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Effects of CO2 on seismic wave speed in Fontainebleau sandstone
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- Author / Creator
- Chowdhury, Md Mizanul Huq
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In geological sequestration CO2 leakage is a vital concern; consequently monitoring and verifying the subsurface movement and phase behaviour of the injected CO2 is very important to ensure the integrity of the reservoir. Seismic methods are thought to be one way to monitor the changes in subsurface because the seismic velocities are sensitive to a rock's pore space content. The study of the effect of CO2 on seismic wave propagation is scientifically interesting because CO2 can exist in gas, liquid, and supercritical fluid phases over the modest temperature and pressure ranges; CO2's critical point lies near 31' C and 7.4 MPa. We have carried out a series of ultrasonic pulse transmission experiments on several samples of fully CO2 saturated Fontainebleau sandstone over pore fluid pressure ranges of 1 MPa to 20 MPa and at two constant temperatures below (21' C) and above (50' C) the critical temperature. These ranges were chosen to cross the gas-liquid and gas-supercritical transitions, respectively. We have noticed a 1.5-2% P-wave speed reduction in our gas to liquid transition while other two transitions show gradual changes. The main motivation of this work is to obtain a good understanding of the rock physics involved with CO2 as pore fluid. This work also provides an idea of remote seismic detectability of CO2 in the monitoring process.
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- Graduation date
- Fall 2014
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.