WO2018191743A1 - Microwave antenna assembly and methods - Google Patents

Abstract

An antenna assembly includes an antenna attached to a conductive base, and a cartridge encasing the antenna or the conductive base. Methods and systems for antenna assisted microwave heating include deploying antenna proximate to a target material, delivering microwave radiation to the antenna that can interact with the antenna assembly to heat a target liquid, and contacting the heated target liquid with the target material.

Description

MICROWAVE ANTENNA ASSEMBLY AND METHODS

Cross-Reference

[0001] This application claims the benefit of United States Provisional Patent Application No. 62/485482 titled "MICROWAVE ANTENNA ASSEMBLY AND METHODS," to Linden Duncan, filed April 14, 2017, the entire disclosure of which is expressly incorporated by reference herein.

Technical Field

[0002] The present disclosure relates generally to the field of microwave energy and, more particularly, to the use of antennas to heat target materials.

Background

[0003] Microwave radiation has long been used to heat dipole molecules, such as water, through a process known as dielectric heating, which proceeds by introducing the dipole molecule to electromagnetic radiation that has a frequency within a resonate frequency of the molecule. The radiation causes the molecule to oscillate, thereby generating friction between neighboring molecules and converting the radiation to heat. Dielectric heating has been observed to have certain advantages over heating methods involving heat transfer (i.e., thermal conduction). For example, dielectric heating may allow for more rapid, uniform heating of a target liquid.

Dielectric heating may also convert the electromagnetic radiation to heat energy more efficiently than thermal conduction heating. The use of microwave radiation for this purpose has been widely deployed in the context of food preparation, as microwave ovens have become ubiquitous household appliances.

[0004] Despite the advantages of microwave induced dielectric heating, application of these principles have been limited outside of food preparation, as microwave radiation is rapidly absorbed by resonate molecules and therefore cannot penetrate targets as deeply as can other frequencies of electromagnetic radiation. Nonetheless, attempts have been made to adapt microwave technology for use in different contexts. One such attempt is disclosed in United States Patent No. 8,936,090 to Sultenfuss et al. ("Sultenfuss"). Sultenfuss discloses a method for accelerating initiation of steam- assisted gravity drainage (SAGD) oil drilling operation that includes position microwave devices at intervals within a steam well that can apparently reheat cooled water. While this and other strategies may assist SAGD drilling operations under certain conditions, there remains ample room for improvement and development of alternative strategies for use oil drilling operations as well as in other contexts.

Summary of the Invention

[0005] In one aspect, a method of extracting oil from an oil-bearing target material includes deploying a distribution of antennas into a well extending from a surface to a sub-surface formation of the oil-bearing target material, each antenna including a conductive rod perpendicularly coupled with a conductive base. The method further includes generating microwave radiation that can interact with an antenna within the distribution of antennas and the corresponding conductive base to focus energy of the microwave radiation, heating a target liquid by way of the energy of the microwave radiation, and contacting the oil-bearing target material with the target liquid in a heated state so as to heat the oil-bearing target material within the sub-surface formation of the oil-bearing target material such that a viscosity of the oil-bearing target material is reduced.

[0006] In another aspect, a system for heating an oil-bearing target material within a sub-surface formation of the oil-bearing target material includes a distribution of antennas positioned within the sub-surface formation of the oil-bearing target material and that is in contact with a target liquid, with a majority of antennas within the distribution of antennas being perpendicularly coupled with a conductive base such that the antennas and the conductive bases can focus energy of received microwave radiation. The system further includes a microwave source for generating microwave radiation within a frequency that interacts with an antenna within the distribution of antennas, and a microwave transmitter for transmitting microwave radiation from the microwave source to the distribution of antennas.

