Abstract:
The present disclosure relates to a system and method for producing a well-fracturing gel using a gel concentrate such that the method and system are capable of timely adjusting the properties of the gel on the fly just prior to introducing the gel into the well. Further, the present disclosure provides for producing a gel with an overall shorter production time as well as adjusting the properties of the gel just prior to injecting the gel into the well.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to fracturing a subterranean zone. 
       BACKGROUND 
       [0002]    Gels for well fracturing operations have traditionally been produced using a process wherein a dry gel and a liquid, such as water, are combined in a single operation. However, the gel mixture requires considerable time to hydrate prior to being introduced down a well. Moreover, the gel continues to be produced while the gel hydrates, creating a working volume of gel that is used in a first in first out manner for the fracturing operation. Thereafter, as the gel is introduced into the well, a change to the gel may be required in order to address the specific needs of the fracturing operation. For example, the gel may require an additive to reduce the reactivity of the gel to the well formation or the viscosity of the gel may require modification in order to properly fracture the well. However, the working volume must be used up before the gel having the modified properties is available to be introduced into the well. As such, there is a significant lag between a change to the composition of the gel and the introduction of the modified gel into the well. This delay can be significant—up to one quarter of the total time to perform a fracturing operation. 
       SUMMARY 
       [0003]    The present disclosure relates to a system and method for producing gel in a reduced time period using a gel concentrate such that the method and system are capable of timely adjusting the properties of the gel on the fly just prior to introducing the gel into the well. Accordingly, the present disclosure provides for producing a gel with an overall shorter production time as well as adjusting the properties of the gel just prior to injecting the gel into the well, thereby significantly reducing or eliminating any lag period between a change in the gel and injection of the gel into the well. 
         [0004]    The details of one or more implementations of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0005]      FIG. 1  is a schematic view of a dry gel production system for producing a fracture stimulation gel using a gel concentrate; 
           [0006]      FIG. 2  is a mobile gel-production apparatus capable of producing a gel concentrate according to one implementation; 
           [0007]      FIG. 3  is a detail view of dry handling system for transporting and delivering a dry gel for the production of a gel or a gel concentrate according to one implementation; 
           [0008]      FIG. 4  is another view of the dry handling system of  FIG. 3 ; 
           [0009]      FIG. 5  is a schematic view of an apparatus for mixing and hydrating a dry gel according to one implementation; 
           [0010]      FIG. 6  shows a conveyor system and cyclone separator of the dry handling system of  FIG. 3 ; 
           [0011]      FIG. 7  shows a perspective view of a gel mixing system according to one implementation; 
           [0012]      FIG. 8  is another view of the gel mixing system of  FIG. 7 ; 
           [0013]      FIG. 9  is a detail view of a hydration tank according to one implementation; 
           [0014]      FIG. 10  is a control system for controlling various functions of a polymer gel production system, according to one implementation; 
           [0015]      FIG. 11  is an output system for controlling an output of a polymer gel concentrate according to one implementation; and 
           [0016]      FIG. 12  is a schematic view of a dry gel production system for producing a fracture stimulation gel directly from a dry gel and a liquid. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 1  is one example of a system  10  adapted to hydrate a dry gel for use in fracture stimulating a subterranean zone. The system  10  includes a hydrated gel producing apparatus  20 , a liquid source  30 , a proppant source  40 , and a blender apparatus  50  and resides at a surface well site. The hydrated gel producing apparatus  20  combines dry gel with liquid, for example from liquid source  30 , to produce a hydrated gel. In certain implementations, the hydrated gel can be a gel for ready use in fracture stimulation or a gel concentrate to which additional liquid is added prior to use in fracture stimulation. Although referred to as “hydrated,” the hydrating fluid need not be water. For example, the hydrating fluid can include a water solution (containing water and one or more other elements or compounds) or another liquid. In some of the embodiments described herein, the blender apparatus  50  receives the gel for ready use in fracture stimulation and combines it with other components, often including proppant from the proppant source  40 . In other instances, the blender apparatus  50  receives the gel concentrate and combines it with additional hydration fluid, for example from liquid source  30 , and other components often including proppant from the proppant source  40 . In either instance, the mixture may be injected down the wellbore under pressure to fracture stimulate a subterranean zone, for example to enhance production of resources from the zone. The system may also include various other additives  70  to alter the properties of the mixture. For example, the other additives  70  can be selected to reduce or eliminate the mixture&#39;s reaction to the geological formation in which the well is formed and/or serve other functions. Although the additives  70  are illustrated as provided from a separate source, the additives  70  may be integrally associated with the apparatus  20 . 
