Since 2004, scientific investigations on underground storage of CO₂ had been conducted within a context of several large-scale national research-projects, with rich international participation. Of primary interest were the specific processes during the injection of CO₂ and the subsequent propagation of the CO₂ plume within the storage horizon. Datasets were gathered and documented by a comprehensive monitoring programme. In the long run, these data also helped to safely operate the storage complex and and assess the impact on its environment.
The co-ordination of these works was done by the German Research Centre for Geosciences in Potsdam. All projects were supervised by the mining authority of the state of Brandenburg (LBGR) in Cottbus. From the beginning, the city of Ketzin/Havel has supported the overall project.
 

At Ketzin, the layers are not lying horizontally but are arched (see also schematic profile). The CO₂ was injected into the reservoir at a depth of about 630 to 650 m at the southern flank of this dome-like structure. For this, the injection well Ktzi 201 was used, which besides the other deep wells (Ktzi 200, 202 and 203) also serves as an observation well to monitor the distribution of the CO₂ in the underground.

The reservoir is sealed by overlying 165 m thick shaly cap rocks. These cap rocks, together with the dome-like structure, ensure a controlled and limited distribution of the CO₂. The shallower well P300 ends above these cap rocks and is used for the monitoring of their tightness.