Polymer dissolving equipment suitable for large-scale hydraulic fracturing operation

Abstract

A compact and transportable apparatus suitable for use in hydraulic fracturing operations on gas or oil fields, the apparatus comprising, in order: a mechanism for unloading powdered polymer, a mechanism for supplying polymer powder to a silo, a silo for storing polymer in powder form, and a means for storing polymer in powder form. The invention relates to a device for metering polymer powder, comprising a silo having a vertical screw located in a vertical duct inside, the lower end of the shaft of the vertical screw extending to the outside of the silo, a feed hopper of a polymer metering device, a device for dispensing the polymer powder, at least one tank for hydrating and dissolving the dispersed polymer from a dispersing and grinding device, at least one positive displacement pump capable of injecting and metering a polymer solution; the invention is characterized in that the lower end of the shaft of the vertical screw comprises a rotating ring which is vertically fixed on the shaft and is equipped with at least three straight blades positioned perpendicular to the horizontal plane of the ring.

Description

Technical Field

[0001] The present invention relates to a compact and transportable device suitable for use in fracturing operations on gas or oil fields in order to have a desired buffer powder volume. The device comprises a screw conveyor system for transporting fine powder to a feed hopper. More precisely, in the description below also referred to as a "screw conveyor system", it comprises an unloading logistics platform, a horizontal unloading screw and a silo. The silo contains a vertical pipe in which an upwardly extending vertical screw is located, the screw having specific features designed to improve the process of transporting fine powder in hydraulic fracturing operations. Background Art

[0002] In hydraulic fracturing operations, several key additives such as drag reducers are present in the form of fine powders. In fact, the choice of fine particles is particularly useful for achieving optimal performance in terms of viscosity enhancement and suspension effects in the injection fluid.

[0003] Fine particles are preferably obtained by sieving and / or grinding the powder after drying. Thus, in general, fine powder refers to a powdered raw material with a particle size smaller than that of ordinary powder, i.e. a particle size between 20 μm and 500 μm. Due to their particle size, fine powders are difficult to handle and transport.

[0004] The main object of the present invention is to optimize the flow characteristics of fine powders during transportation by using improved dedicated equipment.

[0005] CN103381339A discloses a compact device comprising a pneumatic mechanism for supplying a powdered polymer to a silo, a silo for storing the polymer in powdered form, a mechanism for conveying the polymer from the silo into a feed hopper, a feed hopper of a polymer metering device, a device for dispensing the powdered polymer, a device for dispersing and grinding the polymer (also known as a PSU (Polymer Slicing Unit)), and a tank for hydrating and dissolving the dispersed polymer.

[0006] The disclosed conveying system for transporting fine powders is a pneumatic system. Pneumatic systems can encounter problems such as clogging, bridging, and unstable flow patterns, resulting in inefficient operation and production downtime. In addition, they often suffer from problems such as air leaks, low energy efficiency, complex air handling, and high maintenance requirements.

[0007] CN102713131 A discloses a compact and transportable facility suitable for positioning on a trailer. The facility comprises in sequence a track with a crane to unload a 750 kg big bag, a hopper located below the big bag, a horizontal screw, a vertical hopper comprising a vertical screw which brings the powder fed by the previous screw into the hopper, an overflow pipe supplying the screw feeder, a dispersing device like a PSU (polymer slicing unit), a vertical tank to receive the suspension obtained in the dispersing device, and a positive displacement pump to inject and dose the polymer solution obtained at the suction port of the high-pressure pump for fracturing operations.

[0008] Such facilities have several disadvantages, such as processing speeds that are incompatible with large-scale recycling operations, the impossibility of large-scale supply during operation, and the difficulty in distributing and dispersing high concentrations of polymer.

[0009] The problem to be solved then was to develop an improved device that avoids interruptions during operation and uses a mechanical powder transport system instead of a pneumatic system. Summary of the invention

[0010] The present invention eliminates the need for cumbersome and complex pneumatic systems, which are associated with various disadvantages, and provides a radically different solution to the challenges faced in handling and transporting. In fact, the screw conveyor system of the present invention is intended to replace pneumatic fine powder transport systems with a more efficient and reliable solution by incorporating advanced features and optimized design elements.

[0011] The present invention provides significant advantages over conventional pneumatic systems. Notably, the improved vertical screw design solves these problems by incorporating advanced features that promote reliable and consistent powder flow, which is compatible with the storage of powders at high flow rates. The present invention also provides a reliable and low maintenance alternative, thereby reducing operating costs and downtime.

