Abstract:
Disclosed herein is a fracturing unit for hydraulic fracturing having an engine and a fracturing pump connected to the engine through a variable speed torque converter. Also disclosed is a hydraulic fracturing system using multiple fracturing units which are sized similar to ISO containers. A hydraulic fracturing system may also force flow back water, produced water, or fresh water through a heat exchanger so that heat from the fracturing engines can be transferred to these liquids in order to vaporize them. A force cooled fractioning unit then can accept the vapor/steam in order to condense the various components and produce distilled water for re-use in the fracturing process or for release into the environment.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. application Ser. No 61/616,312 filed on Mar. 27, 2012 and is herein incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments generally relate to systems and method related to hydraulic fracturing, specifically those that increase efficiency, and recycle the FBW and/or PW. 
     BACKGROUND OF THE ART 
     The process of hydraulic fracturing oil and gas wells produces industrial wastes referred to as Flow-back Water (FBW initial return) and Produced Water (PW long term return). Millions of gallons of regurgitated FBW/PW, per drill site, contain chemicals and other contaminates brought to the surface of the earth which need to be rendered harmless and disposed of. The O&amp;G industry is searching for new ways to minimize the usage of Fresh Water (FW) being withdrawn from the environment which has increased the interest in recycling of the waste waters. Many methods have been developed but all have drawbacks to some degree; high cost per barrel, mediocre quality outcomes, low production rates. Recycling is being used to minimize the draw of fresh water from the environment, and to minimize the amount of contaminates needing to be disposed of. 
     The existing technology for the treatment and/or disposal of FBW/PW is extremely expensive and is not environmentally friendly. The current practice causes damage to the public&#39;s infrastructure from mass transportation of FBW/PW from the drill site and fresh water to the site, damage to the environment from spills and contamination, and earthquakes from FBW/PW being disposed of in injection wells. All the transporting of both fresh water and FBW/PW adds carbon footprint and greenhouse gases. 
     The practice of driving a fracturing pump with a transmission has inherent drawbacks; sudden load applications, up-shifting problems, horsepower losses through the transmission resulting in more fuel consumption, flow degradation due to less than optimal pump speeds and over torque possibilities in low gears damaging equipment. 
     Open fracturing rigs submit the environment to leak/spill possibilities of the engine fluids and massive spills of the chemically treated fresh water fracturing fluid at high pressure/flow entering the well head from the innumerous hoses, fittings and couplings. These items cause a large footprint on a small space and lend to a very dangerous work environment. The open rigs cause over burdening noise levels to the public also. 
     Some recycling systems are too slow processing low volumes of water and consuming more energy across the board. Some methods render usable low quality water but fluctuations in salinity and chemicals create hardships treating water for re-use. Other methods clean the water well but are left with larger amounts of waste such as dirty filters still needing processed or disposed of. Utilizing a transmission the pump flow is marginalized as the transmission has horse power losses through itself and is not an exact match for maximizing the speed and flow from the pump. 
     FBW/PW treatment generally is not performed on site during fracturing, but is done after the fracturing is completed with other types of equipment. This is an additional expense, another contractor and equipment on the drill site and more energy is consumed. Disposal at permitted facilities is very expensive, requires trucking and separate from the fracturing process. Disposal is also performed injecting FBW/PW into wells contaminating the earth and causing earthquakes. Utilizing a transmission to drive a fracturing pump causes quick hard loading of the engine resulting in killing the engine when coming on line against a high pressure manifold potentially causing damage to all components. Pump sets are traditionally open frame mounted and leaks can be strewn on the ground easily from the engine, transmission and the fracturing pump itself. Open units also cause a very high ambient noise level on the drill site and surrounding environment. 
