Modeling CO${}_2$-brine flow related to CO${}_2$ storage in saline aquifers involves intense numerical simulations. One of the important processes associated with these flows, allowing for safe long term storage of CO${}_2$, is residual trapping. For accurate modeling of trapping, capillary heterogeneity should be incorporated in the models. However, there have been some reports of increased numerical simulation errors associated with these models and yet no systematic study of their accuracy has been carried out.

We compare results of two numerical simulators to a semi-analytical solution of 1D two-phase immiscible steady state flow with capillary heterogeneity. Simulation errors are calculated for a wide range of different flow rates, fluid fractions, capillary pressure curves and heterogeneities. Results show that capillary pressure and saturation errors increase with smaller dimensionless capillary number and reach large values of $25-50\%$ for many cases. It is shown that the errors are related to capillary heterogeneity and therefore increase also with larger variance of log permeability. Finally, a new approach for predicting numerical errors without employing an analytical solution is proposed, i.e., the error indicator analysis.

建模公司${}_2$- 与 CO 相关的盐水流${}_2$咸水层中的储存涉及密集的数值模拟。与这些流动相关的重要过程之一，允许安全长期储存 CO${}_2$, 是残留诱捕。为了准确模拟捕获，毛细管异质性应纳入模型。然而，有一些报告称与这些模型相关的数值模拟误差增加，但尚未对其准确性进行系统研究。

我们将两个数值模拟器的结果与具有毛细管异质性的一维两相不混溶稳态流动的半解析解进行比较。针对各种不同的流速、流体比例、毛细管压力曲线和异质性计算模拟误差。结果表明，毛细管压力和饱和度误差随着无因次毛细管数的减少而增加，并达到较大的值$25-50\%$对于许多情况。结果表明，误差与毛细管非均质性有关，因此随着测井渗透率的较大变化而增加。最后，提出了一种不用解析解来预测数值误差的新方法，即误差指标分析。