Systems and Methods of Controlling In Situ Resistive Heating Elements

Abstract

Systems and methods for controlling in situ resistive heating elements may be utilized to enhance hydrocarbon production within a subterranean formation. An in situ resistive heating element may be controlled by heating a controlled region associated with the in situ resistive heating element, injecting a control gas into the controlled region, and adjusting the electrical conductivity of the controlled region with the control gas. The controlled region may be located such that the heating and injecting may change the shape of the in situ resistive heating element and/or guide the in situ resistive heating element towards subterranean regions of potentially higher productivity and/or of higher organic matter.

1 . A method of controlling an in situ resistive heating element within a subterranean formation containing a controlled region, the method comprising:
 heating the controlled region with the in situ resistive heating element;   injecting a control gas into the controlled region; and   adjusting the electrical conductivity of the controlled region with the control gas.   
     
     
         2 . The method of  claim 1 , wherein the control gas is an oxidizing gas, and wherein the adjusting includes decreasing the electrical conductivity of the controlled region with the control gas. 
     
     
         3 . The method of  claim 1 , wherein the control gas is a reducing gas, and wherein the adjusting includes inhibiting oxidization of the controlled region. 
     
     
         4 . The method of  claim 1 , wherein the control gas is a sweep gas, wherein the adjusting includes reducing the partial pressure of oxidizing gas within the controlled region. 
     
     
         5 . The method of  claim 1 , wherein the heating includes modulating the heating by changing a heating parameter, wherein the heating parameter relates to at least one of a duration of heating and a magnitude of heating. 
     
     
         6 . The method of  claim 1 , wherein the adjusting includes modulating the injecting by changing an injection parameter, wherein the injection parameter relates to at least one of a duration of injecting, a control gas composition, a mass of control gas injected, a volume of control gas injected, a flow rate of control gas injected, a temperature of control gas injected, and a pressure of control gas injected. 
     
     
         7 . The method of  claim 1 , further comprising regulating the electrical conductivity of the controlled region by the heating, the injecting, and the adjusting. 
     
     
         8 . The method of  claim 1 , wherein the regulating includes increasing the electrical conductivity of the controlled region. 
     
     
         9 . The method of  claim 1 , wherein the regulating includes decreasing the electrical conductivity of the controlled region. 
     
     
         10 . The method of  claim 1 , wherein the regulating includes maintaining the electrical conductivity of the controlled region. 
     
     
         11 . The method of  claim 1 , further comprising regulating a spatial extent of the in situ resistive heating element by the heating and the injecting. 
     
     
         12 . The method of  claim 11 , wherein the regulating includes growing an exterior volume of the in situ resistive heating element. 
     
     
         13 . The method of  claim 11 , wherein the regulating includes growing an exterior volume of the in situ resistive heating element while maintaining an interior volume of the in situ resistive heating element. 
     
     
         14 . The method of  claim 11 , wherein the controlled region is adjacent to a restricted region of the subterranean formation; and wherein the regulating includes limiting expansion of the in situ resistive heating element into the restricted region by decreasing the electrical conductivity of the controlled region. 
     
     
         15 . The method of  claim 11 , wherein the controlled region is adjacent to a restricted region of the subterranean formation; and wherein the regulating includes limiting expansion of the in situ resistive heating element into the restricted region by maintaining the electrical conductivity of the controlled region below a predetermined threshold. 
     
     
         16 . The method of  claim 11 , wherein the heating expands the spatial extent of the in situ resistive heating element, wherein the injecting includes injecting a first control gas into the controlled region while expanding the in situ resistive heating element, and wherein the injecting includes subsequently injecting a second control gas into the controlled region while expanding the in situ resistive heating element. 
     
     
         17 . The method of  claim 1 , wherein the injecting includes injecting a plurality of control gases into the controlled region. 
     
     
         18 . The method of  claim 1 , wherein the heating includes heating a plurality of controlled regions with the in situ resistive heating element, and wherein the injecting includes injecting into the plurality of controlled regions by injecting one or more control gases into each of the plurality of controlled regions. 
     
     
         19 . The method of  claim 18 , wherein the injecting includes injecting a first control gas into one of the controlled regions and injecting a second control gas into another of the controlled regions, wherein the second control gas is different from the first control gas. 
     
     
         20 . The method of  claim 1 , wherein the controlled region is within an interior volume of the in situ resistive heating element, and wherein the adjusting decreases the average electrical conductivity of a portion of the interior volume sufficient to split the in situ resistive heating element into two or more independent, electrically-disconnected, in situ resistive heating elements. 
     
