The oil glut itself is largely because of the KSA and Russia in the midst of a mutual price war as well as the US expanding it's own production.

That said, it's still an open question of whether a glut will exist or not - at this point it's China, India, and Japan that's become the primary driver for oil prices because they are getting similar deals from both KSA and Russia, and are trying to pressure other suppliers to give similar deals.