On Wednesday, oil prices rose for the fourth straight session. At the same time, limited supply issues outweighed worries about a slowing global economy. By 11:32 GMT, August Brent crude futures were up 87 cents to $118.85 per barrel. Thursday marks the expiration of the August contract. Meanwhile, the more active September contract was trading at $114.79, up 99 cents or 0.87 percent. West Texas Intermediate (WTI) crude for the US rose $1.20, or 1.1 percent, to a barrel price of $112.96.