On-line mixing instant-preparation instant-injection process and device for powder thickening agent for fracturing fluid

Abstract

The invention relates to the technical field of fracturing fluid preparation, and particularly discloses an on-line mixing instant-preparation instant-injection process and device for a powder thickening agent for fracturing fluid. The process comprises the following steps that firstly, the dry powder thickening agent is conveyed to a site, a spiral conveyor and a mixer are connected through a pipeline, and a water storage tank and the mixer are connected through a pipeline; the degassing equipment is connected with the mixer through a pipeline; then the dry powder thickening agent is conveyed to the powder storage bin through the pneumatic conveying system, and the spiral conveyor conveys the dry powder thickening agent to the mixer; the method comprises the following steps: preparing a dry powder thickening agent, then conveying liquid preparation water to a mixer, mixing the dry powder thickening agent and the liquid preparation water in the mixer to form a premixed liquid, feeding the premixed liquid into degassing equipment, separating gas by using centrifugal force to obtain a degassed concentrated liquid, and diluting and mixing the concentrated liquid with other additives and water to form the final fracturing fluid. According to the device, the fracturing fluid can be injected while being prepared, the operation efficiency is improved, and the mixing uniformity of the fracturing fluid is improved.

Description

Technical Field

[0001] This application relates to the technical field of fracturing fluid preparation, and particularly to an on-line mixing, immediate preparation and immediate injection process and device for a powder thickener used in fracturing fluid. Background Art

[0002] With the continuous development of domestic oil and gas exploration and development, the proportion of tight oil and gas reservoirs in the newly added geological reserves is huge. Such reservoirs mainly adopt fracturing stimulation measures for reservoir transformation. Especially for shale gas, shale oil, tight sandstone gas and deep coal measure strata reservoirs, the fracturing scale is large, and the liquid consumption per well is about 30,000 - 80,000 cubic meters on average. Due to the unique reservoir characteristics of unconventional gas reservoirs, slickwater volume fracturing is the key technology for their efficient development. The drag reducers used in slickwater volume fracturing mainly include powder drag reducers, emulsion drag reducers and suspension drag reducers. Fracturing fluid preparation is a key step in hydraulic fracturing operations, and it is necessary to ensure the safety, environmental protection and effectiveness of fracturing fluid preparation under any conditions. The powder thickener has excellent salt resistance, but it has the problems that the dissolution time of coarse powder is long, the fine powder is not easily uniformly dispersed and prone to "fish eyes". In on-site application, in addition to the liquid mixing device, a transition tank needs to be equipped. The transition tank occupies a large area. The traditional liquid mixing device has a long liquid mixing time and does not meet the purpose of immediate preparation and immediate use under large displacement on site. At the same time, after the construction is completed, the remaining liquid at the bottom of the transition tank accounts for 5% - 7% of the original fracturing fluid volume. These liquids must be treated after the construction to meet the environmental protection requirements, and the treatment of the remaining fracturing fluid increases the construction cost additionally.

[0003] During the process of oil extraction, the mixing quality and efficiency of fracturing fluid play a key role in the effect of fracturing operations. Traditional fracturing fluid mixing devices often have problems such as uneven mixing of powder thickener and liquid, inaccurate mixing ratio, and easy blockage of the liquid mixing device, which affect the smooth progress of fracturing operations. Summary of the Invention

[0004] In order to solve the problem of low efficiency of existing fracturing operations, this application provides an on-line mixing, immediate preparation and immediate injection process and device for a powder thickener used in fracturing fluid.

[0005] On the one hand, an on-line mixing, immediate preparation and immediate injection process for a powder thickener used in fracturing fluid provided by this application adopts the following technical scheme:

[0006] An on-line mixing, immediate preparation and immediate injection process for a powder thickener used in fracturing fluid includes the following steps:

[0007] S10. Device Connection and Preparation: Transport the dry powder thickener to the fracturing site through a supply device, and prepare the mixing device, powder storage device, and screw conveyor. The mixing device includes a water quality analyzer, air compressor, electric control valve, flowmeter, pressure gauge, lifting system, PLC electric control cabinet, mixer, degassing device, and liquid flow device. Connect the screw conveyor and the mixer through a flexible pipeline, connect the liquid flow device and the mixer through a pipeline, and connect the liquid outlet section of the mixer to the degassing device;

[0008] S20. Dry Powder Thickener Supply and Storage: The supply device transports the dry powder thickener to the powder storage device through a pneumatic conveying system. The powder storage device is used to store the dry powder thickener, keep the dry powder thickener dry and have fluidity, and transport and measure the dry powder thickener in the powder storage device through a screw conveyor;

[0009] S30. Fracturing Fluid Mixing and Immediate Injection: The liquid flow device transports the water for preparing the fluid to the mixer through a union connection pipeline, and transports the dry powder thickener to the mixer in a negative pressure powder suction manner through a screw conveyor. The dry powder thickener and the water for preparing the fluid are mixed in the mixer to form a premixed liquid;

[0010] S40. Degassing and Concentration of the Premixed Liquid: The premixed liquid enters the degassing device, and the gas is separated by centrifugal force to obtain a degassed and concentrated liquid. The concentrated liquid enters the sand mixing tank through a flexible pipeline and is diluted and mixed with additives and water to form the final fracturing fluid.