[0007] In still another aspect, an antenna assembly includes an antenna for receiving microwave radiation, a conductive base for receiving and reflecting the microwave radiation, the conductive base coupled with the antenna such that the antenna assembly can focus energy of the microwave radiation, and a cartridge formed in part by a substantially microwave transparent material, the cartridge at least partially encasing the antenna or the conductive base. Brief Description of the Drawings

[0008] Fig. 1 is a partially sectioned diagrammatic view of an antenna assembly, according to one embodiment;

[0009] Fig. 2 is a partially sectioned diagrammatic view of an antenna assembly, according to one embodiment;

[0010] Fig. 3 is a partially sectioned diagrammatic view of an antenna assembly, according to one embodiment;

[0011] Fig. 4 is a flowchart illustrating example methodology for antenna assisted microwave heating, according to one embodiment;

[0012] Fig. 5 is a partially sectioned diagrammatic view of a system for sub-surface steam production that includes a detailed enlargement, according to one embodiment;

[0013] Fig. 6 is a partially sectioned diagrammatic view of a system for hydraulic fracturing, according to one embodiment;

[0014] Fig. 7 is a partially sectioned diagrammatic view of a system for wastewater treatment, according to one embodiment; and

[0015] Fig. 8 is a partially sectioned diagrammatic view of a concrete curing system, according to one embodiment.

Detailed Description

[0016] Referring to Fig. 1 , a microwave antenna assembly ("antenna assembly") 10 is shown according to one embodiment. Antenna assembly 10 may include an antenna 12, and a conductive base ("base") 20 coupled with antenna 12. The basic structure of antenna 12 and base 20 is also described in United States Patent No. 9,752,095, the entire disclosure of which is expressly incorporated by reference in its entirety.

Antenna 12 may be a high electronegativity monopole antenna formed of a conductive rod, and may have a length that corresponds with a frequency band of microwave radiation. In other embodiments, antenna 12 may be a dipole antenna, an array antenna, a loop antenna, an aperture antenna, or any other suitable type of antenna. Antenna 12 is oriented substantially perpendicular to base 20 such that base 20 can act as a ground plane in a manner that allows antenna 12 to function as a two- way antenna.

[0017] Base 20 may include a first or top layer 22 and a second or bottom layer 24, each layer 22, 24 being circular in shape and formed of a conductive material, such as a metal material like copper or aluminum. The terms "top" and "bottom," and "upper" and "lower" are used herein in a relative sense, each in relation to each other when viewing antenna assembly 10 or when viewing the systems, assemblies, or devices being discussed, and should not necessarily be taken to mean that antenna assembly 10 or other components of any systems, assemblies, or devices herein have a particular orientation. Base 20 might have more or less layers in other embodiments, however, or a layer might not be circular, instead having an oblong, polygonal, or other shape. In still other embodiments, one or more layers of base 20 might be formed of a non-metallic material, a non-conductive material, or a material having relatively low conductivity. While top and bottom layers 22, 24 are congruent in shape but not size (i.e., each have a different size dimension, such as diameter or width), in some embodiments, base 20 could have multiple layers that are congruent in both size and shape (as seen in Fig. 3, discussed hereinafter), or could have only a single layer. Top layer 22 includes a top surface 32 that is substantially planar and has a substantially smooth surface for reflecting microwave radiation. In some embodiments, top surface 32 could be textured or contoured, however. For instance, top surface 32 might have bumps, corrugations, abrasions, or other textures or formations thereon.

[0018] Base 20, including the structure and material composition of layers 22, 24 and top surface 32, are structured to interact with antenna 12 to focus energy of microwave radiation received or absorbed by antenna assembly 10 at or near antenna 12 or base 20. In this way, microwave radiation may heat antenna assembly 10 and potentially allows antenna assembly 10 to radiate an amount of the microwave radiation received from a microwave source. These phenomena, either separately or in concert, have been observed to focus or otherwise harness energy of received microwave radiation. This focusing can result in the formation of high energy pockets capable of rapidly heating materials therein, in contact therewith, or proximate thereto. Material heating according to the present disclosure may be advantageous in a number of ways. For example, as will be apparent from the discussion herein, antenna assemblies 10 may be capable of heating materials, such as liquid water, at locations away from a source of the microwave radiation faster and more efficiently than state of the art techniques. [0019] Antenna assembly 10 may also include a cartridge 14 for receiving antenna 12 and base 20. It has been observed that deployment of antenna assembly 10 according to some strategies can result in antenna assembly 10 becoming damaged, which may impair the ability of antenna 12 or base 20 to receive, radiate, reflect, or otherwise focus or direct microwave energy in the manner contemplated herein. As such, cartridge 14 is structured to at least partially encase antenna 12 or base 20. Cartridge 14 is formed of a material that is transparent or substantially transparent to microwave radiation such that microwave radiation can pass through to antenna 12 or base 20. Put differently, cartridge 14 is formed of a material structured to limit reflection or absorption of microwave radiation in a manner that permits antenna 12 or base 20 to interact with the microwave radiation when encased within cartridge 14. For example, cartridge 14 could be formed of borosilicate ceramic, poly crystalline CVD diamond, high-density polyethylene (HDPE), low-density polyethylene (LDPE), crystallized polyethylene terephthalate (CPET), or any other material that is suitably transparent to microwave radiation. Cartridge 14 may also be at least semi -permeable to materials of certain particle or molecular sizes, so as to selectively allow some materials into cartridge 14 while still shielding or otherwise protecting antenna 12 or base 20 from other materials or from potentially dangerous impact forces, for instance. For example, cartridge 14 can be structured to permit liquid water to flow into antenna assembly 10 to surround or otherwise come into contact with antenna 12 or base 20. Contacting antenna 12 or base 20 with liquid water in this way may allow antenna assembly 10 to heat the water within cartridge 14 and cool antenna 12 or base 20, though, in some embodiments, antenna assembly 10 may be instead or additionally structured to heat water or other materials positioned outside of cartridge 14.