     SUMMARY OF THE EXEMPLARY EMBODIMENTS 
     Exemplary embodiments provide a fracturing unit for hydraulic fracturing having an engine and a fracturing pump connected to the engine through a variable speed torque converter. Exemplary embodiments also provide a hydraulic fracturing system using multiple fracturing units which are sized similar to ISO containers. A hydraulic fracturing system may also force flow back water, produced water, or fresh water through a heat exchanger so that heat from the fracturing engines can be transferred to these liquids in order to vaporize them. A force cooled fractioning unit then can accept the vapor/steam in order to condense the various components and produce distilled water for re-use in the fracturing process or for release into the environment. 
     The foregoing and other features and advantages of the present invention will be apparent from the following more detailed description of the particular embodiments, as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of an exemplary embodiment will be obtained from a reading of the following detailed description and the accompanying drawings wherein identical reference characters refer to identical parts and in which: 
         FIG. 1  is a perspective view of an exemplary embodiment of a hydraulic fracturing system (HFS). 
         FIG. 2  is a side view of an exemplary embodiment of a fracturing unit. 
         FIG. 3  is a front view of an exemplary embodiment of a fracturing unit. 
         FIG. 4  is a top view of an exemplary embodiment of a fracturing unit. 
         FIG. 5  is a side view of an exemplary embodiment of the forced cooling fractioning unit. 
         FIG. 6  is a front view of an exemplary embodiment of the forced cooling fractioning unit. 
         FIG. 7  is a top view of an exemplary embodiment of the forced cooling fractioning unit. 
         FIG. 8  is a perspective view of an exemplary embodiment of the engine exhaust heat exchanger (EEHE). 
         FIG. 9  is a detailed view of the exhaust tubes within an exemplary embodiment of the engine exhaust heat exchanger. 
         FIG. 10  is a side view of an exemplary embodiment for a fracturing and flow back water treatment system. 
         FIG. 11  is a side view of an exemplary embodiment for an operations unit. 
         FIG. 12  is a top view of an exemplary embodiment for a fracturing and flow back water treatment system. 
         FIG. 13  is a perspective view of an exemplary embodiment for a fracturing and flow back water treatment system. 
         FIG. 14  is a front view of an exemplary embodiment for a preparation and completion unit. 
         FIG. 15  is a side view of an exemplary embodiment for a preparation and completion unit. 
         FIG. 16  is a side view of an exemplary embodiment for a sand hopper and blending unit. 
         FIG. 17  is a front view of an exemplary embodiment for a sand hopper and blending unit. 
     
    
    
     DETAILED DESCRIPTION 
     The invention is described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Embodiments of the invention are described herein with reference to illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
       FIG. 1  is a perspective view of an exemplary embodiment of a hydraulic fracturing system (HFS). This embodiment of the HFS embodies the employment of ISO shipping containers to house all of the related equipment (Fleet Equipment, FE) required to perform the act of hydraulic fracturing of an oil or gas well. The containers allow stacking of the FE, causing the well pad footprint to be minimized reducing the environmental impact of the fracturing process. A plurality of fracturing units  20  are positioned in close proximity to one another. It is preferable that each fracturing unit  20  fits within an ISO container or an enclosure which has dimensions similar to an ISO container (also known commonly as an intermodal container, freight container, hi-cube container, conex box, and sea can). In this way, they can be stacked atop one another and next to each other. Each embodiment may require more or less fracturing units  20 , but in this particular embodiment a total of ten fracturing units  20  are used. A plurality of access doors  4  are aligned with one another and allow access into each fracturing unit  20 . Each fracturing unit  20  also preferably contains an intake portion for accepting ambient air, here represented by louvers  10 . 
     A foundation  5  may be set on the site prior to installing the fracturing units  20 , and here the foundation  5  is designed for H beams, but could also be done with I beams, concrete, gravel, or other rigid materials that would prevent settling of the underlying earth. Fracturing units  20  may also set on track systems  700  enabling standard engine fleets that are radiator cooled to be mounted in the containers making them mobile to move well to well requiring very little teardown/setup, such as may be required for zipper fracs that contain a single wellhead on the pad. It is preferable for a single fuel tank  6  to be used which supplies fuel to each of the fracturing units  20 , as this allows for single fill port to minimize the risk of fuel spillage. It is preferable that the fuel tank  6  contains NFPA spill containment. Engine exhaust apertures  3  allow engine exhaust to escape, and could be positioned anywhere, but are preferably located on the top of and near the end of the fracturing unit  20 . 