         [0018]      FIG. 2  illustrates an implementation of the apparatus  20  for producing the gel concentrate. The apparatus  20  of  FIG. 2  may also generate a gel directly. As shown, the apparatus  20  is portable, such as by being included on or constructed as a trailer transportable by a truck. The apparatus  20  may include a bulk material tank  80 , a hydration tank  90 , a power source  100 , and a control station  110 . Other features may also be included. 
         [0019]    According to one implementation, the power source  100  may be a diesel engine, such as a Caterpillar® C-13 diesel engine, including a clutch. However, the present description is not so limited, and any engine or other power source capable of providing power to the apparatus  20  may be utilized. The power source may also include hydraulic pumps, a radiator assembly, hydraulic coolers, hydraulic reservoir (e.g., a 70-gallon hydraulic reservoir), battery, clutch, gearbox (e.g., a multi-pad gearbox with an increaser), maintenance access platforms, battery box, and one or more storage compartments. Although not specifically illustrated, these features would be readily understood by those skilled in the art. The power source  100  provides, entirely or in part, power for the operation of the apparatus  20 . The control station  110  provides for control of the various functions performed by the apparatus  20  and may be operable by a person, configured for automated control, or both. The control station  110  may, for example, control an amount of dry gel and liquid combined in a gel mixer (discussed below), the rate at which the gel mixer operates, an amount of gel concentrate maintained in a hydration tank (discussed below), and a gel concentrate output rate. The control station  110  may also control an amount of dry gel dispensed from a bulk-metering tank (discussed below) as well as monitor an amount of dry gel remaining in the bulk-metering tank. Further, the control station  110  may be operable to monitor or control any aspect of the apparatus  10 . The apparatus  20  may also include various pumps, such as liquid additive pumps, suction pumps, and concentrate pumps; mixers; control valves; flow meters, such as magnetic flow meters; conveying devices, such as conveying augers, vibrators, pneumatic conveying devices; and inventory and calibration load cells. 
         [0020]    A dry gel handing system is now described with reference to  FIGS. 3-6 .  FIG. 6  shows a schematic diagram of material flow through the dry handling system  120 . The dry gel handling system (interchangeably referred to as “handling system”)  120  includes a bulk tank  130  having a cyclone separator  140  and fill hatch  150  used to fill the bulk tank  130  with dry gel. The dry gel is a bulk powder material including, for example, hydratable polymers such as cellulose, karaya, xanthan, tragacanth, gum ghatti, carrageenin, psyllium, gum acacia, carboxyalkylguar, carboxyalkylhydroxyalkylguar, carboxyalkylcellulose, carboxyalkylhydroxyalkylcelluose, and the like wherein the alkyl radicals include methyl, ethyl, or propyl radicals. Dry gel materials may also include, for example, hydratable synthetic polymers and copolymers such as polyacrylate, polymethacrylate, acrylamide-acrylate copolymers, and maleic anhydride methylvinyl ether copolymers. Other dry gel polymers include cmhpg, hpg, guar, hec, cmhec. When filling the bulk tank  130 , an amount of dry gel dust it created. Dusting is worsened as the air, being displaced by the incoming dry gel, is forced out of the tank  130 . Consequently, the cyclone separator  140  residing within the bulk tank  130  is utilized to capture and separate the dry gel dust created during filling and/or operation of the handling system  120 . Once separated from the air, the dry gel dust falls into a lower portion of the cyclone separator  140  where it is released back into the tank  130 . According to one implementation, the dry dust falls into a collecting chamber  160  at the bottom of the cyclone separator  140 . The collecting chamber  160  is then emptied at specified intervals back into the bulk tank  130 . According to one implementation, a bulk tank  130  having an 8,000 lb. capacity may be filled within one to three minutes. Air captured by the cyclone separator  140  is then transported to a filter  170  where additional dry gel still entrained in the air may be removed, and the air is then exhausted to the environment through an exhaust pipe  180 . 
