NAME
scope3d - compute 3D volume of attributes under horizon con-
trol for prestack or poststack data
SYNOPSIS
scope3d [ -Nntap ] [ -Ootap ] [ -global ] [ -hwhdrwrd ] [
-rwrefwrd ] [ -awatrwrd ] [ -vvtap ] [ -Mmtap ] [ -Tttap ] [
-Pptap ] [ -sist ] [ -eied ] [ -flfl ] [ -fhfh ] [ -dfdf ] [
-x1x1 ] [ -y1y1 ] [ -x2x2 ] [ -y2y2 ] [ -x3x3 ] [ -y3y3 ] [
-x4x4 ] [ -y4y4 ] [ -cldmcldm ] [ -ildmildm ] [ [ -dmindst-
min ] [ -dmaxdstmax ] [ -ddeldstdel ] [ -fcfcut ] [
-threshfthresh ] [ -minfmin ] [ -maxfmax ] [ -ordiord ] [
-pkthrfpkthr ] [ -diminmindi ] [ -dimaxmaxdi ] [ -liminminli
] [ -limaxmaxli ] ] [ -cdp ] [ -stk ] [ -trp ] [ -R ] [ -nmo
] [ -f2m ] [ -m2f ] [ -V ] [ -? ]
DESCRIPTION
scope3d reads either prestack or poststack data and for each
input trace extracts a window around a time defined either
by a horizon(s) or trace header time and computes a number
of attributes, and their offset dependencies (for prestack)
and writes the results into an output volume. This is a way
of extracting attribute information for massive amounts of
input data since the output attribute volume will consist of
traces with at most a few hundred samples. The output attri-
bute volume(s) and the normalization volume(s) can be time
sliced so that each attribute can be studied for the entire
survey.
Currently the following attributes are computed: max abso-
lute amplitude, its time, maximum positive amplitude, its
time, maximum negative amplitude, its time, standard devia-
tion, peak frequency, Q, maximum envelope, its time,
response phase at maximum amplitude, response amplitude,
response length, instantaneous bandwidth, trace header
attribute value (or zero), the integrated power sprectral
value, the response frequency, plus the spectral amplitudes
at the specified frequency increment. Each output trace will
consist of the following: the first 19 samples are the above
attributes regardless of offset; the next samples are the
spectral amplitudes at the specified frequency increment;
next, the 19 attributes are computed for each offset bin;
next the slopes of each of the fifteen attributes as a func-
tion of offset are computed; the next 19 values are the
result of fitting a parabola to each of the attribute -
offset functions and finding the offset location of the peak
vaue; next, the frequency sprectrum is written out at the
specified increment for each offset bin; finally, the
stacked windowed trace samples are output, normalized by the
number of live samples.
Time slicing the output volume will result in a data set
where each record is one of the above attributes for the
selected portion of the survey. These can then be displayed
or used in correlation studies. The unsliced volume can also
be imported into the interpretive workstation and the 3D
visualization tools used.
There will be a number of output volumes (and normalization
files) equal to the number of horizons in the horizon file.
The input data can be in any sort order (shot, group, cdp,
offset) but pre-stack must at least have the source X-Ys
(SrPtXC and SrPtYC) and the receiver X-Ys (RcPtXC and
RcPtYC) trace header words properly filled in since these
are are critical to calculating where the trace belongs.
Post stack the CDPBCX and CDPBCY trace header entries must
be filled in.
For pre stack data it is assumed that the basic corrections
have been made, e.g. refraction statics, velocity analysis,
residual statics. Other processes such as deconvolution and
coherent noise filtering can be done on the fly before input
into the cdp attribute bin stack. Optionally internal NMO
corrections and time-offset muting can be done given an
input velocity volume.
For post stack data users should be aware that program
windstat also exists and will compute attributes between two
horizons defined by the contents of two user defined header
words. Output format is the same as for scope3d.
scope3d gets both its data and its parameters from command
line arguments. These arguments specify the input and out-
put files, normalization files, and global control parame-
ters.
Command line arguments
-N ntap
Enter the input prestack of poststack 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 attribute stack data set name or file
immediately after typing -O. This output file must be
a disk file and cannot be piped. There must be an equal
number of output files and normalization files as there
are horizons.
-global
Enter the command line argument '-global' to take win-
dow center times from a trace header word (see -hw[]
below). This assumes that NMO has already been applied
to the data and so the -v[] input will be ignored. Also
bypassed will be the horizon file input -P[] and the
mute input file -M[]. This option currently only sup-
ports a single window position, i.e. effectively only
one horizon. The line header value of TmMsFS (time of
first sample) is read in case a previous wind operation
has been done. Trace header times from a horizon file
can be inserted into the trace headers by using program
tim2hed3d which has a number of smoothing/surface fit-
ting options. If a single horizon is used it is recom-
mended that this procedure be used because of the flex-
ibility of tim2hed3d over the scope3d horizon
machinery.
