Laboratory experiments and field study for the detection and monitoring of potential seepage from CO_2 storage sites

摘要

Potential CO_2 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; CO_2 can be injected from the bottom. Two columns are used to simulate the impact of CO_2 on soils; while the third one, which is larger in size, simulates CO_2 seepage in aquatic environments. The main results of the laboratory experiments indicate that increased levels of CO_2 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 CO_2. 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 CO_2 bubbles in water.