[0020] Referring now also to Fig. 2, it can be seen that cartridge 14 may include a hatch 26 structured to cover an opening 28 within cartridge 14. Hatch 26 can also be formed of a microwave transparent material, but could be formed of or include a material substantially impermeable to microwave radiation in some embodiments. Opening 28 is sized and shaped to receive antenna 12 and base 20, thereby enabling each to be removed from cartridge 14 to facilitate maintenance, repair, or

replacement, which might otherwise be expensive, time consuming, or even dangerous. Hatch 26 can be a cap, a plug, or any other type of top or lid that sealably engages with cartridge 14 in a manner that limits the entry of undesirable gases, fluids, or other materials. Cartridge 14 might additionally include other features or structures for encasing antenna 12 or base 20 therein. For instance, cartridge 14 might include a sealing element, such as a rubber O-ring or the like, positioned between cartridge 14 and hatch 26.

[0021] Referring now to Fig. 3, antenna assembly 10 is shown according to another embodiment in which cartridge 14 is structured to receive a distribution of antennas 12. The distribution of antennas 12 seen in Fig. 3 is an ordered distribution, as each antenna 12 has a fixed position or orientation relative to other antennas 12 within the distribution. Conversely, other embodiments might include a random distribution of antennas 12 in which the relative positions and orientations of each antenna 12 are not fixed and therefore can be variable (i.e., relative positions and orientations of antennas 12 are unordered, chaotic). It will be appreciated that, as used herein, the terms "ordered" and "random" are used in a relative sense to describe a relative orientation or position of similar devices within a distribution or other formation, and that these concepts may be applied to distributions or formations of other devices or assemblies, such as a distribution of antenna assemblies 10. The structure of antenna 12 and base 20 of the present embodiment are nearly identical to the structure of antenna 12 and base 20 in the embodiment of Figs. 1-2, except the two conductive layers 22, 24 of the present embodiment are congruent in both size and shape.

[0022] Antenna assembly 10 of the present embodiment additionally includes a spacer 30 separating antenna 12 and base 20, which, among other things, may limit undesirable interference between antenna 12 and base 20 when antenna assembly 10 interacts with microwave radiation. In some embodiments, the focusing of microwave radiation may assist in preventing undue heating of antenna 12 or base 20 during use in that some heat energy may be concentrated away from antenna assembly 10.

Focusing microwave radiation has been observed to result in temperatures that could unduly compromise the physical integrity of the components of antenna assembly 10 in some instances and could ultimately lead to thermal runaway. As such, antenna 12 or base 20 can be structured to limit undesirable heating of antenna assembly 10. Further, heat transfer between components of antenna assembly 10 and water or other liquid or gaseous materials in contact therewith may facilitate cooling of antenna assembly 10, which can further limit the accrual of heat energy that may damage antenna 12 or base 20.

