загадочный UK

"In Section I of this paper I referred to the fact that reserve definitions vary across
jurisdictions, and the UK and Norway are no exception. It could be, then, that higher
recovery factors in the UK represented more generous attribution, allied to tight standards for oil-in-place. If so, that would contribute to the strong role of oil-in-place in appreciation of
UK reserves.
In Norway, generosity in reserve reporting may have veered in the direction of oil-inplace.44
At the same time, justification for recovery factors might have relied heavily on
production performance over time."

имхо, похоже на "более широкие критерии" в плане отнесения запасов к каким-то категориям

In Norway, generosity in reserve reporting may have veered in the direction of oil-inplace. (footnote 44)
At the same time, justification for recovery factors might have relied heavily on
production performance over time.
Definitive information to resolve this issue is not readily at hand. But it is probable that
some of the differences in appreciation patterns between the UK and Norway are accounted
for by variations in reserve reporting standards, differences that would disappear with
application of uniform methods. Some, maybe, but likely not all.