Oil prices turned higher Friday to end a volatile week after a widely watched measure of U.S. drilling activity showed a decline. The latest U.S. oil rig count data from Baker Hughes Inc. BHI 0.28 % showed a decline of 10 rigs in the latest week, a bigger move than seen in recent weeks. While some discount the measure’s usefulness, some in the market do use it as a gauge of how production might rise or fall in the future. Light, sweet crude for December delivery, a contract that expired at settlement, lost 0.4% to $40.39 a barrel. Just before settlement, it briefly dipped to as low as $38.99, the lowest price since August. The more active January contract rose 0.4% to $41.90 a barrel. Brent, the global benchmark, gained 1.1% to $44.66 a barrel on ICE Futures Europe. U.S. oil lost 35 cents, or 0.9%, for the week, […]