SUDMOVZ - DMO for V(Z) media for
common-offset gathers
sudmovz <stdin >stdout cdpmin= cdpmax= dxcdp= noffmix= [...]
Required Parameters:
cdpmin minimum cdp (integer number) for which to apply DMO
cdpmax maximum cdp
(integer number) for which to apply DMO
dxcdp distance between adjacent cdp bins (m)
noffmix number of offsets to mix (see notes)
Optional Parameters:
vfile= binary (non-ascii) file containing interval velocities
(m/s)
tdmo=0.0 times corresponding to interval
velocities in vdmo (s)
vdmo=1500.0 interval velocities corresponding to times in tdmo (m/s)
fmax=0.5/dt maximum frequency in input traces (Hz)
smute=1.5 stretch mute
used for NMO correction
speed=1.0 twist this knob for speed (and aliasing)
verbose=0 =1 for
diagnostic print
Notes:
Input traces should be sorted into
common-offset gathers. One
common-
offset gather ends and
another begins when the offset field of the trace
headers changes.
The cdp field of the input trace headers must
be the cdp bin NUMBER, NOT
the cdp
location expressed in units of meters or feet.
The number of offsets to mix (noffmix) should
typically equal the ratio of
the
shotpoint spacing to the cdp spacing.
This choice ensures that every
cdp will be represented in each offset mix. Traces in each mix will
contribute through DMO to other traces in adjacent cdps within
that mix.
vfile should
contain the regularly sampled interval velocities as a
function of
time. If vfile is not supplied, the
interval velocity
function is defined by linear interpolation
of the values in the tdmo
and vdmo arrays. The times in tdmo must be monotonically increasing.
For each offset, the minimum time to process is determined using
the
smute parameter. The DMO
correction is not computed for samples that
have experienced greater stretch during NMO.
Trace header fields accessed: nt, dt, delrt, offset, cdp.