Importing SBP segy - unable to change Y-coordinate byte location

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Frances Cooke

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Feb 1, 2017, 12:37:13 AM2/1/17
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When I input 2D seismic data it automatically selects byte 73 for x-coordinate range (which is correct) but byte 1 for y-coordinate range.  There is not the option in the drop down to change it to the correct header location (byte 77).  Any ideas how to change this?

Thanks

Frances
2017-02-01 16_23_57-Import SEG-Y Data.jpg

Blacker, Kieran J.

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Feb 1, 2017, 1:26:05 AM2/1/17
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Francis, 

Can you paste the header information, or send it to me as a text file? More than happy to take a look. Might be something wrong there

Thanks, 

Kieran 

Kieran John Blacker

Postgraduate Research Student

Structure & Rock Physics

Department of Geology

The University of Leicester

 

+44 (0) 116 252 2523

 

Alternative email: black...@gmail.com

From: 'Frances Cooke' via OpendTect Users [us...@opendtect.org]
Sent: 01 February 2017 05:26
To: OpendTect Users
Subject: [OpendTect_Users] Importing SBP segy - unable to change Y-coordinate byte location

When I input 2D seismic data it automatically selects byte 73 for x-coordinate range (which is correct) but byte 1 for y-coordinate range.  There is not the option in the drop down to change it to the correct header location (byte 77).  Any ideas how to change this?

Thanks

Frances

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Bert Bril

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Feb 1, 2017, 1:26:07 AM2/1/17
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Hi Frances,
Byte 77 is the preferred location, and it will be selected if there is
good data in that header field.

During the quick scan the tool can find bad data in the field (like 0's
or values way outside the survey). Then the location is removed from the
'possible' choices.

You can try to figure out what is in the header fields by using the
button with the 'hour glass'.

One thing is sure: there is something wrong with at least one of the
trace headers in the file if you are sure the true Y-coordinate should
be in byte 77. You may want to edit the headers using the 'Edit' tool
(right-top button on the window).


Bert


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F A Cooke

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Feb 1, 2017, 9:30:35 PM2/1/17
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Thanks Bert

After a closer look I don't think the y-coordinates are correct - I have negative values, this must be why byte 77 is being ignored.

I don't see the hour glass button..

F A Cooke

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Feb 1, 2017, 9:30:35 PM2/1/17
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Thanks Kieran for offering to help - I see now why byte 77 is not being used because my values are outside of the usable range.

matthew zengerer

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Jul 20, 2017, 7:07:04 AM7/20/17
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Dear Open Dtect users. I'm a complete novice at using this tool. I have stumblingly managed to set up a survey for a 2D job, but now can't import the seismics. There are a bunch of 2D seismics of various vintages and names. I think the tool will only let me import one at a time. However I keep getting stuck on the "Line Name" part with an error. After scanning my selected random 2D line I picked from my bunch of lines, it assigns a name adapted from the file name shown in the picture. However, when I press "OK" it says, "Please enter valid file name". I tried deleting and putting nothing, or writing a new one, using the one supplied as shown, nothing works. Stuck there. If there was one in the drop-down box, it wouldn't make any sense to pick that as that name would already belong to a different line. I went to Help and there was no information that could help.

What do I do??

sincerely

Stuck Novice



import_problem_opendtect.jpg

Victoria Romanova

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Jul 20, 2017, 8:16:39 AM7/20/17
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Hi Matthew,

This message prompts you to enter a name for the seismic data, not for the 2D line. Simply type in an output 2D dataset name to be used in an OpendTect project. Please find more information on the Import Window Help page.

Regarding the multiple 2D lines import, you can use a wildcard *. Let me insert a paragraph from our SEG-Y import doc (clicking on Help in the Import SEG-Y data window will redirect you to the relevant article):

 Import multiple 2D lines with pre- or post-stack data: files must contain individual 2D lines and be indexed with the respective line names as filename_linename1.sgy, filename_linename2.sgy...

    1. Select one of the files;
    2. replace the line name by a wildcard * in the input field: filepath/filename_*.sgy;
    3. those parts of file names replaced by * are used as 2D line names (press Next and see that Line name option is greyed out and set to *).

