Abstract

Abstract

Experimental Studies on Seismic Monitoring of CO2 in Geological Sequestration
Journal of Groundwater Hydrology, 47, 1, 29-44, 2005.
Xue Ziqiu, Ohsumi Takashi

Laboratory experiments were conducted to measure P-wave velocity and deformation strain changes during injection of CO2 into water-saturated Tako sandstone. The rock sample was cylindrical, with its axial parallel to the bedding plane, and fluids of water and CO2 were injected from bottom end of the sample. P-wave velocity changes caused by CO2 injection are typically about 10% , and -16% for the injection of supercritical CO2. Such changes in velocity show that the seismic monitoring method is useful in mapping CO2 movement in aquifers. Strain measured normal to the bedding plane was greater than that parallel to the bedding plane during CO2 injection. In the case of supercritical CO2 injection, bedding plane showed a strong effect on strain measurement. Such strain changes suggest the possibility of monitoring rock mass deformation by using borehole tiltmeters at geological sequestration sites.