     Fracturing pump suction lines  7  are preferable fed from a mixer (described more below) and connect to the suction or low pressure (LP) manifold  9  which supplies each fracturing unit  20 . The suction line  7  hoses preferably supply pump sets with fracturing fluid from the sand and chemical blenders. Another manifold  15  accepts the resulting pressurized fracturing fluid and sand from each fracturing unit  20  and collects this into a single fracturing fluid/sand supply  8  for the well head. A steam manifold  11  may collect the steam from each fracturing unit  20  and direct it to an optional steam turbine or may direct it to the FCFU for fractioning and condensing. An absorption chiller and/or steam turbine  1  is preferably placed in close proximity to the fracturing units  20 , as well as a horizontal forced cooling fractioning unit  2 . An absorption chiller may use the engine exhaust to cool heated water whereby controlling the temperature of the distilled water before entrance into the storage tanks or the well. 
       FIG. 2  is a side view of an exemplary embodiment of a fracturing unit  20 .  FIG. 3  is a front view of an exemplary embodiment of a fracturing unit  20 .  FIG. 4  is a top view of an exemplary embodiment of a fracturing unit  20 . 
     A fracturing pump  22  is preferably in fluid communication with an outlet  40  which connects to the manifold  15 , as well as an inlet  42  which connects to the manifold  9 . The fracturing pump  22  receives fracturing fluid from inlet  42 . The fracturing pump  22  is powered by the engine  26  which is preferably connected to the pump  22  through a variable speed torque converter (VSTC)  24 , but could also be connected through a traditional transmission. However, the VSTC  24  is preferred as it would allow the engine  26  to run at the most efficient speed for the engine  26  without being forced into a specific speed due traditional transmission requirements, maximizing the efficiency of the engine  26 . 
     The engine  26  is preferably cooled using a tube and shell heat exchanger  28 , supplied with FW/FBW/PW supplied by cooling water pump  30 . After the fluids have picked up rejected heat from the engine  26 , fluids will be directed to a second 2-stage engine exhaust heat exchanger (EEHE)  29  where fluids will be heated to near boiling temperature in the first stage where it can be used for many applications such as fracturing fluid temperature conditioning, directing it to FW storage to prevent freezing, or directed into the second stage of the EEHE  29  for distillation. A gas module  31  may supply natural gas, LPG, hydrogen, or bio gasses of any type supplementing the diesel to the engines whereby reducing the use of diesel by up to 80% reducing emissions and fuel costs. The fracturing unit  20  and its components described herein preferably fits within an ISO container enclosure  36 . 
     An AC generator  32  is also preferably connected to the engine  26 . The AC generator  32  may be used to power up all FE during fracturing (electric motors driving blenders, water pumps, sand conveyors, etc and may also be used to power electric water heaters  34  to maximize the purification process during fracturing, or may be used to increase purification rates by using the full capacity of the engine/generator while the well is being serviced and the fracturing pump is not needed. This embodiment also contains a variable speed pump  30  as well as a water heater  34 , which could be powered by a natural gas burner or could contain electric heating elements and powered by one of the generators described herein, most preferably the AC generator  32 . The pump  30  is preferably in fluid communication with water being forced through the heat exchangers  28  and  29  which is used to cool the engine  26 . If necessary, the hot water is then pushed by the pump  30  into the water heater  34  and then exhausted through the steam manifold  11 . 