[0012] Another challenge of pneumatic transport is air handling to remove all fine particles and their hydrophobic properties. Since the transport is carried out under atmospheric conditions, the screw conveyor system of the present invention does not require air handling or dust filters.

[0013] In addition, the screw conveyor system is designed with ease of installation and maintenance in mind. In addition, the design enables direct access and cleaning, which reduces downtime and increases operational efficiency.

[0014] By optimizing powder flow, reducing blockages and improving overall system performance, the invention aims to set new standards for fine powder transport in hydraulic fracturing, thereby contributing to more sustainable and streamlined operations in the industry.

[0015] The present invention relates to a compact and transportable device suitable for use in hydraulic fracturing operations on gas or oil fields, comprising a mechanism for unloading a powdered polymer, a silo for storing the polymer in powdered form, a feed hopper, a device for dispensing the powdered polymer, a PSU, at least one tank for hydrating and dissolving the dispersed polymer, and at least one positive displacement pump capable of injecting and metering the polymer solution.

[0016] According to the invention, the interior of the silo contains a vertical screw located in a vertical duct, the lower end of the shaft of which extends to the outside of the silo and comprises a rotating ring fixed vertically on the shaft and equipped with at least 3 straight blades positioned perpendicular to the horizontal plane of the ring.

[0017] In fact, the blades ensure gentle and controlled fluidization of fine powders. These blades are designed to minimize powder compression and prevent agglomeration, allowing a smooth and uninterrupted flow. The blades ensure a consistent and controlled flow, minimizing powder degradation and particle breakage during transportation.

[0018] More precisely, the present invention relates to a compact and transportable device suitable for use in hydraulic fracturing operations on gas or oil fields, said device comprising in order:

[0019] - a mechanism for unloading powdered polymers with a size ranging from 20 to 500 micrometers (μm),

[0020] - a mechanism for supplying polymer powder to the silo,

[0021] - a silo for storing polymers in powder form, said silo having inside a vertical screw located in a vertical pipe, the lower end of the shaft of the vertical screw extending to the outside of the vertical pipe, the vertical pipe itself extending to the outside of the silo,

[0022] - feed hopper of the polymer metering device,

[0023] - a device for dispensing powdered polymers,

[0024] - an apparatus for dispersing and grinding a polymer, said apparatus comprising:

[0025] - a cone connected to the main water inlet circuit for wetting the powdered polymer,

[0026] - At the lower end of the cone:

[0027] - a grinding and discharge chamber for the dispersed polymer, comprising:

[0028] - a motor-driven rotor equipped with paddles,

[0029] - a fixed stator consisting of a cylinder equipped with fine slots,

[0030] - a ring supplied by a secondary water circuit, on all or part of the periphery of the chamber, the ring communicating with the chamber to ensure the spraying of pressurized water onto the outside of the stator, thus being able to release the ground and swollen polymer on the surface of the stator,

[0031] - at least one tank for hydrating and dissolving the dispersed polymer coming from the dispersing and grinding device,

[0032] - At least one positive displacement pump capable of injecting and metering the polymer solution.

[0033] The invention is characterized in that the lower end of the shaft of the vertical screw comprises a rotating ring fixed vertically on the shaft and equipped with at least 3 straight blades positioned perpendicularly to the horizontal plane of the ring.

[0034] To optimize the handling of different powder densities and flow rates, the vertical screw design incorporates side edges along its entire length.

[0035] In particular, the vertical screw has at least one of the following features:

[0036] - a length between 150 and 350 cm, preferably from 250 to 300 cm,

[0037] - a diameter between 100 mm and 350 mm, preferably from 150 mm to 250 mm,

[0038] - the pitch is between 75 and 150 mm, preferably from 90 to 130 mm,

[0039] - the height of the tooth tip of the tooth is between 5 and 30 mm,

[0040] - Input flow rate and output flow rate are between 1.8 and 3.2 T / hour, preferably from 2 to 2.8 T / hour.

[0041] Always with the same purpose of increasing the efficiency of processing different powders, the space between the vertical duct and the crest of the teeth of the screw is between 3 mm and 12 mm.

[0042] To further enhance performance, the vertical screw is treated with a special surface finish to reduce friction and improve powder flow.