[0011] By adopting the above technical solutions, connecting the powder storage bin, mixer, and degassing device through pipelines realizes the integrated operation of powder supply, mixing, and degassing, reduces manual intervention, and improves operation efficiency. By directly injecting the mixed fracturing fluid into the sand mixing truck, it avoids the residual liquid in the transition tank in the traditional process, reduces the waste liquid treatment cost, reduces the environmental protection pressure, and can also make the dry powder thickener and the water for preparing the fluid mix evenly, and the weighing can make the mixing ratio accurate, improving the fracturing operation efficiency.

[0012] In some embodiments, the powder storage device includes at least one powder storage bin, and a screw conveyor is connected to the bottom of each powder storage bin. The screw conveyor is connected to the mixer. At least one weighing module is installed outside the powder storage bin. The weighing module is used to detect the accuracy of the powder quantity measured by the screw conveyor and the weight of the remaining dry powder thickener inside the powder storage bin. A butterfly valve is arranged between the screw conveyor and the powder storage bin, and the butterfly valve is used to control the transportation and stop of the dry powder thickener.

[0013] By adopting the above technical solutions, multiple powder storage bins work in parallel. When a single tank fails, other tanks can still operate, avoiding the risk of shutdown. The weighing module monitors the powder quantity of the screw conveyor in real time, and combines with the butterfly valve to control the start and stop to ensure the accuracy of the ratio.

[0014] In some embodiments, the fluid flow device includes an inlet pipe, a water distributor, and a water supply pump. One to eight inlet pipes are connected to the water distributor. One end of the inlet pipe is connected to the water distributor, and the other end is connected to the water storage tank for fracturing water or the main water supply line of the sand mixer. The water distributor is connected to the water supply pump through a pipeline. The water supply pump pumps the liquid preparation water to the mixer through a pipe manifold. A pressure gauge, an electric control valve, a flow meter, and a water quality analyzer are provided on the connecting pipe manifold between the water supply pump and the mixer.

[0015] By adopting the above technical solution, the flow meter is linked with the electric control valve to dynamically adjust the flow rate of the liquid preparation water to match different construction requirements; the pressure gauge monitors the pipeline pressure in real time to avoid the influence of pressure fluctuations on the mixing effect; the design of multiple parallel water pipes improves the liquid preparation efficiency and adapts to large-displacement operation scenarios.

[0016] In some embodiments, the mixer includes a solute pipe and a solvent pipe. The solute pipe is inserted into the solvent pipe, and the solute pipe and the solvent pipe are detachably connected. The solute pipe is used for the passage of dry powder thickener, and the solvent pipe is used for the passage of liquid preparation water; the solvent pipe includes an inlet section, a connecting section, and an outlet section. One end of the connecting section is connected to the inlet section, and the other end is connected to the outlet section; the outlet section includes a diameter-changing part and an outlet part. The diameter-changing part is detachably connected to the connecting section, and the outlet part is connected to the diameter-changing part. The solute pipe is coaxially arranged with the outlet section. The diameter of the outlet part is smaller than that of the connecting section. A detachable annular insert is provided at one end of the connecting section close to the outlet section. The solute pipe is coaxial with the annular insert, and the end face of the solute pipe close to the outlet part and the end face of the annular insert close to the outlet part are coplanar. There is an annular gap between the annular insert and the solute pipe.

[0017] By adopting the above technical solution, the mixer makes the flow rate of the solvent pipe increase to form a negative pressure through the Venturi principle, sucks in the dry powder and accelerates the mixing through the diameter-changing section, improving the mixing uniformity. Since the solute pipe and the solvent pipe are detachably connected, it is convenient for cleaning and maintenance, and the service life of the equipment is extended.

[0018] In some embodiments, a first inclined surface is provided on one side of the solute pipe close to the outlet section, and a second inclined surface is provided on one side of the annular insert facing away from the outlet section. The inner diameter D1 of the solute pipe satisfies: 1 cm ≤ D1 ≤ 75 cm, the inner diameter D2 of the solvent pipe satisfies: 3 cm ≤ D2 ≤ 80 cm, the annular gap L1 satisfies: 0.02 cm ≤ L1 ≤ 39 cm, the inner diameter D3 of the outlet part satisfies: 1 cm ≤ D3 ≤ 75 cm, the length L2 of the outlet part satisfies: 0.1 m ≤ L2 ≤ 5 m, and the inner diameter D4 of the annular insert satisfies: 1 cm ≤ D4 ≤ 76 cm.

[0019] In some embodiments, the degassing device includes a degassing housing, to which a liquid inlet pipe, a gas outlet pipe, and a liquid outlet pipe are connected. The liquid inlet pipe and the liquid outlet pipe are respectively arranged on two end faces of the degassing housing, the gas outlet pipe is arranged on the side wall of the degassing housing, the liquid inlet pipe is connected to a mixer, and the liquid outlet pipe is used for discharging the degassed concentrate from the degassing housing. The inner diameter of the liquid inlet pipe is 1 cm to 30 cm, the inner diameter of the gas outlet pipe is 1 cm to 30 cm, the inner diameter of the liquid outlet pipe is 1 cm to 50 cm, and the inner diameter of the degassing housing is 2 cm to 100 cm.

[0020] By adopting the above technical solution, the liquid outlet pipe enables the concentrate to directly enter the sand mixing tank, with a compact structure, reduced pipeline redundancy, and a reduced risk of secondary pollution of the fracturing fluid.

[0021] In some embodiments, spiral fins are arranged inside the degassing housing. The height of the spiral fins is 1 cm to 30 cm, and the pitch of the spiral fins is 1 cm to 50 cm.

[0022] By adopting the above technical solution, the size of the spiral fins is optimized, increasing the rotational kinetic energy of the liquid, improving the gas separation efficiency, and ensuring stable degassing effect.