[0023] Referring now also to Fig. 4, a flowchart 100 setting forth exemplary methodology for antenna assisted microwave heating is shown. The description of the methodology herein will discuss antenna assembly 10 according to the embodiments of Figs. 1-3 but should be understood to apply to other embodiments as well. Antenna 12 may be deployed to a location proximate to a target material at block 102 such that a heated target liquid can be conveyed to the target material when the target liquid is still in a heated state. In many embodiments, antenna 12 and the corresponding antenna assembly 10 are both deployed to a position within the target material such that antenna assembly 12 is in contact the target liquid to be heated— which is typically liquid water but may be any other suitable liquid or aqueous solution. The target liquid might be retained within a target vessel positioned within or near the target material (as seen in Fig. 5, discussed hereinafter), or might be within a suspension or other type of mixture that also includes other target or non-target liquids, solids, or other materials (as seen in Figs. 6-8, discussed hereinafter), for example.

[0024] A microwave source might then generate microwave radiation that can interact with antenna 12 at block 104. The microwave source may be any device capable of generating microwave radiation, such as a magnetron, for example. As will be apparent from the discussion herein, a practical implementation strategy of the present disclosure may include an antenna 12 structured to receive and radiate microwave radiation having a frequency within a resonate frequency of the target liquid. For example, water is known to resonate at a range of frequencies near 2.45 GHz and therefore, in an embodiment in which the target liquid is water, the microwave source may be structured to generate microwave radiation having a frequency at or near 2.45 GHz. In other embodiments, the microwave source may be structured to generate microwave radiation that can interact with antenna 12 or base 20 in a manner that can heat antenna assembly 10.

[0025] The microwave radiation generated by the microwave generator may be transmitted to antenna assembly 10 by a microwave transmitter. The microwave transmitter, which might include an antenna, a waveguide, a klystron, or any other suitable device or combination of devices, communicatively couples deployed antenna 12 with the microwave generator such that the microwave radiation can be delivered thereto. For instance, the microwave transmitter may include a microwave outlet— which could be a vent, a section of microwave transparent material, or any other functionally analogous structure— that permits microwave radiation to escape the microwave transmitter in the direction of deployed antenna 12.

[0026] The target liquid can then be heated at block 106. It has been discovered that antenna assisted heating according to the present disclosure, amongst other things, may be even more energy efficient than state of the art techniques for heating, boiling, or distilling water or other aqueous solutions and emulsions, including known dielectric heating strategies. Deployment of the present disclosure has resulted in observation of unexpected results when heating aqueous solutions. Specifically, boiling of certain liquids at a temperature lower than the liquid's standard IUPAC boiling point has been observed. For example, antenna assembly 10 has been observed to cause liquid water to boil at around 85 degrees Celsius at 1 atm.

[0027] It is believed that these unexpected results may be indicative of a more direct interaction between the individual molecules of the target liquid and the

electromagnetic field generated by a microwave source. This direct interaction may, amongst other things, reduce energy loss inherent when heating liquids by thermal conduction. The target liquid might be heated by dielectric heating or by conductive heating— or perhaps a combination of both. It has been proposed that antenna assembly 10 may receive and radiate microwave radiation in a manner that might induce resonance in the target liquid. Resonance in dielectric molecules, such as water, is known cause warming by way of dielectric heating, which, as discussed above, is typically more energy efficient than thermal conduction heating. Further, it has been observed that antenna assemblies 10 may experience rapid, intense heating in the presence of microwave radiation, which can heat materials in contact therewith. The advantages of faster, more energy efficient heating strategies will be apparent to those of skill in the art from the discussion herein.

[0028] The degree to which the target liquid is heated may vary depending on any number of considerations, including, for example, the temperature, density, viscosity, particle size, or material composition of the target material. For instance, as will be discussed hereinafter, heating the target liquid might include boiling the target liquid such that, in the heated state, the target liquid is in a gaseous state (e.g., steam). In other embodiments, the target liquid may be heated to a temperature below the target liquid's boiling point. Once in a heated state, the target liquid can then be made to contact the target material at block 108. Contacting the target material with the heated target liquid may include, for instance, releasing steam into a formation of the target material, introducing an amount of the heated target liquid into a formation of the target material, partially or fully immersing a quantity of the target material in a bath of the heated target liquid, or any other technique or strategy that may permit heat transfer between the target material and the target liquid in the heated state.

