WO2015076787A1

WO2015076787A1 - Dry gel hopper

Info

Publication number: WO2015076787A1
Application number: PCT/US2013/070795
Authority: WO
Inventors: William Stewart; Brian PARR
Original assignee: Surefire Usa, Llc
Priority date: 2013-11-19
Filing date: 2013-11-19
Publication date: 2015-05-28

Abstract

Apparatuses and methods of preventing moisture contamination and loss of dry gel powder used in on site fracturing operations are disclosed. Apparatuses include specialized hoppers to prevent contamination of surrounding equipment with dry gel powder.

Description

DRY GEL HOPPER

FIELD

[0001] The present disclosure relates to methods of manufacturing hydraulic fracturing fluid. BACKGROUND

[0002] Specialized fluid systems have been developed in the commercial fracking industry used for pumping the fracturing fluid into the wellbore at a rate sufficient to increase pressure downhole at the target zone (determined by the location of the well casing perforations) to exceed that of the fracture gradient (pressure gradient) of the rock.

[0003] These fluids are designed to implement a treatment according to design in order to help increase production and improve a return on investment. In general, the development of these fluid designs has been based on certain key parameters such as: fluid type, viscosity requirements, fluid rheology, cost, geologic formation type, material availability and proppant selection.

[0004] Fluid systems optimized to these parameters can result in minimized formation and fracture face damage for maximized results. Linear gel fracturing fluids are typically formulated with a wide variety of different polymers in an aqueous base. Polymers that are commonly used to formulate these linear gels include guar, hydroxypropyl guar (HPG), carboxymethyl HPG, and hydroxyethyl cellulose. These polymers are dry powders that hydrate or swell when mixed with an aqueous solution and form a viscous gel. Other types of fracturing fluids include gelled oil fluids are a viscous gelled oil system for fracturing that minimizes the possibility of damage in certain formations such as particle migration resulting from water contacting clay. Still another form of fracturing fluids includes foamed fracturing fluids. Such fluids typically contain the liquid phase of a fluid system, a foaming agent and a gas such as nitrogen or carbon dioxide. Foamed fluids can be applied to virtually all types of oil and gas wells over a wide range of pressure. Its low liquid content leaves less liquid to remove from the well. The gel in the foams can be crosslinked for higher viscosity as well. [0005] Liquid gel concentrates are concentrated liquid slurries prepared with polymers. Since the concentrated polymers are in liquid form, the handling and mixing of dry, powered material at the wellhead is eliminated. Liquid gel concentrates can also be added to an already hydrated gel to adjust the viscosity of the existing gel. Further, it can be added to water and premixed as the fluid is being pumped such that the viscosity can be controlled while the treatment is being pumped.

[0006] Conventional blending devices blend various types of solid particulate ingredients, such as dry gel powder. These devices typically include a number of ingredient hoppers, each of which discharges ingredients into individual metering units. These metering units typically include a metering auger, the rotational speed of which can be varied to control the flow rate of the individual ingredients. The metering units typically discharge, or feed, individual ingredients into some sort of common hopper at independently controllable feed rates which can be varied to produce and control the desired blend of individual ingredients. A metering unit, particularly of a batch blender, may also consist of a gate mechanism, the opening time of which can be varied to control the amount of material fed of an individual ingredients.

[0007] Guar and guar based substances used as dry gels for the preparation of hydraulic fracturing fluid are in a powder or granule form prior to mixing. Due to the high surface area of the guar based substances, they are easily dissolvable in water to create the hydraulic fracturing fluid. However, these same properties can cause problems due to moisture contamination during storage.

[0008] One disadvantage of hoppers used in the manufacture of fluid for hydraulic fracturing is that the dry gel used can become sticky, thus impeding cleaning of the mixing equipment. Another disadvantage of conventional hoppers used in the manufacturing of fluid for hydraulic fracturing is that the dry gel, when exposed to moisture, can clump within the hopper. In doing so, the dry gel can either become stuck in the hopper or the clumps can inhibit proper metering of the dry gel into a mixing system for producing a hydraulic fracturing gel with proper viscosity.

