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How to merge LAS file curves into a single LAS file using free tools


This recipe shows how to merge curves from different LAS files. You may have one target LAS file with a particular depth step resolution and start and end depths, and need to add into it, several curves from other source LAS files with different layouts of depth step resolution and start and end depths.


GeolOil offers two approaches to solve this common problem. Your licence may have enabled the feature to edit the Curves Section. The first approach requires simply to use the Export Curve and Import Curve GUI buttons. This is by far the recommended, easiest, quickest and most reliable method to merge LAS file curves. If your licence does not has this feature enabled, you still can merge the LAS file curves, but then you would need to write a small script in our GLS scripting programming language.


Merging LAS file curves using the GUI Export and Import Curves buttons


No matter what is the depth step resolution, or the start and end depths of the different LAS files, GeolOil will append curves to the target LAS file seamlessly. To merge curves from different LAS sources follow these steps:

  1. Open a source LAS file.
  2. Export all desired curves with the Export Curve button, one by one.
  3. Import the just exported curves into the target LAS with the Import Curve button, one by one.
  4. Finally, export the resulting merged LAS file with the Export LAS button. If needed, repeat the procedure with other different source LAS files to add all the needed curves.


The figure below shows the Curves Section TAB, and the buttons Export Curve and Import Curve needed to merge LAS curves.


Merging LAS file curves with GeolOil Software



Merging LAS file curves writing a script using the free GLS Scripting Language


To merge all petrophysical source curves into a target, destination or final LAS file, you can use the free GLS GeolOil Scripting Language following these recipe example steps:

  1. Load the first LAS file from disk to GLS memory.
  2. Export a desired curve from the first LAS to the disk. This will create a two columns text file formatted {(MD, CurveSignal)}
  3. Export any other curves from the first LAS to the disk. This will create plain text files {(MD, CurveSignal)}
  4. Load the second LAS file from disk to memory.
  5. Export any desired curves from the LAS to the disk, as the steps 2 and 3.
  6. Repeat the same steps 1-3 with any amount of LAS files and curves.
  7. Take as template a basis LAS file, with the desired settings of depth resolution and start and end depths.
  8. Load one by one all the exported plain text file curves into this target LAS.
  9. Append the imported new curves to the current original curves of the target LAS.
  10. Export the resulting LAS file with the appended curves.


GeolOil will take care of the proper handling of missed -999.25 curve values, different depth resolutions and starting and ending depths. A particular optional fine tunning action (showed in the example GLS script) is recommended if there are big differences in LAS file depth resolutions.


For instance, let's suppose that the first LAS file comes with 1.0 foot depth resolution and the target LAS file to contain the merged curves is a high resolution one of say 0.25 ft. Likewise, let's suppose that the second LAS file comes with a resolution of 0.5 ft. For the first coarse 1.0 foot depth resolution LAS file, we would like to fill all the implicit 0.25 foot depth steps gaps of the final LAS file to merge. We do this with the command curve.fillGaps 1.0, likewise, for the second curve we would use curve.fillGaps 0.5.


Of course, if for some reason, there are plenty of noisy void gaps with -999.25 vales, we may want to interpolate chunks, say of 2.0 ft. as well with the command: curve.fillGaps 2.0, or other desired amount to fill void gaps with step wise linear interpolations.


You are welcome to freely use the script below for your work, even for commercial projects. But please refer you used, or adapted the script from www.geoloil.com, giving us fair credits. You don't need to type the code, as it comes packaged with the GeolOil license built-in data-set.


On a typical Windows installation just follow: [File] -> [Open_GLS_Script] -> [Open] -> [UserHomeDir] -> [GeolOil_DB] -> [GLS_examples] -> [merge_example.gls] -> [Run]. The script will create a .LAS file called merge_123.las




The figure below shows a GLS script to merge curves from two LAS files into a target LAS file.


GLS script algorithm to merge LAS file curves into a destination LAS file




The figure below highlights in dark blue, two curves from the first LAS file to be merged into a target LAS file.


GeolOil first curve listing of a LAS file to be merged into a final LAS file




The figure below highlights in dark blue, one curve from the second LAS file to be merged into a target LAS file.


GeolOil second curve listing of a LAS file to be merged into a final LAS file




The figure below highlights in dark blue, the three LAS file curves that were merged into the final target LAS file.


GeolOil curve listing of a merged LAS file from two source LAS files





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