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|Author||Topic: Example of a 3D land denoise/despike sequence||6741 Views|
30 November -0001 at 12:00am Last edited: 3 November 2011 3:54pm
please share the example job deck issue defined in the attached file.
30 November -0001 at 12:00am Last edited: 14 November 2011 6:49pm
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.
20 June 2011 at 6:11pm Last edited: 6 September 2011 8:07pm
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.
3 November 2011 at 2:53pm Last edited: 3 November 2011 4:00pm
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.
4 November 2011 at 2:00am Last edited: 6 November 2011 9:18pm
For issue of Ground roll,
please explain the OFFSET/4 and how plot redline present in the ppt file.
please explain briefly.
6 November 2011 at 9:36pm Last edited: 30 November -0001 12:00am
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.
14 November 2011 at 6:53pm Last edited: 14 November 2011 10:23pm
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.
14 November 2011 at 10:23pm Last edited: 16 November 2011 2:55pm
please explain with jobdeck example.
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