I would also recommend you to explore our fully searchable online documentation: Users Doc and Plugin Doc. Personally, I find it very useful in the beginning to work through some exercises from the Training Manual and How-To Instructions as well. 
 
Hoping this helps. 

Best regards,
Victoria

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matthew zengerer

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Jul 20, 2017, 9:50:07 AM7/20/17
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Dear Victoria, 

Thanks for the quick response and your input.

However, therein your comments lie the exact problem. I have already been to that Help Link, and tried the step it described for the Line Name.

It makes no difference whatsoever, I get the error message regarding a Valid Line Name on any name or option I try.

What could be causing the conflict?

This is where I am stuck, it won't accept any line name.


With regards to the multiple import, the wildcard doesn't work either, as most of the lines are from different vintages and have different names. Only a few follow a consecutive naming convention. Your option only works if files have consecutive names. I had already been to help and tried this out.

Even if it did, I can't get past the following step mentioned above.


I did mention both of these things with context in my original email.

Is there any further advice I can be given or am I permanently stuck?


Regards

Matthew



From: Victoria Romanova <victoria...@dgbes.com>
Sent: Thursday, 20 July 2017 9:43 PM
To: us...@opendtect.org
Subject: Re: [OpendTect_Users] Stuck on 2D Import
 
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Julien Moreau

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Jul 20, 2017, 11:22:13 AM7/20/17
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Hi,
From your screenshot, there is no name in the field. So the error message seems accurate.
If you have what you call different vintages, that have a closest equivalent as datasets in OdT, why would you like to have everything under the same dataset? Massive loading from different datasets leads to errors but might be handled in an easier way. You might expect too much from the automation. Do you manage to load a single line?
Best wishes,
Julien

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Victoria Romanova

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Jul 20, 2017, 11:22:15 AM7/20/17
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Matthew,

As I mentioned in my previous email, this error message complaints about a name for the output seismic dataset, not for the 2D line. The Output data set name represents a 2D survey that comprises one or more lines. Please type in a name for the 2D seismic dataset (in the highlighted field on the screenshot below). This dataset can group 2D lines of the same kind (i.e. a particular 2D vintage or type of data). An OpendTect project can have many 2D datasets. 

Inline image 1

Coming back to the multiple lines import... If the SEG-Y files do not have consecutive names, you can replace the whole thing with a wildcard: filepath/*.sgy. If the SEG-Y files are coming from different surveys, they can have different data format. If that's the case, please select "From file header" for Data format, as shown on the screenshot below. In case Z sampling rate and Z ranges are also different, then check the box File Z's on the right panel. Also, I need to mention that such import implies that all the files have same byte locations for X/Y pair, trace number and SP. In case these are different, files have to be imported separately.

Inline image 1

Hoping this clarifies a bit.

matthew zengerer

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Jul 20, 2017, 11:30:25 AM7/20/17
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Hi Julien, thanks for the response.

Nope, you have misread the image. The Trace subselection field is blank, the name field lies above it.

Your second response is redundant, sorry

Matt



From: Julien Moreau <moreau...@gmail.com>
Sent: Friday, 21 July 2017 12:13 AM
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Flocks, James

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Jul 20, 2017, 11:38:05 PM7/20/17
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"In case these are different, files have to be imported separately."

You can write an import script that sets each parameter per line and run it in the Command Driver.

Jim

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matthew zengerer

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Jul 20, 2017, 11:38:05 PM7/20/17
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Hi Victoria

OK, that answer was more useful thanks. 

It was the reference of the Error message to the Name which had me confused. In the window concerned, the only area where a Name is referenced is at the Input Line Name. That makes it look as though the error refers to this. The window field below just says "Output 2D data (attribute)" It doesn't say "Output 2D Line Name" and refers to attributes. This is quite misleading to a new user. You should provide consistency between what Error messages say and the source of the problem ("2D Data field incomplete" would be much more appropriate).

As it is, by default, the output should be automatically the same as the input, unless you desire to change it.


Something for the developers to consider.


I'll take your advice on the multiple imports. BTW, the Import 2D windows you get by clicking on the "SEGY" button in the main window and by using the drop down menu are slightly different, with slightly different proceeding windows. Why aren't these the same??


