You're confusing two unrelated matters. All of the oil companies pay the same 78% tax rate in .no. The state-owned one also pays its profits, but the profits a

You're confusing two unrelated matters. All of the oil companies pay the same 78% tax rate in .no. The state-owned one also pays its profits, but the profits are a rounding error compared to those 78%. All the oil that's pumped from below the seafloor is sold. Selling more oil to domestic drivers wouldn't really increase the world's oil price, or state's tax revenue.