Abstract: A system for treating a subsurface formation includes a plurality of conduits at least partially located in a portion of a hydrocarbon containing formation. At least part of two of the conduits are aligned in relation to each other such that electrical current will flow from a first conduit to a second conduit. The first and second conduits include electrically conductive material and at least one of the first and second conduits is perforated or configured to be perforated. A power supply is coupled to the first and second conduits. The power supply electrically excites at least one of the conductive sections such that current flows between the first conduit and the second conduit in the formation and heats at least a portion of the formation between the two conduits.

Abstract: A system for treating a subsurface formation includes a wellbore at least partially located in a hydrocarbon containing formation. The wellbore includes a substantially vertical portion and at least two substantially horizontal or inclined portions coupled to the vertical portion. A first conductor is at least partially positioned in a first of the two substantially horizontal or inclined portions of the wellbore. At least the first conductor includes electrically conductive material. A power supply electrically excites the electrically conductive materials of the first conductor such that current flows between the electrically conductive materials in the first conductor, through at least a portion of the formation, to a second conductor at least partially positioned in a second of the two substantially horizontal or inclined portions of the wellbore. The current resistively heats at least a portion of the formation between the two substantially horizontally oriented or inclined portions of the wellbore.

Abstract: A system for heating a subsurface formation is described. The system includes an elongated heater in an opening in the formation. The elongated heater includes two or more portions along the length of the heater that have different power outputs. At least one portion of the elongated heater includes at least one temperature limited portion with at least one selected temperature at which the portion provides a reduced heat output. The heater is configured to provide heat to the formation with the different power outputs. The heater is configured so that the heater heats one or more portions of the formation at one or more selected heating rates.

Abstract: A system for treating a subsurface formation includes a wellbore at least partially located in a hydrocarbon containing formation. The wellbore includes a substantially vertical portion and at least two substantially horizontal or inclined portions coupled to the vertical portion. A first conductor is at least partially positioned in a first of the two substantially horizontal or inclined portions of the wellbore. At least the first conductor includes electrically conductive material. A power supply electrically excites the electrically conductive materials of the first conductor such that current flows between the electrically conductive materials in the first conductor, through at least a portion of the formation, to a second conductor at least partially positioned in a second of the two substantially horizontal or inclined portions of the wellbore. The current resistively heats at least a portion of the formation between the two substantially horizontally oriented or inclined portions of the wellbore.

Abstract: A system for treating a subsurface formation includes a plurality of conduits at least partially located in a portion of a hydrocarbon containing formation. At least part of two of the conduits are aligned in relation to each other such that electrical current will flow from a first conduit to a second conduit. The first and second conduits include electrically conductive material and at least one of the first and second conduits is perforated or configured to be perforated. A power supply is coupled to the first and second conduits. The power supply electrically excites at least one of the conductive sections such that current flows between the first conduit and the second conduit in the formation and heats at least a portion of the formation between the two conduits.

Abstract: A method for treating an oil shale formation comprising dawsonite includes assessing a dawsonite composition of one or more zones in the formation. Heat from one or more heaters is provided to the formation such that different amounts of heat are provided to zones with different dawsonite compositions. The provided heat is allowed to transfer from the heaters to the formation. Fluids are produced from the formation.

Abstract: A method for treating an oil shale formation comprising dawsonite includes assessing a dawsonite composition of one or more zones in the formation. Heat from one or more heaters is provided to the formation such that different amounts of heat are provided to zones with different dawsonite compositions. The provided heat is allowed to transfer from the heaters to the formation. Fluids are produced from the formation.

Abstract: A system for heating a subsurface formation is described. The system includes an elongated heater in an opening in the formation. The elongated heater includes two or more portions along the length of the heater that have different power outputs. At least one portion of the elongated heater includes at least one temperature limited portion with at least one selected temperature at which the portion provides a reduced heat output. The heater is configured to provide heat to the formation with the different power outputs. The heater is configured so that the heater heats one or more portions of the formation at one or more selected heating rates.