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Digitizing Logs and Exporting a Single-Line or Multi-Line LAS file Using Didger

In addition to being able to export a single-line LAS file, Didger 4 has the new ability to export a multi-line LAS file. Since Didger only accepts one calibration at a time, this is useful if you are either digitizing a single log or if all your logs use the same scale. The single exported LAS file would contain the data for all digitized lines, be it one line or multiple lines.

 

However, in many cases the different logs use different scales. In this case, you may want to digitize and export multiple lines that have different scales into one LAS file. This can also be done in Didger with a few modifications.

 

Instructions for both cases are described in detail below:

 

Method 1: Digitizing and exporting a single log, or multiple logs that use the same scale

  1. Go to File | Import, select the image file and click Open.
  2. In the Image Registration and Warping dialog, calibrate the image according to the scale of the log(s), and clickOK.
    Image_Registration_and_Warping_Dialog.png
    The Image Registration and Warping dialog is displayed.

  3. Digitize all the log lines as polylines. If the log is a different color than the background grid lines, or if there aren’t any background grid lines, using the Image | Vectorize Image command may be very useful to automatically digitize the log. If you use the Vectorize Image command, you may need to use the Tools | Edit Boundaries | Connect Polylines command on the vectorized objects so that you have just a single polyline. You may also need to use Tools | Reshape to edit the log polyline slightly.
    Calibrated_Log_Image.png
    The log image was imported into Didger 4 and calibrated.
    Both the green GR and orange DT logs were digitized as black polylines.

  4. Enter the Curve Type, Curve Units, and/or Curve Description as the polyline IDs.
    Polyline_ID_Descriptions.png
    Enter the curve type, units and description as the polyline IDs.

  5. Go to File | Export, choose to export as an LAS file, give the file a name, choose where you want to save it to, and click Save.
  6. In the LAS Export dialog box, on the Curve Info tab, set the Start Depth, Ending Depth, and Step values. If you entered the curve settings as an ID for the polyline, be sure to specify the correct ID fields in the Curve Settingssection.
    LAS_Export_Dialog.png
    Set the Start Depth, Ending Depth, and Step values for the LAS file.
    Also set the
    Curve Settings to the appropriate ID, if entered.

  7. Add any additional information to the Well Info tab that you like, such as the well or company name.
  8. Click OK. The single LAS file has been exported with all the digitized data.

 

Method 2: Digitizing multiple lines using different scales and combining into one LAS file


Part 1: Digitize and export the multiple curves from Didger:

  1. Go to File | Import, select the image file and click Open.
  2. In the Image Registration and Warping dialog, calibrate the image according to the first log you want to work with, and click OK.
    Image_Registration_and_Warping_Dialog_2.png
    Import the log image and calibrate it in the Image Registration and Warping dialog box according to the first log you want to digitize.

  3. Digitize the log as a polyline. If the log is a different color than the background grid lines, using the Image | Vectorize Image command may be very useful to automatically digitize the log. If you use the Vectorize Imagecommand, you may need to use the Tools | Edit Boundaries | Connect Polylines command on the vectorized objects so that you have just a single polyline. You may also need to use Tools | Reshape to edit the log polyline slightly.
    Digitize_Polylines_2.png
    The log image was imported into Didger 4 and calibrated according to the Gamma Ray (GR) log.
    The blue Gamma Ray log was then digitized as a yellow polyline.

  4. Enter the Curve Type, Curve Units, and/or Curve Description as the polyline IDs.
    Input_Curve_Description_2.png
    Enter the curve type, units and description as the polyline IDs.

  5. Go to File | Export, choose to export as an LAS file, give the file a name, choose where you want to save it to, and click Save.
  6. In the LAS Export dialog box, on the Curve Info tab, set the Start Depth, Ending Depth, and Step values. Be sure to specify the correct ID fields in the Curve Settings section.
    LAS_Export_Dialog_2.png
    Set the Start Depth, Ending Depth, and Step values for the LAS file.
    Also set the
    Curve Settings to the appropriate ID, if entered.

  7. Add any additional information to the Well Info tab that you like, such as the well or company name.
  8. Click OK. That LAS file has been exported.
  9. Delete the polyline you digitized in Step 3.
  10. Select the image and go to Image | Image Registration and Warping.
  11. Recalibrate the image according to the next log you want to digitize.
    Calibrate_for_Next_Log.png
    Delete the first polyline and go to Image | Image Registration and Warping.
    Recalibrate the image according to the next log.

  12. Digitize the next log line as a polyline and enter the curve type, units and description as the IDs.
  13. Go to File | Export, choose to export as an LAS file, give the file a name, choose where you want to save it to, and click Save.
  14. In the LAS Export dialog box, on the Curve Info tab, set the Start Depth, Ending Depth, and Step values. Make sure these are the same values as those you entered in Step 6 above. Be sure to specify the correct ID fields in the Curve Settings section.
  15. Click OK. That LAS file has been exported.
  16. Repeat Steps 9-15 for all logs in the image. You will end up with multiple LAS files, one for each log you digitized.

 

Part 2: Now combine all the LAS files in Excel into a single LAS file:

  1. Open the first LAS file in Excel, selecting Space delimited.
    Import_LAS_into_Excel.png
    Open the LAS file in Excel, selecting Delimited file type, choosing Space delimiters, and clicking Finish.

  2. Once it opens, under the ~CURVE section, you will see a DEPTH row and then a row of information for your first curve. Insert a new blank row after that first curve for each additional curve you have.
    Insert_Blank_Row.png
    Insert a blank row after the first curve in the ~CURVE section for each curve you have.

  3. Open the LAS file for the second curve in Excel, choosing Space delimited.
  4. In this second LAS file, select the curve info from the ~CURVE section and copy it using Edit | Copy or Ctrl+C.
    Copy_Curve_Information.png
    Copy the curve information from the second LAS file.

  5. Paste the curve information from the second LAS file into the first blank line in the ~CURVE section of the first LAS file using Edit | Paste or Ctrl+V.
    Paste_Curve_Information.png
    Paste the curve information from the second LAS file
    into the first blank line in the first LAS file.

  6. Back in the second LAS file, select all the information from Column C under the ~ASCII section and go to Edit | Copy or press Ctrl+C.
    Copy_Curve_Data.png
    Select and copy the data information in Column C of the
    ~ASCII section from the second LAS file.

  7. In the first LAS file, select the first cell in Column D under the ~ASCII section and go to Edit | Paste or pressCtrl+V.
    Paste_Curve_Data.png
    Paste the information from the second
    LAS file into Column D of the ~ASCII section of the first LAS file.

  8. Repeat Steps 3-7 for all LAS files you have, so that all the information is copied into the first file.
  9. Go to File | Save As.
  10. Enter the entire file name in quotes (ie. “Multiple Logs.las”), choose to save as type Text (Tab delimited)(*.txt), and click Save.
  11. Now this is a combined LAS file you can use in other programs.
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