[0009] Hydraulic fracturing often takes place in remote areas, where equipment must be brought in by trailers. In such instances, a hydraulic fracturing fluid producing trailer can be used to mix the properly viscous fluid on site. However, such trailers often have a hydration tank either within the mixing apparatus or situated on an adjacent trailer. Due to the proximity of hydration tanks for mixing dry gel from hoppers to generate a viscous hydraulic fracturing fluid, the hopper can be exposed to spray, humidity or other moisture such as weather conditions which produce rain, snow, fog and other elements.

[0010] It would therefore be desirable to develop a method or device to prevent contamination of a dry gel used in on site hydraulic fracturing fluid preparation from contamination by unwanted moisture.

SUMMARY

[0011] Certain embodiments of the invention pertain to a dry gel dispensing hopper comprising: a hopper body with external walls facing an outside atmosphere and hopper inside walls facing a hopper interior, the hopper having a distal end and a proximal end; a lid abutting the distal end of the hopper; a filter abutting the lid, the filter fluidly connecting the hopper interior to the outside atmosphere; a reverse flow air line fluidly connected to the hopper interior through the filter; a dry gel entry port and a dry gel exit port, the dry gel entry port being distal to the dry gel exit port; and wherein dry gel entering the hopper interior creates a positive pressure resulting in at least some dry gel powder being trapped in the filter, and wherein the reverse flow air line pumps a gas through the filter to release the dry gel powder trapped in the filter back into the hopper interior.

[0012] In embodiments, concerning pumping gas through the dry gel air line, in some embodiments an operator manually pumps gas through the reverse flow air line. In other embodiments, the hopper comprises a pressure sensor wherein the pressure sensor sends a signal to the reverse air flow line to pump the gas. In such embodiments, signal can be sent to the reverse air flow line when the pressure in the hopper interior is positive. In other embodiments, the signal can be sent when the pressure is ambient or negative in the hopper.

[0013] In embodiments concerning the filter, in certain cases, the filter is contained in a vent housing. In such embodiments, the reverse flow air line is attached to the vent housing and is distal to the filter. [0014] Certain further embodiments concern methods of keeping the hopper inside walls from having clumping dry gel powder that does not exit the hopper properly. In such instances wherein the dry gel powder does not exit the hopper properly, the hopper can weigh too much, thereby providing inaccurate results upon attempting to mix the dry gel powder into a hydraulic fracturing fluid producing system. In certain embodiments, the hopper therefore comprises an air blanket between the dry gel and the hopper inside walls. In such embodiments, air blanket allows for circulation within the air blanket and the dry gel. Further, regarding the air blanket, the portion of the air blanket facing the inside walls is not penetrable by the dry gel. In other embodiments, in lieu of an air blanket, the hopper inside walls are coated with a non-stick coating.

[0015] Further regarding moisture contamination, the dry gel is pumped into the hopper without exposure to the outside atmosphere. Still further, in certain embodiments, the dry gel exit port is operatively connected to a belt feeder with a water tight enclosure.

[0016] Other embodiments of the invention pertain to a method of preventing moisture contamination and loss of dry gel used in hydraulic fracturing, the method comprising: a hopper body with external walls facing an outside atmosphere and hopper inside walls facing a hopper interior, the hopper having a distal end and a proximal end; a lid abutting the distal end of the hopper; a filter abutting the lid, the filter fluidly connecting the hopper interior to the outside atmosphere, the filter being enclosed by a vent housing; a reverse flow air line fluidly connected to the hopper interior through the filter; a dry gel entry port and a dry gel exit port, the dry gel entry port being distal to the dry gel exit port; and wherein a dry gel is pumped into the dry hopper inside pumped without exposure to the outside atmosphere, creating a positive pressure and wherein at least some dry gel powder is trapped by the filter, thereby preventing escape of dry gel from being exposed to moisture, and wherein gas is pumped into the reverse flow air line, pushing the trapped dry gel powder back proximally into the hopper.

