Abstract: A oil shale formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat sources may be used to heat the formation. The heat sources may be positioned within the formation in a selected pattern.

Abstract: Certain embodiments provide a system configured to heat a subsurface formation. The system includes an electrical power supply. A heater section includes one or more electrical conductors electrically coupled to the electrical power supply. At least one of the electrical conductors includes ferromagnetic material. The heater section provides a first heat output when time-varying electrical current is applied to the heater section below a selected temperature, and a second heat output approximately at and above the selected temperature during use. The second heat output is reduced compared to the first heat output. The system is configured to allow heat to transfer from the heater section to a part of the formation. The electrical power supply is configured to provide a relatively constant amount of time-varying electrical current that remains within about 15% of a selected constant current value when a load of the electrical conductors changes.

Abstract: Certain embodiments provide a method for treating a subsurface formation. The method includes providing one or more explosives into portions of one or more wellbores selected for the explosion in the formation. The wellbores are formed in one or more zones in the formation. The explosives are controllably exploded in one or more of the wellbores such that at least some of the formation surrounding the selected wellbores has an increased permeability. One or more heaters are provided in the one or more wellbores.

Abstract: Certain embodiments provide a method for treating a hydrocarbon containing formation. The method includes applying electrical current to one or more electrical conductors located in an opening in the formation to provide an electrically resistive heat output. The heat is allowed to transfer from the electrical conductors to a part of the formation containing hydrocarbons so that a viscosity of fluids in the part and at or near the opening in the formation is reduced. Gas is provided at one or more locations in the opening such that the fluids are lifted in the opening towards the surface of the formation. The fluids are produced through the opening.

Abstract: Certain embodiments provide a system including a heater. The heater includes one or more electrical conductors. The heater is configured to generate a heat output during application of electrical current to the heater. The heater includes a ferromagnetic material. A conduit at least partially surrounds the heater. A fluid is located in a space between the heater and the conduit. The fluid has a higher thermal conductivity than air at standard temperature and pressure (STP) (0° C. and 101.325 kPa). The system is configured to provide (a) a first heat output below a selected temperature when time-varying electrical current is applied to the heater, and (b) a second heat output near or above the selected temperature when time-varying electrical current is applied to the heater.

Abstract: Certain embodiments provide a heating system configured to heat at least a part of a subsurface formation. The system includes an electrical power supply. A heater section includes one or more electrical conductors electrically coupled to the electrical power supply. The heater section is configured to be placed in an opening in the formation. At least one of the electrical conductors includes ferromagnetic material. The heater section provides a first heat output when time-varying electrical current is applied to the heater section below a selected temperature, and provides a second heat output approximately at and above the selected temperature during use. The second heat output is reduced compared to the first heat output. The system is configured to allow heat to transfer from the heater section to a part of the formation. The system is configured to allow a frequency of the applied time-varying electrical current to be varied.

Abstract: Certain embodiments provide a system configured to heat at least a part of a subsurface formation. The system includes an electrical power supply configured to provide modulated direct current (DC). The system also includes a heater section including one or more electrical conductors electrically coupled to the electrical power supply. The heater section is configured to be placed in an opening in the formation. At least one of the electrical conductors includes ferromagnetic material. The heater section provides a first heat output when electrical current is applied to the heater section below a selected temperature. The heater section provides a second heat output approximately at and above the selected temperature during use. The heater section has a turndown ratio of at least 1.1 to 1. The system is configured to heat at least part of a subsurface formation.

Abstract: Certain embodiments provide a heater. The heater includes a ferromagnetic member. The heater also includes an electrical conductor electrically coupled to the ferromagnetic member. The electrical conductor is configured to conduct a majority of time-varying electrical current passing through the heater at about 25° C. The heater is configured to provide a first heat output below the Curie temperature of the ferromagnetic member. The heater is configured to automatically provide a second heat output approximately at and above the Curie temperature of the ferromagnetic member. The second heat output is reduced compared to the first heat output.

Abstract: Certain embodiments provide a method that includes placing a heater element in an opening in a subsurface formation. The heater element is in a conduit. A pressure is reduced inside the conduit to a pressure below the vapor pressure of water at the temperature in the conduit.

Abstract: An in situ thermal desorption system may be used to remove contamination from soil. Off-gas removed from the soil may be transported from the soil to a treatment facility by high temperature hoses and plastic piping. The use of high temperature hose and plastic pipe may reduce the capital cost, installation cost, and operating cost as compared to conventional transport systems from thermal desorption soil remediation systems. The high temperature hose and plastic pipe are highly resistant to corrosion caused by the off-gas. The treatment facility may separate the off-gas into a liquid stream and a vapor stream. The liquid stream and the vapor stream may be processed to reduce contaminants within the liquid stream and vapor stream to acceptable levels.

Abstract: An in situ process for treating a hydrocarbon containing formation is provided. The process may include providing heat from one or more heat sources to at least a portion of the formation. Heat sources may include a natural distributed combustor. The natural distributed combustor may include an oxidizing fluid source to provide oxidizing fluids to a reaction zone in the formation to generate heat within the reaction zone. The heat may be allowed, in some embodiments, to transfer from the reaction zone to a selected section of the formation such that heat from one or more heat sources pyrolyzes at least some hydrocarbons within the selected section. Hydrocarbons may be produced from the formation.

Abstract: A process may include providing heat from one or more heaters to at least a portion of a subsurface formation. Heat may transfer from one or more heaters to a part of a formation. In some embodiments, heat from the one or more heat sources may pyrolyze at least some hydrocarbons in a part of a subsurface formation. Hydrocarbons and/or other products may be produced from a subsurface formation. Certain embodiments describe apparatus, methods, and/or processes used in treating a subsurface or hydrocarbon containing formation.

Abstract: A heater system may include an alternating current supply and an electrical conductor. Alternating current may be applied to one or more electrical conductors at a frequency between about 100 Hz and about 1000 Hz. The electrical conductors may be located in a formation. The electrical conductors may resistively heat upon application of the alternating electrical current. At least one of the electrical conductors may include an electrically resistive ferromagnetic material. The electrical conductor may provide a reduced amount of heat above or near a selected temperature. Heat may transfer from the electrical conductor to a part of formation.