For instance Iran says it will block the Strait of Hormuz:
The first move is to reduce the vulnerability of energy exports from the Persian Gulf. Oil experts have determined that all but the 2 to 3 million barrels a day that Iran itself ships through the Strait of Hormuz could be piped instead to ports on the Red Sea and the Sea of Oman. Pipelines from Iraq, past Kuwait, through Saudi Arabia to the Red Sea, the UAE, and Oman are already in place; they only need to be connected.
This could be done by reopening the Iraqi pipeline across Saudi Arabia that the Saudis seized from Saddam in 2001, and by having anti-drag agents (chemical additives that increase the flow of existing oil pipelines as much as 60 percent) at the ready. It also would require building relatively short spur lines to integrate Omani and UAE pipelines with the Saudi pipeline system (something now under discussion). Most of this project could be completed in roughly 18 months for less than a billion dollars. In addition, it would be useful to build up a stock of oil on ships at sea as a floating reserve. This could provide a supply cushion for several weeks, allowing a smooth transition to moving oil by pipe rather than through the strait.