[0029] Referring now to Fig. 5, a system for sub-surface steam production ("steam system") 200 is shown according to one embodiment. Fig. 5 also includes a detailed enlargement that further illustrates certain features of steam system 200 discussed herein. Steam system 200 can be used to heat an oil-bearing target material ("target material") 274— which may be oil, or a mixture that includes oil— within a formation of the target material ("formation") 204, such as a bitumen deposit, for extraction. For example, steam system 200 could be used to facilitate steam-assisted gravity drainage (SAGD) oil extraction or other steam assisted oil extraction systems, such as cyclic steam stimulation (CSS), high pressure cyclic steam stimulation (HPCSS), vapor extraction (Vapex), or the like. As used herein, the term "oil" refers to naturally occurring petroleum or petroleum-like materials not limited to any particular hydrocarbons. Known systems for producing the steam necessary for steam assisted oil extraction may suffer from several drawbacks. For example, known systems are frequently resource intensive as steam is typically generated at surface level using oil products, such as natural gas, and large quantities of surface water. Steam produced on the surface must then be pumped into pipelines deep below the surface. Cooler temperatures and/or higher pressure below the surface frequently results in a loss of steam volume as steam may condense into liquid water. Steam system 200 may not suffer from these and other drawbacks, however, as steam system 200 may allow for rapid, volumetric heating or non-contact heating of a target liquid 250 at a point of extraction, amongst other things. These and other advantages will be appreciated by those of skill in the art from the discussion of steam system 200 herein.

[0030] Steam system 200 includes an antenna assembly 210 having a distribution of antennas 212 that can be deployed down into an upper or steam wellbore ("steam well") 270 that forms a passage between a surface 272 and formation 204. A lower or production wellbore ("production well") 276 may also be formed near to and having a similar geometry as steam well 270, with each well 270, 276 typically including a casing 208 formed of concrete or another suitable material to provide structural support to wells 270, 276 according to generally known principles.

[0031] Antenna assembly 210 may be similar to the embodiment of antenna assembly 10 seen in Fig. 3 in that antenna assembly 210 may include a cartridge 214 that at least partially encases an ordered distribution of antennas 212, though embodiments in which antenna assembly 212 does not include cartridge 214, or in which antennas 212 have a random distribution are also contemplated. Antenna 212 and an attached conductive base 220 may be identical to antenna 12 and base 20, respectively, with each conductive base 220 including a plurality of conductive layers, including a top layer 222 and a bottom layer 224.

[0032] Steam system 200 further includes a microwave source 230 and a microwave transmitter 234, which includes a waveguide (hereinafter "waveguide 234"). Microwave source 230, which is typically positioned on surface 272 but might be located below surface 272 in some embodiments, is structured to generate microwave radiation 232 that can interact with at least one antenna 212 within the distribution of antennas 212 such that the corresponding conductive layers 222, 224 receive and reflect microwave radiation 232. Microwave radiation 232 may be transmitted down steam well 270 by waveguide 234, and towards an extraction section 206 of steam well 270 within or near formation 204.

[0033] Steam system 200 may also include a fluid source 256 for delivering target liquid 250, which includes water (hereinafter "water 250"), to a target vessel 252. Target vessel 252, which includes a water pipe (hereinafter "water pipe 252"), can be deployed down steam well 270 and positioned near waveguide 234 within extraction section 206._As can be seen in the detailed enlargement of Fig. 5, waveguide 234 includes a microwave outlet 238 that allows microwave radiation 232 to escape in the direction of antenna assembly 210. Microwave radiation 232 received by an antenna 212 within the distribution of antennas may be radiated back out of antenna assembly 210, which can cause water 250 within water pipe 252 to be heated to a heated state— which includes evaporating water 250 to form steam 260— by way of microwave radiation 232 radiated by antenna 212. Antenna assembly 210 is positioned within water pipe 252 such that cartridge 214 is in direct contact with water 250, though antenna assembly 210 could be positioned outside of water pipe 252 in other embodiments. In other embodiments, water 250 could be pumped into cartridge 214. In such an embodiment, antenna 212 and conductive base 220 may be directly in contact with water 250 within cartridge 214 such that heating water 250 creates steam 260 within cartridge 214, which might be structured to allow steam 260 to escape therefrom within extraction section 206, for example. Water pipe 252 includes a steam vent 258 that permits steam 260 to escape water pipe 252 to formation 204. Contacting steam 260 with target material 274 may heat target material 274, which can result in reduced viscosity that can facilitate gravity draining of target material 274 from formation 204 to production well 276.

