Multiphysics Proxy Modeling for Risk Assessment during CCS

Abstract:

Concerns over long-term geologic carbon storage necessitate the development of risk estimation methodologies. Geomechanical fault activation and fracturing and subsequent leakage pose potential threats to the integrity of geologic carbon storage, yet accurate evaluation of these risks remains challenging. Evaluating these threats requires coupled multiphysics simulations of the subsurface accounting for the range of variability in fault zone and aquifer parameters. However, it can be computationally expensive to perform multiple sets of simulations with realizations that span the uncertainties of these parameters. Simpler reduced-order models that neglect or approximate the coupling mechanisms have been suggested in the literature; however, they often lack predictive power in strongly coupled systems, which leads to a lack of confidence in their use in quantifying risk. Therefore, faster models are needed to quantify the risks associated with CO₂ storage in the subsurface while maintaining the coupling between different phenomena. Our work examines the development of a proxy modeling methodology focusing on the leakage risk of CO₂ from a deep saline aquifer into a shallow aquifer and the accompanying geomechanical risk. We examine a novel simulation methodology specifically targeting high-resolution thermo-hydo-mechanical numerical modeling of CO₂ injection and subsequent migration into saline aquifers for use in developing multiphysics proxy models. We find that combination of proxy modeling and simulation methodology holds promise for aiding in geologic carbon storage risk estimation by increasing proxy model accuracy while reducing computational cost.