A Multiscale Finite Element Method For Two-phase Flow Simulation of CO2 In Heterogeneous Saline Aquifers
Résumé
Multiphase fluid flow dynamics of liquid-like supercritical CO2 are very sensitive to layered and structural heterogeneities in deep saline aquifers. To fill the gap between recent advances in geological modeling of aquifers and available computer simulation technology for CO2 storage, development of novel multiscale methods is needed. This work presents a multiscale mixed-hybrid finite element model for two-phase flow of carbon dioxide considering viscous and gravity forces, and its dissolution in the aqueous phase as well. The numerical implementation is based on a coarsening scheme of the global pressure equation, whereas the fine grid is decomposed to many coarse sub-levels. During the sequential iterative solution involving fluid pressure and CO2 saturation equations, only coarse-scale pressure equations are solved. Thus, the computational burden usually involved in nonlinear updating of the phase mobilities is greatly reduced. The obtained coarse-scale pressure solutions are used to reconstruct fine-scale velocities in each coarse sub-domain using memorized local basis functions. The method is validated on selected international benchmark examples, such as SPE10 project for simulation of enhanced oil recovery, and CO2 injection into Johansen formation (Norway). Many hypothetical simulations relevant to the context of the heterogeneous Dogger aquifer in Paris basin (France) demonstrate the usefulness of the multiscale method as a rapid tool to evaluate uncertainty in permeability on lateral CO2 migration and formation storage capacity. Current performances of the developed method enable these 3D simulations to be proceeded very rapidly on commodity hardware unleashing simulation opportunities as required by future industrial and large scale CO2 storage projects.