All petroleum surpluses go into the Government Pension Fund Global (one of three wealth funds that the government manages). The state is allowed to withdraw from this fund, mostly to cover shortfalls in the state budget.

The target maximum withdrawal rate since 2018 has been 3%. This rate is a guideline only, and the government is allowed to exceed it. Since 2000, in most years the withdrawal rate has much far below the limit (see charts here [1]), but sometimes exceeded, most recently in in 2020 and 2021.

[1] https://www.regjeringen.no/no/tema/okonomi-og-budsjett/norsk...

No, only about 3% of the yield is used in the state budget yearly. The oil fund does not invest any of its money in Norway in order to avoid dutch disease. It is not earmarked for any specific use, but instead gets used to make up the difference in tax revenue and state budget. NBIM has more information in English about the fund here: https://www.nbim.no/en/