The Strait of Hormuz closed. Nigeria exports oil. The maths cuts both ways.

The US and Israel bombed Iran on February 28. Iran responded by effectively closing the Strait of Hormuz, the waterway through which 20 percent of the world's daily oil supply moves. Maersk and Emirates SkyCargo suspended Gulf bookings. Tanker traffic is near zero.

Brent crude was $73 a barrel before the strikes. It's above $83 now. JPMorgan says $120 is possible if the closure runs beyond three weeks.

Nigeria's crude doesn't move through Hormuz. When Gulf barrels can't reach buyers, West African oil gets more valuable. Government revenue goes up. On paper, this is good news.

Here's why you shouldn't feel it yet.

Nigeria still imports refined petroleum products. More expensive global oil means more expensive fuel imports. The Dangote refinery is running but not at full capacity. Nigeria isn't refining enough of its own crude to insulate itself from global price shocks on the way back in.

And there's the numbers problem. When the CBN cites Nigeria's external reserves crossing $50 billion as of mid-February, that's the gross figure. The more honest number is $34.8 billion net, after stripping out swap obligations and short-term liabilities Nigeria owes back. That $15 billion gap is money sitting in the account that isn't free to spend.

A sustained oil windfall adds to the gross number first. Whether ordinary Nigerians feel it depends on whether it reaches the net number, and then on whether a government with Nigeria's distribution record actually moves it toward the people who need it.

Watch the pump price over the next two weeks. That'll tell you which direction this actually goes for you.