         [0021]    The handling system  120  also includes a series of conveyors to transport the bulk dry gel to a gel mixer where the dry gel is subsequently mixed with a liquid. A first horizontal conveyor  190  is located at a lower portion of the bulk tank  130 . The first conveyor  190  may be an auger that conducts an amount of the dry gel to a vertical conveyor  200  that may also be an auger. The vertical conveyor  200  conducts the dry gel upwards where the dry gel is released into a hopper  210 . A second horizontal conveyor  220  carries the dry gel to the gel mixer  290 . According to one implementation, the first horizontal and vertical conveyors  190 ,  200  operate at a constant speed. Thus, the conveyors  190 ,  200  have constant dry gel conveying rates. The second horizontal conveyor  210  may be operable at variable speeds according to the concentration and volume of gel required. In one implementation the conveyor  210  may be an Acrison® feeder manufactured by Acrison, Inc., 20 Empire Blvd., Moonachie, N.J. 07074. According to a further implementation, the conveying rate of the conveyors  190 ,  200  may be set so that an amount of dry gel delivered to the hopper  210  will always exceed the amount of dry gel conveyed by the second horizontal conveyor  220 . Consequently, dry gel delivered to the hopper  210  will always exceed an amount of dry gel drawn therefrom so that the quantity of dry gel delivered by the second horizontal conveyor  220  remains uniform. The excess dry gel delivered to the hopper  210  overflows and is returned back to the bulk tank  130 . The dry gel exits the handling system  120  through an outlet  230 . 
         [0022]    The handling system  120  is capable of accurately delivering a desired amount of dry gel via the second horizontal conveyor  220 . Because the hoper  210  is maintained in a full condition by the conveyors  190  and  200 , the system  10  is able to accurately measure an amount of dry gel fed by the conveyor  220  based on the conveyor  220 &#39;s operating speed. However, the handling system  120  may also include a back up or alternate mechanism for ensuring accurate and consistent delivery of dry gel to the gel mixer. Accordingly, the bulk tank  130  may include load sensors (“load cells”)  240  provided at, for example, the corners of the bulk tank  130 . The outputs of the load cells  240  provide an indication of the amount of bulk material, by weight (or mass), contained in the bulk tank. Therefore, the load cells  240  provide not only an indication of an amount of dry gel remaining in the bulk tank  130  but also an indication of the rate the dry gel being fed therefrom based on the rate of change in the weight, as measured by the load cells  240 . Further, an operator of the system  10  (shown in  FIG. 1 ), such as a human operator or computer system, may determine a problem exists if the load cells indicate that, although sufficient dry gel in present in the bulk tank  130  based on the loads detected, the weight of the bulk tank  130  is not changing despite the fact that the conveyors  190 ,  200 , and  220  are operating. Thus, although the conveyor  220  is operating and, therefore, indicating delivery of a specified amount of dry gel, the unchanging loads measured by the load cells  240  indicate that no dry gel is being output from the bulk tank  130  and that a problem exists, requiring corrective action. Further, the rate of weight decrease measured by the load cells  230  may be compared to the specified output of the conveyor  220  to determine if the conveyor  220  is properly calibrated. 
         [0023]    FIGS.  5  and  7 - 8  illustrate a gel concentrate mixing system (“mixing system”)  250  of the apparatus  20  according to one implementation. The mixing system  250  includes a hydration tank  260 , a piping system  270 , a suction pump  280 , and the gel mixer  290 . According to the implementation shown in  FIG. 5 , the piping system  270  includes a plurality of valves (valves  300 - 440 ) to direct the flow of materials through the mixing system  250  according to the needs or desires of an operator. However, the mixing system  250  may include a different quantity of valves and may include a different piping layout than the one illustrated in FIGS.  5  and  7 - 8  while still being within the scope of the present disclosure. According to another implementation, the mixing system  250  is capable of producing both a gel concentrate as well a finished gel. 