[0023] In some embodiments, a liquid addition pump group is arranged in the space below the mixer and / or the powder storage device. The liquid addition pump group is used to convey a liquid thickening agent and other additives to the fracturing fluid.

[0024] By adopting the above technical solution, the liquid addition pump group can independently control the addition amounts of bactericides, drag reducers, etc., to meet the requirements of different reservoirs.

[0025] In some embodiments, after step S40, the following steps are further included:

[0026] S50: Stop the construction operation, and close the butterfly valve and the screw conveyor;

[0027] Gradually reduce the displacement of the water pump 3 to 15 seconds after closing the screw conveyor, and then turn off the water pump;

[0028] Close the powder storage bin, the liquid flow device, and the mixer;

[0029] Check the operating status of the discharge bin of the screw conveyor, check the powder feeding pipeline connecting the mixer, and observe whether the remaining powder in the powder storage bin needs powder replenishment work.

[0030] On the other hand, the present application provides an on-line mixing, immediate preparation, and immediate injection device for a powder thickening agent for fracturing fluid, including the on-line mixing, immediate preparation, and immediate injection process for a powder thickening agent for fracturing fluid as described in any one of the above.

[0031] By adopting the above technical solutions, this application solves the problems of low efficiency, a large amount of waste liquid, uneven mixing, etc. in traditional fracturing fluid mixing by optimizing the equipment structure, precise parameter control, and automated processes, significantly improving the efficiency and environmental friendliness of fracturing operations.

[0032] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0033] 1. The process and device provided by this application can realize the integrated operation of powder replenishment, mixing, and degassing, enabling immediate preparation and injection, reducing manual intervention, and improving operation efficiency;

[0034] 2. By setting multiple powder storage bins to work in parallel, continuous powder supply during construction can be ensured, minimizing downtime caused by single-tank failures; the weighing module can reduce the error of powder dosing and improve the accuracy of the ratio;

[0035] 3. The mixer uses the Venturi principle to increase the flow rate of the solvent pipe to form a negative pressure, suck in the dry powder, and accelerate mixing through the variable-diameter section, improving the uniformity of mixing. Since the solute pipe and the solvent pipe are detachably connected, it is convenient for cleaning and maintenance, extending the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a device diagram of the on-line mixing and immediate preparation and injection process of the powder thickener for fracturing fluid in the embodiment of this application.

[0037] Figure 2 is a schematic diagram of the mixer and the liquid flow equipment in the embodiment of this application.

[0038] Figure 3 is a schematic diagram of the powder storage equipment in the embodiment of this application.

[0039] Figure 4 is a structural schematic diagram of the mixer in the embodiment of this application.

[0040] Figure 5 is an internal sectional view of the mixer in the embodiment of this application.

[0041] Figure 6 is Figure 5 the enlarged view of part A in

[0042] Figure 7 is an internal sectional view of the degassing equipment in the embodiment of this application.

[0043] Figure 8 is a structural schematic diagram of the screw conveyor in the embodiment of the application.

[0044] In the figure:

[0045] 1. Supply equipment; 2. Powder storage equipment; 21. Powder storage bin; 22. Air hammer; 23. Manhole; 24. Filter pressure relief hole; 3. Screw conveyor; 31. Feed hopper; 32. Conveyor pipe; 33. Discharge bin; 34. Drive motor; 35. Air inlet; 36. Observation window; 4. Mixing equipment; 41. Mixer; 42. Solute pipe; 421. First inclined plane; 43. Solvent pipe; 44. Liquid inlet section; 45. Connection section; 46. Liquid outlet section; 461. Reducing section; 462. Liquid outlet part; 47. Annular insert; 471. Second inclined plane; 48. Annular gap; 49. Welding sleeve; 5. Liquid flow equipment; 51. Water inlet pipe; 52. Water distributor; 53. Water pump; 6. Degassing equipment; 61. Degassing housing; 62. Liquid inlet pipe; 63. Gas outlet pipe; 64. Liquid outlet pipe; 65. Spiral fin; 7. Control system; 71. Pressure gauge; 72. Electric control valve; 73. Flowmeter; 74. Water quality analyzer; 75. Air compressor; 8. Fluidized bed. Detailed implementation manners

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0047] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the term "and / or" herein is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects unless otherwise specifically stated.

[0048] Referring to Figure 1 , the present application provides an on-line mixing, immediate preparation and immediate injection process for a powder thickener for fracturing fluid, including the following steps:

[0049] S10. Device connection and preparation: Transport the dry powder thickener to the fracturing site through the supply equipment, and prepare the mixing equipment 4, the powder storage equipment 2 and the screw conveyor 3. The mixing equipment 4 includes a water quality analyzer 74, an air compressor 75, an electric control valve 72, a flowmeter 73, a pressure gauge 74, a lifting system, a PLC electric control cabinet, a mixer 41, a degassing equipment 6 and a liquid flow equipment 5. Connect the screw conveyor 3 and the mixer 41 through a pipeline, connect the liquid flow equipment 5 and the mixer 41 through a pipeline, and connect the liquid outlet section of the mixer 41 to the degassing equipment 6. The connection method can be union, chuck, clamp, thread, flange;

[0050] S20. Dry powder thickener supply and storage: The dry powder is transported from the supply device 1 to the powder storage device 2 through a pneumatic conveying system. The powder storage device 2 is used to store the dry powder thickener, keeping the dry powder thickener dry and fluid.

