Jane Novak links to it in Armies of Liberation-Shipping Smuggled Iraqi Oil to Yemen. From the Guardian:
One tanker captain, who is in his second decade of oil smuggling and owns his own ship, told the Guardian how lucrative the trade could be. "The big profits are to be made in crude oil," he said. "You rent an oil tanker and after your first trip you can buy the tanker."
The infrastructure of smuggling was set up under Saddam in the late 1990s, during the UN sanctions, when illegal oil shipments became the main method of getting cash into the country. Smuggling was an officially condoned policy.
The main risk is being stopped by patrolling US or British vessels. "If I have official papers then all is fine, even if I am carrying twice the stated shipment," said the captain. "When I don't have papers we cross into Iranian waters, we carry an Iranian flag and bribe the Iranian coastguard. It's a great business for them too. If we are arrested by the Iraqi navy, it's easy. They are involved in the party after all."