Download or read book Investigation of Coupled Chemo-hydro-mechanical Processes with Discrete Element Modeling written by Zhuang Sun and published by . This book was released on 2019 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geological storage of CO2 is proposed as a near-term economically viable approach to mitigate CO2 emissions, and is an example of the coupled chemo-hydro-mechanical processes. Although CO2 injection and enhanced oil recovery are viewed as mature technologies in the oil and gas industry, investigation of all possible implications is necessary for secure and effective long-term CO2 storage. The injection of a large volume of CO2 into target storage formations is usually associated with a number of geomechanical processes that are initiated at the pore scale. Therefore, a pore-scale geomechanical model, i.e. Discrete Element Method (DEM), is of great importance to better understand the underlying pore-scale processes and mechanisms that govern the large-scale CO2 geological storage. In this work, we concentrate on several significant pore-scale coupled phenomena. Firstly, CO2 injection into geological formations involves chemo-mechanical processes and shifts the geochemical equilibrium between the minerals and resident brine, which subsequently induces mineral-brine-CO2 reactions and affects CO2 storage mechanical integrity. We utilize a numerical model that couples the Discrete Element Method (DEM) and the Bonded-Particle Model (BPM) to perform simulations on synthetic rocks that mimic tested rock samples. Numerical results, in agreement with experimental evidence, show that both cement and particle dissolution significantly contribute to rock weakening in sandstones with carbonate/hematite cements and pore-filling carbonate. Secondly, reservoir compaction involves hydro-mechanical processes that induce changes in porosity and permeability, and is a significant concern for the oil and gas production. We develop a grain crushing model based on the DEM to investigate the changes in porosity and permeability under the reservoir stress path. Grain crushing is shown to be the dominant mechanism for significant changes in porosity and permeability under a high effective stress. Samples consisting of large and soft grains tend to be more readily compacted. Finally, fluid injection in the subsurface may induce fractures and is another common hydro-mechanical process. We couple the Discrete Element Method (DEM) to solve for the mechanics of a solid granular medium and the Computational Fluid Dynamics (CFD) to model fluid flow and drag forces. We validate the resolved CFD-DEM numerical model against experiments from the literature and investigate the impact of physical properties and injection parameters. This work reveals how the pore-scale processes contribute to fluid-driven fracture initiation