NAME
vxos - the graphical X/Motif application which provides a
user friendly method for evaluating parameters and digitiz-
ing and/or editting mute functions for the optical stack
process. It may also be used to create or edit
time/velocity pairs for application in conventional normal
moveout correction programs.
SYNOPSIS
vxos [ Command Line Arguments. ]
DESCRIPTION
vxos (optical stack analysis tool) is controlled through
popup and pulldown menus invoked from a main control panel.
File selection by "point and click" procedures is provided
through file selection panels. Display parameters are
entered through a popup menu, and variable scaling for both
the temporal and spatial axes of all displays is supported.
Existing pick files (in either the standard pick file format
or one of the velocity card image formats) may be loaded for
display and editting, and new or editted pick files (digi-
tized functions) may be output to a file as either a stan-
dard pick file for input to the optical stack process as a
mute function or as velocity data (time/velocity pairs) for
input to conventional normal moveout correction programs in
either DISCO HANDVEL, SIS/USP TDFN, or USP time/velocity/ri
number format.
INPUT
The input to vxos is:
1) all or a subset of the CDP gathers input to the opt-
ical stack process , conventional velocity analysis, or
tau-p transform (may be cdp-sorted data, shot data, or
radon transform data created by USP programs taupf or
radonf);
2) the semblance or Tp scan data set created by opstd
(see documentation for program opstd or opstf for
description of the Tp scan or semblance data sets), the
semblance panels created by program velspec for conven-
tional velocity analysis, or the semblance panels
created by program taupspec for tau-p domain velocity
analysis;
3) optionally, a file containing the record, trace, and
time coordinates of the automatic picks generated by
program opstk, the picks created in a previous session
of vxos, or time/velocity information in the form of
TDFN, DISCO HANDVEL, or USP time/velocity/ri triplets.
OUTPUT
The output from vxos is a file containing data from the
digitizing procedure. This data may be:
1) a standard pick file in a format compatible with
program xsd. This file can be used as the mute file
input to programs opstk, opstd, or opstr.
2) velocity data in DISCO HANDVEL, USP/SIS TDFN, or
time/velocity/ri triplet format (used by USP program
velin).
PROGRAM EXPLANATION
Program Panel Layout
The control/display panel for the optical stack analysis
tool consists of two control bars, an informational bar, and
a three-paned display area with scroll bars and
expansion/compression sliders. The uppermost control bar is
the menu bar and contains buttons used to control the opera-
tions of the program (as described under Operations below).
The second control bar contains toggle buttons to control
picking (digitizing) operations (see Digitizing under Opera-
tions below). The informational bar (the odometer) displays
the record, trace, time, amplitude, and velocity correspond-
ing to the current location of the mouse cursor in any of
the display panes.
The paned display area is used to display the CDP gathers in
the left-most pane, the CMO (Tp scan sums or semblance
panels) in the center pane, and a graph of the (digitized)
velocity functions or NMO-corrected CDP data in the right-
most pane. The scroll bars on the left-most pane are used
to scroll ALL panes. The two slider bars across the top of
the panes are used to compress or expand the display area
for the left-most two panes. This is useful when no velo-
city graph is desired and the CDP and CMO panes can be
expanded to fill the entire screen.
SPECIAL FEATURE: When the mouse cursor is in the CMO data
pane (center pane), a hyperbola, computed according to the
Dix equation for the velocity corresponding to the location
of the mouse cursor, is drawn in color (red, green, or yel-
low) on the black-on-white CDP data. This feature greatly
aids in identifying the hyperbola(s) contributing to a sum
or semblance value, thereby aiding in picking velocities and
mute functions differentiating between multiple and primary
reflection events. Additionally, when NMO-corrected data is
displayed in the right-most pane, a colored line (red,
green, or yellow) is drawn on the data to clearly indicate
the zero-offset time corresponding to the hyperbola drawn
(in the same color) on the CDP data in the left-most pane
and the semblance value pointed to in the velocity spectrum
in the center pane.
Panel Colors and Font: Your .Xdefaults file may be used to
customize the panel colors and font for program vxos. When
the program begins execution, the panel colors are set to a
default (gray on green) and the font is set to the default
for the window. These characteristics can be overridden by
putting entries into your .Xdefaults file to set them to
colors and fonts of your own choice. For example, the
entries would look something like
vxos.exe*background: lightblue
vxos.exe*fontList: 8x13bold
to set the panel color to light blue and the font to
8x13bold. Note that the program name (vxos.exe) must agree
with the version name of the module being executed. This
name is given in the vxos panel title, and should not change
for the latest distributed version. However, if running a
test version, you will have to change your .Xdefaults file
to that version name, or add to the .Xdefaults file for that
version name. (The test version will usually be
vxos.exe.test.) To make the entries apply, enter the com-
mand
xrdb -load.Xdefaults
after saving the modified file.
