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This work applies a three-dimensional (3D) multiscale approach recently developed by Nguyen et al. ( Int. J. Greenhouse Gas Control, 2016, 46:100-115; Greenhouse Gases: Sci. & Technol. , DOI: 10.1002/ghg.1616) to analyze a complex CO 2 faulted reservoir that includes some key geological features of the San Andreas and nearby faults. The approach couples the STOMP-CO2-R code for flow and reactive transport modeling to the ABAQUS ® finite element package for geomechanical analysis. The objective is to examine the coupled hydro-geochemical-mechanical impact on the risk of hydraulic fracture and fault slip in a complex and representative CO 2 reservoir that contains two nearly parallel faults. STOMP-CO2-R/ABAQUS ® coupled analyses of this reservoir are performed assuming extensional and compressional stress regimes to predict evolutions of fluid pressure, stress and strain distributions as well as potential fault failure and leakage of CO 2 along the fault damage zones. The tendency for the faults to slip and pressure margin to fracture are examined in terms of stress regime, mineral composition, crack distributions in the fault damage zones and geomechanical properties. This model in combination with a detailed description of the faults helps assess the coupled hydro-geochemical-mechanical effect. [ABSTRACT FROM AUTHOR]

This paper applies a multiscale hydro-geochemical-mechanical approach to analyze faulted CO2 reservoirs using the STOMP-CO2-R code that is coupled to the ABAQUS® finite element package. STOMP-CO2-R models the reactive transport of CO2 causing mineral composition changes that are captured by an Eshelby-Mori-Tanka model implemented in ABAQUS®. A three-dimensional (3D) STOMP-CO2-R model for a reservoir containing an inclined fault was built to analyze a formation containing a reaction network with five minerals: albite, anorthite, calcite, kaolinite, and quartz. A 3D finite element mesh that exactly maps the STOMP-CO2-R grid was developed for coupled analyses. The model contains alternating sandstone and shale layers. The impact of reactive transport of CO2 on the geomechanical properties of reservoir rocks are studied in terms of mineral composition changes that affect their geomechanical responses. Simulations assuming extensional and compressional stress regimes with and without coupled geochemistry are performed to study the stress regime effect on the risk of hydraulic fracture. The fault slip is examined as functions of stress regime, geomechanical, geochemical-mechanical effects, fault inclination, and position. The results show that mineralogical changes due to CO2 injection reduce the permeability and elastic modulus of the reservoir, leading to increased fluid pressure and risk of fracture in the injection location and the caprock seal. Shear failure in the fault leading to fault reactivation was not predicted to occur. However, stress regime, fault inclination, and fault position in light of the coupled hydro-geochemical-mechanical analysis have an important impact on the slip tendency factor and elastic fault slip. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This article develops a model to analyze CO 2 reservoirs using the STOMP-CO 2 -R code that is interfaced with the ABAQUS ® finite element package. The STOMP-CO 2 -R/ABAQUS ® simulator accounts for the reactive transport of CO 2 causing changes in mineralogy that modify the geomechanical properties of reservoir rocks and seals. Rocks’ elastic properties that vary during CO 2 injection and govern the poroelastic behavior of rocks are modeled by an Eshelby–Mori-Tanka approach. A three-dimensional (3D) STOMP-CO 2 -R model for a CO 2 reservoir containing a vertical fault was built to analyze a formation containing a reaction network with 5 minerals: albite, anorthite, calcite, kaolinite and quartz. A 3D ABAQUS ® model that maps this STOMP-CO 2 -R model was built for the analysis using STOMP-CO 2 -R/ABAQUS ® . The results show that after a long period of CO 2 injection the mineralogical changes significantly reduced the permeability and elastic modulus of the reservoir in front of the fault leading to a reduction of the pressure margin to fracture at and beyond the injection location. The impact of reactive transport of CO 2 on the geomechanical properties of reservoir rocks and seals are studied in terms of mineral composition changes that affect the rock stiffness, stress and strain distributions, and pressure margin to fracture. [ABSTRACT FROM AUTHOR]