Oil prices slipped on Monday, despite news that OPEC was supportive of extending a six-month deal to cut output as investors continue to grapple with worries about growing US oil output and high inventories. Brent crude futures settled at $51.62 a barrel, down 14 cents. US West Texas Intermediate crude futures settled down 56 cents, or 1.2 percent, to $48.22 a barrel. Prices briefly surged into positive territory after sources within the group said the OPEC was considering extending production cuts into the second half of 2017. (reuters)