US Patent 7322415 Subterranean electro-thermal heating system and method

A subterranean electro-thermal heating system including one or more heater cable sections extending through one or more heat target regions of a subterranean environment and one or more cold lead sections coupled to the heater cable section(s) and extending through one or more non-target regions of the subterranean environment. A cold lead section delivers electrical power to a heater cable section but generates less heat than the heater cable section. The heater cable section(s) and the cold lead section(s) are arranged to deliver thermal input to one or more localized areas in the subterranean environment.