NAME
LLATTRIB3D - module to calculate a variety of user selected
seismic attributes on angle stacked data.
SYNOPSIS
LLATTRIB3D [ -Nntap ] [ -Ootap ] [ -Pptap ] [ -as ] [ -ae ]
[ -ai ] [ -rs ] [ -re ] [ -attattrnum ] [ -V ] [ -DB ] [ -?
] [ -h ] [ -ha ]
DESCRIPTION
General
Program LLATTRIB3D allows the user to calculate a variety of
lobe to lobe seismic attributes on data that has been angle
stacked. Data is expected in nonoverlapping angle stacks,
organized as n stacked volumes for the n angles, distributed
one angle per file, such as is generated by program ANGST3D.
The program will handle up to 63 angle data sets, and gen-
erates one attribute trace per input record.
A least squares curve fit is applied to the input data if
more data volumes are supplied by the user than are actually
needed by the program in order to calculate the requested
attribute.
Up to five sections (user defined) of the input data are
cross correlated with up to ten stacked traces (user
defined) begining at a user defined area of each input data
trace. Each trace is shifted positively and negatively up to
30msec (user defined), one sample at a time and cross corre-
lated at each shift. The absolute maximum for each of these
shifts is then determined. The shifting/cross
correlation/absolute maximum calculation is performed at
each of the sections. The cross correlation section lengths
(user defined) are limited to 60msec. The trace shift is
determined by the number of sample shifts required to give
an absolute maxima in the majority of the cross correlated
sections. If no clear majority is found, the trace is left
unshifted. A cumulative error figure based on the total
number of incorrect shift calculations for all sections of
all traces is given upon completion of the program to give
the user a validity check for the trace shifting algorithm.
The following recon attributes are currently available:
1) B0 Note: Needs a two or three angle bucket input from
angst.
2) B1 Note: Needs a two or three angle bucket input from
angst.
with angles out to a minimum of 15 degrees.
3) B2 Note: Needs a two or three angle bucket input from
angst
with angles out to a minimum of 37 degrees.
4) Bz=SIGN(B0)*B1 Note: Needs a two or three angle bucket
input
from angst with angles out to a minimum of 15
degrees.
5) Bp=B0*B1 Note: Needs a two or three angle bucket input
from angst with angles out to a minimum of 15
degrees.
6) Br=B1/B0 Note: Needs a two or three angle bucket input
from angst with angles out to a minimum of 15
degrees.
7) Middle angle stack - Near angle stack Note: A two or
three angle bucket input from angst needed.
8) Large angle stack - Near angle stack
Note: A three angle bucket input needed from angst.
9) Large angle stack - Middle angle stack
Note: A three angle bucket input needed from angst.
10) Zero crossing angle in degrees. Note: A two or
three angle bucket input from angst needed.
11) Restricted Gradient
Two angle buckets: EE(middle angle)-EE(small angle)
Three angle buckets: EE(large angle)-EE(small angle)
12) dVp/Vp Note: Needs a two or three angle bucket input
from angst with angles out to a minimum of 37
degrees.
13) dVs/Vs Note: Needs a two or three angle bucket input
from angst with angles out to a minimum of 37
degrees.
14) dRho/Rho Note: Needs a two or three angle bucket input
from angst with angles out to a minimum of 37
degrees.
15) dZp/Zp Note: Needs a two angle bucket input
from angst with angles out to a maximum of 30
degrees.
16) dZs/Zs Note: Needs a two angle bucket input
from angst with angles out to a maximum of 30
degrees.
17) d(Vp/Vs)/(Vp/Vs) Note: Needs a two angle bucket input
from angst with angles out to a maximum of 30
degrees.
18) dF Fluid Factor
19) 1/B2 Contact Event Note: Needs a three angle bucket
input
from angst with angles out to a minimum of 37
degrees.
20) Energy Envelope(small angle) Note: Needs at least one
angle bucket input from angst.
21) Energy Envelope(mid angle) Note: Needs at least two
angle buckets input from angst.
22) Energy Envelope(large angle) Note: Needs a three
angle bucket input from angst.
23) Energy Envelope(mid angle) - Energy Envelope(small
angle)
Note: Needs a two angle bucket input from angst.
24) Energy Envelope(large angle) - Energy Envelope(small
angle)
Note: Needs a three angle bucket input from angst.
25) Enhanced Restricted Gradient.
(EE(large angle) - EE(small angle)) * EE(large angle)
Note: Needs a three angle bucket input from angst.
Parameterization
LLATTRIB3D gets its data and parameters from command line
arguments.
Command line arguments
-N ntap
Enter the input data set name or file immediately after
typing -N. 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 'vsp' stored on the 'b' disk.
Multiple input files require multiple -N statements,
one per input file. (Default = pipe input)
-O otap
Enter the output data set name or file immediately
after typing -O. The output data set also requires the
full path name (see above). (Default = pipe output)
-P ptap
Enter the data shift parameter file name immediately
after typing -P. This input file should include the
complete path name if the file resides in a different
directory. Example -P/b/vsp/dummy tells the program
to look for file 'dummy' in directory 'vsp' stored on
the 'b' disk. This file is fixed format, with the
parameter name starting in column 1, and its value
starting in column 10. The parameters specified in
this file along with their default values follow:
1
column 1 0
stakn 1
deltat 12.0
totdt 30.0
nxcor 3
tzero 0.0
"stakn" is the number of traces stacked together that will
be used by the cross correlation routine. The first through
nth trace will be stacked. Minimum value for this parameter
is 1; maximum value is 10.
"deltat" is the time in milliseconds through which the data
will be shifted both positively and negatively. The minimum
value for this parameter is 1, maximum is 30. Since this
parameter is specified in milliseconds, it should be a mul-
tiple of the sample interval.
"totdt" is the total time in milliseconds in each cross
correlated section that is actually cross correlated. The
minimum time for this parameter should be 2*deltat, and the
maximum allowed is 60. This parameter should also be speci-
fied as a multiple of the sample interval.
"nxcor" is the number of sections of each trace to cross
correlate. Minumum value is 1, maximum value is 5.
"tzero" is the start time in milliseconds for the first sec-
tion to be cross correlated. Minimum time is 0.
-as start angle
Enter the angle, in degrees, that was used as the bin
minimum for the first stacked output trace. (Default =
NONE)
-ae end angle
Enter the greatest angle, in degrees, that was con-
sidered in stacking the input data. This value was the
bin maximum for the last stacked output trace. (Default
= NONE)
-ai angle increment
Enter the angular width (in degrees) of the stacking
"bins". (Default = NONE)
-rs start record
Enter the actual number of the record on which to begin
processing. All data prior to this record will be
skipped and not output. (Default = the first record on
the input data set)
-re record end
Enter the actual number of the record on which to end
processing. All data following this record will be
skipped and not output. (Default = last record on the
input data set)
-ns start trace
Enter the actual number of the trace on which to begin
processing. All data prior to this trace will be
skipped and not output. (Default = the first trace on
the input data set)
-ne trace end
Enter the actual number of the trace on which to end
processing. All data following this trace will be
skipped and not output. (Default = last trace on the
input data set)
-att attribute number
Enter the number corresponding to the attribute you
want calculated here. Available attributes are listed
above. (Default = NONE)
-V verbose printout
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.
-h Enter the command line argument -h to get online help.
The program terminates after the help screen is printed.
-ha Enter the command line argument -ha to get an online
list of currently available attributes. The program ter-
minates after the help screen is printed.
AUTHOR
David Woodruff EPTG ATTC
CONTRIBUTORS
Mike Kelly EPTG ATTC
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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