[0051] S30. Fracturing fluid mixing and immediate injection: Open the butterfly valve at the bottom of the powder storage device 2, start the liquid flow device 5, transport the water for preparing the liquid to the mixer 41, start the screw conveyor 3. The screw conveyor 3 measures the powder quantity by rotation speed and detects the accuracy of the powder quantity measured by the screw conveyor 3 through a weighing module. The powder and the water for preparing the liquid are mixed in the mixer 41 to form a premixed liquid.

[0052] S40. Degassing and concentration of the premixed liquid: The premixed liquid enters the degassing device 6, and the gas is separated by centrifugal force to obtain a degassed and concentrated liquid. The concentrated liquid enters the sand mixing tank through a pipeline and is diluted and mixed with additives and water to form the final fracturing fluid.

[0053] S50. Stop construction: Close the butterfly valve at the bottom of the powder storage device 2, turn off the screw conveyor 3. Gradually reduce the discharge of the water pump 15 seconds after turning off the screw conveyor 3, and turn off the water pump after the discharge of the water pump is reduced. Turn off the powder storage device 2 and the mixer 41, and stop the generator. Check the operating status of the powder storage end of the screw conveyor 3, check the powder feeding pipeline connected to the mixer 41, and observe whether the remaining powder in the powder storage device 2 needs powder replenishment work. By delaying the closing of the screw conveyor, it can ensure that the residual powder in the pipeline is completely discharged, avoiding caking and blockage. Gradually reducing the discharge of the water pump can prevent water hammer effect from damaging the pipeline or pump body.

[0054] It is not difficult to understand that the dry powder thickener involved in this application refers to polyacrylamide-based (such as salt-resistant polyacrylamide-based, modified polyacrylamide-based, hydrophobically associating polymer-based, etc. with polyacrylamide as the main component) dry powder thickeners and guar gum-based plant gum dry powder thickeners.

[0055] Specifically, after the dry powder thickener is transported to the site through the supply device 1, connect the powder conveying pipeline, check the working valves, pressure gauges and pipeline connection conditions, connect and start the air compressor system, pressurize the powder feeding tank to 0.1 - 0.3 MPa. After the pressure is stable, open the valve of the powder conveying pipeline. According to the display of the weighing module of the powder storage device 2, the powder conveying quantity can be determined. Optionally, close the valve of the powder conveying pipeline at any time and turn on the gas powder sweeping switch to clean the residual powder in the powder conveying pipeline. There is a filter and pressure relief hole 24 on the powder storage device 2, which is used to filter the dry powder in the powder storage device 2 from entering the air through the pressure relief channel. The diameter of the filter and pressure relief hole 24 is 1 cm to 50 cm. During the powder replenishment process, the powder storage device 2 is in an atmospheric pressure state. After the powder replenishment is completed, stop the machine, disassemble the pipeline and leave the site.

[0056] Place the mixing device 4 and the powder storage device 2 in close proximity to each other, with a distance of 0 to 30 meters between them. Connect the screw conveyor 3 and the mixer 41 through a powder delivery pipe, and connect the liquid flow device 5 and the mixer 41 through a water pipe. Connect the cable and the PLC signal line from the operating room of the mixer 41 to the PLC electric control cabinet interface of the powder storage bin 21. Place the generator system at the designated location and connect the generator cable to the PLC power interface of the mixing device 4.

[0057] Refer to Figure 1 and Figure 2 In this embodiment, the liquid flow device 5 includes a water inlet pipe 51, a water distributor 52, and a water supply pump 53. Multiple water inlet pipes 51 are connected to the water distributor 52, and the multiple water inlet pipes 51 are connected in parallel. One end of each water inlet pipe 51 is connected to the water distributor 52, and the other end is connected to the on-site fracturing water supply storage tank or the main water supply pipeline of the sand mixer (not shown in the figure). The water distributor 52 is connected to the water supply pump 53 through a pipeline. The liquid flow device 5 is used to pump the liquid in the water tank to the mixer 41. A pressure gauge 71, an electric control valve 72, a flow meter 73, and a water quality analyzer 74 are provided on the connecting pipe manifold between the water supply pump 53 and the mixer 41. The flow meter 73 is linked with the electric control valve 72 to dynamically adjust the flow rate of the water used for liquid preparation to match different construction requirements; the pressure gauge 71 monitors the pressure of the mixer in real time to avoid the influence of pressure fluctuations on the mixing effect.

[0058] Specifically, in this embodiment, the inner diameter of the joints at both ends of the water inlet pipeline of the water distributor 52 is 5 cm to 30 cm, the water storage volume of the water distributor 52 is 20 L to 2000 L, and the inner diameter sizes of the water inlet and outlet of the water supply pump 53 are 5 cm to 50 cm.

[0059] Further, the powder storage device 2 includes at least one powder storage bin 21. The powder storage bin 21 is a vertical skid-mounted closed independent conical tank. The bottom of the powder storage bin 21 is conical or conical, and the taper is 5° to 85°. The tank body is made of materials such as carbon steel and stainless steel, having good strength and corrosion resistance. The volume of the powder storage bin 21 is 0.5 to 8 m 3 . The tank body is equipped with a feed port, a discharge port, a manhole 23, a pressure gauge, a safety valve, a valve switch and other components, where the diameter of the manhole 23 is 15 to 100 cm. The bottom of the tank body is designed to be conical or conical for easy discharging to prevent the powder from clogging the discharge port after being piled up and compacted. A fluidized bed (not shown in the figure) is provided in each powder storage bin 21. The fluidized bed is used to make the dry powder thickener have fluidity, keep the dry powder thickener in a loose state, and prevent the dry powder thickener from caking due to long-term stillness, which affects the use. An air hammer 22 is designed outside each powder storage bin 21. The air hammer 22 vibrates and hammers the powder storage bin 21 to facilitate the flow of the dry powder thickener towards the screw conveyor 3.

