Energy firms pulled another 13 rigs from U.S. oil fields this week, the biggest drop in four weeks, data showed on Friday, showing that a near six-month slump in activity had yet to run its course despite a rebound in crude oil prices. That was the 25th straight weekly decline, bringing the total rig count down to 646, the lowest since August 2010, oil services company Baker Hughes Inc said in its closely followed report. However, in the Eagle Ford basin in South Texas, the nation’s second biggest shale oil field, drillers added one oil rig in the third weekly increase in a row, bringing the total up to 90. The market has been eyeing the U.S. rig count and the increases of a few rigs in some basins over the past few weeks ahead of next week’s meeting of the Organization of the Petroleum […]