NAME
swath - Create a Pseudo-v(x,z) Migration
SYNOPSIS
swath -Nintape -Oouttape -Ivfunctions \
-swath.crd"\
TIME ENDTIMEMS PADTIMEMS BEGTIMEMS DTMS
TIME endtime padtime begtime dtms
SIZE DZ TDEPTH DX TWIDTH NFUNC
dz tdepth dx twidth nfunc
SWATH rs1 re1 datasetname1
SWATH rs2 re2 datasetname2
SWATH ... ... ...
SWATH rsn ren datasetnamen
"
#...|....1....|....2....|....3....|....4....|....5
STARTJOB
Create a file that looks like the above synopsis with the
following command:
catpat swath > swath.job
This swath.job file will have some suggested parameter
values entered. Edit the file to suit your needs and submit
swath.job with the following command:
startjob swath.job
DESCRIPTION
swath will create a pseudo-v(x,z) migration from a collec-
tion of v(z) migrations. Program swath converts each v(z)
stacked migration to time, applies a weighting function, and
stacks the results. Inputs to program swath are one or more
migrated seismic datasets that may or may not overlap in the
x-direction, a velocity function or set of velocity func-
tions (see format for functions below), the embedded menu
cards as shown above, and command line arguments.
Command line arguments
-Nintape
Enter the first input dataset (migrated seismic, sam-
pled in depth) after typing -N. You will need to also
specify the name of the first input dataset, as well as
all of the input datasets, on the SWATH line of the
pattern file.
-Oouttape
Enter the output velocity matrix dataset name after
typing -O. This will be a USP-formatted dataset and
velocities will be interval velocities.
-Ivfunctions
Enter the name of the card file containing the velocity
functions after typing -I. The format for these cards
is provided below.
-V Enter -V for a verbose printout.
-h Enter -h for online help. Program will terminate after
printing this.
-? Enter this (or '-?' if you are running in c-shell) to
get online help. The program will terminate after
printing this.
-swath.crd"\
This keyword, -swath.crd"\, must be entered exactly as
shown with no spaces after the backslash. The embedded
menu cards that follow this keyword must be typed
exactly as shown, with the lower case parameter names
being changed to the actual values you want the program
to use. All of the parameter values must be entered in
the correct columns. The double quote following the
embedded menu cards must be present as shown.
Description of Parameters
-ET endtime
The ending time in ms. This parameter is not used.
The output time is computed from the input velocity
functions.
-PT padtime
This parameter is not used.
-BT begtime
Enter the beginning time of the output dataset in ms.
-DT dtms
Enter the sampling interval for the output dataset (in
ms). Default is the sampling interval from the input
line header.
-DZ dz
Enter the depth spacing (ft or meters) of the input
v(z) migrated stacks.
-TDEPTH tdepth
Enter the total depth (ft or meters) of the input v(z)
migrated stacks.
-DX dx
Enter the trace spacing (ft or meters) of the input
v(z) migrated stacks.
-X twidth
Enter the total width (ft or meters) of the output
pseudo v(x,z) time migrated stack. Swath computes the
total number of output traces by dividing the total
width by the DX value.
-NF nfunc
The number of velocity functions contained in the input
"vfunctions" dataset.
TH rs1
This is the trace on the output that corresponds to the
first trace on the first dataset.
TH re1
This is the trace on the output that corresponds to the
last trace on the first dataset.
TH datasetname1
This is the dataset name of the first dataset for
input. There must be one "SWATH" card describing each
input dataset.
FORMAT OF VFUNCTIONS CARDS
You can use the catpat command to create a template like the
one shown below:
MODEL nv xloc
VELOCITIES VINT DEPTH
n1 vel01 dep01
n2 vel02 dep02
. . .
. . .
nv velnv depnv
MODEL nv xloc
VELOCITIES VINT DEPTH
n1 vel01 dep01
n2 vel02 dep02
. . .
. . .
nv velnv depnv
#...|....1....|....2....|....3....|....4....|....5
Description of parameters for vfunctions Cards
MODEL nv
This value is the number of velocities appearing in the
velocity function.
MODEL xloc
The xloc is the trace location (in ft or meters) where
the function is to be applied to the data.
VELOCITIES n1.....nv
This value is the sequential number of this velocity
layer and must be an integer number. These numbers
must increment by 1.
VINT vel01...velnv
This value is the reflected interval velocity. No
default.
This value is the ending depth for the corresponding velocity.
The last end depth must >= TDEPTH parameter described
above. No default.
SEE ALSO:
xrpm, ivad, vlmx, velin, rmsvlmx, mxcvel, vfnd, vtpad,
vtrsiz, vtvzex, vttd
BUGS
None known.
AUTHOR
Gary Murphy
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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