Borehole Effects On Downhole Seismic Measurements
An exact formulation for borehole coupling, which is valid for all frequencies and all azimuthally symmetric and nonsymrnetric components, is given in this paper. The borehole effects on downhole measurements are studied in detail as functions of frequency, incidence angle and polarization of an...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Technical Report |
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Massachusetts Institute of Technology. Earth Resources Laboratory
2012
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| Online Access: | http://hdl.handle.net/1721.1/75196 |
| _version_ | 1826202567212793856 |
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| author | Peng, Chengbin Cheng, C. H. Toksoz, M. N. |
| author2 | Massachusetts Institute of Technology. Earth Resources Laboratory |
| author_facet | Massachusetts Institute of Technology. Earth Resources Laboratory Peng, Chengbin Cheng, C. H. Toksoz, M. N. |
| author_sort | Peng, Chengbin |
| collection | MIT |
| description | An exact formulation for borehole coupling, which is valid for all frequencies and all
azimuthally symmetric and nonsymrnetric components, is given in this paper. The borehole
effects on downhole measurements are studied in detail as functions of frequency,
incidence angle and polarization of an incident wave as well as geophone orientation.
We found that correction of the borehole effect for downhole measurements should be
made for frequencies above 500 Hz in a hard formation. In a soft formation, if the
incidence angle is well away from the resonance angle for a SV incidence, no borehole
correction is needed for frequencies below 300 Hz; while for frequencies above 300 Hz,
the borehole can cause severe problems on downhole measurements. The borehole can
also significantly alter the particle motion direction such that horizontal components
rotation from data itself is unreliable for experiments with frequencies above 1 kHz in
the hard formation and around 500 Hz in the soft formation. |
| first_indexed | 2024-09-23T12:09:34Z |
| format | Technical Report |
| id | mit-1721.1/75196 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T12:09:34Z |
| publishDate | 2012 |
| publisher | Massachusetts Institute of Technology. Earth Resources Laboratory |
| record_format | dspace |
| spelling | mit-1721.1/751962019-04-12T21:17:25Z Borehole Effects On Downhole Seismic Measurements Peng, Chengbin Cheng, C. H. Toksoz, M. N. Massachusetts Institute of Technology. Earth Resources Laboratory Peng, Chengbin Cheng, C. H. Toksoz, M. N. An exact formulation for borehole coupling, which is valid for all frequencies and all azimuthally symmetric and nonsymrnetric components, is given in this paper. The borehole effects on downhole measurements are studied in detail as functions of frequency, incidence angle and polarization of an incident wave as well as geophone orientation. We found that correction of the borehole effect for downhole measurements should be made for frequencies above 500 Hz in a hard formation. In a soft formation, if the incidence angle is well away from the resonance angle for a SV incidence, no borehole correction is needed for frequencies below 300 Hz; while for frequencies above 300 Hz, the borehole can cause severe problems on downhole measurements. The borehole can also significantly alter the particle motion direction such that horizontal components rotation from data itself is unreliable for experiments with frequencies above 1 kHz in the hard formation and around 500 Hz in the soft formation. ERL/nCUBE Geophysical Center for Parallel Precessing Massachusetts Institute of Technology. Borehole Acoustics and Logging Consortium 2012-12-04T15:33:55Z 2012-12-04T15:33:55Z 1992 Technical Report http://hdl.handle.net/1721.1/75196 Earth Resources Laboratory Industry Consortia Annual Report;1992-13 application/pdf Massachusetts Institute of Technology. Earth Resources Laboratory |
| spellingShingle | Peng, Chengbin Cheng, C. H. Toksoz, M. N. Borehole Effects On Downhole Seismic Measurements |
| title | Borehole Effects On Downhole Seismic Measurements |
| title_full | Borehole Effects On Downhole Seismic Measurements |
| title_fullStr | Borehole Effects On Downhole Seismic Measurements |
| title_full_unstemmed | Borehole Effects On Downhole Seismic Measurements |
| title_short | Borehole Effects On Downhole Seismic Measurements |
| title_sort | borehole effects on downhole seismic measurements |
| url | http://hdl.handle.net/1721.1/75196 |
| work_keys_str_mv | AT pengchengbin boreholeeffectsondownholeseismicmeasurements AT chengch boreholeeffectsondownholeseismicmeasurements AT toksozmn boreholeeffectsondownholeseismicmeasurements |