I’m sticking with my forecast of US$10 to US$20 a barrel. The logic behind that February projection still seems valid. Cartels exist to keep prices above equilibrium. But that encourages cheating, as cartel members want more than their allotted share and outsiders sell more to take advantage of the artificially elevated price. So the job of the cartel leader — in OPEC’s case, Saudi Arabia — is to cut its production to accommodate the cheaters and prevent a price collapse. The Saudis had been doing that for decades, and as a result, OPEC production over the last 10 years has been flat, with all the growth instead enjoyed by non-OPEC producers, including U.S. frackers and Canadian oil-sands companies.

http://business.financialpost.com/news/energy/why-crude-oil-prices-still-have-a-long-way-to-fall-gary-shilling