I thought the goal was intimidation, a warning.

(They don't have to keep prices as low as they used to)[http://oilprice.com/Energy/Crude-Oil/Will-US-Shale-Stage-A-Comeback-As-Oil-Nears-50.html], they just need to keep them just low enough that fracking doesn't become as lucrative as it used be to keep production low. My conception of the narrative was that the US fracking glut combined with Chinese economic slow down typically would have led to OPEC decreasing output to maintain prices. But since demand was decreasing in line with supply increasing, that if the Saudis (acting without a coordinated OPEC) kept production up in order ensure that once prices got back up to around $60 it still wouldn't be worth it for US oil companies to reinvest in fracking at the level they had. Obviously OPEC has its issues with coordination but every one seems to have a hard time acknowledging that is Saudis or OPEC collectively hamstring fracking 1 or two more times after it potentially returns, the taste for investment would disappear as investors understand again gains with be short lived.

Another comment suggests that the entire narrative I've alluded to is incorrect and links to a thread in this sub that provides some counter-arguments.