[0060] The screw conveyor 3 is isolated from the powder storage bin 21 by a butterfly valve. When the dry powder thickener needs to be transported to the mixer 41, the butterfly valve is opened to start the screw conveyor 3. The screw conveyor 3 transports the dry powder thickener to the powder outlet of the screw conveyor 3. The powder amount of the dry powder thickener is measured by the rotation speed of the screw conveyor 3. A weighing module is connected to the powder storage pipe 21. The weighing module is used to determine the accuracy of the powder amount. The powder outlet is connected to the mixer 41 through a pipeline, ready for the next mixing operation.

[0061] Reference Figure 8 The screw conveyor 3 includes a feed hopper 31, a conveying pipe 32 (diameter of 5cm to 50cm) and a discharge bin 33. The feed hopper 31 is connected to the bottom of the powder storage bin 21 through a flange (the connection hole size is 5 to 100cm). The conveying pipe 32 is arranged at the bottom of the feed hopper 31. The conveying pipe 32 is used to connect the feed hopper 31 and the discharge bin 33. The bottom of the feed hopper 31 is conical with a taper of 5 to 85 degrees. A stirring paddle is provided in the feed hopper 31 and a spiral blade is provided in the conveying pipe 32. A drive motor 34 is provided on the outside of the feed hopper 31. The drive motor 34 is connected to the spiral blades via a chain to drive the spiral blades to rotate, thereby driving the dry powder to move to the side of the discharge bin 33. The bottom or side of the discharge bin 33 is connected to the mixer 41 via a pipe. The connection method can be a chuck, clamp, quick connector, etc. The discharge bin 33 is provided with an air inlet 35 and a powder outlet. The inner diameter of the air inlet 35 is 1 cm to 20 cm, and the inner diameter of the powder outlet is 1 cm to 20 cm. Observation windows 36 are provided on both the feed hopper 31 and the discharge bin 33 to facilitate observation of the status within the feed hopper 31 and the discharge bin 33 during operation.

[0062] Furthermore, in this embodiment, the mixer 41 is connected to the degassing device 6 via a reducing pipeline. The mixer 41 utilizes the Venturi principle to achieve efficient mixing of dry powder and liquid. Liquid enters the liquid inlet of the mixer 41 via a water supply pump. As it passes through the annular gap 48, its flow rate increases and its pressure decreases, forming a negative pressure zone. Under the action of this negative pressure, the dry powder thickener is transported to the dry powder inlet and drawn into the liquid outlet of the mixer 41, where it is vigorously mixed with the high-speed flowing liquid to form a premixed liquid. The mixed premixed liquid is then pumped into the degassing device 6. Within the degassing device 6, the premixed liquid is further mixed and degassed through a spiral mixing process, resulting in a concentrated liquid. The degassed concentrated liquid, generated by the fracturing fluid, is then directly piped into the mixing tank of the sand mixer truck under the dual effects of gravitational potential energy and pump pressure. The concentrated liquid outlet is located above the liquid level in the mixing tank of the sand mixer truck, where it is further mixed and diluted with other additives and water, ultimately producing a fracturing fluid that meets the construction requirements and is used in subsequent fracturing operations.

[0063] Reference Figure 4 and Figure 5, Specifically, in this embodiment, the mixer 41 includes a solute pipe 42 and a solvent pipe 43. The solute pipe 42 is inserted into the solvent pipe 43, and the solute pipe 42 is detachably connected to the solvent pipe 43. Specifically, a welding sleeve 49 is fixedly welded on the solvent pipe 43, the solute pipe 42 is inserted into the welding sleeve 49, and the solute pipe 42 is detachably connected to the welding sleeve 49. The specific connection methods include flanges, chucks, clamps, unions, bolts, etc. The solute pipe 42 is used for the dry powder thickener to pass through, and the solvent pipe 43 is used for the liquid preparation water to pass through. The solvent pipe 43 includes a liquid inlet section 44, a connection section 45, and a liquid outlet section 46. One end of the connection section 45 is connected to the liquid inlet section 44, and the other end is connected to the liquid outlet section 46. The liquid outlet section 46 includes a reduced diameter portion 461 and a liquid outlet portion 462. The reduced diameter portion 461 is connected to the connection section 45, and the liquid outlet portion 462 is connected to the reduced diameter portion 461. Specifically, the reduced diameter portion 461 is detachably connected to the connection section 45, and can be specifically connected by means such as flanges, chucks, clamps, unions, etc. The solute pipe 42 is coaxially arranged with the liquid outlet section 46. The diameter of the liquid outlet portion 462 is smaller than the diameter of the connection section 45, the diameter of the connection section 45 is larger than the diameter of the solute pipe 42, and an annular insert 47 is arranged at one end of the connection section 45 close to the liquid outlet section 46. The annular insert 47 is coplanar with the outlet of the feeding port of the solute pipe 42. The annular insert 47 is arranged on the inner wall of the connection section 45, and there is an annular gap 48 between the annular insert 47 and the solute pipe 42. The inner diameter D4 of the annular insert 47 satisfies: 1 cm ≤ D4 ≤ 76 cm. By setting the annular insert 47, the annular gap 48 can be changed, so that the gap between the solute pipe 42 and the solvent pipe 43 is reduced, thereby achieving a better mixing effect.

