[saryant]

OPEC is no longer a coordinated entity. For decades OPEC's member nations waged economic war on each other by cutting prices to increase marketshare, in violation of OPEC quotas. The Saudis acted as the swing producer, lowering their output to keep crude prices near the OPEC target. Last year the Saudis abandoned that roll and admitted that OPEC had become a a free-for-all.

[WalterBright]

Cartels are always unstable. It's why they seek forcible enforcement methods.