NAME

     vfill3d - Modify a 3-D Velocity data-set  with  an  interpo-
     lated user input surface.

SYNOPSIS

     level [ -Nntap ] [ -Ootap ] [ -Pptap ] [ -rsirs ] [ -reire ]
     [  -nsins ] [ -neine ] [ -velvel ] [ -zinczinc ] [ -xincxinc
     ] [ -yincyinc ] [ -zbiaszbias ] [ -xbiasxbias ]  [  -ybiasy-
     bias ] [ -V ] [ -? ]

DESCRIPTION

     vfill3d replaces  sample  values  below  a  surface  with  a
     replacement  quantity  (velocity)  for an input 3-D velocity
     dataset. The user defined input surface  is  first  interpo-
     lated.   Three dimensional velocity tapes with moderate com-
     plexity can be created by  piping  together  vfill3d  execu-
     tions, starting with the upward most surface.  This can be a
     realitively painless way of building a 3-D  velocity  model,
     using  interpretive  workstation  output  picks, in depth or
     time which define the surfaces.   No  previsions  have  been
     made for multivalued depth or time surfaces.

     Input picks which define  the  depth  surface  are  linearly
     interpolated,  first in the trace (x) direction, and then in
     the record (y) direction. Input surfaces which do  not  span
     the  entire  model space are extapolate to the model edge by
     repeating the closest (x,y)  depth  value.  The  input  pick
     flat-file  which defines the surface should have the follow-
     ing format, with a at least one blank space  between  values
     on a line:

                      y_location  x_location z_location
                      y_location  x_location z_location
                                           .
                                           .
                                           .
                      y_location  x_location z_location

     Record, trace and sample quantization intervals  along  with
     the  x,y,z origin for record 1, trace 1, and sample 1 of the
     output velocity tape must be supplied. The following command
     line arguments specify how vfill3d will execute:

  Command line arguments
     -Nntap
          Enter input data set name  or  file  immediately  after
          typing  -N;  entering  nothing  specifies a stdin pipe.
          This file should include the complete path name if  the
          file   resides   in  a  different  directory.   Example
          -N/b/vsp/dummy tells  the  program  to  look  for  file
          'dummy' in subdirectory 'vsp' stored in directory b.

     -Ootap
          Enter output data set name or  file  immediately  after
          typing  -O.  This output file is not required when pip-
          ing the output to another process.  The output data set
          also requires the full path name (see above).

     -Ppfile
          Enter the input pick file name which defines  the  sur-
          face.  (no default)

     -rs irs
          first record to process.         (default = 1)

     -re ire
          last record to process.          (default = all)

     -ns ns
          first trace in record to process. (default = 1)

     -ne ne
          last trace in record to process.  (default = all)

     -vel vel
          constant replacement velocity
            (no default)

     -zinc zinc
          Depth or time SAMPLE increment of the  output  velocity
          tape
            (default=1.0)

     -xinc xinc
          distance between adjacent TRACES (defined as  x  direc-
          tion) of the output velocity tape.
            (default=1.0)

     -yinc yinc
          distance between adjacent RECORDS (defined as y  direc-
          tion) of the output velocity tape.
            (default=1.0)

     -zbias zbias
          additive bias, when subtracted for the input pick value
          of z defines the position relative to the first SAMPLE.
            (default=0.0)

     -xbias xbias
          additive bias, when subtracted for the input pick value
          of x defines the position relative to the first TRACE.
            (default=0.0)


     -ybias ybias
          additive bias, when subtracted for the input pick value
          of y defines the position relative to the first RECORD.
            (default=0.0)

     -V   Enter the command line argument '-V' to get  additional
          printout.

     -?   Enter this (or '-?' if you are running in  c-shell)  to
          get online help.  The program terminates after printing
          a list of parameters.

BUGS

       unknown

SEE ALSO

     vttd vi3d

AUTHOR

     W. P. May, 1993

COPYRIGHT

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