[0064] Referring to Figure 5 and Figure 6 , on one side of the solute pipe 42 close to the liquid outlet section 46, a first inclined surface 421 is provided, and the inclination angle of the first inclined surface 421 is 5° - 20°. On the side of the annular insert 47 facing away from the liquid outlet section 46, a second inclined surface 471 is provided. The inner diameter D1 of the solute pipe 42 satisfies: 1 cm ≤ D1 ≤ 75 cm, the inner diameter D2 of the solvent pipe 43 satisfies: 3 cm ≤ D2 ≤ 80 cm, the size L1 of the annular gap 48 satisfies: 0.02 cm ≤ L1 ≤ 39 cm, the inner diameter D3 of the liquid outlet portion 462 satisfies: 1 cm ≤ D3 ≤ 75 cm, and the length L2 of the liquid outlet portion 462 satisfies: 0.1 m ≤ L2 ≤ 5 m.

[0065] Furthermore, referring to Figure 5 , in this embodiment, the end face of the solute pipe 42 close to the liquid outlet portion 462 is coplanar with the end face of the annular insert 47 close to the liquid outlet portion 462. Thus, it can enable the liquid preparation water to enter the outlet end of the solute pipe 42 to achieve a reduced diameter, and at the same time, it can also avoid the splashing of the liquid preparation water as much as possible, prevent the liquid preparation water from mixing with the dry powder thickener in advance and causing pipeline blockage, and contribute to the uniform mixing of the liquid preparation water and the dry powder thickener.

[0066] Referring to Figure 7 , the degassing device 6 includes a degassing housing 61, to which a liquid inlet pipe 62, a gas outlet pipe 63 and a liquid outlet pipe 64 are connected. The liquid inlet pipe 62 and the liquid outlet pipe 64 are respectively arranged on two end faces of the degassing housing 61, and the gas outlet pipe 63 is arranged on the side wall of the degassing housing 61. The liquid inlet pipe 62 is connected to the mixer 41, and the liquid outlet pipe 64 is used for the concentrated liquid to enter the sand mixing tank. In this embodiment, the liquid inlet pipe 62 and the mixer 41 are connected by means of flanges, clamps, unions, bolts, etc. The liquid inlet pipe 62 is used for the premixed liquid after mixing to enter the degassing device 6, the gas outlet pipe 63 is used for discharging gas, and the liquid inlet pipe 62 is used for conveying the concentrated liquid after degassing treatment to the sand mixing tank. The inner diameter of the liquid inlet pipe 62 is 1 cm to 30 cm, the inner diameter of the gas outlet pipe 63 is 1 cm to 30 cm, the inner diameter of the liquid outlet pipe 64 is 1 cm to 50 cm, and the inner diameter of the degassing housing 61 is 2 cm to 100 cm. A spiral blade 65 is arranged in the degassing housing 61. The height of the spiral blade 65 is 1 cm to 30 cm, the pitch of the spiral blade 65 is 1 cm to 50 cm, the degassing device 6 is cylindrical, with a length of 30 cm to 300 cm and an inner diameter of 2 cm to 100 cm.

[0067] A liquid addition pump group is arranged in the mixer 41 and / or the powder storage device 2. The liquid addition pump group is connected to the mixer 41 and / or the powder storage device 2 through pipelines, and the liquid addition pump group is used for conveying additives to the dry powder thickener. The additives are specifically bactericides, drag reducers, flowback aids, etc. The selection of additives can be set according to actual needs and is not limited here.

[0068] In addition, the online mixing, immediate preparation and immediate injection process of the fracturing fluid with powder thickener further includes a control system 7. The control system 7 includes a PLC controller, an electromagnetic flowmeter and a pressure transmitter. The PLC controller is communicatively connected with the electromagnetic flowmeter, the pressure transmitter and the viscometer. The electromagnetic flowmeter and the pressure transmitter are both arranged between the water supply pump 53 and the mixer 41. The electromagnetic flowmeter is used for monitoring the flow rate of the liquid mixing water entering the mixer 41, and the pressure transmitter is used for monitoring the reasonable pressure of 0.1 MPa to 1 MPa during construction.

[0069] The online mixing, immediate preparation and immediate injection process of the fracturing fluid with powder thickener provided by this application connects the powder storage bin 21, the mixer 41 and the degassing device 6 through pipelines, realizes the integrated operation of powder supply, mixing and degassing, realizes immediate preparation and immediate injection, reduces manual intervention, improves the operation efficiency. By directly injecting the mixed fracturing fluid into the sand mixing truck, it avoids the residual liquid in the transition tank in the traditional process, reduces the waste liquid treatment cost, reduces the environmental protection pressure, and can also make the dry powder thickener and the liquid mixing water mix evenly, and the weighing can make the mixing ratio accurate, improving the fracturing operation efficiency.

