Weak oil prices CLc1 shriveled quarterly profit at Exxon Mobil Corp ( XOM.N ) and Chevron Corp ( CVX.N ), compelling both companies to rethink operations and plan for what many expect to be a sustained period of cheap crude. Earnings at Exxon and Chevron, two of the world’s largest oil producers, also missed analysts’ expectations, adding to concerns that perhaps executives had not acted quickly enough to mitigate the impact of an over-50-percent drop in oil prices since last summer. The results also highlighted how smaller and more nimble U.S. shale oil companies had slashed costs faster and more aggressively than global majors. Some shale producers have cut back drilling by 60 percent or more. Exxon’s profit fell by more than half, with the biggest drop in […]