Every CO2 capture and storage chain will contain injection wells. The most important common operations for wells are shut-ins and depressurizations for reservoir characterization, maintenance stops and testing of valves. The aim of this work is firstly to demonstrate the need for experiments on these operations. Secondly, a new experimental set-up is proposed for such experiments. The main conclusion from this paper is that the physical phenomena during shut-ins and depressurizations of CO2 injection wells can be described with models, but that that there are still some uncertainties left. The largest uncertainties occur when the transient flow is rapid and/or CO2 is mixed with water. The proposed experimental set-up consists of a well with casing to be drilled vertically 200-250 meter at the Statoil laboratory in Trondheim, Norway. A U-tube with two legs with different diameter will be suspended in the well. Moreover, water or brine can be added for observing the effects of the H2O-CO2 interaction. The U-tube is to be linked to the existing CO2 transport test facility, which has the necessary vessels, compressor and pump. This rig will hopefully contribute in making CO2 injection wells even safer and more cost efficient.