Oil explorers added rigs for the eighth straight week, extending a ramp-up of activity in the U.S. shale patch as prices hover near $53 a barrel. Rigs targeting crude in the U.S. rose by 13 to 523 this week, Baker Hughes Inc. said Friday. Drillers have added 207 rigs since the count hit a seven-year low on May 27. Most of the recovery in drilling has been in the prolific Permian Basin, which has been a hotbed for acquisitions this year. Rig gains will continue to be primarily in that region until oil prices are “substantially higher,” said Robert Christensen, an analyst at Drexel Hamilton LLC in New York. But don’t expect a surge. “It’s the only place you really can make any money,” he said. “It’s going to be a very rational progression.” West Texas Intermediate crude touched $54.51 […]