genbhodV - BSU program generates bash scripts to determine down-hole tool orientation by PCA VERTICAL IMPACT SOURCE
genbhodV [ no options ]
Basic Seismic Utilities (BSU) EXPERIMENTAL program generates 4 bash script files which can be run to determine 3-C geophone orientations based on the large particle motion. The concept is experimental. In short, one uses the horizontal motion of the Rayleigh wave in the context of the experimental setup to determine horizontal tool orientation. It works well for the reference phone, but your mileage may vary down-hole (depending on the depth of penetration of the Rayleigh wave, and on the subsurface nodal pattern of the Rayleigh wave. Two of the scripts are for a surface, reference geophone, and two are for the down-hole geophone. The Principal Component Analysis (PCA) is actually done by the program, bhod. There are many assumptions made in this code! The code is hard wired for the specific data collection method of the author.
Users are advised to consult the comments in the source code, genbhod.f, and the BSU documentation (BSU User’s Manual).
EXAMPLE:
genbhod
Enter 1char_ALPHA PREFIX
w
enter FIRST FILE NUBER (<=3digits)
1
enter LAST FILE NUMBER (<=3digits)
165
enter azimuth of bowspring (R-component)
45
The above exchange between the program (italics) and user specifies that files w001.seg through w165.seg will be scaled on the vertical component (for convenience in QC plots) and renamed hxxx.seg. The hxxx.seg files will undergo PCA by program,bhod, and tool azimuth will resolve R-component toward 45 degrees azimuth. The user is responsible for changing the permissions on the bash scripts to execute.
In general, one will only run gobhod and gobrunbhod (the down- hole tool scripts). Once down-hole tool orientation has been determined (file bhod.lst from bhod), one will want to insert the horizontal component orientations into headers (program btor). This will be followed by a rotation into alignment with the source polarization with program brot.
DOWN-HOLE TOOL
|
gobhod |
Scales and subtracts alternating down-hole signals, moving the result to hxxxyyy.seg files. Run this file first in directory where 6 channel field records reside. |
gorunbhod
Applies PCA analysis to horizontal traces (2 and 3). This bash script is run second in the directory where the hxxxyyy.seg files reside. Basically, this script executes bhod for each hxxxyyy.seg file.
REFERENCE-PHONE
gobhodR
Scales and subtracts alternating reference signals, moving the result to hxxxyyy.seg files. Run this file first in directory where 6 channel field records reside.
gorunbhodR
Applies PCA analysis to horizontal traces (5 and 6). This bash script is run second in the directory where the hxxxyyy.seg files reside. Basically, this script executes bhod for each hxxxyyy.seg file.
bhelp(1), genbhod(1), bhod(1), bsum(1), bscl(1), btor(1), brot(1)
Michaels, P., 2001, "Use of Principal Component Analysis to Determine Down-Hole Tool Orientation and Enhance SH-Waves", Journ. Environmental and Engineering Geophysics, Vol. 6, No. 4, December, p175-183.
No known bugs. However, you may have to manually edit the scripts depending on how much motion is available in the horizontal plane.
Copyright © 2017 by Paul Michaels
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
P. Michaels, PE. <pm@cgiss.boisestate.edu>