[0043] In particular, the inner surface of the vertical duct and the vertical screw have a fluorinated thermosetting organic resin surface finish. This surface finish is specially formulated to minimize powder adhesion, thereby preventing buildup and blockage within the silo system. Advantageously, the resin is selected from the group comprising polytetrafluoroethylene, perfluoroalkoxy, fluorinated ethylene propylene and ethylene tetrafluoroethylene.

[0044] In order to guarantee a certain volume of available powder, i.e. to avoid interruptions during operation, the silo volume should be at least 5m 3 Such volumes are achieved thanks to a specific geometry.

[0045] According to one particular embodiment, the silo is horizontal, has a parallelepiped shape, and is equipped with a dihedron-shaped base and has a diameter greater than 10 m. 3 The volume.

[0046] In order to supply the feed hopper with powdered polymer, the upper end of the vertical pipe has an extension extending downwardly through the lateral sides of the silo, said extension having means for connecting to the feed hopper.

[0047] According to some other characteristics:

[0048] - the mechanism for supplying the powdered polymer to the silo has the form of a screw inserted into a horizontal pipe,

[0049] - The means for unloading the powdered polymer is in the form of a vibrating hopper configured to receive a large bag filled with the powdered polymer.

[0050] Advantageously, the device of the present invention further comprises protection control devices, instruments and safety electrical equipment arranged in the electrical room, which are controlled by a programmable controller, which allows the entire fracturing operation to be controlled via the main control room to achieve full automation of the device.

[0051] In a preferred embodiment, the device is located in a container or on a trailer.

[0052] The present invention and its advantages will become more apparent from the following exemplary embodiments supported by the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is an overall view of the apparatus of the invention positioned on a trailer.

[0054] Figure 2 is a side view of a portion of a trailer.

[0055] Figure 3 It is a view of the rear of the trailer.

[0056] Figure 4 is an exploded view of the assembly including the mechanism and silos for supplying polymer.

[0057] Figure 5 is a view of the lower part of the assembly formed by the vertical pipe and the vertical screw. DETAILED DESCRIPTION

[0058] Figure 1 and Figure 2 A specific embodiment of the invention is shown, in which the device is positioned on a trailer (1). Such a device is suitable for use in fracturing operations carried out on gas or oil fields. Typically, the weight of the trailer (1) is less than 24 tons, preferably less than 22 tons, taking into account the amount of polymer solution contained in the tank and the amount of powder contained in the silo, thereby allowing immediate start-up. In addition, the length of the device does not exceed 14 meters, preferably does not exceed 12 meters.

[0059] The equipment mainly includes:

[0060] - Unloading logistics platform (2),

[0061] - a horizontal pipe (3) for supplying the polymer powder to the silo (4),

[0062] - silos (4) for storing polymers in powder form,

[0063] - a feed hopper (5),

[0064] - a device (6) for dispensing a powdered polymer,

[0065] - a device for dispersing and grinding the polymer (7),

[0066] - a buffer tank (8) for hydrating and dissolving the dispersed polymer,

[0067] - A positive displacement pump (9) capable of injecting and metering the polymer solution.

[0068] Unloading logistics platform

[0069] Unloading logistics platform (2) Figure 3 is shown in more detail in .

[0070] In order to make the discharge of ultrafine powders easier, the unloading logistics platform is equipped with a vibrating hopper (10) configured to receive large bags (11) filled with powdered polymer. In more detail, the platform comprises a vibrating hopper (10) mounted on a frame (12), the lower part (13) of the vibrating hopper (10) being connected to a mechanism for supplying powdered polymer to the silo (4) via a chamber (14). The outer wall of the vibrating hopper is equipped with vibrators, advantageously 4 vibrators (15). The platform also comprises a track (17a) with a crane (17) to unload the large bags (11). The unloading conditions can be adapted to the logistics conditions.

[0071] In practice, the fine powder arrives in big bags of 500 to 800 kg, more preferably in big bags of 750 kg.The particle size of the fine powder polymer is in the range of 20 to 500 microns (μm), preferably 30 to 400 microns (μm), more preferably 50 to 300 microns (μm).

[0072] Mechanism for supplying silos

[0073] The mechanism for supplying the fine powder polymer to the silo (4) is in the form of a screw inserted into the horizontal pipe (3). Figure 4 As shown, the horizontal pipe is positioned at the base of the silo (4). The horizontal screw has a length of 200 mm and is driven by a motor (31).

