| Byproducts |  |
Select "Data - Byproducts" from the main menu to bring up the gas byproducts dialog:
Gas yields can be entered by component. WellSpring allows you to change the composition by date by adding additional rows and entering the cumulative production.
Note: If you are using gas composition, you should not be using yields and vice versa
Shrinkage can also be specified at a facility (say a gas plant) See Byproduct Extractions