Iran is suffering from the double impact of sanctions and low crude prices. Maybe that is what the Sauds really want.
Right now they can get it out of the ground for about $10 a barrel, so they make money on every barrel pumped, but $20 and pumping 10% more is crap compared to making $90 a barrel and pumping 25% less.
At the moment it is all fine and dandy, but wait a while and I think they will wonder what they did with their once massive oil reserves. It happened to the UK, only now do we look and see that we essentially wasted the income, whereas Norway has done it right by investing the revenue for the population.
They are thinking about how to manage the present, rather than what will happen in the future.
If they cut production, they will have to lower welfare spending and that may not be very good for the future of the Sauds.