TEMPERATURE LIMITED HEATERS USED TO HEAT SUBSURFACE FORMATIONS

摘要

The invention provides a heater, comprising: a ferromagnetic member; an electrical conductor electrically coupled to the ferromagnetic member, wherein the electrical conductor is configured to provide heat output below the Curie temperature of the ferromagnetic member. The electrical conductor is configured to conduct a majority of the electrical current of the heater at 25 ~C. The heater automatically provides a reduced amount of heat approximately at and above the Curie temperature of the ferromagnetic member.