OPERATIONS
Menu Buttons:
The following is a description of the menu buttons and their
uses.
File button
When this button is selected, a list of choices for
loading the seismic (CDP) and the CMO (Tp scan or sem-
blance) data or for exiting the program are presented.
Selecting data files:
When the "Select Data Files" option is selected, a
file selection panel is displayed and is used to
select the input files by file name. The left
selection panel is used to select the "CDP" data
(may be cdp-sorted, shot data, or radon transform
data created by USP programs taupf or radonf),
while the right panel is used to select the "CMO"
data (may be the scan data or semblance data out-
put by program opstd, conventional velocity spec-
tra created by USP program velspec , or tau-p
velocity spectra created by USP program taupspec).
When both the "CDP" and "CMO" data sets have been
selected (according to the file selection pro-
cedures defined below) and the appropriate name
indicated in the label area near the bottom of the
panel, select the OK button at the bottom of the
panel to bring up the parameter display menu.
There may be a slight delay after the selection of
each file name as the program opens and scans the
selected data file.
File selection procedures:
A file selection panel appears when the "Select
Data File" option is selected. This panel is made
up of two separate file selection panels, each
with its own list of files and its own buttons.
These panels present a list of the files in the
current directory on the right side and a
(scrolled) list of related directories on the left
side. The text area at the top of the panel,
labeled "Filter", specifies the current directory.
The text area at the bottom, labeled "Selection",
contains the name of the selected file (it is
blank or contains on the directory name if no file
has been selected).
To use the file selection panel, select a file
from the current list or change to another direc-
tory to see additional file names. Change direc-
tories by either typing the directory name in the
Filter field and selecting the Filter button at
the bottom of the panel, or by selecting the
appropriate directory from the list of directories
on the left side of the panel. Select a file name
by either selecting a file name from the current
list or typing, with fully qualified path, the
file name in the Selection area. Select the "OK"
button at the bottom of the panel to load the file
or select the "Cancel" button to quit without tak-
ing any action. Use the "Filter" button to either
change directories or to update the list of files
in the directory (this will be necessary when the
file was created after the current session of vxos
was started). Note: For selection of files, a
"double click" on the file name will make selec-
tion of the "OK" button unnecessary.
When a file is selected from either file selection
panel, the name of the file will appear beneath
the label for that data set. If no name is
present, no file has been selected.
When both the CDP and CMO data sets have been
selected, select the "OK" button at the bottom
left of the panel to continue and access the
display parameter panel.
EXIT procedures:
If the Exit option is selected, you will be given
the chance to cancel the exit procedures. If
"Cancel" is not selected from the option box which
appears, the program is terminated. Note that
function key 3 can also be used to initiate the
exit procedure.
Display button
This button is used to access the plotting parameter
and color editor panels. Neither of these options can
be accessed until the data has been loaded. The plot-
ting parameter panel is automatically popped up for
access after data files are selected and can be
accessed again to change parameters once the initial
displays have been created. This button also offers
the option to change the color of the hyperbola drawn
on the CDP data. This option can be selected at any
time.
When this button is selected, a list of options for
accessing either the display parameter panel, color
editor panel, or hyperbola color panel is presented.
When the "Enter Display Parameters" option is selected,
the display parameter menu will appear. When the
"Change Colors" option is selected, the color editor
panel will appear. When the "Hyperbola Color" option
is selected, the hyperbola color panel will appear.
The display parameters are discussed below. The color
editor is documented separately and this document may
be accessed via the help button on the color editor
panel.
Display parameters, with the exception of the Traces
per Inch parameter, apply to both the CDP and the CMO
data displays. The Traces per Inch parameter may be
specified for the CDP data and for the CMO data
independently to optimize horizontal resolution for
these two displays. The Inches per Second parameter
also applies to the velocity graph, although its hor-
izontal scale may be changed independently (see the
Velocity button below). To apply the parameters to the
data, click on the "OK" button; to dismiss the parame-
ter panel without changing any of the parameters
already in effect, click on the "Cancel" button. The
display parameters are:
Start Record Number
The number of the first record to be displayed.
The number of the first record on the input data
set is extracted from the CDP data set when it was
selected (see the description of the File button
above) and is entered for this parameter as a
default, under the Actual Record Number column.
Under the Sequential Record Number column, a 1 is
entered as default.
End Record Number
The number of the last record to be displayed.
The number of the first record is supplied as a
default. (Applies to both Actual and Sequential.)