[0017] In such methods, in certain embodiments, the hopper further has a pressure sensor installed. In some embodiments, the pressure sensor sends a signal to the reverse flow line to pump the gas. The signal can be initiated upon a set positive pressure such as 15-30 p.s.i. or some derivation therein. In other embodiments the signal can be initiated when the pressure inside the hopper is ambient or negative with the outside atmosphere. In still further embodiments, the operator can manually pump air into the reverse flow line independent of a pressure sensor signal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order that the manner in which the above-recited and other enhancements and objects of the invention are obtained, we briefly describe a more particular description of the invention briefly rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope, we herein describe the invention with additional specificity and detail through the use of the accompanying drawings in which:

[0019] Fig. 1 is an illustration of the dry gel hopper of the present invention;

[0020] Fig. 2 is an illustration of the trailer of the present invention;

[0021] Fig. 3 is an alternate view of the hopper; and

[0022] Fig. 4 is an illustration of the air blanket in relation to the hopper.

List of Reference Numerals

[0023] 1 dry gel hopper

[0024] 2 hopper lid

[0025] 3 first hopper inlet pipe

[0026] 4 butterfly valve

[0027] 5 hopper window

[0028] 6 butterfly valve handle

[0029] 7 hopper inlet connection [0030] 8 coupling

[0031] 9 second hopper inlet pipe

[0032] 10 first hopper mount

[0033] 11 second hopper mount

[0034] 12 hinge

[0035] 13 hopper lid

[0036] 14 self-cleaning bin vent

[0037] 15 resistive load cell

[0038] 16 hopper pivot mount

[0039] 17 hopper safety catch

[0040] 18 clamp

[0041] 21 quick vent valve

[0042] 22 belt driven feeder

[0043] 24 powder valve assembly

[0044] 32 belt feeder cover

[0045] 34 resistive load cell

[0046] 35 dry gel bucket test hangar

[0047] 36 test bucket

[0048] 37 eductor funnel

[0049] 44 trailer [0050] 45 engine

[0051] 46 hydration tank

[0052] 47 air blanket

[0053] 48 hopper internal sides

[0054] 49 hopper lid support

[0055] 50 reverse flow air line

DETAILED DESCRIPTION

[0056] The following definitions and explanations are meant and intended to be controlling in any future construction unless clearly and unambiguously modified in the following examples or when application of the meaning renders any construction meaningless or essentially meaningless. In cases where the construction of the term would render it meaningless or essentially meaningless, the definition should be taken from Webster's Dictionary 3 rd Edition.

[0057] As used herein, the term "pipe" means and refers to a fluid flow path.

[0058] As used herein, the term "line" means and refers to a fluid flow path.

[0059] As used herein, the term "fluid" refers to a non-solid material such as a gas, a liquid or a colloidal suspension capable of being transported through a pipe, line or conduit. Examples of fluids include by way of non-limiting examples the following: natural gas, propane, butane, gasoline, crude oil, mud, water, nitrogen, sulfuric acid and the like.

[0060] As used herein, the term "attached," or any conjugation thereof describes and refers to the at least partial connection of two items.

[0061] As used herein, the term "proximal" refers to a direction toward the belt feeder. [0062] As used herein, the term "distal" refers to a direction away from the belt feeder. [0063] Embodiments [0064] Certain embodiments of the invention pertain to apparatuses and methods of premixing of a dry gel hopper for delivery of guar and guar derivatives to a system for generating viscous hydraulic fracturing fluid. In further embodiments of the invention, the dry gel is guar or a complex of guar such as hydroxypropyl guar (HPG), carboxymethyl HPG or a combination thereof. Certain further embodiments of the invention pertain to a dry gel hopper which can deliver the aforementioned dry gel to an educator for making a viscous hydraulic fracturing fluid while preventing moisture from contaminating the dry gel.

[0065] In specific embodiments, the invention pertains to apparatuses and methods employed on site at a hydraulic fracturing location.

[0066] Specific embodiments of the invention concern a hopper. The hopper is comprised of any durable material such as a ceramic, a plastic, a metal and the like. In more specific embodiments, the durable material is a steel.