[0074] Silos for storing polymers in powder form

[0075] like Figure 4 As shown, the storage silo (4) is horizontal, parallelepiped-shaped, and equipped with a dihedral-shaped base. The silo volume is 13m 3 .

[0076] In a preferred embodiment, the horizontal storage silo (4) contains vibrators, each having a vibration frequency of 50 Hz and an output of 550 W, and mounted on the outer wall.

[0077] According to the invention, the silo (4) has internally a vertical screw (16) located in a vertical pipe (16a), the lower end of the shaft (18) of the vertical screw (16) extending to the outside of the vertical pipe (16a), and the vertical pipe itself extends to the outside of the silo (4).

[0078] The upper end of the vertical pipe (16a) has an extension (19) extending downwardly through the lateral side (20) of the silo, the extension (19) having a means (21) for connecting to the feed hopper (5). The vertical pipe (16a) has a fluorinated thermosetting organic resin surface finish, such as polytetrafluoroethylene, perfluoroalkoxy, fluorinated ethylene propylene and ethylene tetrafluoroethylene. Preferably, the vertical pipe has a polytetrafluoroethylene surface finish.

[0079] The vertical screw (16) is designed with specific features to optimize the process of transporting fine powders during hydraulic fracturing operations. The vertical screw is driven by a motor (32).

[0080] Therefore, especially Figure 5As shown, the lower end of the shaft (18) of the vertical screw (16) includes a rotating ring (22), which is vertically fixed on the shaft (18) and equipped with 3 straight blades (23), which are positioned perpendicular to the horizontal plane of the rotating ring (22). The blades (23) are L-shaped; the dimensions are 130mm×100mm×2mm. The blades (23) ensure gentle and controllable fluidization of fine powders. The blades (23) are designed to minimize powder compression and prevent agglomeration, thereby allowing smooth and uninterrupted flow. The blades ensure a consistent and controllable flow, thereby minimizing powder degradation and particle breakage during transportation.

[0081] The vertical screw (16) has a series of teeth (26) with lateral edges (27) ranging from 5 to 30 mm to fluidize the fine particles and direct them to the interior, thereby achieving maximum production and efficiency per revolution.

[0082] The vertical screw (16) includes a support system mounted at the upper and lower ends to rotate the screw counterclockwise.

[0083] The vertical screw (16) includes a support system mounted at the upper and lower ends to rotate the screw counterclockwise.

[0084] The vertical screw (16) had a diameter of 200 mm and a length of 297 cm and was used to lift the fine powder above the device for dispersing and grinding the polymer at a flow rate of 2.5 T / hour.

[0085] The vertical screw (16) has a fluorinated thermosetting organic resin surface finish, such as polytetrafluoroethylene, perfluoroalkoxy, fluorinated ethylene propylene and ethylene tetrafluoroethylene. Preferably, the vertical screw has a polytetrafluoroethylene surface finish to prevent powder from sticking to the shaft.

[0086] The spacing between the series of teeth (26) of the vertical pipe (16a) and the vertical screw (16) is between 3 mm and 12 mm.

[0087] The input flow rate of the vertical screw (16) is between 1.8 and 3.2 T / hour, preferably between 2 and 2.8 T / hour.

[0088] The output flow rate of the vertical screw (16) is also between 1.8 and 3.2 T / hour, preferably between 2 and 2.8 T / hour.

[0089] According to another feature, the horizontal pipe (3) is connected to the vertical screw (16) through a chamber (28) which is located outside the silo and surrounds the lower end of the shaft (18) of the vertical screw (16), the rotating ring (22) fixed to the shaft (18) and the blades (23).

[0090] Devices for dispersing and grinding polymers.

[0091] The device (7) for dispersing and grinding the polymer is a PSU of the same type as disclosed in WO2008 / 107492.

[0092] The PSU (7) was improved by increasing the rotor-stator diameter to 210 mm. The PSU (7) was 3 The powder polymer is fed at a rate of 0-20 m / h and at the lower part (7a) 3 The water circulating in the pipeline is supplied at a rate of 1000 rpm / h. The flow rates of water and powder can be adjusted according to the required conditions.

[0093] The water and powder circulating in the pipes (24, 25) are mixed in the wetted cone (7b), which may be coated with polytetrafluoroethylene to prevent the powder from adhering to the cone (7b). In fact, fracking operations usually take place on roughly leveled agricultural land.

