Documentation of statistics: Price of North Sea oil
The use of the oil price collected from S&P Global Commodity Insights, PCAAS00, as well as the calculation of the annual price as a simple average, is specifically mentioned in the comments to the Hydrocarbon Tax Act, the price's precision and representativeness for Danish North Sea oil is affected both by which fields are incorporated into the price for North Sea oil and how S&P Global Commodity Insights makes quality adjustments.
https://www.dst.dk/en/Statistik/dokumentation/documentationofstatistics/price-of-north-sea-oil
Documentation of statistics