Extracting oil from underground reservoirs

Abstract

Methods to extract oil from underground reservoirs are disclosed comprising pumping a gas comprising oxygen into the reservoir, causing combustion, and using the heat and pressure generated by the combustion to drive the oil through a well pipe to the surface. Systems for extracting oil from underground reservoirs are also disclosed comprising a gas compression system operable to pump oxygen from an oxygen source into the underground reservoir. The system has a supply pipe connected to the source of oxygen, a delivery pipe connected to the underground reservoir, a pump capable of pumping a liquid, a first tank with a first pipe and a second pipe, a second tank with a third and a fourth pipe and two pipe switchers operable to switch connections such that the tanks are swapped from a position between the supply pipe and the pump inlet and a position between the pump outlet and the delivery pipe.

What is claimed is: 
     
         1 . A method of heating an underground oil reservoir comprising
 pumping a gas comprising oxygen into the underground oil reservoir, and   causing combustion to take place in the underground oil reservoir.   
     
     
         2 . The method of  claim 1 , further comprising pumping a combustible gas or liquid into the oil reservoir. 
     
     
         3 . A method of extracting oil from an underground oil reservoir, comprising heating the underground oil reservoir by the method of  claim 1 , and further comprising using the heat and pressure generated by the combustion to drive oil through a well pipe to the surface. 
     
     
         4 . A method of extracting oil from an underground oil reservoir, comprising heating the underground oil reservoir by the method of  claim 2 , further comprising using the heat and pressure generated by the combustion to drive oil through a well pipe to the surface. 
     
     
         5 . The method of  claim 1 , wherein combustion takes place spontaneously when oxygen contacts oil in the underground oil reservoir. 
     
     
         6 . A system for extracting oil from an underground reservoir comprising
 a first well pipe,   a source of oxygen, and   a first gas compression system,   wherein the first gas compression system is operable to pump the oxygen from the source into the underground reservoir,   wherein combustion takes place when the oxygen contacts oil in the underground reservoir, and   wherein the heat and pressure generated by the combustion is sufficient to drive oil through the first well pipe to the surface.   
     
     
         7 . The system of  claim 6 , further comprising a second gas compression system configured to pump a combustible gas or liquid into the underground oil reservoir. 
     
     
         8 . The system of  claim 6 , further comprising a second well pipe, wherein the first gas compression system is configured to pump the oxygen from the source into the underground reservoir through the second well pipe. 
     
     
         9 . The system of  claim 7 , further comprising a second well pipe, wherein the first gas compression system is configured to pump the oxygen from the source into the underground reservoir through the second well pipe and the second gas compression system is configured to pump the combustible gas or liquid into the underground reservoir through the second well pipe. 
     
     
         10 . The system of  claim 6 , wherein the first gas compression system comprises
 a supply pipe connected to the source of oxygen;   a delivery pipe connected to the underground reservoir;   a pump capable of pumping a liquid;   a first tank with a first pipe connected to the first tank at the upper end of the first tank and a second pipe connected to the first tank at the lower end of the first tank;   a second tank with a third pipe connected to the second tank at the upper end of the second tank and a fourth pipe connected to the second tank at the lower end of the second tank;   a first pipe switcher operable to switch connections between a first state and a second state, wherein the first state comprises a connection between the supply pipe and the first pipe and a connection between the delivery pipe and the third pipe, and wherein the second state comprises a connection between the supply pipe and the third pipe and a connection between the delivery pipe and the first pipe; and   a second pipe switcher operable to switch connections between a first state and a second state, wherein the first state comprises a connection between the second pipe and the pump inlet and a connection between the fourth pipe and the pump outlet, and wherein the second state comprises a connection between the second pipe and the pump outlet and a connection between the fourth pipe and the pump inlet;   wherein the first state of the first pipe switcher is contemporaneous with the first state of the second pipe switcher, and the second state of the first pipe switcher is contemporaneous with the second state of the second pipe switcher.