[0070] The on-line mixing, immediate preparation and immediate injection process of the powder thickener for fracturing fluid provided by this application. First, place a diesel or gasoline generator set (with a power of 50 - 200 KW) in a designated safe area, connect the cable to the PLC power interface of the mixer 41. Subsequently, place the mixer 41 and the powder storage bin 21 in close proximity (with a spacing of 0 - 30 meters), and connect the cable and the PLC signal line to the electrical control cabinet of the powder storage bin 21. At the same time, connect the powder outlet pipeline of the screw conveyor 3 in the powder storage bin 21 to the powder inlet of the mixer 41, and the liquid flow device 5 is connected to the liquid inlet end of the mixer 41 through a pressure-resistant water pipeline. A filter is connected to the water inlet pipeline of the water distributor, and a water quality monitor is installed at the rear end of the water outlet of the water supply pump 53 to ensure that the water used for preparing the liquid is free of mechanical impurities. After the equipment connection is completed, use a closed supply device 1 (with a volume of 5 - 60 m 3 ) to transport the powder thickener to the site, pressurize it to 0.1 - 0.3 MPa through an air compressor (with a power of 7.5 - 100 KW), and use a pneumatic conveying system to transport the dry powder to the powder storage bin 21. The powder storage bin 21 maintains an atmospheric pressure state through the pressure relief filter hole 24 during the powder replenishment process. There is a filter insert inside the pressure relief filter hole 24 to prevent the powder thickener from entering the air. Monitor the powder transportation volume through the weighing module during the process, and clean the residual powder in the pipeline after the powder transportation ends. Dry air (processed by a cold dryer) is introduced into the fluidized bed inside the powder storage bin 21 to keep the powder in a loose state and prevent caking. The air hammer outside the tank vibrates intermittently (with a frequency of 1 - 5 Hz) to assist the powder flow. The screw conveyor 3 and the tank are isolated by a butterfly valve, which is closed during standby. After starting the power supply of the generator set, the mixer 41 is lifted to the construction height through hydraulic or manual means, open the valve of the liquid flow device 5, and start the water supply pump 53 (with a power of 22 - 75 KW) to increase the flow rate of the water used for preparing the liquid to the designed value (0 - 3 m 3 / min). Subsequently, open the powder discharge butterfly valve of the powder storage bin 21, start the screw conveyor 3 (with a rotation speed of 5 - 200 rpm), accurately control the powder feeding amount through the rotation speed of the screw conveyor 3. The powder is sucked into the mixer 41 under the negative pressure of the screw conveyor 3 and is violently mixed with the high-speed water flow to form a premixed liquid. The premixed liquid enters the spiral degassing device 6 through a reduced-diameter pipeline, and the gas is separated by centrifugal force to obtain a degassed concentrated liquid. The concentrated liquid is transported through the pipeline to the sand mixing tank of the sand mixer truck and is diluted and mixed with other additives (such as breaker, bactericide, etc.) and water to form the final fracturing fluid.

[0071] During the mixing process, the PLC control system 7 collects flow rate, pressure, and viscosity data in real time (through an electromagnetic flowmeter, a pressure transmitter, and an on-line viscometer), and dynamically adjusts the rotation speed of the screw conveyor 3 and the air pressure in the fluidized bed (0.1 - 0.3 MPa) to ensure the mixing uniformity (viscosity deviation < 3%). After the construction is completed, close the powder discharge butterfly valve of the powder storage bin 21, stop the operation of the screw conveyor 3, gradually reduce the water pump displacement after a delay of 3 - 15 seconds, and then close the water pump and valves. Disconnect the pipeline connection, empty the residual liquid in the mixer 41 and the pipeline, check the remaining powder quantity in the powder storage bin 21 and decide whether to replenish the powder. Finally, turn off the generator set, disconnect all cables and communication lines, and remove the on-site equipment.

[0072] The present application also provides an on-line mixing, immediate preparation and immediate injection device for a powder thickener for fracturing fluid, including any one of the on-line mixing, immediate preparation and immediate injection processes for a powder thickener for fracturing fluid as described above.

[0073] The implementation principle of the embodiment of the present application is as follows: First, the dry powder thickener is transported to the fracturing site, and then the dry powder thickener is conveyed to the powder storage device 2. The powder storage device 2 conveys the dry powder to the screw conveyor 3, and under the action of negative pressure, the dry powder thickener is conveyed to the mixer 41. At the same time, the liquid flow device 5 conveys the liquid-making water to the mixer 41. The liquid-making water and the dry powder thickener are mixed at the liquid outlet end of the mixer 41 to form a premixed liquid. The premixed liquid enters the degassing device 6 for degassing treatment to obtain a concentrated liquid. The concentrated liquid is diluted and mixed with other additives and water to form the final fracturing fluid.

[0074] The above are all the preferred embodiments of the present application, and the protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. An on-line mixing and immediate preparation and injection process of a powder thickener for fracturing fluid, characterized in that, It includes the following steps: S10. Device connection and preparation: Transport the dry powder thickener to the fracturing site through the supply equipment (1), and prepare the mixing equipment (4), powder storage equipment (2) and screw conveyor (3). The mixing equipment (4) includes a water quality analyzer (74), an air compressor (75), an electric control valve (72), a flowmeter (73), a pressure gauge (74), a lifting system, a PLC electric control cabinet, a mixer (41), a degassing device (6) and a liquid flow device (5). Connect the screw conveyor (3) and the mixer (41) through a flexible pipeline, connect the liquid flow device (5) and the mixer (41) through a pipeline, and connect the liquid outlet section of the mixer (41) to the degassing device (6); S20. Dry powder thickener supply and storage: The supply equipment (1) transports the dry powder thickener to the powder storage equipment (2) through a pneumatic conveying system. The powder storage equipment (2) is used to store the dry powder thickener, keep the dry powder thickener dry and have fluidity, and transport and measure the dry powder thickener in the powder storage equipment (2) through the screw conveyor (3); S30. Fracturing fluid mixing and immediate injection: The liquid flow device (5) transports the liquid-making water to the mixer (41) through a connecting pipeline, and transports the dry powder thickener to the mixer (41) in a negative pressure powder suction manner through the screw conveyor (3). The dry powder thickener and the liquid-making water are mixed at the liquid outlet end of the mixer (41) to form a premixed liquid; S40. Degassing and concentration of the premixed liquid: The premixed liquid enters the degassing device (6), and the gas is separated by centrifugal force to obtain a degassed and concentrated liquid. The concentrated liquid enters the sand mixing tank through a flexible pipeline and is diluted and mixed with additives and water to form the final fracturing fluid.

