我们将其与Menke等人的实验进行比较。（2015），其中CO ₂将饱和盐水注入微孔碳酸钾酮中，比较随时间的溶出速率。我们发现，在Anabaraonye等人的实验得出的饱和模型的情况下，包括非线性饱和行为会显着改变模拟溶出速率，最高可达0.7倍。（2018），但是这两种情况都没有比实验结果慢几倍的实验结果。由于对流占主导地位的行为，包括耦合的离子迁移的影响几乎不会导致总溶出度发生变化。该模型还显示了Menke等人观察到的溶出度随时间变化的趋势，与实验时间对时间的平方根相关性呈线性关系。