Seaborne crude does not travel over open ocean in a uniform way. It funnels through a small number of narrow passages, and the concentration is extreme enough that each one is a named strategic risk.
The Strait of Hormuz is the largest by volume, carrying crude and condensate out of the Middle East Gulf with no full alternative route for most of it. The Strait of Malacca is the main artery from the Middle East to East Asia. The Suez Canal and the SUMED pipeline together move crude between the Red Sea and the Mediterranean. Bab el-Mandeb controls access to the Red Sea from the south, and the Turkish Straits and the Danish Straits carry Black Sea and Baltic exports respectively.
The analytically useful question about a chokepoint is not its volume but whether an alternative exists. Some have partial bypasses: Suez has SUMED, and there are pipelines that can move some Gulf crude to the Red Sea coast, bypassing Hormuz for a fraction of the volume. Others do not, in any practical sense. A disruption to a chokepoint with a bypass is a cost event, because barrels take a longer or more expensive route. A disruption to one without a bypass is a volume event, and those price entirely differently.
Rerouting is the usual outcome and it has a measurable effect through tonne-miles. Diverting Asia-bound European cargoes around the Cape of Good Hope instead of through Suez adds substantially to voyage length, which consumes tonnage, tightens freight and raises the cost of every cargo on unrelated routes. That second-order effect is often larger and more durable than the direct one.