Abstract: A system used to heat a subsurface formation includes an elongated heater at least partially located in an opening in a hydrocarbon containing layer of the formation. The opening extends from the surface of the formation through an overburden section of the formation and into the hydrocarbon containing layer of the formation. The elongated heater includes an electrical conductor, an insulation layer at least partially surrounding the electrical conductor, and an electrically conductive sheath at least partially surrounding the insulation layer. The elongated heater tapers from a larger thickness at a first end of the heater to a smaller thickness at a second end of the heater. The first end is at or near the junction between the overburden section and the hydrocarbon containing layer and the second end is further into the hydrocarbon containing layer.

Abstract: A method of heating a subsurface hydrocarbon containing formation includes providing heat flux per volume to a first portion of a subsurface hydrocarbon containing formation. The heat flux per volume is provided by two or more first heat sources positioned in the first portion. Heat flux per volume is provided to a second portion of the subsurface hydrocarbon containing formation with the heat flux per volume being provided by two or more second heat sources positioned in the second portion. The heat flux per volume provided by the two or more second heat sources is greater than the heat flux per volume provided by the two or more first heat sources. The second portion is positioned below the first portion.

Abstract: A method for treating a karsted formation containing heavy hydrocarbons and dolomite includes providing heat to at least part of one or more karsted layers in the formation from one or more heaters located in the karsted layers. A temperature in at least one of the karsted layers is allowed to reach a decomposition temperature of dolomite in the formation. The dolomite is allowed to decompose and at least some hydrocarbons are produced from at least one of the karsted layers of the formation.

Abstract: A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat is allowed to transfer from the heaters to at least a portion of the formation. Fluids are produced from the formation through at least one production well that is located in at least two zones in the formation. The first zone has an initial permeability of at least 1 darcy. The second zone has an initial of at most 0.1 darcy. The two zones are separated by a substantially impermeable barrier.

Abstract: A method of recovering energy from a subsurface hydrocarbon containing formation includes introducing an oxidizing fluid in a wellbore positioned in at least a first portion of the formation. At least a portion of the first portion of the formation has been subjected to an in situ heat treatment process. The portion includes a treatment area having elevated levels of coke substantially adjacent the wellbore. The pressure in the wellbore is increased by introducing the oxidizing fluid under pressure such that the oxidizing fluid substantially permeates a majority of the treatment area and initiates a combustion process. Heat from the combustion process is allowed to transfer to fluids in the treatment area. Pressure decreases in the wellbore such that heated fluids from the portion of the formation are conveyed into the wellbore. The heated fluids are transferred to a heat exchanger configured to collect thermal energy.

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: Methods for treating a subsurface formation are described herein. Some methods include providing heat from a plurality of heaters to a section of the hydrocarbon containing formation; controlling the heat from the plurality of heaters such that an average temperature in at least a majority of a first portion of the section is above a pyrolyzation temperature; providing heat from the plurality of heaters to a second portion substantially above the first portion of the section after heating the first portion for a selected time; controlling the heat from the plurality of heaters such that an average temperature in the second portion is sufficient to allow the second portion to expand into the first portion; and producing hydrocarbons from the formation.

Abstract: Systems and methods for treating a subsurface formation are described herein. Some embodiments generally relate to systems, methods, and/or processes for treating fluid produced from the subsurface formation. Some methods include providing heat to a first section of the hydrocarbon containing formation from a plurality of heaters located in the formation; allowing the heat to transfer from the heaters to heat a portion of the first section to mobilize formation fluid; and producing formation fluid from the formation.

Abstract: A system used to heat a subsurface formation includes an elongated heater at least partially located in an opening in a hydrocarbon containing layer of the formation. The opening extends from the surface of the formation through an overburden section of the formation and into the hydrocarbon containing layer of the formation. The elongated heater includes an electrical conductor, an insulation layer at least partially surrounding the electrical conductor, and an electrically conductive sheath at least partially surrounding the insulation layer. The elongated heater tapers from a larger thickness at a first end of the heater to a smaller thickness at a second end of the heater. The first end is at or near the junction between the overburden section and the hydrocarbon containing layer and the second end is further into the hydrocarbon containing layer.

