Constraining Polygons:Turn on constraining polygons to limit the wells whose curves will be used in the calculation. 

Polygons: Open the Select Polygons dialog to select inclusion or exclusion polygons to limit the wells whose curves will be used in the calculation. 
by geographical area.

Use any source: The calculation will be performed on the first curve it encounters in the database.

Use specified source: Select one or more sources from the list to limit the curves being used in the calculation. Multiple sources can be selected using the Ctrl key on your keyboard. Only curves with the selected sources will be used in the curves calculation. 

Predefined: Select this item to choose from a list of predefined calculations. These include Castagna's equation, Faust equation, Gardners equation, Lambda-Rho, Mu-Rho, Poisson's ratio, impedance or porosity calculations.

Normalization: Normalize a curve to a reference well, or to user-defined minimum and maximum values.

Custom: Perform a custom calculation using one or multiple curves.