Resistive heater for in situ formation heating
First Claim
1. A method for heating a subsurface formation using electrically resistive heat, comprising:
- providing a first wellbore located at least partially within a subsurface formation, the first wellbore having an electrically conductive first member, an electrically conductive second member, and an electrically conductive first granular material in the first wellbore, wherein the first granular material is positioned to provide electrical communication between the first member and the second member;
providing a second wellbore located at least partially within the subsurface formation, the second wellbore having an electrically conductive third member, an electrically conductive fourth member, and an electrically conductive second granular material in the second wellbore, wherein the second granular material is positioned to provide electrical communication between the third member and the fourth member;
passing a first electrical current through the first member, the first granular material and the second member, thereby generating first heat, the generated first heat produced primarily through electrical resistive heating of the first granular material;
passing a second electrical current through the third member, the second granular material and the fourth member, thereby generating second heat, the generated second heat produced primarily through electrical resistive heating of the second granular material; and
heating formation hydrocarbons located substantially equidistant from the first wellbore and the second wellbore primarily with the generated first heat, second heat or both.
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Accused Products
Abstract
Improved methods for heating a subsurface formation using an electrical resistance heater are provided. Preferably, the subsurface formation is an organic-rich rock formation, including, for example, an oil shale formation. One embodiment of the method includes providing an electrically conductive first member in a wellbore located in a subsurface formation, and also providing an electrically conductive second member in the wellbore. The method also includes providing an electrically conductive granular material in the wellbore. The granular material is positioned so as to provide an electrical connection between the first member and the second member. An electrical current is established across the first member, the granular material and the second member so as to generate resistive heat within the granular material. The surrounding subsurface formation is thereby conductively heated so as to cause formation hydrocarbons in the formation to be heated, and in some cases, pyrolyzed to form hydrocarbon fluids.
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Citations
50 Claims
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1. A method for heating a subsurface formation using electrically resistive heat, comprising:
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providing a first wellbore located at least partially within a subsurface formation, the first wellbore having an electrically conductive first member, an electrically conductive second member, and an electrically conductive first granular material in the first wellbore, wherein the first granular material is positioned to provide electrical communication between the first member and the second member; providing a second wellbore located at least partially within the subsurface formation, the second wellbore having an electrically conductive third member, an electrically conductive fourth member, and an electrically conductive second granular material in the second wellbore, wherein the second granular material is positioned to provide electrical communication between the third member and the fourth member; passing a first electrical current through the first member, the first granular material and the second member, thereby generating first heat, the generated first heat produced primarily through electrical resistive heating of the first granular material; passing a second electrical current through the third member, the second granular material and the fourth member, thereby generating second heat, the generated second heat produced primarily through electrical resistive heating of the second granular material; and heating formation hydrocarbons located substantially equidistant from the first wellbore and the second wellbore primarily with the generated first heat, second heat or both. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for heating a subsurface formation, comprising:
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forming a wellbore to the subsurface formation; placing a string of conductive casing proximate the bottom of the wellbore; running an elongated conductive element into the wellbore and within the string of conductive casing, thereby forming an annular region between the string of conductive casing and the elongated conductive element; filling at least a part of the annular region with a conductive granular material to act as a resistive heating element; radially passing an electrical current through the string of conductive casing, through the granular material, and through the elongated conductive element within the casing in order to generate resistive heat within the granular material; and continuing to radially pass electricity through the granular material to generate additional resistive heat in order to cause in situ pyrolysis of at least some formation hydrocarbons, thereby forming hydrocarbon fluids. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A method for heating an organic-rich rock formation, comprising:
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providing a plurality of heater wells, each of the plurality of heater wells comprising; a) a first wellbore located at least partially within the organic-rich rock formation; an electrically conductive first member located in the first wellbore; b) a second wellbore, the second wellbore having a bottom portion that intersects the first wellbore; c) an electrically conductive second member located in the second wellbore; and d) an electrically conductive granular material filling at least a part of each of the first and second wellbores so as to provide an electrical connection between the first member in the first wellbore and the second member in the second wellbore, the granular material thereby forming a granular mass and acting as a resistive heating element, the first member, granular material and second member thereby forming an electrical flow path; passing electrical current through each electrical flow path in order to generate heat primarily via electrical resistive heating within the granular material; transferring, by thermal conduction, at least a portion of the generated heat into the organic-rich rock formation, thereby forming a heated volume of the organic-rich rock formation, the heated volume being defined at it'"'"'s extremities by a plurality of the granular masses; and heating a majority of the formation hydrocarbons located in the heated volume of the organic-rich rock formation primarily with the generated heat, thereby causing the formation hydrocarbons to be substantially pyrolyzed to form hydrocarbon fluids. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48)
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49. A method of producing a hydrocarbon fluid, comprising:
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heating an organic-rich rock formation in situ primarily using heat generated by electrical resistive heating of a granular material included in an electrical resistance heater, thereby producing a heated portion of the organic-rich rock formation; controlling the rate of heat generation such that the electrical conductivity of a majority of the heated portion of the organic-rich rock formation does not increase substantially; and producing a hydrocarbon fluid from the organic-rich rock formation, the hydrocarbon fluid having been generated as a result of heating and pyrolysis of formation hydrocarbons located in the heated portion of the organic-rich rock formation, the heating and pyrolysis resulting primarily from the heat generated by electrical resistive heating of the granular material, wherein the electrical resistance heater is formed by; passing electricity through a conductive granular material to generate resistive heat within the granular material, the granular material being disposed between and within at least two adjacent wellbores completed at least partially within the organic-rich rock formation, the granular material providing electrical communication between the wellbores, wherein a majority of the resistive heat is generated within the granular material; and transferring, by thermal conduction, at least a portion of the resistive heat into the organic-rich rock formation in order to cause in situ pyrolysis of the formation hydrocarbons located in the heated portion of the organic-rich rock formation to form the hydrocarbon fluid.
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50. A method of producing a hydrocarbon fluid, comprising:
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heating an organic-rich rock formation in situ primarily using heat generated by electrical resistive heating of a granular material included in an electrical resistance heater, thereby producing a heated portion of the organic-rich rock formation; controlling the rate of heat generation such that the electrical conductivity of a majority of the heated portion of the organic-rich rock formation does not increase substantially; and producing a hydrocarbon fluid from the organic-rich rock formation, the hydrocarbon fluid having been at least partially generated as a result of heating and pyrolysis of formation hydrocarbons located in the heated portion of the organic-rich rock formation, the heating and pyrolysis resulting primarily from the heat generated by electrical resistive heating of the granular material, wherein the electrical resistance heater is formed by; a) providing a wellbore located at least partially within the organic-rich rock, the wellbore having an electrically conductive first member, an electrically conductive second member, and an electrically conductive granular material in the wellbore, wherein the granular material is positioned to provide electrical communication between the first member and the second member; and b) passing an electrical current through the first member, the granular material and the second member, thereby generating heat, the generated heat produced primarily through electrical resistive heating of the granular material.
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Specification