[0067] Further embodiments of the invention concern a self-cleaning bin vent. In such embodiments, the self-cleaning bin vent is distal to the hopper and in fluid connection with the inside of the hopper. In certain specific embodiments the self-cleaning bin vent is comprised of any durable material such as a ceramic, a plastic, a metal and the like. In more specific embodiments, the durable material is a steel.

[0068] In further aspects of the invention, the dry gel, when entering the hopper, generates a large amount of dust. As a precaution, the bin vent system is used to allow the pressure incurred by filling the hopper to evacuate without the dry gel powder leaving.

[0069] Due to the filter system, closed hopper design, and closed belt feeder design, the hopper internals stay free of moisture. Moreover, the external portions of the hopper stay free of dry gel residue due to the bin vent system.

[0070] In further embodiments concerning the self-cleaning bin vent, the bin vent has an internal filter system. The internal filter system comprises cloth, fiberglass, cotton, wool, steel wool, silk, paper derivatives, a foam or combinations thereof. In certain further embodiments, distal to the internal filter system is a reverse flow air-line. In such embodiments, the reverse flow air line provides positive pressure to the self-cleaning bin vent. In further embodiments, the reverse flow air line provides positive pressure to the self-cleaning bin vent to push fine dry gel powder, caught in the filter, back into the hopper.

[0071] In still further embodiments concerning the self-cleaning bin vent, the reverse flow air line provides the positive pressure upon a signal from a pressure sensor located within the self- cleaning bin vent or the hopper. The signal can be set to provide air to the reverse flow air line and into the self-cleaning bin vent when one or more of the following conditions occur: the pressure in the hopper is negative compared to external air pressure, the pressure in the ambient compared to external air pressure, or the pressure is positive compared to external air pressure. In specific embodiments, the air flow is activated when the signal indicates a negative air pressure or an ambient air pressure in the hopper. In other embodiments, the signal is an electronic signal, a mechanical signal, an optical signal, an auditory signal or some combination thereof.

[0072] Further embodiments of the invention concern methods and apparatuses to keep guar or other dry gel powders from sticking to the hopper. In such embodiments, a hopper liner is used. In embodiments concerning the hopper liner, the liner is removable. In specific embodiments, the liner is made of plastic, Teflon, metal or a fibrous material. In more specific embodiments the liner is made of fibrous material.

[0073] In embodiments concerning the liner made of fibrous material, one example of a liner that can be employed is an air blanket. In such embodiments wherein an air blanket is used, the air blanket comprises fibrous material. In certain embodiments, the air blanket is replaceable. In further embodiments of the methods and apparatuses of the invention concerning the air blanket, guar or other dry gel powder is pumped into the hopper and held by the air blanket, such that the air blanket is between the dry gel powder and the internal side of the hopper walls. Further, in certain embodiments, the blanket has an outer side facing the internal hopper walls that is not able to be penetrated by dry gel powder. In such embodiments, air or other gas is able to flow through the powder and through the fibrous material comprising the air blanket which faces the dry powder.

[0074] In practice, an air blanket liner, in certain embodiments, is installed on the inside of the hopper providing constant dry filtered air to keep the guar from sticking to the sides of the wall. This provides constant circulation of the powder, drying of the powder and uniformity of the level of the powder itself. In certain embodiments, the dry filtered air is provided by at least one air inlet connected to an air source to provide air inside the hopper to promote circulation through the dry gel and into the air blanket.

[0075] In certain further embodiments, quick vent valve is also installed as a on the hopper to allow for external air to displace the volume of dry gel powder leaving the hopper to remain constant. In certain embodiments, this same vent also doubles as a backup for the bin vent that opens relieving pressure from the hopper in the advent of clogged filters not able to expel the air pressure from the hopper.

[0076] Other embodiments of the invention concern a belt feeder to remove dry gel powder from the proximal side of the hopper such that the dry gel can be delivered into a system to generate a viscous hydraulic fracturing fluid. In certain embodiments, the system consists of a water tight enclosure, a set of rollers, motor, belts, electronics and load cell.

