NAME
taupr - module to reverse tau-p tranform seismic records
SYNOPSIS
taupr [ -Nntap ] [ -Ootap ] [ -Ccfile ] [ -rsnrst ] [
-renred ] [ -pp1 ] [ -Pp2 ] [ -Jnp ] [ -fmaxfmax ] [ -otnwt1
] [ -itnwt2 ] [ -ftftaper ] [ -D ] [ -S ] [ -M ] [ -V ] [ -?
]
DESCRIPTION
taupr does a slant-stack on input tau-p record & outputs a
range-time record. taupr works in the frequency domain and
is a replacement for program slntrm. It suffers from a
minimum of artifacts. It is recommended that the command
line form of input is used.
taupr 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 distances to be output, the number of dis-
tances, zero padding, 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 will
be applied to the frequency data. This can sometimes
reduce high frequency noise in the transform. Default
= no taper.
-D Enter the command line flag "-D" to force the inverse
transform to reconstruct using the original trace dis-
tances. This will also be triggered by both no -p and
-P entries (see below).
Job Stream Card Input
The following is an example of the format of card input
in a job stream
taupr -Njunkf -Otemp1 -C \
-taupr.crd"\
REF.VEL. nrst nred DXREC FMAX NPAD TAPER OUT
TAPER IN
5000 01 01 150 40
500 8 8
# RANGES RANGE START RANGE INCREMENT
121 -9000 150.
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
-taupr.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 range input is different from
the command line input. There can be a number of these
cards specifying ranges of ranges, the sequence being
terminated by zero entries. Note that This card
arrangement is very similar to that used by taupf; the
differences are that the reference velocity (REF.VEL.)
and DXREC are not needed.
Note: if the jobstream input method is used then
startjob must be used to to execute the job:
startjob taupr.job
Here is an example of a job stream that goes full cir-
cle with a processing step (pred) in between and one at
the end
taupf -Ngabon1 -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
"|
pred -p32 -ol400 | \
taupr -Otemp1 -C \
-taupr.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 -9000 150.
0 0 0
"|
davc -Ntemp1 -s15 -w1000
The vertical bars are pipes connecting the output of
one process to the input of the next
Command Line Input
-v vref
Not needed
-fmax fmax
Maximum frequency used in transform. This entry must
be kept to less than 1/2 nyquist frequency. Default =
1/2 nyquist.
-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 distance in units of [m] or [ft]: (command line
input only) this entry can be negative. Note this entry
must refer to the near positive offset if using the
split spread option below. Default value is 0.0.
-P p2
End distance in units of [m] or [ft]: (command line
input only) this entry can be negative. Default value
is 0.0. Note: if both distance entries are left off
the command line it is assumed that reconstruction will
be done using the original trace distances.
It is important to note that when reconstructing data from
tau-p records one should end up with the same distances as
the original x-t record. Otherwise the trace indices will be
incorrect. One can use different distances (e.g. interpola-
tion) but this should be done after any sorting so that
indices are not required. (see also split spread option
below)
-J numtp
Number of distances. Default = number input
traces/record.
-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.
-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.
-S split
Enter the command line argument '-S' to specify split
spread output using command line option. In this case
the -p and -P entries must be respectively the near and
far offsets of the positive side of the spread only.
-M slnt
Enter the command line argument '-M' to process data
from the MBS program slnt.
-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 slntrm. Note that increasing fmax will
increase the run time linearly. Distances different from the
original x-t record will have incorrect indices (see -P
entry above). One day this will be fixed.
AUTHORS
P. R. Gutowski
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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