Enhanced hydrocarbon recovery from a single well by electrical resistive heating of a single inclusion in an oil sand formation

Abstract

The present invention is a method and apparatus for enhanced recovery of petroleum fluids from the subsurface by electrical resistive heating of the oil sand formation and the heavy oil and bitumen in situ, by electrically energizing vertical inclusion planes containing electrically conductive proppant. The inclusion is propagated into a portion of the formation having a Skempton's B parameter of greater than 0.95 exp(−0.04 p′)+0.008 p′, where p′ is a mean effective stress in MPa at the depth of the inclusion. Multiple propped vertical inclusions at various azimuths are constructed from the well. Electrodes are placed in the well in electrical contact with the inclusions and an alternating direction current is passed through the proppant. By electrically resistive heating of the inclusion, the formation is heated by conduction and associated hydrocarbon fluids are lowered in viscosity and drain by gravity back to the well and produced to the surface. By controlling the reservoir temperature and pressure, a particular fraction of the in situ hydrocarbon reserve is extracted and water inflow into the heated zone is minimized.

1 . A method of improving production of hydrocarbons from a subterranean formation of weakly cemented sediments, the method comprising the steps of:
 a) propagating a first substantially vertical inclusion into the formation at a first depth and in a first preferential direction from a substantially vertical wellbore intersecting the formation, wherein the first vertical inclusion is filled with an injected fluid including electrically conductive proppant particles;   b) locating an open section of the wellbore at a second depth displaced from the first depth;   c) maintaining the open section at a reduced pressure;   d) propagating the first inclusion vertically to the second depth of the open section;   e) passing an electric current through the inclusion by electrodes placed in the wellbore and heating the formation in a process zone in the vicinity of the first inclusion; and   f) producing the heated hydrocarbons up the wellbore.   
     
     
         2 . The method of  claim 1 , wherein the second depth of the open section of the wellbore is below the first depth. 
     
     
         3 . The method of  claim 1 , wherein the method includes propagating a plurality of inclusions at varying azimuths. 
     
     
         4 . The method of  claim 1 , wherein the proppant particles range in size from #4 to #100 U.S. mesh and are ceramic beads substantially coated with an electrically conductive resin. 
     
     
         5 . The method of  claim 4 , wherein the resin is phenol formaldehyde containing fine graphite particles and is heat hardenable, with resin present in an amount sufficient to consolidate the proppant, but insufficient to fill the openings between the proppant. 
     
     
         6 . The method of  claim 1 , wherein the proppant particles range in size from #4 to #100 U.S. mesh and are selected from a group of conductive materials such as metals, melt alloys, metal oxides, metal salts, metal-containing catalysts, calcined petroleum coke or graphite beads, green or black silicon carbide, boron carbide or a mixture thereof. 
     
     
         7 . The method of  claim 1 , wherein the proppant particles range in size from #4 to #100 U.S. mesh and are selected from a group of non-conductive materials such as ceramics, glass and sands coated with a conductive layer either being metal, metal oxide, metal salts, conductive resins or mixtures thereof. 
     
     
         8 . The method of  claim 1 , wherein pressure in the majority of the heated process zone is held at ambient reservoir pressure by injecting into the process zone steam, non-condensing gas, or a hydrocarbon solvent in a vaporized state or a mixture thereof. 
     
     
         9 . The method of  claim 8 , wherein the solvent is one of a group of ethane, propane, butane or a mixture thereof. 
     
     
         10 . The method of  claim 8 , wherein the solvent is mixed with a diluent gas. 
     
     
         11 . The method of  claim 10 , wherein the diluent gas is non-condensable under the process conditions. 
     
     
         12 . The method of  claim 11 , wherein the non-condensable diluent gas has a lower solubility in the hydrocarbons than the saturated hydrocarbon solvent. 
     
     
         13 . The method of  claim 12 , wherein the diluent gas is one of a group of methane, nitrogen, carbon dioxide, natural gas or a mixture thereof. 
     
     
         14 . The method of  claim 1 , wherein the method further includes injecting a hydrogenizing gas into the wellbore and thus into the fluids in the process zone to promote hydrogenation and thermal cracking reactions of at least a portion of the hydrocarbons in the process zone. 
     
     
         15 . The method of  claim 14 , wherein the hydrogenising gas consists of one of the group of H2 and CO or a mixture thereof. 
     
     
         16 . (canceled) 
     
     
         17 . The method of  claim 14 , wherein a metal-containing catalyst is used to catalyze said hydrogenation and thermal cracking reactions. 
     
     
         18 . The method of  claim 17 , wherein the catalyst is contained in a canister in tubing inside of the wellbore. 
     
     
         19 . The method of  claim 1 , wherein the proppant particles in the inclusions include the catalyst for the hydrogenation and thermal cracking reactions. 
     
     
         20 . The method of  claim 1 , wherein the second depth of the open section of the wellbore is above the first depth. 
     