       FIG. 5  is a side view of an exemplary embodiment of the forced cooling fractioning unit (FCFU)  2 . The FCFU, being designed to differing specifications, sizes and applications, will receive vapors from the distillation process, fractioning off water, petroleum products and each chemical at inherent properties to be recovered for reuse. The FCFU may also be used in different industries such as coal mining recycling mine water run-off, bio-fuel fractionation or any process requiring fractionation. Together with engines, a process of Combined Heat and Power (CHP) can be employed with the FCFU to maximize savings for fractionation processes. The FCFU will preferably supply steam and chemical vapors from the distillation process through steam manifolds  11  to steam inlet  50 , proceeding through each cooling segment of differing sizes whereas cooling tubes  60  of differing sizes, cooling vapors incrementally, condensing them for drainage through segment drain  54 . A temperature sensing device  52  that will be used by a controller controlling water pump  30  feeding cool FW/FBW/PW to manifold assemblies  62  directing the fluids through tubes  60  thereby cooling the vapors, simultaneously picking up heat to increase the efficiency/flow rate of the distillation process. 
     Steam which has been collected by the steam manifold  11  is directed into the inlet  50 . The steam then passes through a plurality of condenser sections, each one having a falling/cooling section  56  followed by a rising section  58 . Within each cooling section, one or more cooling tubes  60  contains FW/FBW/PW and cools the steam. As each vapor component of the steam condenses, it is captured by a condensate drain  54  and collected. A temperature probe  52  may be placed at the bottom of each falling/cooling section  56  and is used in a control system to regulate the flow of coolant through the cooling tubes  60  for that section. 
       FIG. 6  is a front view of an exemplary embodiment of the forced cooling fractioning unit  2 .  FIG. 7  is a top view of an exemplary embodiment of the forced cooling fractioning unit  2 . A coolant manifold  62  may be used in each section directing coolant into each cooling tube  60  for that section. 
       FIG. 8  is a perspective view of an exemplary embodiment of the engine exhaust heat exchanger (EEHE)  29 . The EEHE  29  will allow flexibility for usage of the heated fluids on the well site whereas it may be used in standard engine/pump sets to provide BTU to heat fracturing fluids before well injection, or prevent freezing of FW in cold climates. As depicted, flexibility is offered but maximizing BTU efficiency increasing the purification flow rates is desired by raising the fluid temperature to just below vaporization in stage 1 whereas most of the exhaust can be directed through the adjustable valve increasing flow rates, with very little exhaust heat required to flash distill the fluids in stage 2. Stage 2 will encase a basin for the highly concentrated salt slurry to be captured and pumped to the PCU  100 . Crystallized contaminates will also be removed by vibration or sonic waves from the exhaust tubes into the salt slurry to be processed within the PCU  100 . 
       FIG. 9  is a detailed view of the exhaust tubes within an exemplary embodiment of the engine exhaust heat exchanger. This figure provides detail of the entry point for the exhaust tubes, designed to minimize backpressure for the engine exhaust requirements. 
       FIG. 10  is a side view of an exemplary embodiment for a fracturing and flow back water treatment system. A preparation and completion unit  100  is shown alongside the fracturing units  20  with optional steam turbine generators. An operations unit  200  is also shown with a plurality of holding tanks  300 . Again, the use of containers similar to ISO containers allows for stacking which can shrink the FE footprint to around ⅕ of an acre or less. 
       FIG. 11  is a side view of an exemplary embodiment for an operations unit  200 . In this embodiment, the operations unit  200  preferably contains the following: a control module and laboratory  201 ; an electrical control room  202  which can be an electrical distribution module supplying over current protection whereas it receives electrical current from the electrical generator  32  of each fracturing unit  20  distributing and providing control of each pump system, conveyor system, chemical and sand blenders etc; a nitrogen generator  203 , a tool room and optional hydrogen generator  204 , an optional office for a geologist/chemist  205 , an optional fuel tank  206 , an acid/chemical blender  207 , a hydration unit  8 , and a pump module  9 . All of these elements  201 - 209  are also preferably contained within an ISO container or an enclosure which has dimensions similar to an ISO container. 
