Pipeline heavyweight Williams Cos. is expected to file initial paperwork soon with federal energy regulators on a large pipeline expansion project in the Southeast. The proposal – known as the Southeast Supply Enhancement project – aims to “provide reliable natural gas deliveries” to Virginia, the Carolinas, Georgia and Alabama, according to the company’s website. It would expand the existing capacity of the sprawling Transcontinental pipeline, which runs roughly 10,000 miles from Texas to New York.