         [0024]    A liquid, such as water, is introduced into the mixing system  250  via one or more fittings  460 . The liquid may be provided from the liquid source  30  (shown in  FIG. 1 ). Optionally, gel liquid may also be introduced through one or more fittings  470 . If only fittings  460  are used, the valve  310  is closed to prevent the gel liquid from flowing towards the hydration tank  260 , as indicated by arrow  480 . If gel liquid is introduced from one or more of the fittings  460  and  470 , valves  300  and  330  are closed and valve  310  is opened. The valve  320  is also opened so that the liquid may be pumped via the suction pump  280  to the gel mixer  290 . According to one implementation, the suction pump is a 10×8 Gorman-Rupp pump manufactured by the Gorman-Rupp Company, P.O. Box 1217, Mansfield, Ohio 44901, however, it is within the scope of the disclosure that other pumps may be used. The suction pump  280  and the gel mixer  290  may be powered by the power source  100 . 
         [0025]    The liquid flows through a flowmeter  490 , such as a magnetic flowmeter, to determine the flowrate of the liquid introduced into the mixing system  240  and is then conveyed to the gel mixer  290 . Valve  420  may be opened to introduce liquid into the gel mixer  290  at a first location  500  of the gel mixer  290 . Similarly, the valve  410  may also be opened to introduce liquid into a second location  510  of the gel mixer  290 . Valves  410  and  420  may be manipulated so that liquid is introduced in only one of the first or second locations  500 ,  510  or both valves  410  and  420  may be opened to permit the liquid to be introduced at both the first and second locations  500  and  510 . Dry gel exiting from the outlet  230  of the handling system  120  enters the gel mixer  290  through an opening  520 . There the dry gel is mixed with the liquid to form a gel concentrate. Although the system  10  is capable of producing both a completed gel and gel concentrate, production of a gel concentrate, as opposed to a completed gel, provides significant advantages. For example, as described below, producing a gel concentrate can enable significantly improving the reaction time between changing the properties of the gel produced and the time delay after which a modified gel is introduced into the well. Other advantages are described below. 
         [0026]    The gel mixer  290  agitates and blends the dry gel and liquid. In one implementation the agitating and blending is preformed using an impeller as the two components are combined. Consequently, the blending causes a faster, more thorough mixing as well as increases the surface area of the dry gel particles so that the particles are wetted more quickly. Thus, the gel concentrate production time is decreased. Further, this type of gel mixer  290  is capable of mixing the dry gel and liquid at any rate or ratio. Thus, when producing a gel concentrate, as opposed to a finished gel, a reduced amount of liquid is used and, hence, the gel concentrate is produced more quickly. According to one implementation, the gel mixer  290  is of a type described in U.S. Pat. No. 7,048,432, the entirety of which is incorporated herein by reference. 
         [0027]    Conversely, eductors presently utilized to form a fracturing gel are specifically sized for mixing materials at a single, specified ratio. Thus, in order to change the mixing ratio, one eductor had to be removed and a new eductor installed, requiring substantial delay and large manpower requirements to effect the mixing ratio change. Accordingly, presently available eductors are not operable to change a mix ratio of a gel on the fly. Consequently, the present disclosure provides a system for improved flexibility and responsiveness to the requirements of a given well. 
         [0028]    As shown in  FIGS. 7 and 8 , the first location liquid inlet  500  and the gel concentrate outlet are concentric, wherein the gel concentrate exits at  520  while the liquid enters at  500  through an annulus formed between an outer pipe and an inner pipe transporting the gel concentrate. However, other implementations may use a gel outlet that is separate from the liquid inlets of the gel mixer  290 . 
         [0029]    The gel concentrate is then directed through a metering valve  430  to control an amount of gel concentrate exiting the gel mixer and, hence, an amount of gel concentrate produced by the apparatus  20 . After exiting the metering valve  430 , other additives may be added to the gel concentrate at apertures  550 . Various additives may be introduced to change the chemical or physical properties of the gel concentrate as required, for example, by the geology of the well formation and reservoir. The gel concentrate is then conveyed through one of pipes  530  or  540  and into the hydration tank  260 . The gel concentrate may be made to flow along either of pipes  530  or  540  as required or desired. 
