Performing data transformations

With the Transform & Trends form (model > Rock Properties > Transform & Trends) you can apply data transformations to an upscaled grid property so that it can be used in property modeling. One or more data transformations can be applied to a Volume of Interest (VOI). It depends on the modeling method that you assigned on the Assign Method form, whether data transformations are required or not:

  • Data transformation is not applicable to the modeling method Constant. If your VOI is assigned Constant, the Transform & Trends form is automatically skipped and you can proceed with the Control Method form.
  • When using Kriging or IDW, data transformations are optional (the form opens automatically after 'Assign Method')
  • When using SGS, a Normal Score transformation is auto-selected on the form (the form opens automatically after 'Assign Method').

Upon opening the form and selecting a Rock Property Model, simultaneously a customized Transform & Trends View opens, displaying the data distribution (histogram) of the upscaled data of the selected VOI. Subsequently, when you select one or more transformations for your VOI, per transformation a separate histogram is auto-generated in the view, showing the data distribution after the particular transformation.

For parameter settings per data transformation type, see Data transformations - parameter settings.

Assigning one or more transformations

You can apply one transformation to the (upscaled) data in your VOI, or apply a scenario consisting of multiple transformations, which are carried out in the order as specified on the form.

The Transform & Trends form. In the example, 'Shift Scale' and 'Normal Score' are selected for VOI 'Zone C'. You can add, remove, or change the order of transformations with the icons at the top of the Transformations section.    click to enlarge

  1. At the top of the form, select the Model that contains your upscaled grid property. Simultaneously, the customized Transform & Trends View opens, initially showing the data distribution of the upscaled data.
  2. In the Volume of Interest table, select a VOI to which you want to apply one or more transformations. For modeling method 'Constant', transformations do not apply.
    3. Using the context menu options Copy and Paste, you can copy-paste settings between the VOIs which have modeling methods that use data transformations (i.e. IDW, Kriging, SGS). Once you have copied settings, you can select Paste Settings Options. This will open a separate form, which allows you to paste the settings to multiple VOIs at once. Note that checkbox selection can be done in bulk by holding down SHIFT while selecting a range of VOIs (they turn blue), then checking the box of one of them. All other VOIs in the selected range will get checked simultaneously.
  3. In the Transformations section, select a transformation from the drop-down list and click the green cross to add the selected transformation to the transformations list. You can add more transformations if you want, but be aware of the Rules when applying data transformation. The listed transformations will be carried out once you click Apply or OK in the order as listed on the form. Use the icons (arrows for 'up', 'down' and delete ) to update the list of selected transformations.
    4. Uncertainty   For Normal Score transform, the 'Mean' and 'Standard deviation' parameters can be propagated as a parametric uncertainty in a probabilistic volumetric calculation with the study strip. Click the uncertainty symbol behind the entry fields to open the Uncertainty Parameter dialog. For how to use the controls on the dialog, see The Uncertainty Parameter dialog. For information about parametric uncertainties and how to use them in JewelSuite Subsurface Modeling, see Incorporating uncertainty in static or dynamic modeling.
  4. To modify the parameters related to each transformation, click on a transformation in the list: the Parameters section on the right side of the form updates with the selected transformation. For more information about the parameters for each transformation, see Data transformations - parameter settings.

  5. After you have defined the data transformations for your VOI's, click Apply to execute the transformation(s) and keep the form open, or click OK and move to the next step in the workflow Experimental Variogram.

When you click Apply or OK, the transformations are carried out and saved on the form. This way you can always retrieve the settings of the last transformations that were carried out. If you want to retrieve the original (not transformed) upscaled data, remove the transformation(s) from the list with the icon.

For rules of thumb to capture trends, see Capturing trends with JewelSuite Subsurface Modeling - rules of thumb.