Carbon dioxide energy storage and enhanced oil recovery

Abstract

The present invention is a method and apparatus for the subsurface storage of carbon dioxide in reservoir formations, to provide energy storage for electrical load balancing, and to enable the enhanced recovery of hydrocarbon fluids from the subsurface formations by gravity drainage. Multiple propped vertical inclusions are propagated into hydrocarbon fluid bearing reservoir formations at various vertical depths from well casings. Carbon dioxide is injected and stored in the formations. At off-peak power demand periods, carbon dioxide is pumped by a pump/turbine from the low energy formation into a deeper high energy formation, and at peak power demand periods the carbon dioxide is released from the high energy formation and flows to the low energy formation, driving the pump/turbine to generate electricity. Hydrocarbon fluids are produced from the formations depending on the formation conditions. Additional carbon dioxide is injected into the system as hydrocarbon fluids are extracted.

What is claimed is: 
     
         1 . A carbon energy storage and oil recovery method comprising the steps of:
 a. propagating an inclusion filled with a proppant into a high energy formation from a well casing extending from a ground surface into the high energy formation;   b. propagating an inclusion filled with a proppant into a low energy formation from the well casing extending from the ground surface into the low energy formation;   c. injecting carbon dioxide into the high energy formation and the low energy formation through a carbon dioxide conduit disposed in the well casing;   d. during off-peak energy demand times, pressurizing the carbon dioxide in the high energy formation by pumping carbon dioxide from the low energy formation through the carbon dioxide conduit into the high energy formation by means of a pump/turbine;   e. during peak energy demand times, releasing the carbon dioxide from high energy formation to the low energy formation through the carbon dioxide conduit and through the pump/turbine to generate electricity; and   f. producing hydrocarbon fluids in the high energy formation or the low energy formation up an oil production tube in the well casing.   
     
     
         2 . The method of  claim 1 , wherein the well casing comprises a high energy well casing extending from the ground surface into the high-energy formation and a low energy well casing extending from the ground surface into the low energy formation. 
     
     
         3 . The method of  claim 1 , wherein the method further includes a plurality of inclusions at varying azimuths in the high energy formation and the low energy formation. 
     
     
         4 . The method of  claim 3 , wherein the plurality of inclusions are initiated from the well casing by injecting an injection fluid, including the proppant, from the well casing into the high energy formation and into the low energy formation, wherein the inclusions are positioned at progressively shallower depths after the viscosity of the injection fluid in the immediate lower inclusions has reduced so that the plurality of inclusions at the shallower depths intersect and coalesce with the inclusions immediately beneath on their respective azimuths. 
     
     
         5 . The method of  claim 4 , wherein the method further includes providing a plurality of well casings with associated inclusions at varying azimuth in the high energy formation and in the low energy formation. 
     
     
         6 . The method of  claim 1 , wherein the proppant has particles of size ranging from #4 to #100 U.S. mesh and is selected from the group including sand, ceramic beads, resin coated sand, resin coated ceramic beads, fibers, or a mixture thereof. 
     
     
         7 . The method of  claim 1 , wherein the carbon dioxide is injected into the high energy formation and the low energy formation at a supercritical state and above the miscible pressure of hydrocarbon fluids in the high energy formation and the low energy formation. 
     
     
         8 . The method of  claim 1 , wherein the carbon dioxide injection is a continuous injection, and the production of hydrocarbon fluids is continuous. 
     
     
         9 . The method of  claim 1 , wherein the carbon dioxide injection is a pressure pulsed cyclic injection or intermittent injection. 
     
     
         10 . The method of  claim 1 , wherein the high energy formation and the low energy formation form a closed carbon energy storage system for cyclic energy states of the carbon dioxide between the high energy formation and the low energy formation. 
     
     
         11 . The method of  claim 10 , wherein cyclic energy states of the carbon dioxide are cycled by the pump/turbine. 
     
     
         12 . The method of  claim 11 , wherein the pump/turbine is driven by a variable speed generator. 
     
     
         13 . The method of  claim 11 , wherein the pump/turbine is located above the ground surface. 
     
     
         14 . The method of  claim 11 , wherein the pump/turbine is located below the ground surface. 
     
     
         15 . The method of  claim 1 , wherein the injection of the carbon dioxide into the low energy formation is at an injection pressure and temperature so that the carbon dioxide is in its supercritical state and above the miscible pressure of the hydrocarbon fluids. 
     
     
         16 . The method of  claim 1 , wherein the injection of the carbon dioxide injection into the low energy formation is at an injection pressure and temperature that provide a maximum density difference between the hydrocarbon fluids and the carbon dioxide to thereby achieve efficient enhanced recovery of the hydrocarbon fluids by gravity drainage. 
     
     
         17 . The method of  claim 1 , wherein the high energy formation has a Skempton B parameter greater than 0.95 exp(−0.04p′)+0.008p′, where p′ is the mean effective stress in MPa at the depth of the propagating inclusion. 
     
     
         18 . The method of  claim 1 , wherein the low energy formation has a Skempton B parameter greater than 0.95 exp(−0.04p′)+0.008p′, where p′ is the mean effective stress in MPa at the depth of the propagating inclusion. 
     
     
         19 . The method of  claim 1 , wherein methane is produced from the high energy formation and the low energy formation from a first portion of the well casing located at the highest elevation in the high energy formation and from a second portion of the well casing located at the highest elevation in the low energy formation. 
     
