Inherent pore structure of rocks has a significant impact on the acid–rock interaction during the acidizing process. In this study, a new pore-scale reactive transport model applying Darcy–Brinkmann–Stokes method has been developed based on the open-source computational fluid dynamics platform, OpenFOAM, and validated with experimental results. By solving the mass balance equation and advection–diffusion equation, the developed numerical simulation model could capture the evolving pore structure and track the distribution of transported acid. The impacts of different grain sizes and distributions on the dissolution rate of mineral (calcite), evolving porosity, and the transport characteristics of acid have been investigated. In addition, sensitivity analysis has been conducted with respect to the various Damköhler numbers and Péclet numbers in the digital rock image model of Niobrara formation. The changing volume fraction of pores could be categorized into three patterns with different dimensionless numbers—linear growth, pseudo-linear growth, and a flat S-curve growth. The simulation cases of Estaillades carbonate, Massangis Jaune carbonate models, and Sample X segmentation showed that their inherent grain distribution was highly influential on the mineral dissolution rate, where 3-D simulation showed the same results. The developed pore-scale reactive transport model can be applied to various systems with complex pore structures, in order to provide a guidance to predict the system responses such as dissolution rates, surface area, and porosity changes during acidizing in large-scale continuum model.

岩石的固有孔隙结构在酸化过程中对酸-岩相互作用产生重大影响。在这项研究中，基于开源计算流体动力学平台OpenFOAM，开发了一种采用Darcy-Brinkmann-Stokes方法的新的孔尺度反应输运模型，并用实验结果进行了验证。通过求解质量平衡方程和对流扩散方程，所建立的数值模拟模型可以捕获正在演化的孔隙结构并跟踪所输送酸的分布。研究了不同晶粒尺寸和分布对矿物（方解石）的溶解速率，演化的孔隙度以及酸的传输特性的影响。此外，已对Niobrara地层的数字岩石图像模型中的各种Damköhler数和Péclet数进行了敏感性分析。改变的孔体积分数可以分为具有无因次数不同的三种模式-线性增长，伪线性增长和平坦的S曲线增长。Estaillades碳酸盐，Massangis Jaune碳酸盐模型和样品X分割的模拟实例表明，它们的固有晶粒分布对矿物溶出速率有很大影响，其中3-D模拟显示了相同的结果。所开发的孔尺度反应输运模型可以应用于具有复杂孔结构的各种系统，以提供指导以预测系统响应，例如溶出速率，表面积，