CO2 storage in mature hydrocarbon reservoirs is an attractive strategy because infrastructure exists, and the geologyis known from the oil production phase. However, such a strategy requires knowledge of how water and residual oilinfluence the CO2 invasion pattern and storage mechanisms, and conversely how CO2 invasion impacts the behaviorof residual oil ganglia and water. The presence of residual oil in such reservoirs introduces CO2 dissolution in oil andwater that can serve both recovery and storage. Cyclic injection, which often is a realistic option due to low CO2availability, can optimize residual trapping, but reservoir simulation is challenging because flow properties andhysteresis are complex. Little is also known about how this behavior changes when residual oil ganglia are present,and CO2 dissolution alters the oil properties (like viscosity and density), which lead to oil swelling and potentiallychanged wetting state of the porous rock. This project will bring forth advanced pore-scale models for three-phaseflow to investigate how CO2 dissolution in the presence of water and oil affects residual CO2 trapping, oil trapping and mobilization, capillary pressure, relative permeability, and hysteresis behavior over multiple CO2/water invasioncycles in porous rock. The models will be validated against a wide range of advanced CO2/oil/water pore-scaleexperiments provided by our international research partners. The validated pore-scale simulators will be released asopen-source so that users can make their own calculations with the aim at reducing the number of required labmeasurements for CCUS operations. The project will also bring forth suitable macroscale three-phase flow modelsthat capture the effective three-phase flow behavior observed at pore scale, including fluid-ganglia dynamics. This isa first necessary step towards reliable simulation of large-scale CCUS operations in mature hydrocarbon reservoirs.