Method and apparatus for enhancing liquid hydrocarbon production from a single borehole in a slowly producing formation by non-uniform heating through optimized electrode arrays surrounding the borehole
First Claim
1. A method for recovering liquid hydrocarbons from a slowly producing subsurface formation through a boreho1e extendng from the surface of the earth into the formation which comprises:
- ascertaining the geometry and geophysics of the formation,determining a dimension and configuration of an array of vertical electrodes relative to the geometry and geophysics of the formation to optimize estimated liquid hydrocarbon recovery per unit of electric power applied to the electrodes,disposing in the formation surrounding the borehole such an interrelated array of vertical electrodes distinct from the borehole,applying electric power between the electrodes such that the formation is non-uniformly heated, the viscosity of the liquid hydrocarbons around the borehole is reduced, and the pressure gradient of the liquid hydrocarbons is redistributed in the formation substantially beyond the distance that the formation is heated, andproducing liquid hydrocarbons through the borehole.
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Accused Products
Abstract
Method and apparatus for enhancing liquid hydrocarbon production through a single traditional producing borehole recognizing traditional producing well spacing from a slowly producing formation by use of non-uniform heating through interrelated electrode arrays surrounding the borehole. Heating the formation around the borehole through an interrelated electrode array designed for the formations geometry and geophysics favorably redistributes the pressure gradient throughout the formation for a substantial distance beyond the borehole permitting net energy effective production. One optimum electrode array may consist of ring electrodes or electrode segments so disposed as to electrically approximate a ring. Electrically conductive well bore casing in the formation may be used as an electrode. A return electrode of low impedance disposed close to the surface of the earth may be utilized.
336 Citations
39 Claims
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1. A method for recovering liquid hydrocarbons from a slowly producing subsurface formation through a boreho1e extendng from the surface of the earth into the formation which comprises:
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ascertaining the geometry and geophysics of the formation, determining a dimension and configuration of an array of vertical electrodes relative to the geometry and geophysics of the formation to optimize estimated liquid hydrocarbon recovery per unit of electric power applied to the electrodes, disposing in the formation surrounding the borehole such an interrelated array of vertical electrodes distinct from the borehole, applying electric power between the electrodes such that the formation is non-uniformly heated, the viscosity of the liquid hydrocarbons around the borehole is reduced, and the pressure gradient of the liquid hydrocarbons is redistributed in the formation substantially beyond the distance that the formation is heated, and producing liquid hydrocarbons through the borehole. - View Dependent Claims (3, 4)
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2. A method for recovering liquid hydroocarbons from a slowly producing subsurface formation through a borehole extending from the surface of the earth into the formation which comprises:
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disposing in the formation surrounding the borehole an interrelated array of vertical electrodes distinct from the borehole, the dimensions and configuration of which array have been styled, in conjunction with the level of electric power to be applied, relative to the geometry and geophysics of the formation to optimize recovery for energy expended, disposing a return electrode at a shallow depth from the earth'"'"'s surface, the return electrode having a relatively low impedance, applying electric power between the electrode array in the formation and the return electrode to non-uniformly heat the formation and reduce the viscosity of the liquid hydrocarbons around the borehole, and producing liquid hydrocarbons through the borehole from portions of the formation substantially beyond the interrelated array. - View Dependent Claims (13, 14, 15)
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5. A method for recovering liquid hydrocarbons from a slowly producing subsurface formation through a borehole extending from the surface of the earth into the formation which comprises:
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disposing two ring-like electrodes around the borehole in the formation, at least one of which has an inside diameter larger than the borehole, to create two nearly equipotential rings, applying electric power between the electrodes at a rate sufficient to increase the temperature of the formation in regions approximately circumscribed by the ring-like electrodes such that the flowability of the liquid hydrocarbons is improved, and producing the liquid. hydrocarbons through the borehole from portions of the formation substantially beyond the ring-like electrodes. - View Dependent Claims (7, 8, 9, 10, 11, 12, 17, 18, 19, 20, 36, 37)
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6. A method for recovering liquid hydrocarbons from a slowly producing subsurface formation through a borehole extending from the surface of the earth into the formation which comprises:
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disposing one ring-like electrode around the borehole in the formation having a diameter larger than the borehole, disposing a return electrode at a shallow depth from the earth'"'"'s surface outside the production formation, the return electrode having a relatively low impedance, applying electric power between the electrodes at a rate sufficient to increase the temperature of the formation in regions approximately circumscribed by the ring-like electrode such that the flowability of the liquid hydrocarbons is improved, and producing the liquid hydrocarbons through the borehole from portions of the formation substantially beyond the ring-like electrode. - View Dependent Claims (16)
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21. An apparatus for recovering liquid hydrocarbons from a slowly producing subsurface formation through a borehole extending from the surface of the earth into the formation which comprises:
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two ring-like electrodes disposed in the formation formation surrounding the borehole such that they create two nearly equipotential rings at least one of which has an inside diameter larger than the borehole, a source of electric power, conducting the electric power to means for conducting the electric power to the two ring-like electrodes such that the regions in the formation approximately circumscribed by the two ring-like electrodes are heated to improve the flowability of the liquid hydrocarbon, and means for producing liquid hydrocarbon through the borehole from portions of the formation substantially beyond the ring-like electrodes. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 32, 33, 34, 35, 38, 39)
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22. An apparatus for recovering liquid. hydrocarbonss from a subsurface formation through a borehole extending from the surface of the earth into the formation which comprises:
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one ring-like elecrode disposed in the formation surrounding the borehole having a diameter larger than the borehole, a return electrode disposed at a shallow depth form the earth'"'"'s surface outside the producing formation, the return electrode having a relatively low impedance, a source of electric power, means for conducting the electric power to the ring-like eIectrode and the return electrode such that the region in the formation approxiamtely circumscribed by the ring-like electrode is heated to improve the flowability of the liquid hydrocarbon, and means for producing liquid hydrocarbon through the borehole from portions of the formation substantially beyond the ring-like electrode. - View Dependent Claims (30, 31)
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Specification