Determination Of The Orientation Of Open Fractures From Hydrophone VSP
Open fractures are of interest in many areas such as ground water contamination, hazardous waste disposal, oil and gas recovery, and geothermal energy extraction. In borehole geophysics and engineering, fractures are usually located by acoustic borehole televiewer logging, however, not all of the...
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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/1721.1/75243 |
| _version_ | 1826211368044331008 |
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| author | Lee, Jung Mo Toksoz, M. Nafi |
| author2 | Massachusetts Institute of Technology. Earth Resources Laboratory |
| author_facet | Massachusetts Institute of Technology. Earth Resources Laboratory Lee, Jung Mo Toksoz, M. Nafi |
| author_sort | Lee, Jung Mo |
| collection | MIT |
| description | Open fractures are of interest in many areas such as ground water contamination, hazardous waste disposal, oil and gas recovery, and geothermal energy extraction. In
borehole geophysics and engineering, fractures are usually located by acoustic borehole
televiewer logging, however, not all of the observed fractures are permeable. The
caliper log, on the other hand, provides the information about the change of borehole
diameter, but increasing diameter does not prove the existence of open fractures. Nor
can the combination of these two methods-televiewer logs and caliper logs-provide
direct information about open fractures. However, tube waves, generated by P- and/or
S-waves in hydrophone vertical seismic profiling (VSP) or cross-well seismic profiling
section can detect open fractures intersecting the borehole.
A new technique is developed to determine the orientation of open fractures using
the normalized ratios of an S-wave-generated tube wave to a P-wave-generated tube
wave. The fracture orientations determined by this method represent the average over
the fracture planes for large radii, generally on the order of a meter. Numerical tests
show that, given a good experiment design, a set of two independent measurements of
these ratios with polarization information, or a set of three independent measurements
without polarization information, provides a unique solution. The developed technique
is stable in the presence of noise.
This technique is applied to hydrophone VSP data from the Kent Cliffs test well
in southeastern New York state. The orientations of the three major fractures which
generate primary tube waves in the seismic profiling sections are obtained. The results
agree well with the orientations measured from the borehole televiewer images in general.
Any discrepancy may be attributed to the difference between the sampling size of this
method and the borehole televiewer, to the deviation of rays from the straight lines
due to inhomogeneity, and/or to possible BH-wave motion due to anisotropy and lateral
inhomogeneity. |
| first_indexed | 2024-09-23T15:05:06Z |
| format | Technical Report |
| id | mit-1721.1/75243 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T15:05:06Z |
| publishDate | 2012 |
| publisher | Massachusetts Institute of Technology. Earth Resources Laboratory |
| record_format | dspace |
| spelling | mit-1721.1/752432019-04-10T18:05:18Z Determination Of The Orientation Of Open Fractures From Hydrophone VSP Lee, Jung Mo Toksoz, M. Nafi Massachusetts Institute of Technology. Earth Resources Laboratory Lee, Jung Mo Toksoz, M. Nafi Open fractures are of interest in many areas such as ground water contamination, hazardous waste disposal, oil and gas recovery, and geothermal energy extraction. In borehole geophysics and engineering, fractures are usually located by acoustic borehole televiewer logging, however, not all of the observed fractures are permeable. The caliper log, on the other hand, provides the information about the change of borehole diameter, but increasing diameter does not prove the existence of open fractures. Nor can the combination of these two methods-televiewer logs and caliper logs-provide direct information about open fractures. However, tube waves, generated by P- and/or S-waves in hydrophone vertical seismic profiling (VSP) or cross-well seismic profiling section can detect open fractures intersecting the borehole. A new technique is developed to determine the orientation of open fractures using the normalized ratios of an S-wave-generated tube wave to a P-wave-generated tube wave. The fracture orientations determined by this method represent the average over the fracture planes for large radii, generally on the order of a meter. Numerical tests show that, given a good experiment design, a set of two independent measurements of these ratios with polarization information, or a set of three independent measurements without polarization information, provides a unique solution. The developed technique is stable in the presence of noise. This technique is applied to hydrophone VSP data from the Kent Cliffs test well in southeastern New York state. The orientations of the three major fractures which generate primary tube waves in the seismic profiling sections are obtained. The results agree well with the orientations measured from the borehole televiewer images in general. Any discrepancy may be attributed to the difference between the sampling size of this method and the borehole televiewer, to the deviation of rays from the straight lines due to inhomogeneity, and/or to possible BH-wave motion due to anisotropy and lateral inhomogeneity. Massachusetts Institute of Technology. Earth Resources Laboratory 2012-12-05T19:49:12Z 2012-12-05T19:49:12Z 1995 Technical Report http://hdl.handle.net/1721.1/75243 Earth Resources Laboratory Industry Consortia Annual Report;1995-04 application/pdf Massachusetts Institute of Technology. Earth Resources Laboratory |
| spellingShingle | Lee, Jung Mo Toksoz, M. Nafi Determination Of The Orientation Of Open Fractures From Hydrophone VSP |
| title | Determination Of The Orientation Of Open Fractures From Hydrophone VSP |
| title_full | Determination Of The Orientation Of Open Fractures From Hydrophone VSP |
| title_fullStr | Determination Of The Orientation Of Open Fractures From Hydrophone VSP |
| title_full_unstemmed | Determination Of The Orientation Of Open Fractures From Hydrophone VSP |
| title_short | Determination Of The Orientation Of Open Fractures From Hydrophone VSP |
| title_sort | determination of the orientation of open fractures from hydrophone vsp |
| url | http://hdl.handle.net/1721.1/75243 |
| work_keys_str_mv | AT leejungmo determinationoftheorientationofopenfracturesfromhydrophonevsp AT toksozmnafi determinationoftheorientationofopenfracturesfromhydrophonevsp |