HR: 0802h
AN: NS11C-0692    [Abstracts]
TI: Three-Dimensional SIP Imaging of Rock Core Sample: Numerical Examples
AU: * Son, J
EM: jsson@kigam.re.kr
AF: Korea Institiute of Geoscience and Mineral Resources, Gwahang-no 92, Yuseong-gu, DaeJeon, 305-350, Korea, Republic of
AU: Kim, J
EM: junho@kigam.re.kr
AF: Korea Institiute of Geoscience and Mineral Resources, Gwahang-no 92, Yuseong-gu, DaeJeon, 305-350, Korea, Republic of
AU: Yi, M
EM: muse@kigam.re.kr
AF: Korea Institiute of Geoscience and Mineral Resources, Gwahang-no 92, Yuseong-gu, DaeJeon, 305-350, Korea, Republic of
AB: SIP (spectral IP) method is known as complex resistivity method because it measures and uses both the magnitude and the phases. SIP method had been mainly used in the field of mineral explorations, but recently SIP method extended its application to the environmental problem, because the real and imaginary components of interpreted complex resistivity are related to the hydraulic property of subsurface. In this study, we used the SIP method to monitor the physical property change during injection of CO₂ gas into a rock sample in the laboratory experiments. For this purpose, we developed three-dimensional SIP modeling and inversion algorithm based on the complex resistivity. We chose the FEM (finite element method) in the modeling algorithm, and we deformed a rectangular grid to a cylinder shape to build the cylinder model, like core samples. To verify the SIP modeling algorithm, we tested our algorithm to a simple isolated block model in homogeneous half space and compare its results with those from three-dimensional integral equation method. Results from the different two methods are quite well matched. To verify the inversion algorithm developed, we applied it to the simple isolated earth model and compared its inversion result with true model. Inverted result shows smoother distribution of conductivity and phase than true model due to the smoothness constraints which are necessary for the stability of inversion. Although the values of conductivity and phase are somewhat underestimated than true value and its distribution is smoother than the given model, we can clearly see the location of conductive anomaly. We could confirm the validity of developed inversion algorithm from these results. After finishing the verification, we applied the developed algorithm to imaging of a rock core model. The core model has conductive and reactive anomalous body at the center of the model. We simulate the SIP survey using 16 electrodes on the surface of the model, and then apply developed inversion to the simulated SIP responses. Although the number of electrode is limited to 16, we can clearly see the conductive and reactive anomalous zone from the inverted results. For we have finished the development of numerical modeling and inversion algorithms, we are going to apply it to the results of laboratory test results in the near future. We hope that our developed algorithm could image the change of physical property during the CO₂ injection into the rock sample.
DE: 0644 Numerical methods
SC: Near-Surface Geophysics [NS]
MN: 2007 Fall Meeting