         [0030]    Once the gel concentrate has entered the hydration tank  260 , the gel concentrate passes through a serpentine path formed by a series of weirs  560  contained within the hydration tank  260 . According to one implementation, the interior of the hydration tank  260  includes a plurality of weirs  560  in a spaced, parallel relationship to establish a flow between one of the pipes  530 ,  540  and one of the outlets  580 ,  590 . As a result of the shape and placement of the weirs  560 , the flow of the gel concentrate through the hydration tank  260  forms a zig-zag shape both in vertical plane and in a horizontal plane. Accordingly, the weirs provide for an extended transient period during which the gel concentrate travels through the hydration tank  260 . The hydration tank  260  may also include one or more flow divider screens  570  (shown in  FIG. 9 ). The hydration tank  260  allows the gel concentration (and completed gel, where applicable) to hydrate as the gel concentrate passes therethrough. According to one implementation, the hydration tank  260  is of a type described in U.S. Pat. No. 6,817,376, the entirety of which is incorporated herein by reference. 
         [0031]    After passing through the hydration tank  260 , the gel concentrate is released from the tank from an outlet. Two outlets are provided in the implementation shown in FIGS.  5  and  7 - 9 , although other implementations may include more or fewer outlets. The outlet used to release the gel concentrate may depend upon the location where the gel entered the hydration tank  260 . For example, if the gel concentrate entered the hydration tank through the pipe  530 , the gel concentrate may be released from outlet  580  when valve  300  is opened. The gel concentrate may then be released from the mixing system  250  via the fittings  470 . Alternately, if the gel concentrate entered the hydration tank  260  via the pipe  540 , the gel concentrate may leave the hydration tank  260  through the outlet  590 . The gel concentrate may then be released from the mixing system  250  through fittings  600  when valve  380  is closed and valves  440  and  590  are opened. Discharging the gel concentrate through the portion of the mixing system  250  including the fittings  600  is advantageous because the flowrate of the gel concentrate can be better controlled, as explained below. Accordingly, the hydration tank  260  is ambidextrous, providing added flexibility to the apparatus  20 . This is especially useful on a worksite that may have space limitations and repositioning the apparatus  20  is not convenient or possible. Thus, the apparatus  20 , such as the apparatus shown in  FIG. 2 , may be positioned only once on a work site without regard to orientation. 
         [0032]    The ambidextrous quality of the apparatus  20  is further illustrated by the two transverse pipes  640  and  650  extending between the longitudinal pipes  660  and  670 , as illustrated in  FIG. 5 . Thus, rather than inputting the liquid into the apparatus at the fixtures  460  and/or  470 , the liquid may be input at fittings  630  (and  620 , if desired, by opening valve  400  and closing valve  390 ). The liquid is then conveyed to the suction pump  280  by closing the valves  400  (if liquid is only being supplied to fittings  650 ) and  320 . The liquid may be combined with the dry gel as described above and directed to the hydration tank  260  as also described above. 
         [0033]    Further, the finished gel may be released directly after being produced by the gel mixer  290  through fittings  610  and/or  470  by opening one or more of valves  330  and  360  and closing valves  340  and  350 . Further, if desired, the finished gel could also be released via the fittings  460  and  620  by opening valves  310  and  390 , respectively, and closing valves  400  and  320 . Thus, the finished gel may be transported to an another holding tank or other location for subsequent use or processing. 
         [0034]    An additional advantage of the present disclosure is that the mixing system  250  is configurable into a First In/First Out (“FIFO”) configuration. Thus, as the gel concentrate is produced, the gel concentrate first to enter the hydration tank  260  is also the first gel concentrate to leave the hydration tank  260  after passing through the zig-zag path formed by the weirs  560  and divider screens  570 . As a result, the most hydrated gel concentrate is withdrawn from the mixing system  250  first. 
