Patent ID: 8162059
Filing Date: 2012-04-24
Classification: E21B,H01F,H01J,Y10T

Abstract:
1. A heating system for a subsurface formation, comprising: a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation; and a ferromagnetic conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor; wherein the electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300° C.