Abstract: Systems and methods used in treating a subsurface formation are described herein. Some embodiments also generally relate to barriers and/or methods to seal barriers. A method used to treat a subsurface formation may include heating a portion of a formation adjacent to a plurality of wellbores to raise a temperature of the formation adjacent to the wellbores above a mobilization temperature of bitumen and below a pyrolysis temperature of hydrocarbons in the formation; and allowing the bitumen to move outwards from the wellbores towards a portion of the formation comprising water cooler than the mobilization temperature of the bitumen so that the bitumen solidifies in the formation to form a barrier.

Abstract: A method of heating a subsurface hydrocarbon containing formation includes providing heat flux per volume to a first portion of a subsurface hydrocarbon containing formation. The heat flux per volume is provided by two or more first heat sources positioned in the first portion. Heat flux per volume is provided to a second portion of the subsurface hydrocarbon containing formation with the heat flux per volume being provided by two or more second heat sources positioned in the second portion. The heat flux per volume provided by the two or more second heat sources is greater than the heat flux per volume provided by the two or more first heat sources. The second portion is positioned below the first portion.

Abstract: Methods of treating a tar sands formation is described herein. The methods may include providing heat to a first section of a hydrocarbon layer in the formation from a plurality of heaters located in the first section of the formation. Heat is transferred from the heaters so that at least a first section of the formation reaches a selected temperature. At least a portion of residual heat from the first section transfers from the first section to a second section of the formation. At least a portion of hydrocarbons in the second section are mobilized by providing a solvation fluid and/or a pressurizing fluid to the second section of the formation.

Abstract: A method for treating a tar sands formation includes providing heat from a first heater located between a steam injection well and a production well in a hydrocarbon containing layer. The first heater, the steam injection well, and the production well are located substantially horizontally in the layer. Heat is provided from a second heater horizontally offset from the first heater. The second heater is located vertically above an injection/production well and substantially horizontally in the layer. Steam is injected into the layer through the steam injection well after a selected amount of heat is provided from the first heater. Hydrocarbons are produced from the layer through the production well. Steam is injected and hydrocarbons are produced alternately through the injection/production well after a selected amount of heat is provided from the second heater.

Abstract: A method of recovering energy from a subsurface hydrocarbon containing formation includes introducing an oxidizing fluid in a wellbore positioned in at least a first portion of the formation. At least a portion of the first portion of the formation has been subjected to an in situ heat treatment process. The portion includes a treatment area having elevated levels of coke substantially adjacent the wellbore. The pressure in the wellbore is increased by introducing the oxidizing fluid under pressure such that the oxidizing fluid substantially permeates a majority of the treatment area and initiates a combustion process. Heat from the combustion process is allowed to transfer to fluids in the treatment area. Pressure decreases in the wellbore such that heated fluids from the portion of the formation are conveyed into the wellbore. The heated fluids are transferred to a heat exchanger configured to collect thermal energy.

Abstract: An oil shale formation may be treated using an in situ thermal process. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat input into the formation may be controlled to raise the temperature of portion at a selected rate during pyrolysis of hydrocarbons within the formation. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. The mixture may be separated into condensable hydrocarbons and non-condensable hydrocarbons. The condensable hydrocarbons removed from the formation may be a high quality oil that has a relatively low olefin content and a relatively high API gravity.

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: Methods for treating a tar sands formation are described herein. The tar sands formation may include dolomite and hydrocarbons. Methods may include providing heat at less than the decomposition temperature of dolomite from one or more heaters to at least a portion of the formation. At least some of the hydrocarbon fluids are mobilized in the formation. At least some of the hydrocarbon fluids may be produced from the formation.

Abstract: An in situ process for treating a hydrocarbon containing formation is provided. The process may include providing heat from one or more heaters to at least a portion of the formation. The heat may be allowed to transfer from the one or more heaters to a part of the formation such that heat from the one or more heat sources pyrolyzes at least some hydrocarbons within the part. Hydrocarbons may be produced from the formation.

Abstract: A method for treating a tar sands formation is disclosed. The method includes heating a first portion of a hydrocarbon layer in the formation from one or more heaters located in the first portion. The heat is controlled to increase a fluid injectivity of the first portion. A drive fluid and/or an oxidizing fluid is injected and/or created in the first portion to cause at least some hydrocarbons to move from a second portion of the hydrocarbon layer to a third portion of the hydrocarbon layer. The second portion is between the first portion and the third portion. The first, second, and third portions are horizontally displaced from each other. The third portion is heated from one or more heaters located in the third portion. Hydrocarbons are produced from the third portion of the formation. The hydrocarbons include at least some hydrocarbons from the second portion of the formation.