Abstract: Systems and methods for an in situ heat treatment process that utilizes a circulation system to heat one or more treatment areas are described herein. The circulation system may use a heated liquid heat transfer fluid that passes through piping in the formation to transfer heat to the formation. In some embodiments, the piping may be positioned in at least two of the wellbores.

Abstract: A heating system for a subsurface formation includes a conduit located in an opening in the subsurface formation. An insulated conductor is located in the conduit. A material is in the conduit between a portion of the insulated conductor and a portion of the conduit. The material may be a salt. The material is a fluid at operating temperature of the heating system. Heat transfers from the insulated conductor to the fluid, from the fluid to the conduit, and from the conduit to the subsurface formation.

Abstract: A method for heating a subsurface formation includes applying heat from a plurality of heaters to at least a portion of the subsurface formation. A portion of one or more of the heaters are allowed to move relative to the heaters respective wellhead using sliding seals to accommodate thermal expansion of the heaters.

Abstract: An in situ heat treatment system for producing hydrocarbons from a subsurface formation includes a plurality of wellbores in the formation. At least one heater is positioned in at least two of the wellbores. A self-regulating nuclear reactor provides energy to at least one of the heaters to increase the temperature of at least a portion of the formation to temperatures that allow for hydrocarbon production from the formation. Heat input to at least a portion of the formation over time at least approximately correlates to a rate of decay of the power from the self-regulating nuclear reactor.

Abstract: An in situ heat treatment system for producing hydrocarbons from a subsurface formation includes a plurality of wellbores in the formation. At least one heater is positioned in at least two of the wellbores. A self-regulating nuclear reactor provides energy to at least one of the heaters to heat the temperature of the formation to temperatures that allow for hydrocarbon production from the formation. A temperature of the self-regulating nuclear reactor is controlled by controlling a pressure of hydrogen supplied to the self-regulating nuclear reactor, and wherein the pressure is regulated based upon formation conditions.

Abstract: A method of heating a subsurface formation includes introducing a molten salt into a first passageway of a conduit-in-conduit heater at a first location. The molten salt is passed through the conduit-in-conduit heater in the formation to a second location. Heat transfers from the molten salt to a treatment area during passage of the molten salt through the conduit-in-conduit heater. The molten salt is removed from the conduit-in-conduit heater at a second location spaced away from the first location.

Abstract: A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

Abstract: A heating system for a subsurface formation includes an elongated electrical conductor located in the subsurface formation. The electrical conductor extends between at least a first electrical contact and a second electrical contact. A ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. 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.

Abstract: A heating system for a subsurface formation includes an electrical conductor and an insulation layer at least partially surrounding the electrical conductor. A jacket that includes ferromagnetic material at least partially surrounds the insulation layer. 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.

Abstract: A heating system for a subsurface formation includes a conduit located in an opening in the subsurface formation. An insulated conductor is located in the conduit. A material is in the conduit between a portion of the insulated conductor and a portion of the conduit. The material may be a salt. The material is a fluid at operating temperature of the heating system. Heat transfers from the insulated conductor to the fluid, from the fluid to the conduit, and from the conduit to the subsurface formation.

Abstract: Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

Abstract: Systems and methods for an in situ heat treatment process that utilizes a circulation system to heat one or more treatment areas are described herein. The circulation system may use a heated liquid heat transfer fluid that passes through piping in the formation to transfer heat to the formation. In some embodiments, the piping may be positioned in at least two of the wellbores.