[0034] Referring now to Fig. 6, a system for hydraulic fracturing ("fracking system") 300 is shown according to one embodiment. Fracking system 300 may allow for heating of an oil-bearing target material ("target material") 374 within a subsurface formation of the oil-bearing target material ("formation") 304, such as shale, to induce or facilitate a flow of target material 374 out of formation 304. In fracking system 300, a wellbore or well 370 is formed that extends between a surface 372 and formation 304, with fractures 378 then being formed within formation 304 to allow target material 374 to drain to well 370 according to generally known principles. Known strategies for fracking may suffer from a number of drawbacks, however. Target material 374 may be slow to drain through fractures 378, or it may be difficult to induce a flow of target material 374, for example. As will be appreciated from the discussion herein, fracking system 300 may not suffer from these and other drawback, and may therefore allow for quicker, more efficient oil extraction in many instances. In other embodiments, fracking system 300 could be used to heat a different target material 374, such as fracturing fluids, which typically include a slurry of water, proppants, and chemical additives. In such embodiments, fracking system 300 could, for example, be configured to heat target material 374 within well 370 while being conveyed from surface 372 to formation 304.

[0035] Fracking system 300 may be similar to steam system 200 in many respects. For instance, fracking system 300 includes a distribution of antennas 312 deployed down well 370. The distribution of antennas 312 are structured to interact with microwave radiation 332 transmitted from a microwave source 330 down well 370 towards formation 304. Unlike the embodiment of steam system 200 shown in Fig. 5, however, the distribution of antennas 312 is a random distribution, with each antenna 312 attached to a conductive base 320 to form a plurality of antenna assemblies 310. Such a configuration may be desirable in the present context for a number of reasons. For example, the plurality of antenna assemblies 310 might be mixed in with a slurry of fracturing fluids, which might include a target liquid (not shown), and proppants such that antenna assemblies 310 can be deployed by pumping the slurry into well 370. In this way, antenna assemblies 310 can flow from well 370 into fractures 378. Further, antenna assemblies 310 may not include a cartridge, although embodiments in which antenna assembly 310 includes a cartridge are also contemplated. It will be appreciated that in some embodiments, antennas 312 may act as proppants in the slurry of fracturing fluids, although the slurry can also include other proppants as well.

[0036] Microwave radiation 332 transmitted into well 370 can be directed towards or released to fractures 378 by a microwave transmitter 334. Releasing microwave radiation 332 in this way may allow for the heating the target liquid to a heated state by way of interaction with antenna assemblies 310. Contacting the heated target liquid with target material 374 might then heat target material 374 such that a viscosity of target material 374 is reduced, thereby allowing target material 374 to more readily flow out of formation 304 into well 370.

[0037] Referring now to Fig. 7, a system for wastewater treatment ("wastewater system") 400 is shown according to one embodiment. Wastewater system 400 may be structured to separate a target liquid 450, typically water (hereinafter "water 450"), from a wastewater 478, which includes the target material (not pictured) suspended within water 450. Operation of wastewater system 400 may facilitate the removal of harmful or otherwise undesirable particulate matter or other contaminates such as brine, toxic metals, or radioactive waste from wastewater 478. As such, water 450 recovered from wastewater 478 might be reusable, and the target materials can be more efficiently stored or transported to a remote site for treatment or disposal. For example, hydraulic fracturing operations generate mass quantities of wastewater 478 that often must be transported to a treatment facility for disposal, the transportation of which comes at considerable expense. One known strategy to mitigate these expenses involves storing wastewater 478 in storage tanks or evaporating pools, which may enable some water 450 to evaporate off, thereby reducing transportation costs. Still, evaporation is often a slow process and storage of wastewater 478 involves additional expense. As such, systems that facilitate efficient wastewater treatment remain desirable. Wastewater system 400 may provide for certain advantages over known wastewater treatment systems as will become apparent from the discussion herein.

