Efficiency factors are multiplied when specified at multiple levels of
the well/group hierarchy.
The factors are included as follows:
* Well Rate - No efficiency factor
* Well Total - WEFAC & GEFAC (whole hierarchy)
* Group Rate - WEFAC & GEFAC (only subgroups)
* Group Total - WEFAC & GEFAC (whole hierarchy)
* Field Rate - WEFAC & GEFAC (whole hierarchy)
* Field Total - WEFAC & GEFAC (whole hierarchy)
* Region Rate - WEFAC & GEFAC (whole hierarchy)
* Region Total - WEFAC & GEFAC (whole hierarchy)
* Completion Rate - No efficiency factor
* Completion Total - WEFAC & GEFAC (whole hierarchy)
Authored by Sveinung Rundhovde and Lars Petter Hauge