Units

Every PetroVR variable is expressed in a unit. You can change the unit of a variable by using the Unit command; see Commands available (variables). However, this change will be limited by the unit type to which that unit belongs.

Unit menu

Units are classified in predefined unit types, that is, measurement systems that PetroVR knows and can handle. Some of these types are general (Density, Area, Money, etc.), and some are very specific to the petroleum industry (Facility Gas Rate, Reservoir Volume, Well Liquid Rate). PVR variables have a fixed unit type which cannot be modified; User-Defined Variables, on the other hand, can be assigned a new type at any time.

When you change the current unit of a variable, its displayed value is updated according to an equivalence table. Actually, PetroVR internally stores that value in a base unit which is fixed for all variables of the same type. When displayed on the interface, the variable is silently converted from the base unit to the current unit, i.e. the one that you can see and change.

When writing FML expressions it is important to keep in mind that some unit types might not be algebraically consistent with others, and therefore conversion factors can be required. See On Unit Consistency in FML.

When working with scenarios, care should be taken when changing the unit type for items that are reported in results (such as Resources or PetroVR Econ variables); if the same object has different unit types in several scenarios inaccurate result differences will probably be obtained, since the system would be trying to compare values of a different order.

Note also that simply changing the unit of a variable does not amount to a change in the model and is not recorded as such (see The Change System ).

Units can be created and modified from the Unit Setup, which you can access using the Units command in the Tools Menu and also from the Preferences Tab. The Preferences tab additionally offers the option to change the unit of all variables of the same unit type in a single step.

Also see Working with Units.