System and method for the use of a subsurface heating device on underground Tar Sand formation

摘要

Disclosed is a heating system for a subsurface formation. The heating system includes an electrical conductor; an insulation layer at least partially surrounding the electrical conductor; and a jacket surrounding insulation layer and comprising ferromagnetic material. A majority of the inside of the jacket is in contact with the insulation layer and a majority of the outside of the jacket is exposed. The outside surface of the jacket is configured to be at little or no electric potential while the electrical conductor is conducting electricity and while the jacket is at temperatures below the Curie temperature of the ferromagnetic material. The jacket has a thickness of at least 2 times the skin depth of the ferromagnetic material at 50 °C below the Curie temperature of the ferromagnetic material.