NOTE: The Start and End Record Numbers may
be selected as Actual record numbers, or as
Sequential record numbers by means of
selecting the appropriate button to the
right of the Start Record Number. Make
sure that you fill in the appropriate
values under the appropriate column,
depending upon whether you select Actual or
Sequential Record Numbers.
Inches per Second
The temporal display scale. A default value of 2.5
is supplied.
Traces per Inch
Horizontal display scale. Default values of 25 for
the CDP data and 50 for the scan or semblance data
are supplied.
Maximum Overlap
The maximum deflection, in traces, of a wiggle
trace for a value of 2047. Any value greater than
2047 has its deflection truncated at this deflec-
tion, while any value less than 2047 has a
correspondingly smaller deflection. A default
value of 3 is supplied.
Scale Factor
The data are scaled internally, for display only,
to this fraction of 2047, with normalization deter-
mined by the maximum average absolute amplitude of
all traces in the input data, to determine maximum
deflection of the wiggle trace. The Scale Factor
is equivalent to the percentage of 2047 used in a
job constant gasp application, where the temporal
window used to determine the scale factor is the
entire trace length.
AGC Window Length (ms)
Enter the length, in ms, of the sliding window to
be used to determine the AGC gain function to be
applied to the data traces as they are displayed.
Note that the gain function applied affects THE
DISPLAY ONLY. The stored data is retained in its
original form and the data amplitude values
displayed are taken from the original data. Also
note that this parameter defaults to 500 ms, which
means that if you set it to 0 and request AGC by
selecting the "Yes" button under "Apply AGC", you
will actually get a 500 ms window. The only way to
"turn off" AGC is to select the "No" button (see
Apply AGC below).
Apply AGC
If you wish to apply AGC (MAA mode only) to the CDP
data and the Moveout Corrected Data, select the
"Yes" button and fill in the desired AGC Window
Length. This option, once selected, remains in
effect until turned off by selecting the "No" but-
ton. Note that ONLY THE DISPLAY is effected by the
AGC. The amplitude values displayed in the infor-
mation area (the "odometer" area) are the ampli-
tudes for the input data.
Picks button
Use this button to select the option to load pick files
previously saved, set the format of the pick file and
save current picks to a file, clear current picks, or
to copy the picks for one record to another record.
When the Load Picks option is selected, a file selec-
tion panel (described under the control panel File
button discussion) is displayed. Select or enter the
appropriate file name, as described previously. As
picks are loaded, they are displayed as an overlay on
the appropriate data (in the middle pane). The picks
may be in either the standard pick file format or in
any of the velocity card image formats (HANDVEL, TDFN,
USP tvr, and xsd picks for velspec) supported by the
program. The program scans the file to determine the
format of the picks and then reads it appropriately.
When the Save Picks option is selected, a panel is
displayed to allow you to select the format of the out-
put file and the action to take when the file name
selected is an existing file. After making your
choice, select the "OK" button to cause the file selec-
tion menu to be presented. Select the name of the out-
put file from the list or enter a new name. The
current picks may be saved in several formats, with or
without conversion to time/velocity format. The possi-
ble formats include "Standard Pick Format", "Velocity
in DISCO format", "Velocity in TDFN format", and "Velo-
city in Time/Velocity Pairs". If the "Standard Pick
Format" option is selected, the data are written as an
ASCII file in a format compatible with program xsd and
the Optical Stack suite of programs. If the "Velocity
in DISCO format" option is selected, a DEFINE file
(*CALL DEFINE) is created for the HANDVEL option of
DISCO. If the "Velocity in TDFN Format" option is
selected, the data are converted to the SIS/USP TDFN
format. If the "Velocity in Time/Velocity Pairs"
option is requested, the data are written as an ASCII
file containing records with Time/Velocity/Record sets,
with comma separators. This format is read by the USP
program velin.
The Copy Picks option may be used to expedite picking
of velocity spectra when the spectra are not changing
significantly. When the "Copy Picks" option is
selected, you will be requested to supply the "from"
and "to" record numbers through a data entry panel.
Once the parameters are entered, the program adjusts
its pick storage and draws the "new" picks in the
proper location. The "new" picks may then be editted
to fit the "new" velocity spectrum. The numbers you
enter must be the numbers appearing as the label for
the records (the USP Record Number), not the sequential
record number. For example, if you have displayed an
analysis data set containing records with record
numbers 1, 5, 11, 17, and 21, and you have created (by
digitizing or loading from a file) picks for the second
record and you wish to copy to the fourth record, you
would specify the "from" record as 5 and the "to"
record as 17. Copies can be made in either direction
(low record numbers to high, or high record numbers to
low). If you specify the "to" record as one for which
picks already exist, the program will copy the
requested picks over the existing picks, thus eliminat-
ing the existing picks.
