NAME
taupred - do predictive deconvolution on tau-p traces
SYNOPSIS
taupred [ -Nntap ] [ -Ootap ] [ -Aatap ] [ -ppr ] [ -pminp-
min ] [ -olol ] [ -Pprew ] [ -vvel ] [ -sist ] [ -eiend ] [
-nsnstr ] [ -nenetr ] [ -rsnrst ] [ -renred ] [ -TV ] [
-wlslide ] [ -S ] [ -R ] [ -M ] [ -G ] [ -C ] [ -B ] [ -V ]
[ -? ]
DESCRIPTION
taupred does predictive deconvolution of selected tau-p
traces and will generate either the standard prediction
error output or optionally the predictable part of the sig-
nal. This code is almost exactly the same as pred except
that both the design window and the prediction distance are
functions of the ray parameter (which taupf puts in the
unsigned trace distance header word).
taupred gets both its data and its parameters from command
line arguments. These arguments specify the input, output,
the design window, the start and end traces, and verbose
printout, if desired.
The record and trace limits specify what part of each record
or what part of the line is to be precessed through the pro-
gram. The data outside these limits will be passed
untouched.
Command line arguments
-N ntap
Enter the input data set name or file immediately after
typing -N unless the input is from a pipe in which case
the -N entry must be omitted. This input 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 directory '/b/vsp'.
-O otap
Enter the output data set name or file immediately
after typing -O. This output file is not required when
piping the output to another process. The output data
set also requires the full path name (see above).
-A atap
Enter the name of the optional predictable part of the
deconvolution (can not be piped). This is the
equivalent of subtracting the deconvolved data from the
original input data, i.e. what the decon is removing.
-p pr
This is the zero ray parameter wavelet length or the
prediction distance in ms. As the ray parameter
increases the travel time of the plane wave decreases
according to a cosine relation, thus the prediction
distance should also be decreased by the same function.
Prediction distance will be set to that of the unit
prediction filter when the cosine relationship goes to
zero or is undefined. Care should be taken to make this
entry correspond approximately to the nth zero crossing
of the trace. Running auto on the tau-p/radon
transformed data is highly recommended.
-pmin pmin
This is the minimum prediction distance allowed (ms)
for any ray parameter. Setting pmin to a value greater
than one sample (the default) will force a wavelet
shaping versus spiking decon at the larger absolute
value ray parameters where the cosine relationship
makes the prediction distance small.
-ol ol
Enter the operator length in ms. This entry should
span the multiple period of interest and is constant
with respect to p.
-P prew
Enter the prewhitening as a fraction. This is neces-
sary to prevent numerical instabilities in the calcula-
tions. The effect on the output traces of increasing
prew is an overall smoothing of the data. The default
is .01.
-v vel
Enter the reference velocity in m or ft/s. This value
will be used along with the ray parameters to compute
the cosine function used in varying the design window
start time and the operator length. It must be equal
to the velocity corresponding to the maximum ray param-
eter. For output from program radonf the reference
velocity can be calculated by dividing the xmax dis-
tance by the mmax time. No Default.
-s ist
Enter the zero ray parameter start time (ms) of the
design window. The actual start time will be a func-
tion of the trace ray parameter. The default is the
beginning of the trace (which will be the same for all
ray parameters).
-e iend
Enter the zero ray parameter end time (ms) of the
design window. The default is the end of the trace.
-ns nstr
Enter the start processtrace number. Trace numbers
below this value will not be processed. The default is
1.
-ne netr
Enter the end processtrace number. Trace numbers above
this value will not be processed. The default is the
last trace number on the input data set.
-rs nrst
Enter start process record number. Record numbers below
this value will not be processed. Default value is the
first record.
-re nred
Enter end process record number. Record numbers above
this value will not be processed. Default value is
last record.
-TV Enter the command line argument '-TV' to apply time
varying predictive decon (see required parameter
below). With this option all design window parameters
above still apply although the decon is applied only
within the design window. The -G, -S options below and
the optional predictable output above are ignored.
-w lslide
Enter length (ms) of the sliding window. Effectively a
decon is done for each win dow postion on the trace;
the window is moved down by 1/2 its length and the
decon
is computed again. The individual results are merged
together by linear interpol ation. To see large
effects the sliding window length should be longer than
the operator length.
-S Enter the command line argument '-S' to output the
predictable part of the signal, otherwise the standard
unpredictable part or prediction error will be output.
-R Enter the command line argument '-R' to use as input
data the output of radonf
-M Enter the command line argument '-M' to use as input
data the output of Whitmore's MBS program SLNT
-G Enter the command line argument '-G' to apply decon
filter only to the data within the design window, the
rest of the trace remaining the same. This option is
not available if -S or prediction option is flagged.
-C Enter the command line argument '-C' to apply cosine
bell taper to the autocorrelation
-B Enter the command line argument '-B' to apply bartlett
(linear) taper to the autocorrelation
-V Enter the command line argument '-V' to get additional
printout.
-? Enter the command line argument '-?' to get online
help. The program terminates after the help screen is
printed.
NOTE 1.
The flow radonf|taupred|sctvf|radonr can be very effective
in suppressing surface and interbed multiples as well as
collapsing reverberating refractions and other guided waves.
A good testing procedure might include running the flow
radonf|taupred -S|sctvf|radonr on a record or two to deter-
mine what the strength of the multiples are in the (x-t)
domain.
See Also
radonf,radonr,slnt,pred,avepred,auto
Author
Paul Gutowski, APR (1986).
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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