Around 3.4 million barrels per day (b/d) of oil production is cash negative at a Brent oil price of $35, Wood Mackenzie, a source of commercial intelligence for energy sector says in its latest report.

Since the dramatic drop in prices from late 2014, there have been few halts in production with around 100,000 b/d shut-in globally to date, the intelligence group said

http://www.oilandgaspeople.com/news/7177/why-arent-oil-producers-turning-off-the-taps/

Geopolitical: Attempts to maintain oligopoly by forcing shale producers out of business, in addition Saudi Arabia pressuring OPEC to keep pumping in an effort to stifle Iran from ramping up production in the wake of the removal of sanctions. Iran is well below their theoretical production capacity but if prices remain low they will likely not benefit economically from increasing production.

Also the US has assented to this scheme because it is punishing Russia's economy....

Bottom line is more proxy wars and political games to screw with everyone instead of working towards a better situation for all.