Then there is the "Classic" which is different again. More confusion for novice.


Thanks for the help Victoria, cheers

Matthew



From: Victoria Romanova <victoria...@dgbes.com>
Sent: Friday, 21 July 2017 12:37 AM

To: us...@opendtect.org
Subject: Re: [OpendTect_Users] Stuck on 2D Import
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matthew zengerer

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Aug 1, 2017, 9:37:09 AM8/1/17
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Hi User group

I'm suddenly getting errors in 2D seismic data import, and still haven't been able to successfully load seismic into my project.

I have checked my 2D seismic data in other software and they are fine.

However whether I am trying to load a single seismic line, or multiple lines, using the Segy Classic Tool, I get the following error as seen in attached screenshot.

I simply don't believe the message. I even tried re-initiating a new Survey and rescanning before importing seismics, made no difference at all.

There's nothing wrong with the segy data. When you do multiple imports, click try again and next, just same error. Single, same.

Quit Open dtect and start again. Now it thinks there is already some geometry there and asks if you if you want to overwrite, you say yes, and still get same error.

Why is this conflict occurring and how do I solve it?

I'm still finding simply loading 2D data in Open dTect an extremely confusing operation for something that should be simple.

Regards

Matthew

error_identical_positions.jpg

Bert Bril

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Aug 1, 2017, 10:13:05 AM8/1/17
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Hi all,



Matthew wrote:

> Why is this conflict occurring and how do I solve it?

I see the default (byte 5) selected for the trace number. But the
examine window shows that byte 5 header values are all 1, hence it is
not a usable trace number for this line.

By simply changing the byte number for the trace number to 21 (the CDP
number) or 1 (the trace sequence number) you'll be fine. Using the new
SEG-Y reading wizard, this 'tracr' field would have been filtered out as
being an impossible choice.


> I'm still finding simply loading 2D data in Open dTect an extremely
> confusing operation for something that should be simple.

First of all, we've tried to make it easier (and simpler) with the new
wizard but it seems not everyone has chosen to use it.

Secondly, figuring out exactly what is in a legacy SEG-Y file without
the help of humans requires a very high level of Artificial Intelligence
techniques. Rather, there are real choices that can be made. In the new
wizard, we have progressed making things easier. Possible fields are
selected, results of choices are immediately shown.


Lastly, please note that proper SEG-Y revision 1 files have very few
loading problems, the only real issue with those is that Rev.1 still
does not require or define a trace key number (it does define a shot
point number, but shot point numbers are not necessarily unique). That
is why you still have to identify a number that can serve as key for the
traces. Which ones suits you best is your choice.

matthew zengerer

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Aug 1, 2017, 11:04:01 AM8/1/17
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Thanks Bert.


I've just been stuck twice on seemingly impossible error, even my friend who knows Open dtect today didn't think of this. I'll try and remember in future.

Onto whatever next hurdle is....

Best Regards

Matthew

From: Bert Bril <bert...@dgbes.com>
Sent: Tuesday, 1 August 2017 11:37 PM
To: us...@opendtect.org
Subject: Re: [OpendTect_Users] Single or multiple 2D import errors - too many identical positions
 
An open source seismic interpretation environment for processing, visualizing and interpreting multi-volume seismic data.

dGB Earth Sciences is a company that provides innovative seismic software interpretation solutions to the oil & gas Industry



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Ahmad Maidinsar

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Aug 2, 2017, 2:55:39 AM8/2/17
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Hi MZ,

Would you mind sending me one line SEGY for me to test.

Obridago


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Gery .

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Aug 8, 2017, 11:49:27 PM8/8/17
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Hi,


You should take a look at the header of your SEGY first.


>> I'm still finding simply loading 2D data in Open dTect an extremely confusing operation for something that should be simple.


Well, I find it indeed very intuitive and useful, perhaps I am the only one thinking this, though.... but don't think so =)

Cheers,

Gery
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Aug 9, 2017, 1:45:05 PM8/9/17
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Hi people,

 

“one man's meat is another man's poison”

 

To me, Opendtect seismic loading is considered the simples if compared to others I’ve worked with.

 

This is my personal opinion, others might conclude the opposite.

 

Kind regards,

 

Sent from Mail for Windows 10

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