Robust simulation of sharp-interface models for fast estimation of CO₂ trapping capacity in large-scale aquifer systems

Modeling geological carbon storage represents a new and substantial challenge for the subsurface geosciences. To increase understanding and make good engineering decisions, containment processes and large-scale storage operations must be simulated in a thousand-year perspective. Large differences in spatial and temporal scales makes it prohibitively expensive to compute the fate of injected CO₂ using traditional 3D simulators. Instead, accurate forecast can be computed using simplified models that are adapted to the specific setting of the buoyancy-driven migration of the light fluid phase.

This paper presents a family of vertically integrated models for studying the combined large-scale and long-term effects of structural, residual, and solubility trapping of CO₂. The models are based on an assumption of a sharp interface separating CO₂ and brine and can provide a detailed inventory of the injected CO₂ volumes over periods of thousands of years within reasonable computational time. To be compatible with simulation tools used in industry, the models are formulated in a black-oil framework. The models are implemented in MRST-co2lab, which is an open community software developed especially to study and optimize large-scale, long-term geological storage of CO₂. The resulting simulators are fully implicit and handle input from standard geomodeling tools.