On Unit Consistency in FML
Older versions of PetroVR up to and including 11.2 offered two systems for working with units in FML expressions: Legacy and Consistent. The Legacy system required the inclusion of conversion factors in operations between variables with different unit types: for instance, Time was internally handled in days and Money per Time in $/years (see Units), so you needed to add a conversion factor to any expression combining both. The Consistent system bypassed this issue by making all unit types are mutually consistent so that no conversion was required.
From version 12.1 on the Legacy system is no longer supported. This means that models created with the Legacy system cannot be migrated to the current version. In such cases the Migration Wizard will issue a warning - contact the PetroVR Help Desk, who will help you migrate your project manually (see Support and Version Upgrading).
The following table shows the conversions required in the Legacy PetroVR version that are no longer needed in the all-consistent version:
| Unit | When combined with | Requires Normalization | Description |
|---|---|---|---|
| Area | Length | 43, 560 | 1 acre = 43,560 ft² |
| Liquid Volume | Length | 5.6146 | 1 bbl = 5.6146 ft³ |
| Liquid Volume | Area | 7,758.3443 | 1 bbl = 43.560 / 5.6146 acre-ft |
| Steam Volume | Length | 5.6146 | See Liquid Volume. |
| Steam Volume | Area | 7,758.3443 | See Liquid Volume. |
| Cost Per Length | Length | 189.39393939 | 1 $MM/mile = (1,000,000/5,280) $/ft |
| Money per Time | Time | 1/365 | (FML uses $/year) 1 year = 365 day |
| Money per Gas Calorific Value | 0.0122087243 | See Gas Calorific Value. | |
| Money per Area | Length | 1/43,560 | See Area. |
| Time per Length | Length | 1/5,280 | 1 mile = 5,280 ft |
| Density | Liquid Volume | 158,987.3 | 1 bbl = (30.48³ 5.6146) cm³ |
| Gas Calorific Value | Gas Volume | 0.0122087243 | 1 BTU/scf = 0.0122087243 kw.day/M scf |
| GOR | Gas Volume or Gas Rate | 0.001 | 0.001 M scf = 1 ft³ |
| Inverse Density | Liquid Volume | 1/158,987.3 | See Density. |
| Liquid Yield | Gas Volume or Gas Rate | 0.001 | See GOR. |
| Gas Volume | Length | 1,000 | 1 M scf = 1,000 ft³ |
| Gas Volume | Area | 43.56 | 1 M scf = 43,560 / 1,000 acre-ft |