SYNOPSIS
PERL PROGRAM NAME:
AUTHOR: Juan Lorenzo (Perl module only)
DATE:
DESCRIPTION:
Version:
USE
NOTES
Examples
SYNOPSIS
SEISMIC UNIX NOTES SUKDSYN2D - Kirchhoff Depth SYNthesis of 2D seismic data from a
migrated seismic section
sukdsyn2d infile outfile [parameters]
Required parameters:
infile is stdin input migrated section
outfile is stdout file for output seismic traces
ttfile= file for input traveltime tables
The following 9 parameters describe traveltime tables:
fzt= first depth sample
nzt= number of depth samples
dzt= depth interval
fxt= first lateral sample
nxt= number of lateral samples
dxt= lateral interval
fs= x-coordinate of first source
ns= number of sources
ds= x-coordinate increment of sources
The following 6 parameters describe the migration section:
fz= first z-coordinate in migrated section
dz= vertical spacing of migrated section
nz= number of depth points in migrated section
fx= first x-coordinate of migrated section
dx= horizontal spacing of migrated section
nx= number of lateral points in migrated section
Optional Parameters:
nt=501 number of time samples
dt=0.004 time sampling interval (sec)
ft=0.0 first time (sec)
nxo=1 number of source-receiver offsets
dxo=25 offset sampling interval
fxo=0.0 first offset
nxs=101 number of shotpoints
dxs=25 shotpoint sampling interval
fxs=0.0 first shotpoint
fmax=1/(4*dt) maximum frequency in migration section (Hz)
aperx=nxt*dxt/2 modeling lateral aperature
angmax=60 modeling angle aperature from vertical
v0=1500(m/s) reference velocity value at surface
dvz=0.0 reference velocity vertical gradient
ls=1 flag for line source
jpfile=stderr job print file name
mtr=100 print verbal information at every mtr traces
Notes:
This program takes a migrated seismic section and a set of travel time
tables generated using rayt2d for a specific background velocity model
and generates synthetic seismic data in the form of common shot gathers.
(Common offset gathers may be generated by using nxo=1.) (Demigration.)
This program is a tool which may be used for the migration residual
statics estimation technique of Tjan, Audebert, and Larner 1994. 1. The traveltime tables are generated by program rayt2d (or other ones)
on relatively coarse grids, with dimension ns*nxt*nzt. In the
modeling process, traveltimes are interpolated into shot/geophone
positions and migration section grids. 2. The input migration section must be an array of binary floats (no SU
headers). ", 3. The synthesized traces are output in common-shot gathers in SU format.
4. The memory requirement for this program is about
(ns*nxt*nzt+nx*nz+4*nr*nzt+3*nxt*nzt)*4 bytes
where nr = 1+min(nxt*dxt,0.5*offmax+aperx)/dxo.
Author: CWP: Zhenyue Liu, 07/24/95, Colorado School of Mines
References:
Tjan, T., F. Audebert, and K. Larner, 1994,
Prestack migration for residual statics estimation in complex media
(Appeared in 1994 Project Review, CWP-153.)
Tjan, T., 1995, Residual statics estimation for data from structurally
complex areas using prestack depth migration: M.Sc. thesis, Colorado
School of Mines. (In progress.)
Larner, K., and Tjan, T., 1995, Simultaneous statics and velocity
estimation for data from structurally complex areas.
(Appeared in 1995 Project Review, CWP-185.)
Trace header fields set: ns, dt, delrt, tracl, tracr, fldr, tracf
offset, sx, gx, trid, counitUser's notes (Juan Lorenzo) untested
CHANGES and their DATES
Import packages
instantiation of packages
Encapsulated hash of private variables
sub Step
collects switches and assembles bash instructions by adding the program name
sub note
collects switches and assembles bash instructions by adding the program name
sub clear
sub angmax
sub aperx
sub ds
sub dt
sub dvz
sub dx
sub dxo
sub dxs
sub dxt
sub dz
sub dzt
sub fmax
sub fs
sub ft
sub fx
sub fxo
sub fxs
sub fxt
sub fz
sub fzt
sub infile
sub jpfile
sub ls
sub mtr
sub nr
sub ns
sub nt
sub nx
sub nxo
sub nxs
sub nxt
sub nz
sub nzt
sub outfile
sub ttfile
sub v0
sub get_max_index
max index = number of input variables -1