       FIG. 12  is a top view of an exemplary embodiment for a fracturing and flow back water treatment system. Again here, the FCFU  2  is placed close to the fracturing units  20 . The preparation and completion unit (PCU)  100  may be placed on either side of the wellheads as it may remain for months after the fracturing process is completed to continue to purify the FBW/PW flowing from the wells after fracturing is completed. The sand blender  475  module may be placed beside the fracturing units  20  and is being supplied by the sealed sand conveyor  450  sand tanks  325  for sand supply. Distilled water tanks  375  may provide storage of distilled water upon completion of purification. The wellhead string and piping  500  may carry FBW/PW and gas to the PCU  100  for treatment. 
       FIG. 13  is a perspective view of an exemplary embodiment for a fracturing and flow back water treatment system. 
       FIG. 14  is a front view of an exemplary embodiment for a preparation and completion unit (PCU)  100 . A sulfur dioxide scrubber and gas compressor  101  may clean the natural gas of the FBW/PW before the NG is delivered to the engines  26  to supplement the diesel fuel. Feeding the engines  26  with NG from tank  31  will also prevent raw methane from entering the atmosphere and put the methane to a productive use instead of flaring. A vessel  102  may store NG before entering the sulfur dioxide scrubber and gas compressor  101  for treatment. The PCU  100  may also contain a control module  103  for the PCU  100 , which controls and monitors the process. A salt slurry holding tank and a de-mineralization unit  104  may prepare for final completion of the recycling process. A smaller FCFU  105  may handle the flow rates of the PCU  100  with chemical holding tanks below it. The initial sealed tanks  106  may accept the FBW/PW so that sand will settle out of the fluid withdrawing the sand from the rear of the tank for recapture and use in the fracturing process. The tank  106  may incorporate a slanted v-shaped bottom to direct the sand to the outlet and may have a raised outlet to control fluid level, whereas the fluid will then enter a second tank  107  to then settle out large suspended solids being withdrawn from the rear of the tank to be hauled off for possible further treatment and disposal. Tank  107  may also use an outlet whereby directing the fluid to centrifuge  108  for further removal of small suspended solids by centrifuge before delivering the cleaned water to the engines for engine cooling and purification. Diesel or gas engine/generator sets  109  and  110  may supply power to the well site for completion activities and to supply heat for the completion unit  100 . The amount of generator sets may vary as the PCU  100  may be used as a temporary central processing facility in order to purify FBW/PW from other sites for the well developer or as a service for other developers without the exemplary embodiments herein, thereby lowering the cost of disposal for them and preventing injection back into the earth via class II injection wells. The PCU  100  may also be on site prior to fracturing but during drilling activities providing site power while recycling drilling muds. 
       FIG. 15  is a side view of an exemplary embodiment for a preparation and completion unit. 
       FIG. 16  is a side view of an exemplary embodiment for a sand hopper and blending unit  475 .  FIG. 17  is a front view of an exemplary embodiment for a sand hopper and blending unit  475 . 
     The sand is brought in through the sand conveyor entrance  460  at the top of the sand hopper and blending unit  475 . The sand is dropped from the entrance  460  into the sand blending pumps  480  where the sand is mixed with the fracturing fluid entering one side of the module, moving through the blending pumps  480 , and exiting on the other side of the module for delivery to the fracturing pumps  22 . A pair of suction fans  490  may be used to create a vacuum that will pull air out of the unit  475  and  450  paired with a dust filter  495  to remove particulate that may be airborne, especially silica dust. The filters  495  may be cleaned by vibration, dropping the dust back into the sand. 
     Having shown and described a preferred embodiment of the invention, those skilled in the art will realize that many variations and modifications may be made to affect the described invention and still be within the scope of the claimed invention. Additionally, many of the elements indicated above may be altered or replaced by different elements which will provide the same result and fall within the spirit of the claimed invention. It is the intention, therefore, to limit the invention only as indicated by the scope of the claims.