[0038] Wastewater system 400 may be similar to steam system 200 in many respects. Like steam system 200, wastewater system 400 includes an ordered distribution of antenna 412 attached to a conductive base 420 within a cartridge 414 to form an antenna assembly 410. Antenna assembly 410 is deployed to a location proximate to the target material for interacting with microwave radiation 432 transmitted from a microwave source 430, which may ultimately result in the evaporation of water 450 to form steam 460. Microwave source 430 may be identical to microwave source 230, and may be coupled to wastewater container 452 by a waveguide 434, which is similar in structure and function to waveguide 234.

Waveguide 434 may be communicatively coupled with antenna assembly 410 by a microwave outlet 438 formed in a wastewater container 494 that permits the passage of microwave radiation 432 therethrough.

[0039] Unlike steam system 200, however, water 450 is in contact with the target material within wastewater container 494 prior to being heated. Further, wastewater system 400 includes a distillation conduit 466 coupling wastewater container 494 with a collection vessel 468. Distillation conduit 466 may be formed of a variety of pipes, pumps, and other structures configured to facilitate distillation of steam 460 to water 450, such as, for instance, a steam section 464, a condenser section 486, a pump 482, and a collection section 490.

[0040] Steam 460 formed by heating water 450 by way of antenna assembly 410 may escape wastewater container 494 through a steam vent 458 to steam section 464. Distillation conduit 466 can then direct steam 460 to a condenser 480, which might have a cooling unit 488 structured to cool steam 460 passing through condenser section 486, thereby distilling steam 460 to water 450. Pump 482 can then pump distilled water 450 through collection section 490 to collection vessel 468.

[0041] Referring now to Fig. 8, a concrete curing system ("concrete system") 500 is shown according to one embodiment. Concrete system 500 may be structured to facilitate heating of a concrete mixture 578 that includes a target liquid (not pictured), which includes water (hereinafter "water"), a target material (not pictured), which includes cement, and an aggregate (not pictured). Put differently, concrete system 500 may be structured to reduce a cure time of concrete mixture 578 through use of both ex situ and in situ instrumentalities that work in concert to facilitate concrete hydration. It has been observed that heat may facilitate concrete hydration, but temperatures in excess of approximately 65-70 degrees Celsius may cause a decrease in the strength of cured concrete. Accordingly, concrete system 500 may be structured to facilitate heating the water in concrete mixture 578 in a manner similar to the heating of water 250, 350 in steam system 200 and wastewater system 400, respectively, except that concrete system 500 may be structured to heat the water to a temperature below the temperature at which the water evaporates.

[0042] Concrete system 500 may be similar to systems 200, 300, 400 in many respects. For instance, concrete system 500 has an antenna assembly 510, which includes an antenna 512 attached to a conductive base 520 within a cartridge 514. Antenna assembly 510 is structured to interact with microwave radiation 532 transmitted from a microwave source 530 by a microwave transmitter 534 for the purpose of heating water within concrete mixture 578 by way of this interaction.

[0043] Like antenna assembly 410, antenna assembly 510 is deployed within a mixture of the target liquid and the target material. In concrete system, 500, antenna assembly 510 is positioned within a sub-surface concrete wellbore ("concrete well 596") that can then be filled with concrete mixture 578. As seen in Fig. 8, antenna assembly 510 may be similar to antenna assemblies 210, 410 in that an ordered distribution of antennas 512 might be encased within cartridge 514 and deployed in a liquid solution. In other embodiments, however, concrete system 500 might include a plurality of antenna assemblies 510 positioned within concrete mixture 578 or positioned outside concrete well 596. In still other embodiments, antenna assembly 510 may be similar to antenna assembly 310 in that antenna assembly 510 might include a random distribution of antennas 512. While concrete system 500 of the present embodiment is formed mostly under a surface 572, an alternative embodiment in which concrete mixture 578 is retained within a freestanding container positioned partially or entirely above surface 572 is also contemplated.

[0044] A microwave well 592 may be formed near concrete well 596 for transmitting microwave radiation 532 from microwave source 530 to antenna assembly 510. Microwave transmitter 534 might extend down into microwave well 592, although in some embodiments, microwave transmitter 534 may not extend below surface 572. Microwave radiation 532 may escape microwave well 592 through a microwave outlet 538 to concrete mixture 578, such that at least some microwave radiation 532 might interact with antenna assembly 510 to heat the water within concrete mixture 578.

