Controlling The Flow of Oil - The New Caliphate or Ottoman Empire Two

In my posting on Sept 13 regarding the strategies of the enemy, I speculated the following:

Cutting Off Supply Lines: Controlling 40% or more of the world's oil and controlling the water ways that allow quick distribution (like Suez Canal or Indonesian water ways) would severely hamper any country's ability to prosecute a war(...)

Why am I concerned? Go to the inner sanctum.
In a recent article regarding the Indonesian bombing of the Australian Embassy, and found at the Command Post,intelligence suggests that the Islamists are preparing to control or, at least, hamper the flow of oil and other products through the busy shipping lanes of Indonesia:

Fanatics from the Islamic terror faction blamed for last week’s suicide attack on the Australian embassy in Indonesia are planning to hijack an oil tanker or freighter and turn it into a floating bomb, The Telegraph has learned.
United States intelligence has passed on warnings about the plot to launch an attack in the region’s busy shipping lanes to several countries, including Indonesia, Singapore and Malaysia. They acted after intercepting communications between activists from Jemaah Islamiah (JI), a network linked to al Qa’eda.

The terrorists have been discussing plans to seize a vessel using local pirates. The hijacked ship would be wired with explosives and then directed at other vessels, sailed towards a port or used to threaten the narrow and congested sea routes around Indonesia.

Any idea what would happen to certain economies in the area or oil supplies or trade through those water ways if an attack was successful?

We are not dealing with a bunch of amateurs in warfare here. This is no small potatoes. This isn't about Osama. This is about the New Ottoman Empire, coming soon to a country near you.