TEMPERATURE LIMITED HEATER, WHICH USES PHASE TRANSFORMATION OF FERROMAGNETIC MATERIAL Russian patent published in 2017 - IPC E21B36/04 E21B43/24 

FIELD: heating.

SUBSTANCE: heater for heating a subterranean formation comprises a ferromagnetic conductor and the electrical conductor electrically coupled to the ferromagnetic conductor. Herewith, the heater configuration provides a first amount of heat at a lower temperature and a second reduced amount of heat, when the heater reaches a selected temperature, or enters a selected temperature range, at which the ferromagnetic conductor undergoes a phase transformation from ferrite to austenite. A method of heating a subterranean layer using the heater is an electric current that is supplied to the heater providing heat to at least portion of the subterranean formation.

EFFECT: increased efficiency and uniform heating of the formation.

13 cl, 4 tbl, 20 dwg