     
         20 . A carbon energy storage and oil recovery system for recovery hydrocarbon fluids from a formation having a high energy formation and a low energy formation, the system comprising:
 a. high energy well system located in the high energy formation comprising:
 i) a well casing extending from a ground surface into the high energy formation; 
 ii) a high energy expansion device in the well casing for propagating an inclusion filled with a proppant into the high energy formation from the well casing; 
 iii) a high energy carbon dioxide conduit with a first end and a second end wherein the first end communicates with the inclusions in the high energy formation; and 
 iv) an oil production tube with a first end communicating with the formation and a second end extending to the ground surface for delivery of hydrocarbons from the formation to the ground surface for recovery; 
   b. low energy well system located in a low energy formation comprising:
 i) the well casing further extending into the low energy formation; 
 ii) a low energy expansion device in the well casing for propagating an inclusion filled with a proppant into the low energy formation from the well casing; 
 iii) a low energy carbon dioxide conduit with a first end and a second end wherein the first end communicates with the inclusions in the low energy formation; and 
   c. a carbon dioxide source for injecting the carbon dioxide into the high energy formation and the low energy formation by means of the high energy carbon dioxide conduit and the low energy carbon dioxide conduit;   d. a pump/turbine connected between the second end of the high energy carbon dioxide conduit and the second end of the low energy carbon dioxide conduit for pressurizing the carbon dioxide in the high energy formation by pumping carbon dioxide from the low energy formation during off-peak energy demand times and for generating electricity by the release of the carbon dioxide from the high energy formation to the low energy formation during peak energy demand times; and   e. a hydrocarbon production pump for pumping hydrocarbons in the formation up the oil production tube.   
     
     
         21 . The system of  claim 20 , wherein the well casing comprises a high energy well casing extending from the ground surface into the high-energy formation and a low energy well casing extending from the ground surface into the low energy formation. 
     
     
         22 . The system of  claim 20 , wherein the system further includes a plurality of inclusions at varying azimuths in the high energy formation and the low energy formation. 
     
     
         23 . The system of  claim 22 , wherein the plurality of inclusions are initiated from the high energy expansion device of the well casing by injecting an injection fluid, including a proppant, from the well casing into the high energy formation and are initiated from the low energy expansion device of the well casing by injecting the injection fluid, including the proppant, from the well casing into the low energy formation, wherein the inclusions are positioned at progressively shallower depths after the viscosity of the injection fluid in the immediate lower inclusions has reduced so that the plurality of inclusions at the shallower depths intersect and coalesce with the inclusions immediately beneath on their respective azimuths. 
     
     
         24 . The system of  claim 23 , wherein the system further includes providing a plurality of well casings with associated inclusions at varying azimuth in the high energy formation and in the low energy formation. 
     
     
         25 . The system of  claim 20 , wherein the proppant has particles of size ranging from #4 to #100 U.S. mesh and is selected from the group including sand, ceramic beads, resin coated sand, resin coated ceramic beads, fibers, or a mixture thereof. 
     
     
         26 . The system of  claim 20 , wherein the carbon dioxide source injects the carbon dioxide through the high energy carbon dioxide conduit into the high energy formation and through the low energy carbon dioxide conduit into the low energy formation at a supercritical state and above the miscible pressure of hydrocarbon fluids in the high energy formation and the low energy formation. 
     
     
         27 . The system of  claim 20 , wherein the carbon dioxide source injects the carbon dioxide in a continuous injection, and the production of hydrocarbon fluids is continuous. 
     
     
         28 . The system of  claim 20 , wherein carbon dioxide source injects the carbon dioxide in a pressure pulsed cyclic injection or intermittent injection. 
     
     
         29 . The system of  claim 20 , wherein the high energy carbon dioxide conduit and the low energy carbon dioxide conduit form a closed carbon energy storage system with the pump/turbine for cyclic energy states of the carbon dioxide between the high energy formation and the low energy formation. 
     
     
         30 . The system of  claim 29 , wherein cyclic energy states of the carbon dioxide are cycled by the pump/turbine system. 
     
     
         31 . The system of  claim 30 , wherein the pump/turbine is driven by a variable speed generator. 
     
     
         32 . The system of  claim 30 , wherein the pump/turbine is located above the ground surface. 
     
     
         33 . The system of  claim 30 , wherein the pump/turbine is located below the ground surface. 
     
     
         34 . The system of  claim 20 , wherein carbon dioxide source injects the carbon dioxide into the low energy formation at an injection pressure and temperature so that the carbon dioxide is in its supercritical state and above the miscible pressure of the hydrocarbon fluids. 
     
     
         35 . The system of  claim 20 , wherein the carbon dioxide source injects the carbon dioxide into the low energy formation at an injection pressure and temperature that provide a maximum density difference between the hydrocarbons and the carbon dioxide to thereby achieve efficient enhanced recovery of the hydrocarbon fluids by gravity drainage. 
     
     
         36 . The system of  claim 20 , wherein the high energy formation has a Skempton B parameter greater than 0.95 exp(−0.04p′)+0.008p′, where p′ is the mean effective stress in MPa at the depth of the propagating inclusion. 
     
     
         37 . The system of  claim 20 , wherein the low energy formation has a Skempton B parameter greater than 0.95 exp(−0.04p′)+0.008p′, where p′ is the mean effective stress in MPa at the depth of the propagating inclusion. 
     
     
         38 . The system of  claim 20 , wherein methane is produced from the high energy formation and the low energy formation from a first portion of the well casing located at the highest elevation in the high energy formation and from a second portion of the well casing located at the highest elevation in the low energy formation.