     
         21 . The method of  claim 1 , wherein a portion of the formation in which the first inclusion is formed has a Skempton B parameter greater than 0.95 exp(−0.04 p′)+0.008 p′, where p′ is a mean effective stress in MPa at the depth of the first inclusion and the water saturation in the formation pores is greater or equal to 10%. 
     
     
         22 . A hydrocarbon production well in a subterranean formation of weakly cemented sediments having an ambient reservoir pressure and temperature comprising:
 a) a substantially vertical bore hole in the formation to a first depth;   b) an injection casing grouted in the bore hole to create a substantially vertical wellbore, the injection casing being radially expandable by the introduction of a fluid;   c) a vertical first inclusion in the formation created by the fluid delivered into the injection casing with sufficient pressure to dilate the injection casing and to create the first inclusion in the formation, wherein the first inclusion is filled with the fluid including electrically conductive proppant particles and wherein the first inclusion is oriented in the formation in a first preferential direction extending from and in communication with the substantially vertical wellbore   d) an open section of the wellbore located at a second depth displaced from the first depth;   e) means for maintaining a reduced pressure at the open section;   f) the first inclusion extending from the first depth to the second depth; and   g) electrodes placed in the wellbore for passing an electric current through the inclusion for heating the formation in a process zone in the vicinity of the first inclusion and thereby producing the heated hydrocarbons up the wellbore from the formation.   
     
     
         23 . The hydrocarbon production well of  claim 22 , wherein the second depth of the open section of the wellbore is below the first depth. 
     
     
         24 . The hydrocarbon production well of  claim 22 , wherein the production well includes a plurality of inclusions propagated at varying azimuths. 
     
     
         25 . The hydrocarbon production well of  claim 22 , wherein the proppant particles range in size from #4 to #100 U.S. mesh and are ceramic beads substantially coated with an electrically conductive resin. 
     
     
         26 . The hydrocarbon production well of  claim 25 , wherein the resin is phenol formaldehyde containing fine graphite particles and is heat hardenable, with resin present in an amount sufficient to consolidate the proppant, but insufficient to fill the openings between the proppant. 
     
     
         27 . The hydrocarbon production well of  claim 22 , wherein the proppant particles range in size from #4 to #100 U.S. mesh and are selected from a group of conductive materials such as metals, melt alloys, metal oxides, metal salts, metal-containing catalysts, calcined petroleum coke or graphite beads, green or black silicon carbide, boron carbide or a mixture thereof. 
     
     
         28 . The hydrocarbon production well of  claim 22 , wherein the proppant particles range in size from #4 to #100 U.S. mesh and are selected from a group of non-conductive materials such as ceramics, glass and sands coated with a conductive layer either being metal, metal oxide, metal salts, conductive resins or mixtures thereof. 
     
     
         29 . The hydrocarbon production well of  claim 22 , wherein pressure in the majority of the heated process zone is held at ambient reservoir pressure by injecting into the process zone steam, non-condensing gas, or a hydrocarbon solvent in a vaporized state or a mixture thereof. 
     
     
         30 . The hydrocarbon production well of  claim 29 , wherein the solvent is one of a group of ethane, propane, butane or a mixture thereof. 
     
     
         31 . The hydrocarbon production well of  claim 29 , wherein the solvent is mixed with a diluent gas. 
     
     
         32 . The hydrocarbon production well of  claim 31 , wherein the diluent gas is non-condensable under the process conditions. 
     
     
         33 . The hydrocarbon production well of  claim 32 , wherein the non-condensable diluent gas has a lower solubility in the hydrocarbons than the saturated hydrocarbon solvent. 
     
     
         34 . The hydrocarbon production well of  claim 33 , wherein the diluent gas is one of a group of methane, nitrogen, carbon dioxide, natural gas or a mixture thereof. 
     
     
         35 . The hydrocarbon production well of  claim 22 , wherein the production well further includes means for injecting a hydrogenizing gas into the wellbore and thus into the fluid in the process zone to promote hydrogenation and thermal cracking reactions of at least a portion of the hydrocarbons in the process zone. 
     
     
         36 . The hydrocarbon production well of  claim 35 , wherein the hydrogenising gas consists of one of the group of H2 and CO or a mixture thereof. 
     
     
         37 . The hydrocarbon production well of  claim 35 , wherein a metal-containing catalyst is used to catalyze said hydrogenation and thermal cracking reactions. 
     
     
         38 . The hydrocarbon production well of  claim 37 , wherein the catalyst is contained in a canister in tubing inside of the wellbore. 
     
     
         39 . The hydrocarbon production well of  claim 22 , wherein the proppant particles in the inclusion include the catalyst for the hydrogenation and thermal cracking reactions. 
     
     
         40 . The hydrocarbon production well of  claim 22 , wherein the second depth of the open section of the wellbore is above the first depth. 
     
     
         41 . The hydrocarbon production well of  claim 22 , wherein a portion of the formation in which the first inclusion is formed has a Skempton B parameter greater than 0.95 exp(−0.04 p′)+0.008 p′, where p′ is a mean effective stress in MPa at the depth of the first inclusion and the water saturation in the formation pores is greater or equal to 10%.