[0077] In practice, the belt feeder is responsible for delivering the proper amount of dry belt powder from the hopper based on a calculated speed and weight. Together with the combined calculations of the amount of weight of guar and the flow rate of water being mixed a theoretical viscosity can be made. A viscometer taking a constant slip street test on the outlet of the hydration unit confirms whether or not more guar is to be added or subtracted there by slowing or speeding the delivery of the guar on the weigh belt up or down.

[0078] Further, in practice, the hopper is supported by hinges on the lower back side of the frame and sits on a set of load cells in the front. In certain embodiments, this allows the weight to be calculated. The user therefore knows the amount of dry gel, such as guar entering the hopper. The user also knows the amount of dry gel leaving the hopper and going into the hydraulic fluid producing system. For this, the hopper has a level gauge similar to that of a fuel gauge used in a car.

[0079] Fig. 1 is an illustration of the present invention depicting a hopper. As can be seen in the illustration, the dry gel hopper 1, at its distal side, has a windowed hopper lid 2. Adjacent to the hopper lid 2 is a hopper window 5 which allows a user to view the inside of the hopper and view the dry gel. Centered within the hopper lid, and extending distally, is the quick vent valve, which allows excess pressure to vent from the hopper. Centered within the hopper lid is a quick vent valve 21 to compensate for sudden changes in pressure if any. Distal to the hopper 1, and adjacent to and abutting the windowed hopper lid 2, is the second hopper lid 13. Extending distally from the second hopper lid 13 is the self-cleaning bin vent 14. The self-cleaning bin vent 14 possesses filters to prevent fine guar powder from escaping and coating the hopper and related machinery with gel residue. Attached to the self-cleaning bin vent 14, is a reverse flow air line 50, which, when sensing a pressure differential between the inside of the hopper 1 and the outside of the hopper, provides air to the self-cleaning bin vent 14 to push guar residue back into the hopper 1. Both the hopper lid 2 and the second hopper lid 13 are held onto the hopper 1 by clamps 18. The hopper lid is opened by a hinge 12 as depicted in Fig. 1.

[0080] Proximal to the hopper lid 2 and second hopper lid 13, and coming out of the dry gel hopper 1 on its near side is a first hopper inlet pipe 3 and a second hopper inlet pipe 9 to the hopper 1. The air source flowing to the first hopper inlet pipe 3 and the second hopper inlet pipe 9 is controlled by a butterfly valve 4, with a butterfly valve handle 6. Each of the first hopper inlet pipe 3 and a second hopper inlet pipe 9 connect to a hopper inlet connection 7 using a coupling 8. The hopper inlet pipe couplings 8 are connected to a source for guar or other dry gels. The dry guar powder is pumped into the hopper 1 through these pipes in order to prevent fine powder particulates from coating the outside of the hopper 1 through delivery by opening the hopper lid 2 and the second hopper lid 13 to deposit dry gel powder from above. Another advantage of supplying the dry gel from the first hopper inlet pipe 3 or the second hopper inlet pipe 9 is that the dry gel powder comes directly from a supply source with dry air. Thus, no moisture should arrive in the hopper through the delivery of the dry gel.

[0081] Also proximal to the hopper 1, is the powder valve assembly 24, which allows the guar or other dry gel powder to flow in a proximal direction from the hopper 1 holding the powder. From the powder valve assembly 24, the dry gel powder moves into the belt driven feeder 22. The belt driven feeder then drops the dry gel into the dry gel bucket tester 29 located proximally to the belt driven feeder 22. The dry gel bucket tester 29 comprises a test bucket 36, the distal end of which is connected to a dry gel bucket test hanger 35. The dry gel bucket test hanger is attached to a resistive load cell 34. [0082] As further exemplified in Fig. 1, the belt driven feeder 22 is used for metering the amount of guar powder from the hopper to the educator. This unique application provides significant advantages. The system consists of a water tight enclosure, a set of rollers, motor, belts, electronics and load cell. The weigh belt is responsible for delivering the proper amount of guar from the hopper based on a calculated speed and weight. Together with the combined calculations of the amount of weight of guar and the flow rate of water being mixed a theoretical viscosity can be made. A viscometer taking a constant slip street test on the outlet of the hydration unit confirms whether or not more guar is to be added or subtracted there by slowing or speeding the delivery of the guar on the weigh belt up or down.

