Preliminary field study on CO₂ dispersion from fracture zone in shallow water saturated formation

The potential of leakage in a geological CO2 sequestration project should be an important consideration since it may affect the effectiveness of adequate injected carbon dioxide (CO2). Leakage pathway is often associated with cracks due to geological structures such as fault lines and fracture or through the wellbores. Therefore, it is necessary to understand discontinuities of rock and CO2 movement through the leakage pathway. From this point of view, an engineered analogue test field for CO2 dispersion phenomena has been constructed at ITO campus, Kyushu University (known as the INAS test field site) in order to investigate CO2 gas dispersion or diffusion phenomena used with two drilled wellbores 100 m in depth. The wellbore camera was utilized in two wellbores which were drilled to track the discontinuities along the side wall of the wellbores. The baseline observation was carried out by using multiparameter (MP) TROLL 9000 to measure in situ groundwater parameters such as pH, temperature, pressure and conductivity, and mass spectrometer to analyze groundwater chemistry.