Abstract
Monitoring and detecting CO2 injected into water-saturated sandstone with joint seismic and resistivity measurements
Exploration Geophysics, 42, 1, 58-68, 2011.
Kim Jongwook, Matsuoka Toshifumi, Xue Ziqiu
As part of basic studies of monitoring carbon dioxide (CO2) storage using
electrical and seismic surveys, laboratory experiments have been conducted
to measure resistivity and P-wave velocity changes due to the injection
of CO2 into water-saturated sandstone. The rock sample used is a cylinder
of Berea sandstone. CO2 was injected under supercritical conditions (10
MPa, 40 degrees Celsius). The experimental results show that resistivity
increases monotonously throughout the injection period, while P-wave velocity
and amplitude decrease drastically due to the supercritical CO2 injection.
A reconstructed P-wave velocity tomogram clearly images CO2 migration in
the sandstone sample. Both resistivity and seismic velocity are useful
for monitoring CO2 behaviour. P-wave velocity, however, is less sensitive
than resistivity when the CO2 saturation is greater than ~20%. The result
indicates that the saturation estimation from resistivity can effectively
complement the difficulty of CO2 saturation estimations from seismic velocity
variations. By combining resistivity and seismic velocity we were able
to estimate CO2 saturation distribution and the injected CO2 behaviour
in our sample.BR>
Copyright(C) Research Institute of Innovative
Technology for the Earth (RITE). All rights reserved.