Compute attributes between horizons or along horizon 2D

[Kristina Kucinskaite]

Dear OpendTect team,

I am trying to compute attributes between (1) two horizons and (2) along horizon on 2D seismic line. However, both approaches does give me the message "no data exists". I have attached screenshots of the message logs.

Is there any way to solve this or find a way around?

Best regards,

Kristina

[Paul de Groot]

Hi Kristina,

I'm afraid you ran into a bug. I tried it myself and encountered the same problem. I will file a report in Jira, our bug reporting system.

The good news is that this utility is only a convenience tool. You can replicate this with 3 attributes: two horizon attributes to get the Z-value of top and base of the interval and a mathematics attribute that you apply via the Processing -> Create Seismic output -> Single attribute -> 2D ... menu.

Let's call the output of the 1st horizon attribute Ztop and the output of the 2nd horizon attribute Zbot. Then in the Mathematics attribute you specify the following equation:

Z < Ztop || Z > Zbot? undef : attr

in words: IF Z is smaller than Ztop OR larger than Zbot OUTPUT the undefined value ELSE output the attribute.

Best regards,

Paul.

--

Paul de Groot

Special Adviser

-----------------------------------------------------------------------------------------------------------------------   dGB Earth Sciences
Phone: +31 53 4315155 E-mail: paul.d...@dgbes.com Internet: dgbes.com

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[Kristina Kucinskaite]

Dear Paul,

Thank you for your reply!

I am trying your proposed approach, however it is impossible to select horizons for Ztop and Zbot, since I cannot calculate the horizon attributes due to the bug. The horizon attributes simply are not in the selection. As well as the horizons themselves. I hope you understand what I am saying, here I attach a screenshot of the selection (horizon attribute called Ztop is not there):

I hope there is another alternative to this inside the software.

Best regards,

Kristina

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[Paul de Groot]

Hi Kristina,

Apparently, my explanation was a bit too cryptic. Please find below 4 screenshots. The first one is the attribute that you want to compute inside the interval marked by a top and a bottom horizon. Replace this by whatever you like to compute. Attributes 2 and 3 are the horizon attributes that return the Z value of the respective horizons. These Z values are used in the 4th attribute that sets the attribute to undefined in the intervals above and below the interval of interest and computes the attribute in the interval only. I hope this is clearer.

Best regards,

Paul.

Attribute 1: Energy (but this can be anything you like)

Attribute 2: horizon attribute returns the Z value of the top horizon.

Attribute 3: horizon attribute returns the Z value of the bottom horizon.

Attribute 4: Mathematics attribute computes attribute 1 inside the interval and returns undefined values outside

--

Paul de Groot

Special Adviser

-----------------------------------------------------------------------------------------------------------------------   dGB Earth Sciences
Phone: +31 53 4315155 E-mail: paul.d...@dgbes.com Internet: dgbes.com

----------------------------------------------------------------------------------------------------------------------- 

To view this discussion visit https://groups.google.com/a/opendtect.org/d/msgid/users/CA%2Br_Z35mrP4DaVkkDT21hv%2BDTLhOqo5xy-Uo3p_oLhhZHqM1ZA%40mail.gmail.com.

[Kristina Kucinskaite]

Hi Paul,

Thank you so much for the clarification! I managed to do it now!

Best regards,

Kristina

To view this discussion visit https://groups.google.com/a/opendtect.org/d/msgid/users/CABuvx8E6NGS5XD_QWH2VveVyaP6QRmWZwvuobLTzwQWT_r0jmg%40mail.gmail.com.

[Paul de Groot]

Hi Kristina,

Glad it worked and thanks for sharing your results. FYI you can change the transparency of the attribute layer to see the seismic response underneath. The attached image is made with 50% transparency (Display - > Change transparency ... menu) applied to the attribute layer.

Best regards,

Paul.

--

Paul de Groot

Special Adviser

-----------------------------------------------------------------------------------------------------------------------   dGB Earth Sciences
Phone: +31 53 4315155 E-mail: paul.d...@dgbes.com Internet: dgbes.com

----------------------------------------------------------------------------------------------------------------------- 

To view this discussion visit https://groups.google.com/a/opendtect.org/d/msgid/users/CA%2Br_Z34wfkocZCJLtKN9y9R-yocBvC-etk77n4CKuj%3DcVR3RcQ%40mail.gmail.com.