If the Clear Picks option is selected, ALL CURRENT
PICKS are cleared. Use this option only if you are
sure that you want to clear ALL picks (you are not
given the chance to change your mind, and you can't get
the picks back unless you have saved them to a file).
Otherwise, use one of the editting features of the
digitizing facility to just edit your picks.
Velocity Button
Use this button to change the scale for the
stacking/interval velocity graph or to request applica-
tion of a picked velocity function(s) to the CDP data.
When the scale change is requested by selecting the
"Set Velocity Range" button, a menu appears in which
you may enter the minimum and maximum velocities for
the scale and the width (in inches) of the graph.
Select the "OK" button from the menu to make the indi-
cated changes. Select the "Cancel" button to ignore
any indicated changes. Use the "Apply Current Func-
tion" button to apply current velocity picks to the
displayed CDP data. When this button is selected, the
digitized points are converted to times and velocities
and applied to the data. If more than one CDP is
displayed but only one velocity spectrum has been
picked, the one function is applied to all the
displayed data. If more than one spectrum has been
picked, the first function will be applied to all data
up to the next record that has been picked. The last
picked function will be applied to all remaining data.
Moveout corrected data is displayed in the same window
(right-most pane) used to display the velocity graph.
After application of the moveout function(s), the velo-
city graph is replaced with the corrected data display.
To restore the velocity graph, select one of the Pick-
ing mode buttons.
Help Button
Use this button to cause the documentation for this
application to be displayed on the screen in an
independent scrollable window in hypertext format.
Digitizing:
Three modes of picking (digitizing) are supported. These
are:
New - create new pick files,
Edit - edit display picks, and
Move Picks - move displayed picks from one point to
another within the same record.
These options are described below.
New
The New picks option is selected by selecting the tog-
gle button labeled "New" in the upper portion of the
program panel. When this option is selected, the func-
tion of each of the three mouse buttons is displayed on
the right side of the same control bar.
Caution: If picks already exist for the record to be
digitized, they are replaced with the new picks. Use
the Edit or Move option to simply modify existing
picks.
To digitize new picks, move the mouse cursor to the
desired record and digitize according to the indicated
button functions. "Rubber banding" is used between
successive points to simplify the procedure. As points
are digitized, graphs of both the stacking and interval
velocity functions appear in the velocity (right) pane.
Imaginary interval velocities are graphed with a dotted
line.
Edit
The Edit picks option is selected by selecting the tog-
gle button labeled "Edit" in the upper portion of the
program panel. When this option is selected, the func-
tion of each of the three mouse buttons is displayed on
the right side of the same control bar. Move the cur-
sor to the desired record and edit according to the
indicated button functions.
Move Picks
The Move picks option is selected by selecting the tog-
gle button labeled "Move Picks" in the upper portion of
the program panel. When this option is selected, the
function of each of the three mouse buttons is
displayed on the right side of the same control bar.
Move to the desired record and move the picks according
to the indicated button functions. "Rubber banding" is
used to simplify the procedure.
Mute Functions
Program vxos is used to create, by digitizing from input
analysis panels, the mute functions to be applied in pro-
grams opstk, opstd, and opstr. These functions are digi-
tized segments which separate from primary reflection events
any undesirable data (such as multiples and noise) detected
on the analysis panels. The functions are saved as pick
files output in Standard Format (see the Picks button
above).
Selecting mutes for the Optical Stack programs is typically
a laborious process. Mutes should be selected by analyzing
only a subset of the data to be processed. Select data for
this subset which is representative of the entire data set.
The processing programs will use linear interpolation to
construct mute functions for records between those analyzed.
To create the sum or semblance panels to be analyzed in
vxos, process the subset of data with opstf and opstd, sav-
ing the sum and/or semblance data. Be sure to save the
parameters used to create the analysis set. The parameters
used to process the data with mute application MUST be the
same as those used to create the analysis panels. Otherwise,
mute application will be incorrect.
To pick mute functions, select the "New" digitizing option,
as explained previously, and move the cursor to the scan or
semblance panel from which the mutes are to be picked.
Using the velocity and amplitude information displayed in
the odometer area and the hyperbola overlain on the CDP
data, digitize a function which separates (in a horizontal
sense) the primary reflection events from the multiple or
noise events. Repeat this for all records in the analysis
set and save the digitized functions in "Standard Format".
This file can now be used as the input mute file for pro-
grams opstk, opstd, and opstr.
BUGS
Could there be any? If problems are encountered, or you
have suggestions for improving the displays, please advise.
AUTHOR
Richard Crider EPTG, Houston (original)
Marilyn Miller EPTG, Tulsa (modifications and updates)
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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