System and method for enhancing oil recovery from a subterranean reservoir

Abstract

A system and method is disclosed for enhancing the distribution of an enhanced oil recovery fluid utilizing electrokinetic-induced migration for enhancing oil recovery from a subterranean reservoir. An enhanced oil recovery fluid is injected into the hydrocarbon bearing zone through the injection well. An electric field is generated through at least a portion of the hydrocarbon bearing zone to induce electrokinetic migration of the enhanced oil recovery fluid. Electrokinetic induced migration allows for the enhanced oil recovery fluid to contact portions of the reservoir that previously were unswept, which as a result enhances recovery of hydrocarbons through the production well.

What is claimed is: 
     
         1 . A method for enhancing hydrocarbon recovery in subterranean reservoirs, the method comprising:
 (a) providing an injection well and a production well that extend into a hydrocarbon bearing zone of a subterranean reservoir and are in fluid communication therewith;   (b) providing a pair of electrodes having opposite charges in the hydrocarbon bearing zone, wherein the temperature of the hydrocarbon bearing zone between the electrodes is at a first temperature;   (c) injecting an enhanced oil recovery fluid into the hydrocarbon bearing zone through the injection well;   (d) generating an electric field of less than 50 volts per meter (V/m) between the pair of electrodes and emitting a direct current having a current density of less than 20 amps/m2 through at least a portion of the hydrocarbon bearing zone to induce electrokinetic migration of the enhanced oil recovery fluid, wherein the current density is controlled to maintain a resultant second temperature of the hydrocarbon bearing zone that is no more than 20° C. higher than the first temperature; and   (e) recovering hydrocarbons from the hydrocarbon bearing zone of the subterranean reservoir through the production well.   
     
     
         2 . The method of  claim 1 , wherein the electric field is generated by emitting a direct current between the pair of electrodes and wherein the electrodes are spaced apart between 100 feet to 10,000 feet from one another within the hydrocarbon bearing zone. 
     
     
         3 . The method of  claim 1 , wherein the electric field is generated by emitting a direct current between a first electrode coupled to the injection well and a second electrode coupled to the production well. 
     
     
         4 . The method of  claim 1 , wherein the electric field is generated by emitting a direct current between a plurality of electrodes interspersed within the hydrocarbon bearing zone. 
     
     
         5 . The method of  claim 1 , wherein the electric field is generated by emitting a direct current having a current density of less than 10 amps/m2 between the pair of electrodes. 
     
     
         6 . The method of  claim 1 , wherein the generated electric field is less than 20 volts per meter. 
     
     
         7 . The method of  claim 1 , wherein the current density is controlled to maintain a resultant second temperature of the hydrocarbon bearing zone that is no more than 10° C. higher than the first temperature. 
     
     
         8 . The method of  claim 1 , wherein the enhanced oil recovery fluid comprises any of water, a surfactant, an oxidant, and mixtures thereof. 
     
     
         9 . The method of  claim 1 , wherein the enhanced oil recovery fluid alters a physical property of a formation matrix of the hydrocarbon bearing zone. 
     
     
         10 . A method for enhancing hydrocarbon recovery in subterranean reservoirs, the method comprising:
 (a) providing an injection well and a production well that extend into a hydrocarbon bearing zone of a subterranean reservoir and are in fluid communication therewith;   (b) providing a pair of electrodes having opposite charges and being spaced apart from one another within the hydrocarbon bearing zone, wherein the temperature of the hydrocarbon zone between the electrodes is at a first temperature;   (c) injecting an enhanced oil recovery fluid into the hydrocarbon bearing zone through the injection well;   (d) emitting a direct current having a current density of less than 20 amps/m2 between the pair of electrodes to induce electrokinetic migration of the enhanced oil recovery fluid, wherein the current density is controlled to maintain a resultant second temperature of the hydrocarbon bearing zone that is no more than 20° C. higher than the first temperature; and   (e) recovering hydrocarbons from the hydrocarbon bearing zone of the subterranean reservoir through the production well.   
     
     
         11 . The method of  claim 10 , wherein the current density is less than 10 amps/m2. 
     
     
         12 . The method of  claim 10 , wherein an electric field of less than 20 volts per meter is generated between the pair of electrodes. 
     
     
         13 . The method of  claim 10 , wherein the direct current is periodically pulsed. 
     
     
         14 . The method of  claim 10 , wherein polarity of the pair of electrodes is periodically reversed. 
     
     
         15 . The method of  claim 10 , wherein one electrode of the pair of electrodes is coupled to the injection well and one electrode of the pair of electrodes is coupled to the production well. 
     
     
         16 . The method of  claim 10 , wherein the enhanced oil recovery fluid comprises any of water, surfactant, an oxidant, and combinations thereof. 
     
     
         17 . A method for enhancing hydrocarbon recovery in subterranean reservoirs, the method comprising:
 (a) providing an injection well and a production well that extend into a hydrocarbon bearing zone of a subterranean reservoir and are in fluid communication therewith;   (b) providing a pair of electrodes within the hydrocarbon bearing zone of a subterranean reservoir, wherein the temperature of the hydrocarbon bearing zone between the electrodes is at a first temperature;   (c) injecting an enhanced oil recovery fluid into the hydrocarbon bearing zone through the injection well;   (d) generating an electric field of less than 50 volts per meter (V/m) between the pair of electrodes and emitting a direct current between the pair of electrodes to induce electrokinetic migration of the enhanced oil recovery fluid, wherein the direct current between the pair of electrodes is controlled to have a current density such that a resultant second temperature of the hydrocarbon bearing zone that is no more than 20° C. higher than the first temperature; and   (e) recovering hydrocarbons from the hydrocarbon bearing zone of the subterranean reservoir through the production well.   
     
     
         18 . The method of  claim 17 , further comprising:
 (f) adjusting the direct current emitted between the pair of electrodes such that the enhanced oil recovery fluid migrates to unswept areas of the hydrocarbon bearing zone.   
     
     
         19 . The method of  claim 17 , wherein the current density is less than 10 amps/m2. 
     
     
         20 . The method of  claim 17 , wherein the resultant second temperature of the hydrocarbon bearing zone is no more than 5° C. higher than the first temperature.