Pipeline operator Energy Transfer Partners LP said it will buy Sunoco Inc. for $5.3 billion in stock and cash to get into the more lucrative crude oil transportation business as natural gas prices stay weak, Reuters said. Oil and gas production from shale formations in the United States has surged over the past two years, creating a scramble to build infrastructure to get supplies to refining hubs. The resulting oversupply has sent natural gas prices to their lowest levels in a decade, Reuters said. Sunoco, which plans to get out of the refining business after 120 years, said it will continue talks with private equity firm Carlyle Group LP for a joint venture to run its 335,000-barrel-per-day Philadelphia refinery.