The more stringent US sanctions on Iranian oil as of May increase the large number of factors that restrict the world supply of medium-heavy crude oil, raising prices for the fewest barrels and establishing a confrontation between buyers and sellers.
Measures against Iranian shipments are in addition to Washington's veto over Venezuelan oil and production problems in Angola, another major producer of dense crude oil, which are best suited for the production of lucrative refined products such as jet fuel.
US officials say the global supply of oil will continue to be plentiful even with sanctions and especially with the rise of shale in the United States. But much of the offer, led by the United States, Saudi Arabia and Russia, is lighter.
The price of heavier oils, like the Norwegian Grane and Heidrun, has been asserted in recent months, a North Sea trader says. In April, the Grane rose from a dated Brent price (spot market) plus 10 cents to a level close to the cost of Brent dated plus $ 1 per barrel.
In addition, refineries want more of the heavy crude oil offered by Iran and Venezuela to produce low-sulfur fuel oil before new emission rules for next year's shipments.
EYES IN ANGOLA, CHINA
Price offers for several Angolan crude products, an alternative to Iranian and Venezuelan crude oil, were at their highest level, traders said.
Sources said last week Angolan state Sonangol sold a shipment of one of its heavier notes, Dalia, for $ 2 a barrel on the dated Brent, a rise of $ 7 compared to two years ago. In general, the degrees are negotiated at a discount of $ 1 or more.
While some customers are willing to buy at high prices, others are resisting. The dispute is partially reduced to doubts about how much Iranian oil may continue to flow after May 1, when US exemptions for Iran's clients expire.
Analysts hope China will ignore restrictions, especially as Washington may be reluctant to punish Chinese companies, which import Iranian crude oil, but are also the top buyers of oil and natural gas in the United States.