         [0035]    While the gel concentrate may be released from the apparatus  20  without any flow control, controlling the flow of gel concentrate out of the apparatus  20  may be desirable in some implementations. Accordingly, the mixing system  250  of the apparatus  20  may include a concentrate output system  680 , shown in  FIG. 11 . The concentrate output system  680  may include the valve  440  and the fittings  600  as well as a pump  690 , a flowmeter  700 , and a metering valve  710 . According to one implementation, the pump  690  is a Mission Magnum 8×6 centrifugal pump available from National Oilwell Varco, 10000 Richmond Ave., Houston, Tex. 77042, although the present disclosure is not so limited, and other pumps may be utilized. Additionally, the flowmeter  700  may be a number of possible different flow measuring devices, such as a Rosemount magnetic flowmeter available from Rosemount at 8200 Market Blvd., Chanhassen, Minn. 55317, and the metering valve  710  may be a number of possible different valves or mechanisms to throttle or meter the flow of the gel concentrate, such as a tub level valve. Similarly, flowmeter  700  and metering valve  710  are not limited to the examples provided but may be any device operable to measure and control the flowrate of the gel concentrate, respectively. The pump  690 , flowmeter  700 , and the metering valve  710  may provide for a constant, specified flowrate of the gel concentrate that can be dynamically changed on the fly, for example, depending on the changing needs of a well fracturing operation. The gel concentrate may be directed to the concentrate output system by opening valve  440  and closing valve  380 , as shown in  FIG. 5 . The gel concentrate output system  680  provides for a controlled output of the gel concentrate in which a control unit  730  (described in greater detail below) may monitor the flowrate of the gel concentrate with an output from the flowmeter  700 . The control unit  730  may then increase or decrease the pumping rate of the pump  690  to maintain a specified flow of the gel concentrate. 
         [0036]    After leaving the apparatus  20 , the gel concentrate is transported to the blender apparatus  50  where the gel concentrate is combined with additional liquid and sand from the liquid source  30  and sand source  40 , respectively. The blender apparatus  50  agitates and combines the ingredients to quickly produce a finished gel and sand mixture that is subsequently injected into the well  60 . Thus, when the gel concentrate and liquid are blended in the blender apparatus, the combination dilutes quickly to form a finished gel. 
         [0037]    The system  10  may also include a control system  720 , shown in  FIG. 10 , for accurately measuring and controlling the rate and properties of the gel being injected into the well  60 . The control system  720  may include control unit  730  having a processor  740 , memory  750 , application  760 , and information  770 . 
         [0038]    The control unit  730  may be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structural means disclosed in this specification and structural equivalents thereof, or in combinations of them. The control unit  730  can be implemented as one or more computer program products, i.e., one or more computer programs tangibly embodied in an information carrier, e.g., in a machine readable storage device or in a propagated signal, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program (also known as a program, software, software application, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file. A program can be stored in a portion of a file that holds other programs or data, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network. 
         [0039]    Processor  740  executes instructions and manipulates data to perform the operations and may be, for example, a central processing unit (CPU), a blade, an application specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). Although  FIG. 10  illustrates a single processor  740 , multiple processors may be used according to particular needs and reference to processor  740  is meant to include multiple processors where applicable. Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, the processor will receive instructions and data from ROM or RAM or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of nonvolatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. In the illustrated embodiment, processor  740  executes application  760 . 
         [0040]    Memory  750  may include any memory or database module and may take the form of volatile or non-volatile memory including, without limitation, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable local or remote memory component. Illustrated memory  750  may include application data for one or more applications, as well as data involving VPN applications or services, firewall policies, a security or access log, print or other reporting files, HTML files or templates, related or unrelated software applications or sub-systems, and others. Consequently, memory  750  may also be considered a repository of data, such as a local data repository for one or more applications. 
         [0041]    The control system  720  may also include an output device  780 , such as a display device, e.g., a cathode ray tube (“CRT”) or LCD (liquid crystal display) monitor, for displaying information to the user as well as an input device  790 , such as a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well to provide the user with feedback. For example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. 
