In Norway ALL rig crews have to be certified for their position, incl. drill crews:
Several Training Academies are available for Drilling and Well service personnel:
https://nortrain.no/en/
Mandatory training and certificationfor well service personnel after the “Bravo blowout”:
The Bravo Blowout 22.April, 1977 - Offshore - gCaptain Forum
For drill crews it has been in place since the early 1980s and applies for everybody, regardless of nationality.
Since the first drilling rig was registered under Norwegian flag the OIM has always been a Master Mariner. (even on non-propelled Jackups)
After the Alexander Kielland capsized in 1980:
Remembering the Alexander L. Kielland Disaster of 1980 - Life in Norway
Additional specialized training has been mandatory.
(Basic drilling technology and well control training are required)
PS> The start of offshore drilling and production in Norway is different from that of the US.
In Norway it was started by US companies with US rigs and US personnel in the mid 1960s, with some Norwegians getting jobs as Roustabout, Roughnecks and Motormen. Most of those with seafaring experience.
When Norwegian Shipowners got into the game in early 1970s they got rigs built in the US and had US partners to supply the drilling expertise, both on the rigs and ashore.
In mid-1970s the Aker H-4 rig design and the UT 704 OSV design was developed and built in Norway At the same time Norwegians gained knowledge and experience to where they slowly replaced the foreigners in senior positions, both offshore and onshore, over the next decades.