[0083] Also seen in Fig. 1, which is the belt feeder cover 32, which can be used to access the belt feeder, and the eductor funnel 37. The eductor mixes the dry gel with the aqueous solution to generate a concentrated dry gel. As can be further seen, the hopper 1 is mounted on the first hopper mount 10 and the second hopper mount 11.

[0084] Fig. 2 is an illustration of the trailer of the present invention. The first hopper mount 10 and the second hopper mount 11 are thereby mounted on a trailer 44 as seen in Fig. 2. As can be further seen in Fig. 3, the hopper 1 is placed between the engine 45 and the hydration tank 46.

[0085] Fig. 3 is an alternate view of the hopper 1. Regarding the aforementioned self-cleaning bin vent 14, this unit has a reverse flow air line 50, which is seen protruding from the distal portion of the self-bin vent. In typical usage, as seen in Fig. 1, the self-cleaning bin vent 14, prevents the fine powdered guar dust or guar derivatives from exiting the hopper 1 during the process wherein the powder is pumped into the tank from the first hopper inlet pipe 3 and a second hopper inlet pipe 9. During the pumping process of placing the powder in the hopper 1, a positive pressure is exerted into the hopper 1. Without a proper vent, the dry powder can seep out of the windowed hopper lid 2 or the quick vent valve 21 can release fine powdered guar into the air, which can ultimately leave a gum residue on the fracturing equipment. Further, too much positive pressure can lead to excess guar deposited onto the belt driven feeder 22. It is contemplated that in the invention herein, the reverse flow air line is capable of using any gas which is non-reactive with the dry gel. Examples of such gas include nitrogen, oxygen, argon, neon, helium and the like. [0086] In practice, when there is positive pressure in the hopper 1, the fine powder guar is trapped by filters in the self-cleaning bin vent 14. When a pressure change occurs, such that the hopper 1 is ambient with outside pressure or negative compared to outside pressure, the reverse flow air-line 50 pushes air into the self-cleaning bin vent 14. This allows for the powder guar on the filter to be pushed back into the hopper 1 by the air pressure supplied by the reverse flow airline.

[0087] Fig. 4 is an illustration of the air blanket 47 in relation to the hopper 1. As indicated above, another feature to prevent guar contamination of the hopper 1 components is the use of an air blanket 47. As can be seen, the air blanket 47 is removable and is placed between the hopper internal sides 48 and any guar. As is further illustrated in Fig. 5, the air blanket 47 is retained by a hopper lid support 49.

[0088] In methods of using the aforementioned invention, the dry gel is dispersed by a hopper into a liquid medium in order to produce a concentrated gel from the dry gel.

[0089] The hopper is operatively attached to a belt feeder to move the dry gel from the container to a liquid medium.

[0090] The mixing of the dry gel with the liquid medium is performed by pouring the dry gel into the liquid, by sprinkling the dry gel into the liquid, by stirring the dry gel into the liquid, by spraying the dry gel into the liquid, by pouring the liquid onto the dry gel, by spraying the liquid onto the dry gel, by pumping the dry gel into the liquid, by using an eductor to mix the dry gel with the liquid to create a concentrated gel with a high viscosity.

[0091] Additional embodiments of the invention pertain to mixing the concentrated gel with further liquid to generate a correctly viscous liquid capable of being used in hydraulic fracturing operations. In such embodiments, the concentrated gel is pumped or pushed through pressure into a hydration tank. They hydration tank, in certain embodiments, already contains a liquid. In other embodiments, the concentrated gel is pumped into the hydration tank and then the liquid is pumped into the hydration tank. In still other embodiments, the concentrated gel is pumped into the hydration tank at the same time as the liquid. [0092] In embodiments wherein the concentrated gel is diluted in the hydration tank, the concentrated gel and liquid are mixed to add additional shear energy to the fluid. The mixing is accomplished by one or more shear baffle, a static mixer, one or more high shear paddles or a combination thereof.

