Multifidelity Modeling and Analysis of Matrix Acidizing Under Radial Flow Conditions

Abstract

Abstract Simulating the complex physics and dynamics associated with carbonate acidizing and wormholing phenomenon has been attempted with various types of modeling techniques. In this paper, we follow two modeling approaches with different fidelity levels to simulate carbonate acidizing under radial flow conditions, and describe the wormholing process. The first approach is based on a two-scale continuum technique extended to a three-dimensional cylindrical grid. This model requires discretizing and numerically solving a set of coupled partial differential equations governing the reactive transport of acid at darcy scale and the pore scale dynamics through the structure-property relations. The model shows good capability to reproduce qualitatively the change in the wormhole morphology when varying the acid flow rate. The model is also used to discern the impact of the rock heterogeneity on the wormhole initiation and propagation. While this high-fidelity approach is powerful in terms of capturing the main physical features of the wormholing dynamics at the core scale, the extensive computational resources and time associated with the use of this model could limit the capability of assessing different configurations and operating conditions for design and optimization purposes and upscaling to the field level. This shortcoming presents the need for the development of simplified models that embody relevant physical aspects and provide fast and reliable assessment of the acidizing performance. As such, we consider a second approach with reduced complexity based on combining two quantitative models of linear and radial acid flows in carbonate rocks to track the wormhole penetration and predict the pressure drop resulting from the acidizing of radial cores. A comparative study with experimental results shows that the model predicts well the pressure response and pore volume to breakthrough.