Experimental and theoretical studies of reactive transport processes in soluble porous rocks

Abstract

Underground reactive transport processes involve fluid flow and reactions (dissolution, precipitation, and pressure solution) driving the evolution of the rock-fluid systems, which may result in favorable processes such as increased oil production by reservoir acid stimulation, or undesired processes such as caves and subsidence. Flow and reaction in the rock matrix often induce wormholes, which are long, finger-like channels that form due to the dissolution heterogeneity in the matrix. These wormholes become major flow pathways, which greatly increase the permeability of the rock. To study the reactive transport processes and the formation of wormholes, experimental and theoretical studies were conducted. More specifically, a new experimental setup and data analysis methods were introduced to the tube flow tests and core flood tests to experimentally study the evolution of the rock-fluid system. Theoretical studies with analytical and numerical models were used to simulate the experimental results and provide theoretical explanation for the experimental observations. Through the experimental and theoretical studies, this research improved the fundamental understanding of reactive transport processes in rock-fluid systems. This in turn provided accurate prediction of the evolution of the rock-fluid systems driven by the reactive transport processes.