Sequential Model Coupling for Feasibility Studies of CO2 Storage in Deep Saline Aquifers

Modelling carbon dioxide (CO2 ) storage in saline aquifers on a reservoir scale is very demanding with respect to computational cost. In realistic scenarios, large heterogeneous geometries need to be described. In addition, the governing physical processes are very complex. The models need to take into account nonisothermal, multiphase, and compositional processes that occur during CO2 storage. However, in most cases, it is not necessary to describe all the physical processes for the whole simulation time period. The processes which dominate during CO2 storage operations vary over time. This time-dependent behaviour allows for the use of models of reduced/adapted complexity for the description of the dominant processes within a given timescale. It is shown that by coupling these models of reduced complexity, the model efficiency can be increased without neglecting the relevant phenomena. Sequential coupling of models thus represents a first step in the direction of increased model efficiency.