         [0042]    The application  760  is any application, program, module, process, or other software that may utilize, change, delete, generate, or is otherwise associated with the data and/or information  770  associated with one or more control operations of the system  10 . “Software” may include software, firmware, wired or programmed hardware, or any combination thereof as appropriate. Indeed, application  760  may be written or described in any appropriate computer language including C, C++, Java, Visual Basic, assembler, Perl, any suitable version of 4GL, as well as others. It will be understood that, while application  760  may include numerous sub-modules, application  760  may instead be a single multi-tasked module that implements the various features and functionality through various objects, methods, or other processes. Further, while illustrated as internal to control unit  730 , one or more processes associated with application  760  may be stored, referenced, or executed remotely (e.g., via a wired or wireless connection). For example, a portion of application  760  may be a web service that is remotely called, while another portion of application  760  may be an interface object bundled for processing at remote client  800 . Moreover, application  760  may be a child or sub-module of another software module or application (not illustrated). Indeed, application  760  may be a hosted solution that allows multiple parties in different portions of the process to perform the respective processing. 
         [0043]    The control system  720  receives information from numerous sources and control various operations of the system  10 . According to one implementation, the control unit  730  monitors and controls the dry gel handling system  120  by receiving data from the load cells  240  and the second horizontal conveyor  220 . Because the rate at which the second horizontal conveyor  220  is able to deliver the dry gel to the gel mixer  290  when the hopper  210  if maintained in a full condition is known, the control unit  730  can confirm that the dry system  120  is operating properly by monitoring the change in the output from the load cells  240 . If the output from the load cells  240  are not changing over time or if the changes are less than expected (based on the known output rate at which the second horizontal conveyor  220  when operational), the control unit  720  may issue a warning, such as by illuminating a light or placing a message on a screen, or stop the operation of a portion or all of the apparatus  20  or any other portion of the system  10 . 
         [0044]    The control unit  730  may also control and monitor an amount of liquid delivered to the gel mixer  290 , for example, to produce a gel concentrate of a defined mix ratio. According to one implementation, the control unit  730  receives flowrate information of the liquid from the flowmeter  490 . The control unit  730  may then control the flow of the liquid at a specified set point by adjusting the pump speed of the suction pump  280 . For example, if the flowrate of the liquid delivered to the gel mixer  290  is below the set point, the control unit  730  may increase pump speed to increase the flowrate of liquid. Conversely, if the flowrate of liquid delivered to the gel mixer  290  is too high, the control unit  730  may reduce the pump speed of the suction pump  280  to reduce the flowrate of the liquid. Accordingly, by controlling the weight of dry gel and liquid delivered to the gel mixer  290 , the control unit  730  is capable of monitoring and controlling the mixing ratio and, hence, weight of the gel concentrate exiting the gel mixer  290 . 
         [0045]    The control unit  730  may also control the flow of the gel concentrate exiting the gel mixer  290  by adjusting the metering valve  430 . Adjusting the output of gel concentrate from the gel mixer  290  via the metering valve  430  may be utilized to control a level of the gel concentrate in the hydration tank  260 . Thus, the flow of gel concentrate to the hydration tank  260  may be increased or decreased depending on the outflow rate of gel concentrate from the hydration tank to maintain a desired or specified level of gel within the hydration tank. Concurrent with adjusting the outflow rate of gel concentrate from the gel mixer  290  with the metering valve  430 , the control unit  730  may also adjust the suction pump  280  speed and the second horizontal conveyor  220  feed rate to control an amount of liquid and dry gel, respectively, being supplied to the gel mixer  290 . 
         [0046]    The control unit  730  may also be utilized to control the final mix ratio of the finished gel. Referring again to  FIG. 1 , the liquid source  30  provides a liquid to both the apparatus  20  as well as the blender apparatus  50 . The apparatus  20  provides the gel concentrate to the blender apparatus  50 . According to one implementation, the liquid source  30  provides a constant or substantially constant flow of liquid to the blender apparatus  50 . Therefore, to maintain a specified mixture ratio of liquid to gel concentrate so that a gel having desired properties (such as a required viscosity) is produced, the control unit  730  adjusts the metering valve  710  of the concentrate output system  680  (shown in  FIG. 11 ) to control the amount of gel concentrate provided to the blender apparatus  50 . Referring to  FIG. 10 , the control unit  730  receives a flowrate measurement of the gel concentrate from the flowmeter  700  and controls the output of the gel concentrate, e.g., increases or decreases the gel concentrate flowrate from the hydration tank  260 , by adjusting the metering valve  710 . Additionally, sand from the sand source  40  may be added to the blender apparatus  50  where the liquid, gel concentrate, and sand are mixed to form the gel, which is subsequently injected into the well  60 , for example, to perform a fracturing operation on the well  60 . 
