Assigning a function

With the Assign Function form (model > Rock Properties > Function-based Property Modeling > Assign Function), you assign a function to populate your 3D grid with properties. You assign a function to each one of your Volumes of Interest (VOIs), i.e. the sub-sets of your 3D grid, one by one.

Click here for an overview and the highlights of the workflow.

Volume of Interest (VOI)  A sub-set of your 3D grid. It allows you to populate your 3D grid with properties by assigning a function to each VOI separately.

Defining VOIs  You define your VOIs based on the selections you make on the Create Model form, under 'Volume definition' and 'Nest within'.

Assigning a function per VOI  Once you have created the functions with the Function Tool you assign a function to each VOI. While you assign a function, you also assign the grid properties or models that are input to the function(s). At the end of the workflow, you can run your model for all or only certain VOIs you selected.

Function-based property model  The container which holds all the associated metadata: volume definition (i.e. VOIs), function per VOI and assigned grid properties or models that are input to the function(s).

Function-based grid property  The resultant grid property, which is a combination of all modeled VOIs. Once you have run your model, it will be available in the JewelExplorer (3D Grids > Your 3D Grid > Properties > Rock Properties > Your Function-based Grid Property). It is read-only and has the same name as the function-based property model.

To assign a function

1. Open the Assign Function form and select the function-based property model from the Model drop-down list.
You can hover over the factsheet icon () next to the drop-down list to check the key inputs (e.g. 3D grid, volume definition) to the function-based property model you have selected.
2. Select a Volume of Interest (VOI) from the table on the left side of the form.
3. Select the function that you want to apply to the selected VOI from the Function drop-down list.
Important  The property type you have selected for the function-based property model on the Create Model form must be exactly the same as the property type of the function. The Function drop-down list is populated with the functions of the same type. For example, if the function-based property model has a property type 'Porosity, Effective', the function(s) assigned to it must also be of property type 'Porosity, Effective'. The functions of type 'Porosity' or 'Porosity, Total' will not be displayed in the Function drop-down list.
You can also copy-paste the function from one VOI to another VOI using the context menu options Copy and Paste. Once you have copied a function, you can select Paste Function Options. This will open a separate form which allows you to paste the function to multiple VOIs at once.

Paste function options

With the Paste Function Options form, you can paste a copied function to multiple VOIs, i.e. target VOIs, at once. The grayed out boxes display information about the Input VOI from which you have copied the function. You can select the Target VOIs of your choice by checking the check boxes.

When you select a function, the function expression is displayed in the expression field below. The expression consisting of variables and coefficients is for review purposes only and cannot be edited.

Toolbar adjacent to the Function drop-down list

By using this toolbar, you can quickly access the Function Tool to create a new function, to review or edit the selected function or to check the associated metadata of the function.

	Opens the Function Tool, where you can create a new function.
	Opens the Function Tool, where you can review or edit the selected function.
	When hovered over, displays the descriptive metadata of the selected function.

4. In the Assign Properties to Variables section of the form, you need to assign a property to each variable that is being used by the function expression.

The drop-down lists for Property are populated with models and grid properties:

• Model  If a grid property is created with a modeling workflow, its model will be available in the drop-down list. Select a model to use its associated grid property. Models are displayed with icons specific to their model type. For example, facies, rock property and permeability models are displayed with the following icons respectively: , , .
• Grid Property  If a grid property is created without a modeling workflow, it will be available in the drop-down list.  For example, you may have created a property with the Property Calculator. Such grid properties are always displayed with the icon. 
If you have assigned a model, make sure that the model is run and its grid property is available. Otherwise, you will receive an error message as a pop-up window when you run your property model at the end of the workflow.
5. In the Coefficients section of the form, you can review the coefficients that are being used by the function expression. This table is for review purposes only and cannot be edited.
6. Click Apply to assign the function(s) and keep the form open, or click OK to assign and proceed to the Run Function-based Property Model form.