Yes, they have always adjusted their production to keep their market share at 40% of world demand. Now, the cartel seems to be loosing its control of production levels. Too many of them need to keep pumping to support their debts/outgoing cash flow.
Oil and OPEC: This Time is Not as Different as You Think It Is
http://blogs.cfr.org/levi/2014/12/01/oil-and-opec-this-time-is-not-as-different-as-you-think-it-is/
It’s similarly premature to declare that sort of new era now: OPEC countries would be sticking to past behavior if they failed to cut production now but stepped in in a few weeks or months if prices fell considerably further.