Abstract:
The enhanced oil recovery (EOR) system includes a solar tower that heats air, which is fed to an ion transport membrane (ITM) unit. The ITM unit separates oxygen from the preheated air. The separated oxygen is injected into the oil well to burn part of the well&#39;s oil, thereby generating the heat required for thermally enhance oil recovery. Combustion of part of the well&#39;s oil reduces the viscosity of the remainder, enhancing extraction of oil from the well.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to oil recovery technology, and, more specifically, to an enhanced oil recovery system that includes a solar-assisted ion transport membrane to produce oxygen for combustion in the well for thermally enhanced oil recovery. 
     2. Description of the Related Art 
     Traditional methods of primary and secondary oil production generally recover about one-third of the oil in the reservoir while leaving the rest behind, since the cost to extract the remaining oil would likely be greater when compared to the cost to extract oil from a newly discovered oil field. Regardless, to maintain a high rate of oil recovery, many oil producers have started utilizing enhanced oil recovery (EOR) techniques to extract heavy oil from aged reservoirs. 
     Typically, EOR techniques utilize different methods, such as thermal recovery or injection of gas, chemicals, or brine water. Thermal injection represents the largest EOR implemented technology and accounts for approximately 51.5% of the EOR techniques currently on the market. Gas EOR technology and chemical EOR technology are expected to increase to 38.5% and 10.3%, respectively, of the EOR technology market by 2023. 
     However, although in situ combustion and down-hole heating have great potential as new thermal EOR technologies emerge, many current in situ combustion and down-hole heating thermal EOR technologies require the use of large amounts of natural fuel, such as natural gas. As such, due to their associated carbon dioxide emissions, thermal EOR technologies typically leave a significant environmental footprint. Moreover, as a result of the quantity of natural gas consumed, utilizing the current in situ combustion down-hole techniques is not only very expensive, but can also be an inefficient use of a region&#39;s natural gas reserves. 
     Thus, an enhanced oil recovery system solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The enhanced oil recovery (EOR) system includes a solar tower that heats air, which is fed to an ion transport membrane (ITM) unit. The ITM unit separates oxygen from the preheated air. The separated oxygen is injected into the oil well to burn part of the well&#39;s oil, thereby generating the heat required for thermally enhance oil recovery. Combustion of part of the well&#39;s oil reduces the viscosity of the remainder, enhancing extraction of oil from the well. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The sole drawing FIGURE is a schematic diagram of an enhanced oil recovery system, according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in the sole drawing, the enhanced oil recovery system  100  includes a compressor section  118 , having a first compressor unit  110 , which includes an air intake portion  115   a  and a pressurized air PA discharge portion  115   b . The compressor section  118  also includes a gas turbine  140  having a turbine intake portion  142   a  and a turbine discharge portion  142   b . The gas turbine  140  is coupled to the first compressor unit  110  by a shaft  116 . The system also includes a solar tower  120 , which is positioned in communicating relation to the first compressor unit  110 , including the pressurized air PA discharge portion  115   b  and the turbine intake portion  142   a , and in communicating relation to an ion transport membrane (ITM) unit  170 , so that atmospheric air A can be converted into pressurized air PA by the first compressor unit  110  and can subsequently be heated in the solar tower  120 . The hot pressurized air PA can then be injected into the ITM unit  170 , where oxygen  302  can be separated from the pressurized air PA. The oxygen  302  can then be injected into an oil well OW so that the oxygen  302  can be burned along with methane gas in the oil well OW to generate sufficient heat to enhance oil recovery, such as by decreasing the viscosity of oil. 
     The system  100  can include a power source  105  positioned in communicating relation with the gas turbine  140 , the power source  105  being configured for operating the gas turbine  140 . The system  100  also has a splitter  150  and a storage tank  160  positioned in communicating relation with the splitter  150 . A generator  200  (such as an electric generator) is positioned in communicating relation with the gas turbine  140 . A second compressor unit  180  having a carbon dioxide intake portion  182   a  and a carbon dioxide discharge portion  182   b  and a third compressor unit  190  having a nitrogen intake portion  192   a  and a nitrogen discharge portion  192   b  are disposed between the ITM unit  170  and the oil well OW. The power source  105  can also be configured for operating the second compressor unit  180  and/or the third compressor unit  190 . Further, the system  100  can include a plurality of pipes, such as a first pipe P 1 , a second pipe P 2 , and a third pipe P 3 . A plurality of check valves, such as a first check valve  210   a  and a second check valve  210   b , are configured for allowing the pressurized air PA to be injected into the storage tank  160 , and for allowing the pressurized air PA from the storage tank  160  to enter the ITM unit  170 , respectively. 
     The first compressor unit  110  can be any suitable type of compressor unit known in the art that can compress atmospheric air A to form the pressurized air PA. The gas turbine  140  can rotate the shaft  116 , causing the first compressor unit  110  to operate. The gas turbine  140  can also power the generator  200  to generate sufficient electricity to power at least one auxiliary accessory, such as a light L, utilized in the extraction of oil. It is to be noted that as the first compressor unit  110  operates, it can inject the pressurized air PA into the solar tower  120 , such as through the pressurized air PA discharge portion  115   b  of the first compression unit  110 . The pressurized air PA can then be heated in the solar tower  120 . 
     The solar tower  120  can be any suitable type of solar tower known in the art that can generate sufficient heat to heat the pressurized air PA from the first compressor unit  110  to an appropriate temperature, such as approximately 1200° C. It is to be noted that the solar tower  120  can have at least one solar collector  130  coupled to the solar tower  120 , the solar collector  130  being configured to convert solar energy from the sun S into heat and/or electricity. The at least one solar collector  130  can be any suitable type of solar collector  130 , such as a solar panel, known in the art and can have any suitable size. Once the pressurized air PA is heated in the solar tower  120  to the appropriate temperature, the pressurized air PA can be drawn into the gas turbine  140 , after which the hot pressurized air PA can be injected into the ITM unit  170 . 
     Prior to reaching the ITM unit  170 , the pressurized air PA can enter the splitter  150  where the hot pressurized air PA can be diverted through the first check valve  210   a  into the storage tank  160 , which is configured for storing hot pressurized air PA for use during periods of low solar radiation, such as night time or during a cloudy day. For example, during periods of high solar radiation, the first check valve  210   a  can be opened and the second check valve  210   b  can be closed to allow hot pressurized air PA to flow into the storage tank  160  and be stored in the storage tank  160 . Once the storage tank  160  is full, the first check valve  210   a  can be closed to allow the hot pressurized air PA to be injected into the ITM unit  170 . During times of low solar radiation, the first check valve  210   a  can be closed and the second check valve  210   b  can be opened to allow the hot pressurized air PA stored in the storage tank  160  to be injected into the ITM unit  170 . 
     It is to be noted that the hot pressurized air PA can have a temperature in the range of about 700° C. to 800° C. at the time that the hot pressurized air PA is injected into the ITM unit  170 . Further, the rate at which the hot pressurized air PA is injected into the ITM unit  170  can vary depending on various environmental factors, such as the amount of oil O remaining in the oil well OW, the viscosity of the oil O, the ambient temperature, and the time of day. 
     The ITM unit  170  can be any type of suitable unit having an ion transport membrane including metal oxides that can separate the oxygen  302  from the hot pressurized air PA. Heat from the solar tower  120  can be used to heat the ITM unit  170  to enhance oxygen permeation across the ITM unit  170 . The hot pressurized air PA can be injected into a feed side FS of the ITM unit  170 , as illustrated in the sole drawing. As the hot pressurized air PA passes through the ITM unit  170 , the oxygen  302  can be separated from the hot pressurized air PA. For example, as the pressurized air PA passes through the ITM unit  170 , the oxygen  302  can pass through the ITM unit  170  to a permeate side PS and mix with the carbon dioxide  300 , while nitrogen  304  remains on the feed side FS of the ITM unit  170  due to the permeability and selectivity of the ITM unit  170 . Oxygen permeates through the membrane, leaving the remaining gases from the air, predominantly nitrogen, on the other side of the membrane. This nitrogen-enhanced gas can be compressed in the third compressor  190  and discharged through nitrogen discharge portion  192   b  into the well for further immiscible enhanced oil recovery. It is to be noted that the permeability and selectivity of the ITM unit  170  can vary, depending to the types of gases that are to be inserted into the oil well OW. 
     After passing through the ITM unit  170 , the carbon dioxide  300  and the oxygen  302  can be injected into the oil well OW by any suitable means, such as through the first pipe P 1 , where it can combine with methane gas produced by the oil O in the oil well OW. The oxygen  302  can then be burned with the methane gas to generate sufficient heat necessary to enhance oil recovery, such as by decreasing the viscosity of the oil O remaining in the oil well OW so that the oil O can be extracted from the oil well OW, such as through the second pipe P 2 . Carbon dioxide generated by combustion of the methane with oxygen can be compressed in the second compressor unit  180  and discharged into the well through the carbon dioxide discharge portion  182   b  for further immiscible enhanced oil recovery. 
     The second compressor unit  180  can be any suitable compressor unit known in the art that can compress the carbon dioxide  300 . The second compressor unit  180  can be positioned in communicating relation with the second pipe P 2  to receive the carbon dioxide  300  produced from the combustion of the oxygen  302  and methane gas. For example, carbon dioxide  300  can be drawn into the carbon dioxide intake portion  182   a  of the second compressor unit  180  from the oil well OW through the second pipe P 2 . Once inside the second compressor unit  180 , the carbon dioxide  300  can be compressed and subsequently exhausted through the carbon dioxide discharge portion  182   b  of the second compressor unit  180  into the permeate side PS of the ITM unit  170 , where the carbon dioxide can enhance the oxygen  302  separation. 
     Further, the third compressor unit  190  can be any suitable compressor unit known in the art that can compress the nitrogen  304  remaining on the feed side FS of the ITM unit  170  and inject the nitrogen  304  into the oil well OW, such as through the third pipe P 3 . For example, the nitrogen  304  can be drawn into the third compressor unit  190  through the nitrogen intake portion  192   a  and injected into the third pipe P 3  via the nitrogen discharge portion  192   b  of the third compressor unit  190 . Injecting nitrogen  304  into the oil well OW through the third pipe P 3 , such as by any suitable means, can result in immiscible enhanced oil recovery. 
     By way of operation, the power source  105  can be activated at startup to provide power to the gas turbine  140  in order to rotate the shaft  116 , which, in turn, provides power to the first compressor unit  110 . Subsequently, the atmospheric air A can be drawn into the first compression unit  100  through the first intake portion  115   a  and converted into pressurized air PA. During normal operation, the pressurized air PA is supplied to the solar tower, such as through the pressurized air PA discharge portion  115   b  of the first compression unit  110 . While in the solar tower  120 , the pressurized air PA can be heated up to approximately 1200° C. using the heat generated from the sun S by the at least one solar collector  130 . The gas turbine  140  can also be used to power the generator  200  to generate electricity for the at least one auxiliary accessory utilized in the extraction of oil, such as electricity to power the light L. 
     After the pressurized air PA is heated, it can be drawn into the gas turbine  140  through the turbine intake portion  142   a  and subsequently expelled from the turbine discharge portion  142   b . It is to be noted that upon being discharged from the gas turbine  140  the hot pressurized air PA can have a temperature in the range of about 700° C. to 800° C. before it enters the ITM unit  170 . 
     The pressurized air PA can then be injected into the splitter  150 . Once in the splitter  150 , the first check valve  210   a  can be opened such that the hot pressurized air PA can be stored in the storage tank  160  for use at time of low solar radiation, such as at night time or during cloudy days. It is to be noted that during the time that hot pressurized air PA is being sent to the storage tank  160 , the second check valve  210   b  should remain closed. After the storage tank  160  is full, the first check valve  210   a  can be closed so that the hot pressurized air PA can be injected into the ITM unit  170 , such as through the feed side FS of the ITM unit  170 . It is to be noted that at times of low solar radiation, such as at night time or during cloudy days, the first check valve  210   a  can be closed and the second check valve  210   b  can be opened so that hot pressurized air PA can be injected into the ITM unit  170 , such as through the feed side FS of the ITM unit  170 . 
     Once the pressurized air PA is in the ITM unit  170 , the oxygen  302  can be generated, such as by separating the oxygen  302  from the hot pressurized air PA. Due to the selectivity and permeability of the ITM unit  170 , nitrogen  304  can remain on the feed side FS of the ITM unit  170 , while the oxygen  302  can pass through to the permeate side PS of the ITM unit  170  and mix with the carbon dioxide  300  in the permeate side PS of the ITM unit  170 . The carbon dioxide  300  can then be recycled to enhance the oxygen  302  separation in the ITM unit  170 , while the oxygen  302  can be injected into the oil well OW through the first pipe P 1  so that the oxygen  302  can be burned with the methane gas in the oil well OW to generate sufficient heat to enhance oil recovery, such as by decreasing the viscosity of the oil O. 
     The burning of the oxygen  302  and methane gas can generate additional carbon dioxide  300 , such as the carbon dioxide  300  extracted through the second pipe P 2 , that can be used to purge the oxygen  302  and enhance the separation of the oxygen  302  from the hot pressurized air PA. Further, the nitrogen  304  that did not pass through the ITM unit  170  and remained on the feed side FS of the ITM unit  170  can be injected, such as by the third compressor unit  190 , into the oil well OW, such as through the third pipe P 3 , for immiscible enhanced oil recovery. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.