[0045] The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present disclosure in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. It will be appreciated that certain features and/or properties of the present disclosure, such as relative dimensions or angles, may not be shown to scale. As noted above, the teachings set forth herein are applicable to a variety of different devices, assemblies, and systems having a variety of different structures than those specifically described herein. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims. As used herein, the articles "a" and "an" are intended to include one or more items, and may be used interchangeably with "at least one." Where only one item is intended, the term "one" or similar language is used. Also, as used herein, the terms "has," "have," "having," or the like are intended to be open-ended terms.

Claims

Claims What is claimed is:

1. A method of extracting oil from an oil-bearing target material comprising:

deploying a distribution of antennas into a well extending from a surface to a sub-surface formation of the oil-bearing target material, each antenna including a conductive rod perpendicularly coupled with a conductive base;

generating microwave radiation that can interact with an antenna within the distribution of antennas and the corresponding conductive base to focus energy of the microwave radiation;

heating a target liquid by way of the energy of the microwave radiation; and contacting the oil-bearing target material with the target liquid in a heated state so as to heat the oil-bearing target material within the sub-surface formation of the oil- bearing target material such that a viscosity of the oil-bearing target material is reduced.

2. The method of claim 1 wherein deploying the distribution of antennas further includes positioning an antenna within the sub-surface formation of the oil- bearing target material.

3. The method of claim 2 wherein the distribution of antennas is an ordered distribution of antennas.

4. The method of claim 1 wherein the antenna is at least partially encased in a cartridge formed at least in part by a substantially microwave transparent material.

5. The method of claim 1 further including heating an antenna within the distribution of antenna by way of the focused energy of the microwave radiation, and wherein heating the target liquid by way of the energy of the microwave radiation includes contacting the target liquid with the heated antenna.

6. The method of claim 1 wherein focusing the energy of the microwave radiation includes the antenna radiating microwave radiation.

7. The method of claim 1 wherein the target liquid is water, and heating the water further includes evaporating the water to create steam.

8. A system for heating an oil-bearing target material within a sub-surface formation of the oil-bearing target material comprising:

a distribution of antennas positioned within the sub-surface formation of the oil-bearing target material and in contact with a target liquid, a majority of antennas within the distribution of antennas being perpendicularly coupled with a conductive base such that the antennas and the conductive bases can focus energy of received microwave radiation;

a microwave source for generating microwave radiation within a frequency that interacts with an antenna within the distribution of antennas; and

a microwave transmitter for transmitting microwave radiation from the microwave source to the distribution of antennas.

9. The system of claim 8 further including a cartridge formed in part by a substantially microwave transparent material, the cartridge at least partially encasing an antenna within the distribution of antennas or a conductive base coupled with an antenna within the distribution of antennas.

10. The system of claim 9 wherein the substantially microwave transparent material is borosilicate ceramic.

1 1. The system of claim 9 wherein the cartridge at least partially encases a plurality of antennas within the distribution of antennas, the plurality of antennas having an ordered distribution within the cartridge.

12. The system of claim 8 wherein the distribution of antennas are randomly distributed.

13. The system of claim 8 further including a target vessel for retaining a quantity of the target liquid, the target vessel being positioned within the sub-surface formation of the oil-bearing target material.

14. The system of claim 13 wherein a plurality of antennas within the distribution of antennas are positioned within the target vessel.

15. The system of claim 13 wherein the target liquid is liquid water.

16. An antenna assembly comprising:

an antenna for receiving microwave radiation;

a conductive base for receiving and reflecting the microwave radiation, the conductive base coupled with the antenna such that the antenna assembly can focus energy of the microwave radiation; and

a cartridge formed in part by a substantially microwave transparent material, the cartridge at least partially encasing the antenna or the conductive base.

17. The assembly of claim 16 wherein the conductive base includes a plurality of conductive layers.

18. The assembly of claim 16 wherein the antenna is a high

electronegativity antenna formed of a conductive rod.

19. The assembly of claim 16 wherein the substantially microwave transparent material is borosilicate ceramic.

20. The assembly of claim 16 further including a spacer coupling the antenna with the conductive base.