-hw hdrwrd
For the -global option enter the trace header word
mnemonic containing the window center times.
-rw refwrd
Enter the optional trace header word mnemonic contain-
ing a window reference time. This is used to reference
the analysis window time back to the start of the trace
and appears only in the time calculations, e.g. time of
maximum positive amplitude. Default = 0.
-aw atrwrd
Enter the optional trace header word mnemonic contain-
ing an attribute value. The program extarcts whatever
it finds in this trace header word and keeps track of
it in its attribute calculations, i.e. offset depen-
dence. Default = no trace hdr attribute.
-v vtap
Optional: enter the name of the RMS velocity disk file
for optional internal NMO correction. There must be a
velocity function at every bin location and there must
be an equal number of samples per trace as the input
data.
-M mtap
Enter (optional) the name of the file containing a
distance-time mute function which will be applied after
NMO correction. The format is similar to that for a
velocity flat file: each line consists of a time (ms),
an offset (ft,m), and a record number. The function is
terminated by a negative time (followed by any two
values). Currently only a single function is allowed so
you can put any record number in the third column (but
you must put something). There is also a default ramp
of 48ms applied starting at zero 48ms earlier then the
given mute time and ramping to one at the mute time. If
an input trace offset lies outside the mute function
distance range no muting is done. Default is to do no
muting at all if the -m[] is left off the command line.
-T ttap
Enter the name of the normalization file. This must be
a disk file. There must be an equal number of output
files and normalization files as there are horizons.
-P ptap
Enter the name of the horizons file in 5-col Landmark
format (must all be floating point values, i.e. no
integers). If there are more than one horizon they must
be separated by a blank or null line. There must be an
equal number of output files and normalization files as
there are horizons.
-s ist
Enter the time in ms above the horizon time to start
windowing. No default. Total window length will be ist
+ ied
-e ied
Enter the time in ms below the horizon time to end win-
dowing. No default. Total window length will be ist +
ied
-fl fl
Enter the start frequency (Hz) of interest. Default = 5
-fh fl
Enter the end frequency (Hz) of interest. Default =
nyquist/2
-df df
Enter the frequency increment (Hz). This will be the
increment of the output spectra written into the output
attribute volume. Default = 5
-fc fcut
Enter the cutoff frequency for Q estimation in fraction
of nyquist. Default = nyquist / 2
-x1,-y1,-x2,-y2,-x3,-y3,-x4,-y4 [x1,y1,x2,y2,x3,y3,x4,y4]
Enter the area of interest over the survey with the X-Y
coordinates (ft,m) defining the four corners of a
parallelogram on the ground. Going either clockwise or
counter clockwise (clockwise recommended) from Corner 1
the first move to Corner 2 should be in the direction
of a receiver or shot line. The direction 1-2 will
always define the Y or DI direction. The DIs will
always start from side 1-4 and increase in the 1-2 (Y)
direction; the LIs will always start from side 1-2 and
increase in the 1-4 (X) direction. The values must be
the same units as those given in the source, receiver,
and midpoint X-Ys in the trace headers.
-cldm cldm
Enter the crossline (along X or side 2-3) cell dimen-
sion (ft,m). For most shooting geometries this will be
1/2 the line or group spacing depending on the orienta-
tion of side 2-3 with respect to the receiver lines.
The sides are defined to be X along side 1-4 (roughly
cross-line direction), Y along side 1-2 (roughly in-
line direction). Remember when setting up the coordi-
nate system the line joining Corner (1) to Corner (2)
should be in the direction of a receiver or shot line.
No default.
-ildm ildm
Enter the inline (along Y or side 1-2) cell dimension
(ft,m). For most recording geometries this will be 1/2
the line or group spacing depending on the orientation
of side 1-2 with respect to the receiver lines. The
sides are defined to be X along side 1-4 (roughly
cross-line direction), Y along side 1-2 (roughly in-
line direction). Remember when setting up the coordi-
nate system the line joining Corner (1) to Corner (2)
should be in the direction of a receiver or shot line.
No default.
-dmin dstmin
Optional: Enter the minimum offset to use in the model
spread geometry. This will define the number of offset
bins to use. The total number of bins will be (dstmax -
dstmin) / dstdel. Try not to make this number too
large. We are after gross offset dependent features of
the windowed data. In most cases 4 or 5 offset bins
will be sufficient to capture the essential offset
dependent features in the data.