[0093] Regarding the entry of liquid into the system to create the concentrated gel and the diluted gel, the liquid enters the process through an inlet manifold. The system comprises pipes to move liquid and gel from one location to another. The pipes are of any diameter necessary to produce the necessary amount of dilute gel for hydraulic fracturing operations. For instance, the pipes can have an internal diameter of 1 inch to three feet or some derivation therein. However, the diameter is not limited to this range.

[0094] To provide pressure to move the liquid or gel, a c pump is employed in the system. In such embodiments, the suction pump is employed downstream of the inlet manifold, but upstream from the eductor and hydration tank. In certain further embodiments, a water meter capable of detecting water pressure or water volume passing through the meter in a given time is positioned downstream of the pump, but upstream of a liquid path bifurcation.

[0095] This bifurcation allows liquid to flow into the hydration tank the eductor, or both the hydration tank and the eductor. In further embodiments, the eductor is positioned downstream of the bifurcation and upstream of the hydration tank.

[0096] To control the flow of liquid coming from the liquid path bifurcation, butterfly valves are used.

[0097] The valves are placed in the system wherever control or shutoff of the liquid or gel is desired. In certain embodiments, a valve is positioned downstream of the eductor so as to prevent concentrated gel from entering the hydration tank. In other embodiments, a valve is positioned downstream of the liquid path bifurcation wherein there is a direct inflow line connecting the liquid path bifurcation to the hydration tank. Still further, in embodiments concerning the flow of the viscous fluid from the hydration tank to be used in the fracturing operation, the hydration tank outlet line possesses a valve downstream of the hydration tank. [0098] In certain further embodiments, the viscosity of the diluted gel within the hydration tank is measured to determine if it is the correct viscosity for the fracturing operation. In such embodiments, the viscosity meter is within the hydration tank or fluidly connected to the hydration tank. In embodiments wherein the viscosity of the diluted gel is too low, the direct inflow line connecting the liquid path bifurcation to the hydration tank is shut off at a valve. Likewise, the upstream eductor line, carrying liquid from the liquid path bifurcation to the educator or the downstream eductor line, carrying liquid from the eductor to the hydration tank, or both, can have valves turned on to release concentrated gel into the hydration tank.

[0099] When the viscosity is too low in the hydration tank, the aforementioned procedure is reversed in certain embodiments.

[00100] In alternative embodiments, the hydration tank outlet line is connected to a recirculation line downstream of the hydration tank. In such embodiments, the recirculation line is positioned upstream of the hydration tank outlet line, which, in certain embodiments, is bifurcated between the recirculation line and a discharge manifold. The recirculation line is also positioned upstream of the pump of the system. To increase viscosity of the gel in the holding tank, access to the discharge manifold from the hydration tank outlet line is closed and the less than desirably viscous gel flows into the recirculation line which is opened such that the fluid recirculates through the system. Part of the less viscous gel returns to the hydration tank as before and another part flows into the eductor line to be mixed with dry gel to create a concentrated viscous gel.

[00101] In certain embodiments, once the viscosity meter, operatively connected to the hydration tank in certain embodiments, indicates that the viscosity of the liquid in the hydration tank is the desired viscosity, the valve in the recirculation line is closed and access to the discharge manifold from the hydration tank outlet line is opened.

[00102] In certain embodiments, the system disclosed herein is mounted on a truck trailer. In certain embodiments, the hydration tank possesses additive injectors to add different chemicals to the gel used for hydraulic fracturing. In certain other embodiments, the eductor line possesses additive injectors for this purpose. In additive or alternative embodiments, the direct inflow line possesses additive injectors for this purpose. [00103] From the foregoing description, one of ordinary skill in the art can easily ascertain the essential characteristics of this disclosure, and without departing from the spirit and scope thereof, can make various changes and modifications to adapt the disclosure to various usages and conditions. For example, we do not mean for references such as above, below, left, right, and the like to be limiting but rather as a guide for orientation of the referenced element to another element. A person of skill in the art should understand that certain of the above-described structures, functions, and operations of the above-described embodiments are not necessary to practice the present disclosure and are included in the description simply for completeness of an exemplary embodiment or embodiments. In addition, a person of skill in the art should understand that specific structures, functions, and operations set forth in the above-described referenced patents and publications can be practiced in conjunction with the present disclosure, but they are not essential to its practice.

