Hi Manabu -
I apologize for my late response ...
Thank you for your kind note. The goal of my writings and YouTubes is to make something
clear. I am very glad I could do that for you regarding SEG-Y and SU trace header byte
locations.
Regards, David
. . . . . . . . . . . . . .
On Sunday, October 23, 2022 at 04:30:54 PM MDT, <tanahashi.m(a)gmail.com> wrote:
Dear David, Seismic Rocks, LLC
Thank you for the information on your lecture movies about Seismic Unix on youtube
channel. I now understand the meaning of #180 and beyond in the SEG-Y trace headers and
how to identify and handle it.
Best regards,
Manabu Tanahashi
Tsukuba, Japan
From: David Forel <davidforel(a)yahoo.com>
Sent: Saturday, October 22, 2022 3:12 AM
To: seisunix(a)mailman.seismic-unix.org; dominique.rousset(a)univ-pau.fr;
tanahashi.m(a)gmail.com
Subject: Re: [Seisunix] Re: How to handle trace header information?
Hi Manabu -
I have a YouTube channel (Seismic Rocks LLC) (
https://www.youtube.com/channel/UCp66KhTgHf1V6KfEfH2OnnQ ) that has a video about
importing SEG-Y files that require "remap":
- "Seismic Unix: Complicated SEG-Y Import"
-
https://www.youtube.com/watch?v=1rHnxz5EkwI
Note that the description that goes with the video includes a link to a PDF of the same
information.
Regards, David
. . . . . . . . . . . . . .
On Thursday, October 20, 2022 at 03:31:26 AM MDT, <tanahashi.m(a)gmail.com> wrote:
Dear Dominique,
Thank you for the reply to my question.
As you suggested, I have to remap the inline and cross line numbers at #189-192 and
#193-196 to the unused integer keyword.
I was also personally informed from my friend in Japan how to remap trace header words
during segyread.
segyread tape=Source3D.sgy remap=swdep,gwdep byte=189l,193l | suresamp rf=0.5|segyhdrs |
segywrite tape=Output3D.sgy
The time resampled SGY data with inline and cross line numbers on #61-64 and #65-68 was
obtained.
It is good enough to load resampled data into my interpretation system.
Thank you very much again.
Best regards,
Manabu Tanahashi
Tsukuba, Japan
From: Dominique ROUSSET <dominique.rousset(a)univ-pau.fr>
Sent: Thursday, October 20, 2022 5:35 PM
To: seisunix(a)mailman.seismic-unix.org
Subject: [Seisunix] Re: How to handle trace header information?
Hi,
In the SU format, the bytes you use for inline and cross line numbers are allocated to SU
use (see sukeyword -o ; d2 and f2 are floats in SU). Bytes # 189-192 and # 193-196 are
inline/crossline numbers in segy rev1 for 3D post stack data. SU is not 3D fully capable
and segywrite does not use them for segy rev0 output.
I tried this simple test.
suplane | sushw key=d2,f2 a=3,4 | segyhdrs | segywrite tape=plane.segy
segyread tape=plane.segy | surange
tracl 1 32 (1 - 32)
tracr 1 32 (1 - 32)
offset 400
ns 64
dt 4000
d2 0.000000
f2 0.000000
:-(
I don't see any solution at the user level without modifying segywrite to introduce
header remapping à la segyread.
Within SU, I suggest that you use other keywords to store the inline and cross line
numbers (such as swdep/gwdep, 4 bytes integers) and apply header remapping to read the
data in other software. Anyway, using bytes # 189-196 in SU will complicate data display.
suplane | sushw key=swdep,gwdep a=3,4 | segyhdrs | segywrite tape=plane.segy
segyread tape=plane.segy | surange
tracl 1 32 (1 - 32)
tracr 1 32 (1 - 32)
offset 400
swdep 3
gwdep 4
ns 64
dt 4000
D.
Le 20/10/2022 à 01:35, tanahashi.m(a)gmail.com a écrit :
Dear all,
I have performed a time resample of some 500ns sampled 3D seismic data to 1ms intervals
using the suresamp command as shown below, but was unable to transcribe the 189-192 bytes
of the Inline and the 192-196 bytes of the crossline numbers.
segyread tape=Source3D.sgy|suresamp rf=0.5|segyhdrs|segywrite tape=Output3D_1ms.sgy
I solved this problem by using the ASCII input/output function for trace header on SeiSee,
a free Windows software, to write out the header information of the original file and then
write it into the header of the output file.
Is there a way to transcribe inline and crossline numbers using the SU function?
Manabu Tanahashi
Tsukuba, Japan
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-- |Dominique Rousset LFCR UMR5150 / E2S UPPA / Dpt des géosciences| |Univ. Pau
et des Pays de l'Adour BP 1155 F-64013 Pau Cedex -
France||mailto:dominique.rousset@univ-pau.fr
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