-dmax dstmax
Optional: Enter the maximum offset to use in the model
spread geometry. This will define the number of offset
bins to use. The total number of bins will be (dstmax -
dstmin) / dstdel. Try not to make this number too
large. We are after gross offset dependent features of
the windowed data. In most cases 4 or 5 offset bins
will be sufficient to capture the essential offset
dependent features in the data.
-ddel dstdel
Optional: Enter the offset bin size to use in the model
spread geometry. This will define the number of offset
bins to use. The total number of bins will be (dstmax -
dstmin) / dstdel. Try not to make this number too
large. We are after gross offset dependent features of
the windowed data. In most cases 4 or 5 offset bins
will be sufficient to capture the essential offset
dependent features in the data.
-limin, limax minli, maxli
Optional: enter the minimum and maximum line indexes to
output. The output survey will have so many bins in the
inline direction and so many bins in the crossline
direction. This is a handy way to start and end output-
ting bins at specified sequential inline numbers.
Default is the first and last inline bin as determined
from the 4 corners of the survey provided on the com-
mand line..
-dimin, dimax mindi, maxdi
Optional: enter the minimum and maximum crossline
indexes to output. The output survey will have so many
bins in the inline direction and so many bins in the
crossline direction. This is a handy way to start and
end outputting bins at specified sequential crossline
numbers. Default is the first and last crossline bin as
determined from the 4 corners of the survey provided on
the command line..
-max max
Enter maximum MEM order to use. Each frequency peak in
the sprectrum will have an order of two associated with
it, e.g. two peaks will require an order 4 MEM computa-
tion. The more complicated the spectrum the higher the
order required but in general for Q calculations use as
low an order as possible. Default = 2
-min min
Enter minimum MEM order to use. Each frequency peak in
the sprectrum will have an order of two associated with
it, e.g. two peaks will require an order 4 MEM computa-
tion. The more complicated the spectrum the higher the
order required but in general for Q calculations use as
low an order as possible. Default = 2
-ord iord
Enter order of smoothing to be done to the frequency
spectra in the Q-calculation. This value must be at
least three time smaller than the total number of fre-
quencies. Default = 7
-thresh thresh
Enter sprectral amplitude cutoff in db for Q estima-
tion. Amplitude below this value will not be used.
Default = 12
-pkthr pkthr
Enter peak picking threshold as a fraction of 1.0 for
asig calculations. Default = .15
-cdp Enter the command line argument '-cdp' to use CDPBCX &
CDPBCY trace header words for XYs; otherwise source &
receiver XYs will be used and the midpoint XYs will be
computed.
-stk Enter the command line argument '-stk' if input data is
poststack. If this is flagged there will be no offset
dependencies. CDPBCX & CDPBCY header words are used to
get XY information.
-R Enter the command line argument '-R' to restart a pre-
vious run that has stopped for some reason. The stderr
messages will announce every sequential record about to
be processed so the user can easily determine where in
the input data set the process stopped. By using suit-
able editt parameters the cdp run can be continued at
the point at which it stopped without the previous data
being wiped.
-nmo Enter the command line argument '-nmo' if NMO is to be
applied internally. If this is flagged then a suitable
RMS velocity volume must exist.
-trp Enter the command line argument '-trp' to interpolate
the input horizon times. If this is flagged there will
be no holes left in the horizons. If there are holes
left in the horizon on purpose then no attribute
analysis will be done within that zone and you do not
want to interpolate.
-f2m Enter the command line argument '-f2m' to convert the
input XYs from feet to meters
-m2f Enter the command line argument '-m2f' to convert the
input XYs from meters to feet
-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.
BUGS
No checks on the input trace headers to see if they have
valid source, receiver, or midpoint X-Ys.
EXAMPLE
Create an attribute volume from disk input:
gather -N/data1/idat1 -N/data1/idat2 -N/data1/idat3 -S | \
pred -p32 -ol200 -TV | \
scope3d -Oatts -x13000 -y12000 -x20 -y23000 -x30 -y30 \
-x43000 -y40 -vvel -ildm50 -cldm100 -sfI48 -e48 \
-df5 -dmin200 -dmax6800 -ddel1600 -Phorzs -fl5 -df5 \
-Ttmp
where the the X-axis corresponds to the receiver lines and
we go counter clockwise starting from the upper right
(northeast) corner along a receiver line. The input data is
spread out over 3 disk partitions and we use gather to
assemble them in sequence. The input stream is also passed a
time varying predictive decon. The horizon file horzs con-
tains a single horizon and our window will be +- 48ms above
and below the horizon time for each cell. The spread
geometry is defined by 4 bins and the frequency output will
be from 5Hz to half nyquist (62.5Hz for 4ms data) in 11 5Hz
wide bins.
SEE ALSO
windstat, asig, qest
AUTHOR
Paul Gutowski (socon 422) 3146, email pgutowski@amoco.com
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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