     
         21 . The method of  claim 1 , further comprising monitoring a subterranean parameter relating to at least one of the subterranean formation, organic matter in the subterranean formation, the in situ resistive heating element, and the controlled region, wherein the subterranean parameter includes at least one of a shape, an extent, a volume, a composition, a density, a porosity, a permeability, an electrical conductivity, an electrical property, a temperature, a pressure, a duration of heating, a magnitude of heating, a gas composition, a chemical environment, a chemical redox state, and hydrocarbon production; and further wherein the adjusting includes regulating injection of control gas based at least in part on the subterranean parameter. 
     
     
         22 . The method of  claim 1 , further comprising monitoring a subterranean parameter relating to at least one of the subterranean formation, organic matter in the subterranean formation, the in situ resistive heating element, and the controlled region, wherein the subterranean parameter includes at least one of a shape, an extent, a volume, a composition, a density, a porosity, a permeability, an electrical conductivity, an electrical property, a temperature, a pressure, a duration of heating, a magnitude of heating, a gas composition, a chemical environment, a chemical redox state, and hydrocarbon production; and further wherein the heating includes regulating heating based at least in part on the subterranean parameter. 
     
     
         23 . The method of  claim 1 , wherein the heating includes transmitting electrical power through the in situ resistive heating element, and the method further comprising monitoring a transmission parameter, wherein the transmission parameter includes at least one of electrical power transmitted, electrical current transmitted, and a duration of the transmitting; and further wherein the adjusting includes regulating injection of control gas based at least in part on the transmission parameter. 
     
     
         24 . The method of  claim 1 , wherein the heating includes transmitting electrical power through the in situ resistive heating element, and the method further comprising monitoring a transmission parameter, wherein the transmission parameter includes at least one of electrical power transmitted, electrical current transmitted, and a duration of the transmitting; and further wherein the heating includes regulating heating based at least in part on the transmission parameter. 
     
     
         25 . The method of  claim 1 , further comprising monitoring an injection parameter, wherein the injection parameter includes at least one of a duration of injecting, a gas composition, a mass of control gas injected, a volume of control gas injected, a flow rate of the control gas, a temperature of the control gas, and a pressure of the control gas; and further wherein the adjusting includes regulating injection of control gas based at least in part on the injection parameter. 
     
     
         26 . The method of  claim 1 , further comprising monitoring an injection parameter, wherein the injection parameter includes at least one of a duration of injecting, a gas composition, a mass of control gas injected, a volume of control gas injected, a flow rate of the control gas, a temperature of the control gas, and a pressure of the control gas; and further wherein the heating includes regulating heating based at least in part on the injection parameter. 
     
     
         27 . The method of  claim 1 , further comprising selecting the control gas to adjust the electrical conductivity of the controlled region. 
     
     
         28 . A system for controlling an in situ resistive heating element within a subterranean formation containing a controlled region, the system comprising:
 an in situ resistive heater configured to heat the controlled region, the in situ resistive heater including:
 an in situ resistive heating element within the subterranean formation electrically connected to two or more spaced-apart electrodes; and 
 an electrical power source electrically connected through a pair of spaced-apart electrodes to the in situ resistive heating element; 
   a gas delivery system configured to inject a control gas into the controlled region and to adjust an electrical conductivity of the controlled region with the control gas, the gas delivery system including:
 a gas injection well fluidically connected to the controlled region; and 
 a gas source configured to supply the control gas to the gas injection well, wherein the control gas is selected to adjust the electrical conductivity of the controlled region; and 
   a sensor to monitor a parameter relating to at least one of the subterranean formation, the in situ resistive heater, the gas delivery system, and the controlled region, wherein the parameter includes at least one of an electrical conductivity, an electrical property, an electrical power, an electrical current, a temperature, a pressure, a gas composition, a chemical environment, and a chemical redox state.   
     
     
         29 . The system of  claim 28 , wherein the gas delivery system is configured to
 selectively inject one or more control gases based at least in part on the parameter.   
     
     
         30 . The system of  claim 28 , wherein the gas delivery system includes a plurality of control gases, wherein at least one of the control gases is selected to increase and/or maintain an electrical conductivity within a portion of the subterranean formation when the portion is heated, and wherein at least one of the control gases is selected to decrease an electrical conductivity within a portion of the subterranean formation when the portion is heated. 
     
     
         31 . The system of  claim 28 , wherein the subterranean formation includes a plurality of controlled regions, wherein the gas delivery system includes a plurality of gas injection wells, each gas injection well fluidically connected to at least one controlled region.