NAME

     ppobgmt - Compute an Overburden Gradient Field

SYNOPSIS

     ppobgmt [-VELntap] [-OBGotap]  [-DENotap2]  [-nsns]  [-nene]
     [-rsirs]  [-reire]  [-wvwatvel] [-spspsi] [-ascale] [-bexpo]
     [-nhgnhg] [-V] [-?]  [-h]

DESCRIPTION

     ppobgmt will compute an overburden  gradient  field  and  an
     optional density field using a "pseudo presgraf method".

     ppobgmt gets its dataset names and its parameters from  com-
     mand  line  arguments.   This  program  will read a velocity
     dataset to determine the water bottom depth, and it  expects
     the  header value "Dz1000" to be present in the line header.
     The input and output datasets are USP formatted.

  Command line arguments
     -VELntap
          Enter the name of the input velocity field after typing
          -VEL.  This input file should include the complete path
          name if the file  resides  in  a  different  directory.
          Example  -L/b/vsp/dummy  tells  the program to look for
          file 'dummy' in directory 'vsp' stored on the 'b' disk.

     -OBGotap
          Enter the name of the output overburden gradient  field
          after typing -OBG.  This dataset also requires the full
          pathname (see above).

     -DENotap2
          Enter the name of the output density field after typing
          -DEN.   This  dataset  also  requires the full pathname
          (see above). This dataset may not be a pipe.   This  is
          an  optional dataset, and if the name is not present on
          the command line, no density dataset will be written.

     -nsns
          Enter the trace number of the first  trace  to  process
          after  typing  -ns.   The  default  is to use the first
          trace of the record.

     -nene
          Enter the trace number of the  last  trace  to  process
          after typing -ne.  The default is to use the last trace
          of the record.

     -rsirs
          Enter the record number of the first record to  process
          after  typing  -rs.   The  default  is to use the first
          record of the dataset.

     -reire
          Enter the record number of the last record  to  process
          after  typing  -re.   The  default  is  to use the last
          record of the dataset.

     -wvwatvel
          Enter the water velocity after typing -wv.  The default
          is 1480.

     -spspsi
          Enter the surface psi after typing -sp.  The default is
          .844.

     -ascale
          Enter the scaling factor for the formula  after  typing
          -a. The default is .000415.

     -bexpo
          Enter the exponent for the formula after typing -b. The
          default is .6.

     -nhgnhg
          Enter the  normal  hydrostatic  gradient  after  typing
          -nhg.  The  default  is .465 which is the correct value
          for the USA Gulf Coast.

     -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  will terminate after
          printing this.

     -h   Enter this option to get online help.  The program will
          terminate after printing this.

SEE ALSO

     vel2den, pptrn, pptrnehz, ppetn, ppdenobg

BUGS

     None known.

AUTHOR

     Mary Ann Thornton

COPYRIGHT

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