Basically, OPEC needs a situation where they can reduce supply by 10% and get more than 10% increase in price. Otherwise they may increase the price, but still

Basically, OPEC needs a situation where they can reduce supply by 10% and get more than 10% increase in price. Otherwise they may increase the price, but still lose revenue overall. That would only be true if you had a zero cost of production (and OK in Saudi Arabia's case, they nearly do). A decrease in volume decreases both your costs and revenue, but an increase in price goes all to revenue. So if, for example, at the current oil price you had a margin of 25% (eg. $15/barrel cost of production and $20/barrel price), you only need a 2.8% increase in price to balance a 10% drop in volume. Even SA's ~$5 production & transport costs still means an 8.3% increase in price balances a 10% drop in volume.