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Noise Attenuation

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Author Topic: Example of a 3D land denoise/despike sequence 7156 Views

Re: Example of a 3D land denoise/despike sequence Link to this post

please share the example job deck issue defined in the attached file.

Re: Example of a 3D land denoise/despike sequence Link to this post

For groundroll, you used the SETHEADER module and apply this rec_water=offset/4, and using the ZEROMUTE module to mute out this. in land data how we deel with negative value of offset.
for land data ,if we apply this flow up to Zeromute and display the data then we see the positive offset data mute out and negative offset remains. what we do to mute out the negative offset data.
regards
masood

Example of a 3D land denoise/despike sequence Link to this post

The attached presentation shows how a 3D Land noise attenuation and despike series can be built up and tested in stages. The ability to duplicate a trace, process the two copies differently and then merge them back at a "splice point" with tapers (using STORE1, STORE2 and MERGE under older versions, or PSEUDOMATH for V5.5+) adds a lot of flexibility into managing noise issues.

Re: Example of a 3D land denoise/despike sequence Link to this post

Masood,

Attached is an example of the work flow that we implimented and is described in the powerpoint
presentation. You will need to optimise the parameters for your own dataset. Any questions let us know.

Regards

Andy

Re: Example of a 3D land denoise/despike sequence Link to this post

For issue of Ground roll,
please explain the OFFSET/4 and how plot redline present in the ppt file.

please explain briefly.

Re: Example of a 3D land denoise/despike sequence Link to this post

Masood,

In the example dataset used for the ppt presentation the ground roll/surface wave noise has a linear moveout equivalent to 400m/s, and is plotted is as the red line on the display. And in this case as the offsets are defined in metres this redline can be defined as a simple mathematical equation Offset/4 and written to the trace headers using the HDRMATH module.

To test the optimal LMO fit for the ground roll you can use the Plot OFFSET HEADER option found under the Utilities menu of the XVIEW or SV window, and by varying the velocity component on the parameter form tune the LMO into best fit your dataset.

Re: Example of a 3D land denoise/despike sequence Link to this post

Masood,

The simplest thing to do is use SETHEADER to copy the original offsets to a new header location to preserve the original sign of the offset, Then using an IF loop to select only the negative offsets use SETHEADER to reassign the OFFSET header as a positive offset by multiplying by -1. When you have completed your denoise processing flow you can copy your original OFFSET values back into the OFFSET header.

Regards

Andy

Re: Example of a 3D land denoise/despike sequence Link to this post

please explain with jobdeck example.

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