Monitoring Carbon Dioxide Sequestration Using Electrical Resistance Tomography (ERT) [electronic resource] : Sensitivity Studies
- Washington, D.C. : United States. Dept. of Energy, 2001.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 21 : digital, PDF file
- Additional Creators:
- Lawrence Berkeley National Laboratory
United States. Department of Energy
United States. Department of Energy. Office of Scientific and Technical Information
- If geologic formations are used to sequester carbon dioxide (CO₂), monitoring the CO₂ injection will be required to confirm the performance of the reservoir system, assess leaks and flow paths, and understand the geophysical and geochemical interactions between the CO₂ and the geologic minerals and fluids. Electrical methods are well suited for monitoring processes involving fluids, as electrical properties are sensitive to the presence and nature of the formation fluids. High resolution tomographs of electrical properties are now possible using it 3D technique called electrical resistance tomography (ERT). Surveys are commonly conducted utilizing vertical arrays of point electrodes in a cross-well configuration. Recent field results obtained using steel well casings as electrodes are promising. When 3D ERT imaging can be performed using existing well casings as long electrodes, the need for additional drilling of observation wells is minimized. Using a model patterned after an oil field undergoing CO₂ flood, forward and inverse simulations of ERT surveys have been run to test the sensitivity of the method to changes resulting from CO₂ migration. Factors considered include resistivity contrast, anomaly proximity to electrodes, anomaly size and shape, measurement noise, and the electrode configuration used to perform the measurements. Field data suggest that CO₂ migration changes the resistivity of a layer, producing an anomalous region. In our numerical study, the anomalous region s resistivity ranges from 0.2 to 10 times that of the initial value. Its geometry ranges from a thin, horizontal finger to a planar, horizontal mass having vertical protrusions simulating leakage of CO₂ through caprock. Results of simulations run assuming that well casings are used as long electrodes or with arrays of point electrodes (simulating high resolution surveys) show useful information for even the narrowest simulated CO₂ fingers.
- Published through SciTech Connect.
1st National Conference on Carbon Sequestration, Washington, DC, May 14 - May 17, 2001.
Newmark, R L; Daily, W D; Ramierz, A L.
- Funding Information:
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