NAME
taupf - do forward tau-p tansform on seismic records
SYNOPSIS
taupf [ -Nntap ] [ -Ootap ] [ -Ccfile ] [ -rsnrst ] [
-renred ] [ -vvref ] [ -dxdxrec ] [ -pp1 ] [ -Pp2 ] [ -Jnp ]
[ -fmaxfmax ] [ -otnwt1 ] [ -itnwt2 ] [ -ftftaper ] [
-npnpad ] [ -V ] [ -? ]
DESCRIPTION
taupf does a slant-stack on input record & outputs a tau-p
record. taupf works in the frequency domain and is a
replacement for program slntf. It suffers from a minimum of
artifacts. It is recommended that the command line form of
input be used.
taupf gets both its data and its parameters from command
line arguments or card images in a job stream. These argu-
ments specify the input, output, the start and end records,
the start and end ray parameters (or angles), the number of
ray parameters or angles (with a reference velocity), and
tapering options.
Program Parameter Input
-N ntap
Enter the input data set name or file immediately after
typing -N on the command line. This input put file
should include the complete path name if the file
resides in a different directory. Example -Nvsp/dummy
tells the program to look for file 'dummy' in directory
'vsp'.
-O otap
Enter the output data set name or file immediately
after typing -O on the command line. This output file
is not required when piping the output to another pro-
cess. The output data set also requires the full path
name (see above).
-C cfile
Enter the name of a card file (if there is one) on the
command line. Entering just -C cues the program to
accept the rest of its input parameters on card images
in the job stream (rather than a parameter file). No -C
entry at all cues the program to use command line
input.
-ft ftaper
Enter the start frequency at which a cosine taper is to
be applied to the frequency transforms. This can some-
times quiet high frequency transients in the transform.
Default = no taper.
Job Stream Card Input
The following is an example of the format of card input
in a job stream
taupf -Ngabon1 -Otemp1 -C -V \
-taupf.crd"\
REF.VEL. nrst nred DXREC FMAX NPAD TAPER OUT
TAPER IN
5000 01 01 150 40
500 8 8
# ANGLES ANGLE START ANGLE INCREMENT
121 -60 1.0
0 0 0
"
The parameters on the first card are explained below
under command line input.
If the job stream approach is used then the key
-taupf.crd (followed by a double quote and backslash)
initiates the card sequence. Each card is preceded by a
character card which identifies the parameters to fol-
low. Exact column arrangement is not necessary. Notice
that with card input the angle (or ray parameter) input
is different from the command line input. There can be
a number of these cards specifying ranges of angles
(ray parameters), the sequence being terminated by zero
entries.
Note: if the jobstream input method is used then
startjob must be used to to execute the job:
startjob taupf.job
Command Line Input
-v vref
Enter the reference velocity for the source/receiver
medium. If this entry is not given then it is assumed
that ray parameters will be used, otherwise angles
(measured from the vertical) are assumed.
-fmax fmax
Maximum frequency used in transform. This entry must
be kept to less than 1/2 nyquist frequency.
-dx dxrec
(Optional) This entry is the distance between records
on the ground. It will cause a ray parameter dependent
static to be placed in the static trace word that
effectively puts each plane wave in its proper phase
across the line. This static can be actually applied by
using program rest. This is useful for comparing con-
stant angle sorts and for generating sections for
Migration before Stack (MBS). Default = 0
-rs nrst
-re nred
Only records between and including these values will be
used. Default values are the first and last records.
-p p1
Start ray parameter in units of 1/[m/s] or 1/[ft/s]:
this entry can be negative. Default value is 0.0. If
the reference velocity is nonzero then the start and
end entries, p1 and p2 (below), are interpreted to mean
angles. In this case the phase velocities will be given
by the formula:
sin ( angle )/ vref
-P p2
End ray parameter in units of 1/[m/s] or 1/[ft/s]: this
entry can be negative. Default value is 1.0. If the
reference velocity is nonzero then the start and end
entries, p1 (above) and p2, are interpreted to mean
angles.
-J np
Number of ray parameters: this should be high enough
to ensure adequate sampling of p in tau-p space. If the
name of the game is to go full circle then there should
be at least as many ray parameters (or angles) as there
are ranges in the input spread. Default = input number
of traces.
-ot ot
This is the number of traces at the end of the spread
to which a linear taper is applied. The taper starts
with a weight of unity and reaches a weight of 1/nt at
the end of the array. Default = not taper.
-it it
This is the number of traces at the center of the
spread (if spread is split) to which a linear taper is
applied. The taper starts with a weight of unity and
reaches a weight of 1/nt at the end of the array.
Default = not taper.
-np npad
Time padded to the bottom of the traces. Sometimes this
can help reduce noise caused by large amplitude events
near the bottom of traces. Default = 0
-V verbose
Enter the command line argument '-V' to get additional
printout.
-? Enter the command line argument '-?' or -h to get
online help. The program terminates after the help
screen is printed.
SEE ALSO
taupr
BUGS
There are probably unknown bugs in this code, although it is
far cleaner than slntf. Note that increasing fmax will
increase the run time linearly. Also, it is assumed that
statics problems with the data have been solved before run-
ning this code.
AUTHORS
P. R. Gutowski
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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