Resistive heater for in situ formation heating
First Claim
1. A method for heating a subsurface formation, comprising:
- 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 an electrically 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.
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Abstract
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. Preferably, the subsurface formation is an organic-rich rock formation, including, for example, an oil shale formation.
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Citations
12 Claims
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1. 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 an electrically 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 (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification