Abstract:
Presented is a system for extracting subsurface oil using microwave or RF energy generated above the ground surface, and directed to an underground oil bearing location using a coaxial transmission line functioning as a wave guide.

Description:
PRIORITY/CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority date of the provisional application entitled APPARATUS AND METHOD FOR IN-SITU ELECTROMAGNETIC EXTRACTION AND PRODUCTION FO HYDROCARBONS FROM GEOLOGICAL FORMATIONS filed by George M. Harris on Apr. 3, 2008, with application Ser. No. 61/042,150, the disclosure of which is incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention generally relates to an apparatus for underground oil recovery, and more particularly to a microwave assisted system of oil recovery. 
       BACKGROUND OF THE INVENTION 
       [0003]    There are huge quantities of oil which would be available for use if the oil could be extracted from the substrate with which it is combined. This includes oil bearing substrates such as oil shale, tar sands, and other similar hydrocarbon bearing geological formations. 
         [0004]    Many strategies have been put forward for extracting oil from such geologic formations. One strategy is to drill a number of shafts in such a geologic formation, and use explosives to fracture and pulverize a large quantity of material, which by heat and pressure would then cause the oil to separate from the geologic substrate, and be pumpable out of the underground region that is the site of the explosion. 
         [0005]    Other methods have involved mining the substrate, such as by pit mining or strip mining and then processing the material through a heat process which would free the oil from the substrate. 
         [0006]    All of these strategies have their problems, and what is needed is an apparatus and method which does not require excavation of huge quantities of underground material, nor which utilizes dangerous underground explosions. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention embodies both an apparatus and a method for the production of hydrocarbons using high power microwave or radio frequency, (RF) energy, in-situ, within hydrocarbon-bearing geological formations. The invention converges two major technologies; one is the efficient application of electromagnetic energy, (microwaves or RF), and the other involves gathering the hydrocarbon that is produced in-situ, electromagnetically and then transporting it to the surface where it is collected. This invention can be used to produce and recover hydrocarbon products from geological components such as oil shale, tar sands and other similar hydrocarbon-bearing geological formations. 
         [0008]    The invention uses microwaves that are applied in-situ, (actually within the formation, usually in the ground), to produce hydrocarbon products from hydrocarbon products from hydrocarbon-bearing material such as fine-grained sedimentary rock that makes up oil shale or other components of a geological formation where hydrocarbon material is sought. 
         [0009]    The invention is implemented using a combination of five major elements: 
         [0010]    1. A high power microwave applicator that launches electromagnetic energy directly into a geological formation in-situ. 
         [0011]    2. A mechanical pumping mechanism located just below the high power electromagnetic applicator. 
         [0012]    3. A system of mechanical couplings and actuators that transport the mechanical pumping power from the pump actuator motor to the pump section of the invention itself. 
         [0013]    4. A system of electromagnetic energy transmission system such coaxial line or waveguide that transports the energy from a transmitter to the applicator where it is applied, in-situ to the geological formation for hydrocarbon product production. 
         [0014]    5. A high power electromagnetic energy transmission system such coaxial line or waveguide that transports the energy from a transmitter to the applicator where it is applied, in-situ to the geological formation for hydrocarbon product production. 
         [0015]    The entire assembly is usually placed in a hole or well, usually drilled, bored, or dug into a geological formation containing the hydrocarbon-bearing material. High power microwaves or radio frequency, (RF), energy from a transmitter or high power microwave or RF generator is transmitted through the coaxial transmission line or waveguide system to the applicator portion of the invention. The applicator launches the energy directly into the formation where it interacts volumetrically with the hydrocarbon compounds in the formation, liberating the hydrocarbons as well as reducing the components&#39; viscosity, thereby making it easier for the hydrocarbon material to run freely. The produced hydrocarbon product then flows by gravity into the shaft occupied by the invention, and migrates toward the lower portion of the apparatus where it is extracted. There, a pump on the lower end of the invention extracts the hydrocarbon material and pumps it to the surface where it is recovered. 
         [0016]    In the present embodiment of the invention, the electromagnetic energy used in the extraction and/or pre-processing of the hydrocarbon is kept separate from the hydrocarbon once it is produced from the geological formation and drawn into the pump portion of the apparatus using a system of electromagnetic choke structures. These choke structures allow connection of pipes carrying the liquid hydrocarbon to the collector, usually located at the surface, to the high power microwave or RF transmission line system responsible for transmitting the high power microwave or RF energy to the applicator. The apparatus is also designed so that the mechanical components that transmit mechanical power to the pump are kept separate from the high power electromagnetic energy used to produce the hydrocarbon product. 
         [0017]    The purpose of the Abstract is to enable the public, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection, the nature and essence of the technical disclosure of the application. The Abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. 
         [0018]    Still other features and advantages of the claimed invention will become readily apparent to those skilled in this art from the following detailed description describing preferred embodiments of the invention, simply by way of illustration of the best mode contemplated by carrying out my invention. As will be realized, the invention is capable of modification in various obvious respects all without departing from the invention. Accordingly, the drawings and description of the preferred embodiments are to be regarded as illustrative in nature, and not as restrictive in nature. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a cross sectional view of the apparatus of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    While the invention is susceptible of various modifications and alternative constructions, certain illustrated embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims. 
         [0021]    In the following description and in the FIGURES, like elements are identified with like reference numerals. The use of “e.g.,” “etc.,” or “or,” indicates non-exclusive alternatives without limitation unless otherwise noted. The use of, “including” means, “including, but not limited to,” unless otherwise noted. 
         [0022]      FIG. 1  shows a cross-sectional view of a preferred embodiment of the invention. Shown in a hydrocarbon bearing substrate  46  which has a surface  48  on the surface  48  is located a microwave source  12 . The microwave source  12  can take a number of configurations but one embodiment which is considered to be preferable is a 125 kilowatt microwave source. Depending on the installation, this could operate at 915 MHz or 460 MHz. Other frequencies are also possible depending on the design of the particular installation. 
         [0023]    Attached to the microwave source  12  is an interview inlet section  14 . This includes an inlet inner conductor  16 , and is the connection between the microwave energy source and a coaxial transmission line  44 . The coaxial transmission line  44  includes a first choke section  26 . The first choke section  26  is a short section of coaxial transmission line  44 , which is one quarter wave length in length. This particular configuration causes microwave energy which enters the energy inlet section  14  to be blocked from entering the first choke section  26 , and thus all of the microwave energy is directed downward to the coaxial transmission line  44 . This choke is short circuited with the outer conductor in the same manner as the second choke is short circuited. The coaxial transmission line  44  functions in the role of the wave guide for either microwave or radio frequency (RF) energy. These energies are considered equivalent in the context of this application, and energy greater than 300 MHz, by convention are all considered to be a form of microwave energy. 
         [0024]    The down tube outer conductor  18  and the down tube inner conductor  20 , act as a wave guide and do, in a microwave context, direct energy along the path without absorbing energy. In this case, the microwave or RF energy is directed towards the bottom end of the down tube outer conductor  18 . The down tube outer conductor  18  is placed in a bore hole  22  which has been drilled into the hydrocarbon substrate  46 . As the microwave energy travels down the coaxial transmission line  44  it encounters a number of radiating centers  36 . The radiating structures or radiating centers  36  are provided to allow energy, extracted from the coaxial transmission line  44  to exit the coaxial transmission line  44 . The energy thus released from the coaxial transmission line  44  heats the hydrocarbon bearing substrate  46  which is adjacent to the bore hole  22 . The substrate which is heated releases the oil which is absorbed or bonded to the substrate. In this way the oil is mobilized, and a region of productive, heated substrate expands radially away from the inner diameter of the bore hole wall, starting from the bore hole. 
         [0025]    An oil production front expands into the adjacent substrate  46 , and as oil is released from the substrate, the substrate becomes semi-transparent to the microwave or the RF energy. As oil is produced it flows into the bottom of the bore hole  22 , where it is in contact with the pump out port  32  of the down tube inner conductor  20 . 
         [0026]    The down tube inner conductor is also a steel pipe, with its outer surface interacting with the inner surface of the down tube outer conductor  18  to act as a wave guide for energy between the two surfaces. Inside the down tube inner conductor is a reciprocating pump rod. The reciprocating pump rod  28  extends out the end of the first choke section, and passes through a sliding seal  40 . The reciprocating motion is imparted to the reciprocating pump rod  28  by a reciprocating motive force above the surface of the ground. This causes the reciprocating pump rod  28  to move up and down in a reciprocating motion. In a down hole pump section a down hole pump is located. It is the down hole pump which raises oil above the surface of the ground. The oil cannot be withdrawn by vacuum, because that would only lift it a short distance. Therefore the oil  34  is lifted by pushing the oil  34  with a down hole pump  30  in the down hole pump section. This pump operates in a manner similar to other oil pumping operations which are driven by a reciprocating rod from the surface of the ground. Oil is lifted inside the down tube inner conductor  20 , and surrounds the reciprocating pump rod  28 . As it fills the interior of the down tube inner conductor  20 , it eventually reaches a point above the surface where there is located a second choke section  24 . The second choke section  24  is the oil output section. This section includes an outer tube and an inner tube, with the inner tube extending out from a short-circuiting closure plate and oil being routed through the inner conductor of the second choke section. The second choke section is also one quarter of one wavelength in length, and therefore forms a choke to the microwave energy. Thus, no microwave energy travels into the second choke section  24 . 
         [0027]    The exemplary embodiments shown in the FIGURES and described above illustrate but do not limit the invention. It should be understood that there is no intention to limit the invention to the specific form disclosed; rather, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims. For example, while the exemplary embodiments illustrate a microwave source, the invention is not limited to use with a microwave source and may be used with other energy sources such as RF energy sources. While the invention is not limited to use with microwaves, it is expected that various embodiments of the invention will be particularly useful with this type of energy. Hence, the foregoing description should not be construed to limit the scope of the invention, which is defined in the following claims. 
         [0028]    While there is shown and described the present preferred embodiment of the invention, it is to be distinctly understood that this invention is not limited thereto but may be variously embodied to practice within the scope of the following claims. From the foregoing description, it will be apparent that various changes may be made without departing from the spirit and scope of the invention as defined by the following claims.