Laboratory experiments and field study for the detection and monitoring of potential seepage from CO2 storage sites

Potential CO2 seepages from geological storage sites or from the injection rig may affect the surrounding environment. To develop reliable detection techniques for such seepages a laboratory rig was designed that is composed of three vertical Plexiglas columns. The columns can be filled with sediments and water; CO2 can be injected from the bottom. Two columns are used to simulate the impact of CO2 on soils; while the third one, which is larger in size, simulates CO2 seepage in aquatic environments. The main results of the laboratory experiments indicate that increased levels of CO2 generate a quick drop in pH. Once the seepage is stopped, a partial recovery towards the initial values of pH is recorded. The outcomes of the laboratory experiments on the aquatic seepage are compared with observations from a submarine natural emission of CO2. In this natural underwater seepage multi-parametric probes and laboratory analysis were used to analyze the composition and the chemical effects of the emitted gas; basic acoustic techniques were tested as tools for the prompt detection of CO2 bubbles in water.