Abstract: A method for treating a hydrocarbon containing layer in a subsurface formation is described. The method may include removing at most about 20% by weight of the nahcolite from one or more intervals in the hydrocarbon containing layer that include at least about 40% by weight nahcolite. Heat may be provided from a plurality of heaters to the hydrocarbon containing layer such that at least some hydrocarbons in the hydrocarbon containing layer are mobilized. At least some mobilized hydrocarbons may be produced through at least one production well.

Abstract: Electrical current flow is induced in a ferromagnetic conductor providing time-varying electrical current at a first frequency to an electrical conductor located in a formation. The ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The ferromagnetic conductor resistively heats up to a first temperature of at most about 300° C. Water in the formation is vaporized with heat at the first temperature. Subsequently, time-varying electrical current at a second frequency is provided to the elongated electrical conductor to induce electrical current flow at the second frequency such that the ferromagnetic conductor resistively heats up to a second temperature above about 300° C. Heat transfers from the ferromagnetic conductor at the second temperature to at least a part of the formation to mobilize at least some hydrocarbons in the part of the formation.

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.

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.

Abstract: A method for treating a hydrocarbon containing layer in a subsurface formation includes forming a plurality of substantially vertical fractures in the formation at selected intervals along a length of at least one production wellbore positioned substantially horizontally in the hydrocarbon containing layer. Heat is provided from a plurality of heaters to the hydrocarbon containing layer such that at least some hydrocarbons in the hydrocarbon containing layer are mobilized. At least some of the plurality of heaters are positioned substantially horizontally in the hydrocarbon containing layer. At least some mobilized hydrocarbons are produced through at least one production wellbore.

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.

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.

Abstract: A method for treating a hydrocarbon containing layer in a subsurface formation is described. The method may include removing at most about 20% by weight of the nahcolite from one or more intervals in the hydrocarbon containing layer that include at least about 40% by weight nahcolite. Heat may be provided from a plurality of heaters to the hydrocarbon containing layer such that at least some hydrocarbons in the hydrocarbon containing layer are mobilized. At least some mobilized hydrocarbons may be produced through at least one production well.

Abstract: A plurality of first barrier wells are formed in a formation for a first barrier. A substantially constant spacing separates adjacent first barrier wells. The formation is analyzed to determine the principal fracture direction of at least one layer of the formation. An offset distance of second barrier wells relative to first barrier wells is determined based on the principal fracture direction to limit a maximum separation distance between a closest barrier well and a theoretical fracture extending between the first barrier and the second barrier along the principal fracture direction to a distance of less than one half of the spacing that separates adjacent first barrier wells. The second barrier wells are offset from the first barrier wells by a distance that is at least substantially the same as the offset distance.

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.

Abstract: Electrical current flow is induced in a ferromagnetic conductor providing time-varying electrical current at a first frequency to an electrical conductor located in a formation. The ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The ferromagnetic conductor resistively heats up to a first temperature of at most about 300° C. Water in the formation is vaporized with heat at the first temperature. Subsequently, time-varying electrical current at a second frequency is provided to the elongated electrical conductor to induce electrical current flow at the second frequency such that the ferromagnetic conductor resistively heats up to a second temperature above about 300° C. Heat transfers from the ferromagnetic conductor at the second temperature to at least a part of the formation to mobilize at least some hydrocarbons in the part of the formation.

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.

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 plurality of first barrier wells are formed in a formation for a first barrier. A substantially constant spacing separates adjacent first barrier wells. The formation is analyzed to determine the principal fracture direction of at least one layer of the formation. An offset distance of second barrier wells relative to first barrier wells is determined based on the principal fracture direction to limit a maximum separation distance between a closest barrier well and a theoretical fracture extending between the first barrier and the second barrier along the principal fracture direction to a distance of less than one half of the spacing that separates adjacent first barrier wells. The second barrier wells are offset from the first barrier wells by a distance that is at least substantially the same as the offset distance.

Abstract: A system for treating a hydrocarbon containing formation includes a steam and electricity cogeneration facility. At least one injection well is located in a first portion of the formation. The injection well provides steam from the steam and electricity cogeneration facility to the first portion of the formation. At least one production well is located in the first portion of the formation. The production well in the first portion produces first hydrocarbons. At least one electrical heater is located in a second portion of the formation. At least one of the electrical heaters is powered by electricity from the steam and electricity cogeneration facility. At least one production well is located in the second portion of the formation. The production well in the second portion produces second hydrocarbons. The steam and electricity cogeneration facility uses the first hydrocarbons and/or the second hydrocarbons to generate electricity.

Abstract: Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for providing acidic gas to a subsurface formation is described herein. The method may include providing heat from one or more heaters to a portion of a subsurface formation; producing fluids that include one or more acidic gases from the formation using a heat treatment process. At least a portion of one of the acidic gases may be introduced into the formation, or into another formation, through one or more wellbores at a pressure below a lithostatic pressure of the formation in which the acidic gas is introduced.

Abstract: An in situ conversion system for producing hydrocarbons from a subsurface formation is described. The system includes a plurality of u-shaped wellbores in the formation. Piping is positioned in at least two of the u-shaped wellbores. A fluid circulation system is coupled to the piping. The fluid circulation system is configured to circulate hot heat transfer fluid through at least a portion of the piping to form at least one heated portion of the formation. An electrical power supply is configured to provide electrical current to at least a portion of the piping located below an overburden in the formation to resistively heat at least a portion of the piping. Heat transfers from the piping to the formation.

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: Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for providing acidic gas to a subsurface formation is described herein. The method may include providing heat from one or more heaters to a portion of a subsurface formation; producing fluids that include one or more acidic gases from the formation using a heat treatment process. At least a portion of one of the acidic gases may be introduced into the formation, or into another formation, through one or more wellbores at a pressure below a lithostatic pressure of the formation in which the acidic gas is introduced.

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.