BMRG

Often data collected in surveys results in a number of files which are numbered sequentially. For example, in down-hole surveys, each file may relate to a down-hole station for a single source effort. There may be a number of components recorded at each station. This would also be the case in walk-a-way surface data collection. BMRG permits one to select a sequence of files, and specific traces in each file to output into a single file.
 bmrg pfix iffile ilfile ifinc iftrc iltrc  
  
 pfix:  =prefix for input file names 
  NOTE:pfix length is no. of invarient charcters
   Ex. If file names run s001 to s090 then pfix=s0
   Ex. If file names run s001 to s132 then pfix=s
 iffile =number of first file (suffix) 
   EXAMPLE:  if file=s001.seg, iffile=001 
  
 ilfile =number of last file (suffix) 
   EXAMPLE:  if file=s092.seg, ilfile=092 
  
 ifinc  =increment for file number (suffix) 
 iftrc  =first trace each file 
 iltrc  =last trace each file

For example, consider a down-hole survey with files w001.seg through w166.seg. The file order in each file is:

 Channel  Component
    1        Vertical   (down-hole)
    2        Radial     (down-hole)
    3        Transverse (down-hole)
    4        Vertical   (ref. phone)
    5        Radial     (ref. phone) 
    6        Transverse (ref. phone)
The reference phone is fixed at the surface and the down hole phone is logged from bottom to surface. We want to collect the transverse down-hole phone, channel 3, and output that to a single file. The command:
bmrg w 001 166 2 3 3
If we want every source effort, the command is:
bmrg w 001 166 1 3 3
Figure 66 shows both cases. Since the source blow is 135 degrees from the vertical, the horizontal T-component will show different polarity of source effort (every trace has the checkered look, peaks against troughs, plotted by elevation).

The data have not been rotated to a standard orientation. The T-component in this example drifts from 313 to 288 degrees azimuth as determined by PCA analysis (see BHOD 10.1.11). Program BTOR 12.2.2 applies the PCA results to data headers, and program BROT 12.2.4 actually does the rotation to a standard orientation (with respect to the source axis for horizontal component hammer blows).

Figure 66: BMRG: A)is plot of all shot efforts (166 traces) and B) is plot of only very other shot (83 traces). NOTE: data are not rotated to a standard orientation, azimuth of T-component drifts up the hole.
\includegraphics[scale=.7]{Figurebmrg.pdf}