[0094] Each pipe (24, 25) is supplied with water by a water pump, making it possible to avoid very large pressure variations in the supply line during operation. The flow rate is 80 m at a pressure of 3 bar and 3 m NPSH (Net Positive Suction Head). 3 / h.

[0095] The suspension obtained in the PSU (7) was sent to a 750 L buffer tank (8).

[0096] At the outlet of the buffer tank (8), the solution is metered out by a variable speed positive displacement pump (9). The pump may advantageously be a Waukesha lobe pump model 60, flow rate 80 m / s. 3 / h. The flow can be modified in the main control room according to the observed injection pressure.

[0097] All control, protection, instrumentation and safety electrical equipment are located in the electrical room (29) and are controlled by a programmable controller that allows the entire fracturing operation to be controlled via the main control room to achieve full automation of the equipment.

[0098] Finally, the installation also comprises a generator (30) allowing an autonomous power supply of 240 kW of the onboard equipment and having a fuel tank allowing full operation.

Claims

1. A compact and transportable apparatus suitable for hydraulic fracturing operations on a gas or oil field, said apparatus comprising, in order: Mechanism for unloading powdered polymers with a size range of 20 to 500 micrometers (μm), Mechanism for supplying polymer powder to silos, A silo for storing polymers in powder form, the silo having inside it a vertical screw located in a vertical pipe, the lower end of the shaft of the vertical screw extending to the outside of the vertical pipe, the vertical pipe itself extending to the outside of the silo, Feed hoppers for polymer metering units, Device for dispensing powdered polymers, An apparatus for dispersing and grinding a polymer, the apparatus comprising: Cone connected to the main water inlet circuit for wetting the powdered polymer, At the lower end of the cone: A dispersed polymer grinding and discharge chamber comprising: A motor-driven rotor equipped with paddles, A fixed stator consisting of a cylinder equipped with fine slots, a ring supplied by a secondary water circuit, on all or part of the periphery of said chamber, said ring communicating with the chamber to ensure the spraying of pressurized water onto the outside of the stator, thus being able to release the ground and swollen polymer on the surface of said stator, at least one tank for hydrating and dissolving the dispersed polymer coming from the dispersing and grinding device, at least one positive displacement pump capable of injecting and metering the polymer solution; Characterized in that the lower end of the shaft of the vertical screw comprises a rotating ring, which is vertically fixed on the shaft and is equipped with at least 3 straight blades positioned perpendicular to the horizontal plane of the ring.

2. A compact and transportable device according to claim 1, characterized in that The upper end of the vertical conduit has an extension extending downwardly through the lateral sides of the silo, the extension having means for connection to a feed hopper.

3. A compact and transportable device according to any one of the preceding claims, characterised in that The vertical screw has at least the following characteristics: Length between 150 and 350 cm, Diameter between 100mm and 350mm, The pitch is between 75 and 150 mm, The height of the tooth top of the tooth portion is between 5 and 30 mm.

4. A compact and transportable device according to any one of the preceding claims, characterised in that The vertical screw (16) has an input flow rate and an output flow rate between 1.8 and 3.2 T / hour.

5. A compact and transportable device according to any one of the preceding claims, characterised in that The space between the vertical pipe (16a) and the top of the tooth portion of the screw is between 3 mm and 12 mm.

6. A compact and transportable device according to any one of the preceding claims, characterised in that The inner surface of the vertical pipe (16a) and the vertical screw (16) are surface-finished with a fluorinated thermosetting organic resin.

7. A compact and transportable device according to any one of the preceding claims, characterised in that The silo (4) is horizontal, has a parallelepiped shape, is equipped with a dihedral base and has a diameter greater than 10 m. 3 The volume.

8. A compact and transportable device according to any one of the preceding claims, characterised in that The mechanism for supplying the powdered polymer to the silo is in the form of a screw inserted into a horizontal pipe.

9. A compact and transportable device according to any one of the preceding claims, characterised in that The mechanism for unloading the powdered polymer includes a vibrating hopper configured to receive a large bag containing the powdered polymer.

10. A compact and transportable device according to any one of the preceding claims, characterised in that The device further comprises a protection control device, an instrument and a safety electrical device arranged in the electrical room, wherein the protection control device, the instrument and the safety electrical device are controlled by a programmable controller, which allows the entire fracturing operation to be controlled via the main control room to achieve full automation of the device.

11. A compact and transportable device according to any one of the preceding claims, characterised in that The equipment is positioned in a container or on a trailer.

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