         [0047]    According to other implementations, the control unit  730  may control the formation of gel utilizing the gel concentrate without monitoring the gel concentrate level in the hydration tank  260 . This may be accomplished by monitoring the flowrate of gel concentrate exiting the concentrate output system  680  via the flowmeter  700  while also monitoring the flow of gel concentrate out of the gel mixer  290 . Because gel concentrate into the hydration tank  260  must equal the gel concentrate out of the hydration tank  260  to maintain continuity, i.e., maintain the gel concentrate within the hydration tank at a specified level, the control unit  730  may ensure that the hydration tank  260  maintains a minimum or specified level without having to directly monitor the hydration tank  260 . To maintain continuity, the control unit  730  may control the outlet of the gel concentrate with the metering valve  710  (shown in  FIGS. 5 and 11 ) and the inlet of gel concentrate with pump speed of the suction pump  280  and the metering valve  430 . 
         [0048]    According to other implementations, the control system  720  may monitor and/or control more or fewer operations of the system  10 , such as the amount of additives  70  introduced into the dry gel at the nozzles  550  or an amount of liquid from the liquid source  30  delivered to the blender apparatus  50 . 
         [0049]    According to further implementations, the control system  10  may be remotely monitored and manipulated with the control system  720  via wired or wireless connection at a remote location, such as remote client  800 , shown in  FIG. 10 . Thus, a user located at a separate location may be able to monitor and control the system  10  over the Internet, for example. 
         [0050]    The apparatus  20  may also be capable of producing gel directly, as shown in  FIG. 12 . The completed gel may be produced in a manner similar to the process described above, except that a greater volume of liquid, e.g., water, is combined with the dry gel when the two components are mixed together at the gel mixer  290 . As illustrated, liquid is provided from the liquid source  20  only to the apparatus. That is, no liquid is provided to the blender apparatus  50  for the purpose of combining with the gel. Additives  70  may also be provided to the apparatus  20  for inclusion in the gel. After the gel is produced by the apparatus  20 , the gel is conveyed to the blender apparatus  20  and combined with sand from sand source  40 . Moreover, the direct gel production method has the added disadvantage that any required change in properties of the gel, such as viscosity, do not take effect immediately. Rather, the already produced gel contained in the hydration tank  260  acts as a buffer and mixes with the newly produced gel at a different viscosity until the already produced gel is consumed. According to one implementation, an external hydration tank has a working volume of 500 barrels (bbl). This volume equates to roughly one hour&#39;s worth of use in a fracturing operation, which, on the average, may run about four hours. Therefore, in order to affect a change in viscosity of the directly produced gel, operators must wait approximately one quarter of the total time of the well fracturing operation before any changes are seen down well. Accordingly, responsiveness to changes in gel formed by a direct gel production operation is very low. 
         [0051]    On the contrary, gel produced using a gel concentrate, requires significantly less total time. For example, in one implementation, forming the gel from the gel concentrate in the blender apparatus  50  prior to injection into the well produces the resulting gel almost instantaneously. Thus, any changes in gel properties, such a change in the gel viscosity, may be made on the fly by changing a ratio of the gel concentrate and liquid combined in the blender apparatus  50 . Thus, fracturing operations using a gel made from gel concentrate may be performed more efficiently since changes in properties (e.g., viscosity) may be changed substantially instantaneously with injection of the gel into the well, eliminating the time lag between using up a batch of gel having one set of properties and the start of the use of a new batch of gel having a different, desired set of properties. 
         [0052]    Additionally, the gel produced using a gel concentrate does not require the addition of any hydrocarbon carriers, such as liquid gel concentrate (LGC), surfactants, or thickening agents. Thus, the gel may be produced with only a dry gel polymer and a liquid, such as water. Accordingly, the gel produced by the system and method of the present disclosure is less expensive due to the elimination of any other required materials and provides for a smaller environmental impact. 
         [0053]    A number of implementations of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other implementations are within the scope of the following claims.