Abstract
In crosswell observation of electromagnetic tomography, now there is no feasible way to calibrate the in-situ radiation constant, while the effect of induced wave-field always exists in observational data. Therefore the absorption coefficient obtained by a common-used image reconstruction method is only a relative value. The consistency of tomograms in linked profiles inevitably is affected seriously. An improved equation involving the effect of induced wave-field and an alternative tracing method to calculate the in-situ radiation constant is proposed in the present paper. Based on the results from a series of parameter calibration performed in water and the experiments with rock samples, the standard meter readings of borehole electromagnetic systems, types EW-1 and JWQ-3, are accurately defined here. Additionally, frequency reduction and boundary smoothing of linked profiles are discussed. In research on groundwater prospecting in Tanggongta, Inner-Mongolia, we used the above mentioned method and obtained the tomograms of linked profiles with good consistency. The absorption coefficient in the tomogram are not only reasonable and reliable, but also coincided with the result from rock parameter measurement. The depth, extension direction and water-bearing structure of two aquifers were well detected. This result correctly guides hydrologic drilling there.
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References
Betlofski A D, 1971. Electromagnetic Wave Method for Physics of Earth’s Interior. Nedra
Betlofski A D and Bobo A A, 1977. Guidebook of Electromagnetic Wave Method for Mining Geophysics. Nedra
Cao J X, Zhu J S, and Yan Z Q, 1995. Fracture imaging using electromagnetic crosshole tomography. Proc. 3rd SEGJ/SEG International Symposium, Geotomography, Tokyo, 220–227
Feng R, Chen J G, Guo Q X, et al., 1992. Application of geotomography to civil engineering in urban, Acta Geophysica Sinica, 35, Suppl., 348–357 (in Chinese)
Feng R, Lou J D, Zhou H N, et al., 1994. Application of geotomography to hydroelectric engineering, Chen Y T (ed), Advances in Solid Earth Geophysics in China, Beijing: China Ocean Press, 397–407 (in Chinese)
Feng R, Wu J P, and Sun C C, et al., 1995. Prospecting for auriferois ore by electromagnetic tomography. Proc. International Symposium on Recent Advances in Exploration Geophysics, Kyoto, 90–97
Feng R, Lin X M, Tao Y L, Zhou H N, et al., 1996. Geotomographic research on cap rock destruction caused by mining coal seam, Acta Geophysica Sinica, 39(1): 114–124 (in Chinese)
Hao J Q, Zhou J G, and Qiao J H, 1955. The measurement of electromagnetic parameters of rocks in tomography study, Chen Y T (ed), Progress in Observation Techniques of Geosciences and Space Sciences, Beijing: Seismological Press, 455–465 (in Chinese)
Liu L Z, Chang H Y, He J W, and Tang Y M, 1994. Development of geotomography for geophysical exploration, Geological Information and Technique, 10(3): 17–24 (in Chinese)
Mahrer K, 1995. Review of the radio frequency (RIM) method and its utilization in near-surface investigations. The Leading Edge, 14(4): 249–256.
Wu Y R and Xing F T, 1992. Method of Borehole Electromagnetic Wave, Beijing: Geological Press, 237pp (in Chinese)
Wu Y R, Li X G, and Tang Y M, 1994. Field patterns in multisource plane to underground electromagnetic waves method, Acta Geophysica Sinica, 37(2), 245–252 (in Chinese)
Yin J, Feng R and Li Q S, 1992. Maximum entropy image reconstruction in crosshole tomography, Acta Geophysica Sinica, 35(2): 234–241 (in Chinese)
Zhang J T, Zhou H M, and Teng Y T, 1996. The data collection system for electromagnetic geotomography, Earthquake Research in China, 12(1), 35–42 (in Chinese)
Zhou H M, 1995. Design for the EW—1 electromagnetic system, Chen Y T (ed), Progress in Observation Techniques of Geosciences and Space Sciences, Beijing: Seismological Press, 455–465 (in Chinese)
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Contribution No. 96A0078, Institute of Geophysics, SSB, China.
The present project is supported by National Science Foundation of China, contract No. 49374203.
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Feng, R., MA, KX., Guo, H. et al. Electromagnetic tomography: consistency of images and groundwater prospecting. Acta Seimol. Sin. 10, 649–661 (1997). https://doi.org/10.1007/s11589-997-0028-9
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DOI: https://doi.org/10.1007/s11589-997-0028-9