5 Aug
2020
5 Aug
'20
10:29 p.m.
Hello All
I am trying to pick first break arrivals in Zero Offset VSP on the
Crewes toolbox and another software. My problem is that I start picking
from 4th trace because I cannot see the first three traces when I look at
my data, which results in wrong velocities.
My data is passive zero-offset VSP data, utilizing ambient noise sources. I
created this by using a modeling code.
I added one of my data and the problem's screenshot
Can I fix this on Seismic Unix?
6 Aug
6 Aug
5:59 a.m.
I would use sushift to delay the traces and then subtract the delay from the subsequent
picks generated by sufbpickw
Regards
Rob
From: Seisunix <seisunix-bounces(a)mailman.seismic-unix.org> On Behalf Of Erdi Apatay
Sent: Wednesday, 5 August, 2020 11:30 PM
To: seisunix(a)mailman.seismic-unix.org
Subject: [Seisunix] VSP Processing
Hello All
I am trying to pick first break arrivals in Zero Offset VSP on the Crewes toolbox and
another software. My problem is that I start picking from 4th trace because I cannot see
the first three traces when I look at my data, which results in wrong velocities.
My data is passive zero-offset VSP data, utilizing ambient noise sources. I created this
by using a modeling code.
I added one of my data and the problem's screenshot
Can I fix this on Seismic Unix?
8:22 a.m.
Erdi - from your image it looks like you are generating the synthetic
data using a zero-phase wavelet but are then picking using a first-break
approach (assuming that the arrow represents the pick on the 4th trace).
I would suggest either picking on a peak using a threshold or modelling
using a minimum phase wavelet. As Rob says, you could shift the data
down with sushift but I suspect that the modelling has not created any
data before T=0 so this might not work.
Another alternative would be to set a negative start time in the
modelling if this is an option.
Regards
John Chamberlain
On 06/08/20 06:59, rob(a)xsgeo.com wrote:
I would use sushift to delay the traces and then subtract the delay
from the subsequent picks generated by sufbpickw
Regards
Rob
*From:*Seisunix <seisunix-bounces(a)mailman.seismic-unix.org> *On Behalf
Of *Erdi Apatay
*Sent:* Wednesday, 5 August, 2020 11:30 PM
*To:* seisunix(a)mailman.seismic-unix.org
*Subject:* [Seisunix] VSP Processing
Hello All
I am trying to pick first break arrivals in Zero Offset VSP on the
Crewes toolbox and another software. My problem is that I start
picking from 4th trace because I cannot see the first three traces
when I look at my data, which results in wrong velocities.
My data is passive zero-offset VSP data, utilizing ambient noise
sources. I created this by using a modeling code.
I added one of my data and the problem's screenshot
Can I fix this on Seismic Unix?
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2 comments
3 participants
participants (3)
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Erdi Apatay -
John Chamberlain -
rob＠xsgeo.com