Coupled Thermo-Hydro-Mechanical Modeling of CO2 Injection in A Water Formation
Abstract
This thesis proposed a new coupling model for the thermo-hydro-mechanical process during CO2 injection in the water formation by coupling the geomechanical and fluid flow models. This thesis aims to couple fluid flow with geomechanical effects, predict the magnitude of formation strain and pore pressure change, and evaluate the over-burden and under-burden formation stabilities for carbon storage projects in the water formation.
The new proposed model uses a finite-difference simulator, ECLIPSE, and an in-house finite-element simulator, Geo3D. The mechanical model is featured by the non-linear stress-strain relations, so it is more accurate to handle geomechanical effects. The reservoir simulator, ECLIPSE, calculates the pressure and temperature distribution, and the pressure and temperature variations and the strain field changes are transferred between two models via an interface program.
In order to validate the coupling model, the study is divided into two parts. First, we compare analytical and numerical solutions of reservoir compaction and ground surface subsidence induced by pressure and temperature changes to validate the ability of Geo3D in handling geomechanical effects. The errors in ground surface subsidence and reservoir compactions are around 0.023% and 0.17%, respectively. Second, the coupling model is validated by Terzaghi’s 1D compaction problem using the fixed total stress method. The validation evaluates pressure distribution and formation compaction.
The application of the coupling model is conducted in a conceptual model with a radial grid system. Stress polygons are applied to analyze the under- and over-burden stability at different time steps. Pressure distribution and strain field are also compared between coupled model and the ECLIPSE-only model. Overall, the coupling of the fluid flow model and geomechanical model has helped us obtain more accuracy in reservoir simulation and provided us with a tool to evaluate the formation stability.
Citation
Fu, Jia (2021). Coupled Thermo-Hydro-Mechanical Modeling of CO2 Injection in A Water Formation. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /195287.