They need the money. Why would it be more complicated than that?
Saudi pumping the amount it does drives down the price of oil. They have massive amounts of money so can last for a few years running the kind of deficits are now, though not forever. The question is why they are keeping the price artificially low.
http://www.wsj.com/articles/saudi-arabia-issues-bonds-worth-...
So yes, they somehow need some cash.