If the strait were to suddenly fully open <now> then reserves in (say) Singapore would continue to deplete until an oil ship or three reaches Singapore, which may take a while.
If the strait were to suddenly fully open <now> then reserves in (say) Singapore would continue to deplete until an oil ship or three reaches Singapore, which may take a while.
Also, reserves do not magically refill until their operators decide to pay to refill them, which competes with ordinary non-reserve demand.