Abstract
Hydrophone VSP (vertical seismic profiling) experiment is under way as a technique for detecting subsurface water-permeable cracks by use of boreholes and for evaluating their characteristics (permeability index, crack direction, dip angle). In this report, tube waves observed by hydrophone VSP are subjected to analysis for the determination of water-permeable crack characteristics, the impact caused by errors in the value inputted for analysis is estimated, and a model calculation is performed in case there is no agreement between data from the borehole and data from VSP, all for examining the VSP records for accuracy. When an error rate of 15% is given to the tube wave/P-wave amplitude ratio, a change of 40% or lower results in the permeability index, and a change of 10deg or less in the dip angle, which means that an error in the amplitude ratio does not affect the analysis very much. Changes in the amplitude ratio resulting from changes in crack direction and dip angle differ, dependent on the offset rate. When angular differences among plural crack directions are within 90deg and dip angles within 60deg, the result of analysis represents the average characteristics of the plural cracks. 7 refs., 5 figs., 2 tabs.
Kiguchi, T;
Ito, H;
Kuwahara, Y;
Miyazaki, T;
[1]
Yabuuchi, S;
Hasegawa, K
[2]
- Geological Survey of Japan, Tsukuba (Japan)
- Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan)
Citation Formats
Kiguchi, T, Ito, H, Kuwahara, Y, Miyazaki, T, Yabuuchi, S, and Hasegawa, K.
Accuracy of parameters of permeable fractures by hydrophone VSP; Hydrophone VSP ni yoru tosuisei kiretsu no tokusei hyoka no seido.
Japan: N. p.,
1997.
Web.
Kiguchi, T, Ito, H, Kuwahara, Y, Miyazaki, T, Yabuuchi, S, & Hasegawa, K.
Accuracy of parameters of permeable fractures by hydrophone VSP; Hydrophone VSP ni yoru tosuisei kiretsu no tokusei hyoka no seido.
Japan.
Kiguchi, T, Ito, H, Kuwahara, Y, Miyazaki, T, Yabuuchi, S, and Hasegawa, K.
1997.
"Accuracy of parameters of permeable fractures by hydrophone VSP; Hydrophone VSP ni yoru tosuisei kiretsu no tokusei hyoka no seido."
Japan.
@misc{etde_622761,
title = {Accuracy of parameters of permeable fractures by hydrophone VSP; Hydrophone VSP ni yoru tosuisei kiretsu no tokusei hyoka no seido}
author = {Kiguchi, T, Ito, H, Kuwahara, Y, Miyazaki, T, Yabuuchi, S, and Hasegawa, K}
abstractNote = {Hydrophone VSP (vertical seismic profiling) experiment is under way as a technique for detecting subsurface water-permeable cracks by use of boreholes and for evaluating their characteristics (permeability index, crack direction, dip angle). In this report, tube waves observed by hydrophone VSP are subjected to analysis for the determination of water-permeable crack characteristics, the impact caused by errors in the value inputted for analysis is estimated, and a model calculation is performed in case there is no agreement between data from the borehole and data from VSP, all for examining the VSP records for accuracy. When an error rate of 15% is given to the tube wave/P-wave amplitude ratio, a change of 40% or lower results in the permeability index, and a change of 10deg or less in the dip angle, which means that an error in the amplitude ratio does not affect the analysis very much. Changes in the amplitude ratio resulting from changes in crack direction and dip angle differ, dependent on the offset rate. When angular differences among plural crack directions are within 90deg and dip angles within 60deg, the result of analysis represents the average characteristics of the plural cracks. 7 refs., 5 figs., 2 tabs.}
place = {Japan}
year = {1997}
month = {Oct}
}
title = {Accuracy of parameters of permeable fractures by hydrophone VSP; Hydrophone VSP ni yoru tosuisei kiretsu no tokusei hyoka no seido}
author = {Kiguchi, T, Ito, H, Kuwahara, Y, Miyazaki, T, Yabuuchi, S, and Hasegawa, K}
abstractNote = {Hydrophone VSP (vertical seismic profiling) experiment is under way as a technique for detecting subsurface water-permeable cracks by use of boreholes and for evaluating their characteristics (permeability index, crack direction, dip angle). In this report, tube waves observed by hydrophone VSP are subjected to analysis for the determination of water-permeable crack characteristics, the impact caused by errors in the value inputted for analysis is estimated, and a model calculation is performed in case there is no agreement between data from the borehole and data from VSP, all for examining the VSP records for accuracy. When an error rate of 15% is given to the tube wave/P-wave amplitude ratio, a change of 40% or lower results in the permeability index, and a change of 10deg or less in the dip angle, which means that an error in the amplitude ratio does not affect the analysis very much. Changes in the amplitude ratio resulting from changes in crack direction and dip angle differ, dependent on the offset rate. When angular differences among plural crack directions are within 90deg and dip angles within 60deg, the result of analysis represents the average characteristics of the plural cracks. 7 refs., 5 figs., 2 tabs.}
place = {Japan}
year = {1997}
month = {Oct}
}