NAME
spike3d - module to compute 3d synthetic surfaces, plane,
hyperboloid or cone.
SYNOPSIS
spike3d [ -Nntap ] [ -Ootap ] [ -xmaxxmax ] [ -ymaxymax ] [
-tmaxtmax ] [ -xminxmin ] [ -yminymin ] [ -tmaxtmax ] [
-dxdx ] [ -dydy ] [ -dtdt ] [ -x0x0 ] [ -y0y0 ] [ -t0t0 ] [
-dipdip ] [ -azimazim ] [ -rmaxrmax ] [ -vvel ] [ -ampamp ]
[ -P ] [ -C ] [ -H ] [ -V ] [ -? or -h ]
DESCRIPTION
spike3d computes trace-wise stick-o-grams based on an input
model description and fills out a three dimensional volume
of trace data [see Discussion below. Although spike3d
produces only one surface per execution but may be cascaded
to produce multi-event volumes.
spike3d gets both its data and its 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 is not required when piping
from another volume or if this is the initial spike3d
iteration. If picking up from a previous volume which
is not in the current directory be sure to use a fully
qualified dataset name.
-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.
-xmax xmax
Enter the maximum model volume X co-ordinate [ft or m].
The default is 1250.
-ymax ymax
Enter the maximum model volume Y co-ordinate [ft or m].
The default is 1250.
-tmax tmax
Enter the maximum model time [msec]. The default is
2000.
-xmin xmin
Enter the minimum model volume X co-ordinate [ft or m].
The default is -1250.0
-ymin ymin
Enter the minimum model volume Y co-ordinate [ft or m].
The default is -1250.0
-dx dx
Enter model volume X co-ordinate increment [ft or m].
The default is 25.
-dy dy
Enter model volume Y co-ordinate increment [ft or m].
The default is 25.
-dt dt
Enter model volume time sample increment [msec]. The
program interprets any sample interval greater than 32
as microseconds and applies the appropriate velocity
correction. The default is 2.
-x0 x0
Enter the X co-ordinate for the origin for the model
surface [ft or m]. This is the origin of symmetry
about which the surface will be generated. The default
is 0.
-y0 y0
Enter the Y co-ordinate for the origin for the model
surface [ft or m]. This is the origin of symmetry
about which the surface will be generated. The default
is 0.
-t0 t0
Enter the time co-ordinate for the origin for the model
surface [msec]. This is the origin of symmetry about
which the surface will be generated. The default is
0.0
-dip dip
Enter the dip in degrees for the model surface in the
case of a plane or a cone. The dip parameter is not
used in the case of an hyperboloid. The default is 0.
-azim azim
Enter the azimuth in degrees toward which the surface
is dipping in the case of a plane. This parameter is
not used in the case of either a cone or an hyper-
boloid. The default is 0.
-rmax rmax
Enter the distance [ft or m] away from the origin that
the surface should be generated. To generate a surface
over the whole model volume be certain that this param-
eter is larger that the largest offset from the origin
to the furtherest boundary of the model volume. The
default is 1000.
-v vel
Enter the desired velocity [ft/s or m/s]. The default
is 10000.
-amp amp
Enter the amplitude of the spikes, e.g. 307 for 15% of
2047 (default = 1). Note that if in the calculations
the spike3d time happens to fall between 2 samples a
linear interpolation is done spreading the amplitude of
the spike3d over the 2 sample points.
-P If present the surface generated will be a plane dip-
ping toward an azimuth of -azim at -dip degrees
from the horizontal embeded in a media of velocity -v
and illuminated from a surface position of [-x0,-y0] .
-C If present the surface generated will be a cone whose
limbs dip at an angle of -dip degrees from the hor-
izontal embeded in a media of velocity -v and
illuminated from a surface position of [-x0,-y0] .
-H If present the surface generated will be an hyperboloid
generated from a planar surface of zero dip with an
apex centered under the surface position of illumina-
tion [-x0,-y0] at a time of -t0 . The velocity -v
exists above the surface.
-V Enter the command line argument '-V' to get additional
printout.
-? or -h ]
Enter the command line argument '-?' or -h to get
online help. The program terminates after the help
screen is printed.
DISCUSSION
The size of the output dataset is governed by the parameters
affecting the model volume. These are -xmin -xmax -ymin
-ymax -tmax -dt -dx -dy . The X dimension is associated
with traces while the Y dimension is associated with
records. The model bin co-ordinates are placed in the trace
header mnemonics CDPBCX, CDPBCY . The trace header mnemon-
ics RecNum and LinInd are co-incident as are TrcNum
and DphInd . The surface position of the last source used
is contained in SrPtXC, SrPtYC . The radial distance of a
bin from the last source surface position is contained in
both DstSgn and DstUsg . Should a trace lie outside the
limits imposed by -rmax the static mnemonic StaCor will
be flagged with 30000 denoting a dead trace only if there is
no input model to the program, i.e this is the initial sur-
face being generated.
You may generate any one of three types of surfaces with
this package, a plane, a cone or an hyperboloid. Each is
defined in terms of depth and times are calculated as a
function of the dip, azimuth and velocity associated with
the model as required.
The plane utilizes -dip, -azim and -v in it's calculation.
The time of the plane beneath the surface position of the
source is -t0 .
The cone utilizes -dip and -v in it's calculation. The
time of the apex of the cone beneath the surface position of
the source is -t0 .
The hyperboloid utilizes only -v in it's calculation as
dip and azimuth of the surface may be emulated by moving the
apex of the hyperboloid around within the volume using the
-x0, -y0, -t0 parameters.
In all cases the surfaces are only generated for a radial
distance of -rmax from the source. To get a surface gen-
erated over the entire volume be sure to make -rmax large
enough.
BUGS
Although not strictly a bug, it is necessary to explicity
state the -xmin -xmax -ymin -ymax -tmax -dt -dx -dy -t0 -x0
-y0 information for each sucessive iteration. This allows
one to move the source around and produce events at dif-
ferent levels in the data. The -xmin -xmax -ymin -ymax
-tmax -dt -dx -dy entries must not vary for subsequent
surfaces generated within a single volume. If they do the
routine will abort with an error message to the printout
file.
AUTHOR
Paul G. Garossino: APR
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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