NAME

     pkmig - Event Migrate Picks Using a Velocity Field

SYNOPSIS

     pkmig [-VELvelocity] [-Ooutput] [-Ptimepicks] or  [-POdepth-
     picks]  [-dtdtms] [-ismooismooth] [-ieventievent] [-iunitsi-
     units]

DESCRIPTION

     pkmig converts xsd time picks to xsd  depth  picks  using  a
     velocity  field  dataset.  Each pick in a segment (event) is
     moved from the surface to the subsurface along a ray  traced
     through  the  velocity  field.  The initial direction of the
     ray is computed from the ray's time dip and the  appropriate
     surface velocity.  The ray is traced for a time equal to the
     two-way travel time of that pick.  The  inputs  are  a  file
     containing  xsd  picks,  a  velocity field, and command line
     arguments.  The outputs are a file containing  the  migrated
     events and a file containing the depth picks.

  Command line arguments
     -VELvelocity
          Enter the name of the input velocity dataset after typ-
          ing -VEL.  This is a USP-formatted dataset where sample
          values are interval velocities.

     -Ooutput
          Enter the name of the output dataset after  typing  -O.
          This  is  a  USP-formatted file containing the migrated
          events.

     -Ptimepicks
          Enter the name of the file containing  the  input  time
          picks after typing -P.

     -POdepthpicks
          Enter the name of the file to contain the output  depth
          picks after typing -PO.

     -dtdtms
          Enter the time sample increment in ms after typing -dt.

     -ismooismooth
          Enter the smoothing factor  after  typing  -ismoo.  The
          smoothing parameter defines the number of passes of a 3
          point smoother over  the  velocity  field.  Recommended
          value is 3.

     -ieventievent
          Enter the segment number after  typing  -ievent.   This
          number  should  represent  the  number of the event for
          which you want the rays to be  plotted  on  the  output
          event tape. If this value is blank or zero no rays will
          be plotted on the output.

     -iunitsiunits
          Enter the flag for the desired  type  of  output  units
          after  typing -iunits.  If iunits is set to 0, the out-
          put picks will be in trace and sample numbers. If  iun-
          its  is  less  than or greater than 0, the output picks
          will be in their  physical  x  and  z  units  (feet  or
          meters).

     -h   Enter -h for online help. The  program  will  terminate
          after printing this.

     -?   Enter this (or '-?' if you are running in  c-shell)  to
          get  online  help.   The  program  will terminate after
          printing this.

COMMENTS

     WARNING:  The horizontal (x) spacing of the picks must match
     that of the velocity field.

     Note: The picks are located on the Sun. When executing  this
     code on the Cray, it will require copying picks to the Cray,
     executing pkmig, and then copying the picks back to the Sun.

     To automate this you can create a script on your Sun to copy
     picks to the Cray, execute pkmig, and copy picks back to the
     Sun. An example of such a script is:

     /m/t1/apcexpl/explprod.cray/phase1/trcgeop/mbs/pat/pkmig.run

     You may copy this script to the Sun and give it a try.  Com-
     ments on how to use the script are included in the script.

BUGS

     None known.

AUTHOR

     N. D. Whitmore, Jr.

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved
          an affiliate of BP America Inc.