[00104] The invention can be embodied in other specific forms without departing from its spirit or essential characteristics. A person of skill in the art should consider the described embodiments in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. A person of skill in the art should embrace, within their scope, all changes to the claims which come within the meaning and range of equivalency of the claims. Further, we hereby incorporate by reference, as if presented in their entirety, all published documents, patents, and applications mentioned herein.

Claims

CLAIMS We claim:

1. A dry gel dispensing hopper comprising: a. a hopper body with external walls facing an outside atmosphere and hopper inside walls facing a hopper interior, the hopper having a distal end and a proximal end; b. a lid abutting the distal end of the hopper; c. a filter abutting the lid, the filter fluidly connecting the hopper interior to the outside atmosphere; d. a reverse flow air line fluidly connected to the hopper interior through the filter; e. a dry gel entry port and a dry gel exit port, the dry gel entry port being distal to the dry gel exit port; and wherein dry gel entering the hopper interior creates a positive pressure resulting in at least some dry gel powder being trapped in the filter, and wherein the reverse flow air line pumps a gas through the filter to release the dry gel powder trapped in the filter back into the hopper interior.

2. The hopper of claim 1, wherein an operator manually pumps gas through the reverse flow air line.

3. The hopper of claim 1, further comprising a pressure sensor, wherein the pressure sensor sends a signal to the reverse air flow line to pump the gas.

4. The hopper of claim 3, wherein the signal is sent to the reverse air flow line when the pressure in the hopper interior is positive.

5. The hopper of claim 3, wherein the signal is sent to the reverse air flow line with the pressure in the hopper is negative or ambient to the outside atmosphere.

6. The hopper of claim 1, wherein the filter is contained in a vent housing.

7. The hopper of claim 1, wherein the reverse flow air line distal to the filter.

8. The hopper of claim 1, wherein the hopper further comprises an air blanket between the dry gel and the hopper inside walls.

9. The hopper of claim 8, wherein the air blanket allows for circulation within the air blanket and the dry gel.

10. The hopper of claim 8, wherein the portion of the air blanket facing the inside walls is not penetrable by the dry gel.

11. The hopper of claim 1, wherein the hopper inside walls are coated with a nonstick coating.

12. The hopper of claim 1, wherein the dry gel is pumped into the hopper without exposure to the outside atmosphere.

13. The hopper of claim 1, wherein the dry gel exit port is operatively connected to a belt feeder with a water tight enclosure.

14. The hopper of claim 1, wherein the hopper is operatively attached to a system for generating a hydraulic fracturing fluid.

15. A method of preventing moisture contamination and loss of dry gel used in hydraulic fracturing, the method comprising: a. a hopper body with external walls facing an outside atmosphere and hopper inside walls facing a hopper interior, the hopper having a distal end and a proximal end; b. a lid abutting the distal end of the hopper; c. a filter abutting the lid, the filter fluidly connecting the hopper interior to the outside atmosphere, the filter being enclosed by a vent housing; d. a reverse flow air line fluidly connected to the hopper interior through the filter; e. a dry gel entry port and a dry gel exit port, the dry gel entry port being distal to the dry gel exit port; and wherein a dry gel is pumped into the dry hopper inside pumped without exposure to the outside atmosphere, creating a positive pressure and wherein at least some dry gel powder is trapped by the filter, thereby preventing escape of dry gel from being exposed to moisture, and wherein gas is pumped into the reverse flow air line, pushing the trapped dry gel powder back proximally into the hopper.

16. The method of claim 15, wherein the hopper further has a pressure sensor installed.

17. The method of claim 15, wherein the pressure sensor sends a signal to the reverse flow line to pump the gas.

18. The method of claim 17, wherein the signal is initiated upon a set positive pressure.

19. The method of claim 17, wherein the signal is initiated upon signal that the pressure is ambient with the outside atmosphere or negative with respect to the outside atmosphere.

20. The method of claim 16, wherein an operator manually pumps air into the reverse flow air line.