2. The on-line mixing, immediate preparation and immediate injection process of the powder thickener for fracturing fluid according to claim 1, characterized in that The powder storage equipment (2) includes at least one powder storage bin (21), and a screw conveyor (3) is connected to the bottom of each powder storage bin (21). The screw conveyor (3) is connected to the mixer (41). At least one weighing module is installed outside the powder storage bin (21). The weighing module is used to detect the accuracy of the powder quantity measured by the screw conveyor (3) and the weight of the remaining dry powder thickener inside the powder storage bin (21). A butterfly valve is arranged between the screw conveyor (3) and the powder storage bin (21). The butterfly valve is used to control the transportation and stop of the dry powder thickener.

3. The online mixing, immediate preparation and immediate injection process of the powder thickener for fracturing fluid according to claim 1, characterized in that, The liquid flow device (5) includes a water inlet pipe (51), a water distributor (52) and a water supply pump (53). 1 to 8 water inlet pipes (51) are connected to the water distributor (52). One end of the water inlet pipe (51) is connected to the water distributor (52), and the other end is connected to the water storage tank for fracturing water or the main water supply pipeline of the sand mixing truck. The water distributor (52) is connected to the water supply pump (53) through a pipeline. The water supply pump (53) pumps the liquid-making water to the mixer (41) through a pipe manifold. A pressure gauge (71), an electric control valve (72), a flowmeter (73) and a water quality analyzer (74) are arranged on the connecting pipe manifold between the water supply pump (53) and the mixer (41).

4. The on-line mixing, immediate preparation and immediate injection process of the powder thickener for fracturing fluid according to claim 1, characterized in that, The mixer (41) includes a solute tube (42) and a solvent tube (43). The solute tube (42) is inserted into the solvent tube (43), and the solute tube (42) is detachably connected to the solvent tube (43). The solute tube (42) is used for allowing a dry powder thickener to pass through, and the solvent tube (43) is used for allowing water for preparing liquid to pass through. The solvent tube (43) includes a liquid inlet section (44), a connection section (45), and a liquid outlet section (46). One end of the connection section (45) is connected to the liquid inlet section (44), and the other end is connected to the liquid outlet section (46). The liquid outlet section (46) includes a diameter-changing part (461) and a liquid outlet part (462). The diameter-changing part (461) is detachably connected to the connection section (45), and the liquid outlet part (462) is connected to the diameter-changing part (461). The solute tube (42) is coaxially arranged with the liquid outlet section (46). The diameter of the liquid outlet part (462) is smaller than the diameter of the connection section (45). A detachable annular plug-in (47) is arranged at one end of the connection section (45) close to the liquid outlet section (46). The solute tube (42) is coaxial with the annular plug-in (47), and the end face of the solute tube (42) close to the liquid outlet part (462) is coplanar with the end face of the annular plug-in (47) close to the liquid outlet part (462). An annular gap (48) exists between the annular plug-in (47) and the solute tube (42).

5. The online mixing, immediate preparation and immediate injection process of a powder thickener for fracturing fluid according to claim 4, characterized in that, A first inclined surface (421) is arranged on one side of the solute tube (42) close to the liquid outlet section (46). A second inclined surface (471) is arranged on one side of the annular plug-in (47) facing away from the liquid outlet section (46). The inner diameter D1 of the solute tube (42) satisfies: 1 cm ≤ D1 ≤ 75 cm. The inner diameter D2 of the solvent tube (43) satisfies: 3 cm ≤ D2 ≤ 80 cm. The annular gap (48) L1 satisfies: 0.02 cm ≤ L1 ≤ 39 cm. The inner diameter D3 of the liquid outlet part (462) satisfies: 1 cm ≤ D3 ≤ 75 cm. The length L2 of the liquid outlet part (462) satisfies: 0.1 m ≤ L2 ≤ 5 m. The inner diameter D4 of the annular plug-in (47) satisfies: 1 cm ≤ D4 ≤ 76 cm.

6. The online mixing, immediate preparation and immediate injection process of the powder thickener for fracturing fluid according to claim 1, characterized in that The degassing device (6) includes a degassing outer shell (61). An inlet pipe (62), an outlet gas pipe (63), and an outlet liquid pipe (64) are connected to the degassing outer shell (61). The inlet pipe (62) and the outlet liquid pipe (64) are respectively arranged on two end faces of the degassing outer shell (61). The outlet gas pipe (63) is arranged on the side wall of the degassing outer shell (61). The inlet pipe (62) is connected to the mixer (41). The outlet liquid pipe (64) is used for allowing the degassed concentrated liquid to be discharged from the degassing outer shell (61). The inner diameter of the inlet pipe (62) is 1 cm to 30 cm. The inner diameter of the outlet gas pipe (63) is 1 cm to 30 cm. The inner diameter of the outlet liquid pipe (64) is 1 cm to 50 cm. The inner diameter of the degassing outer shell (61) is 2 cm to 100 cm.

7. An on-line mixing, immediate preparation and immediate injection process of a powder thickening agent for fracturing fluid according to claim 6, characterized in that, A spiral fin (65) is arranged inside the degassing housing (61). The height of the spiral fin (65) is 1 cm to 30 cm, and the pitch of the spiral fin (65) is 1 cm to 50 cm.

8. The on-line mixing, immediate preparation and immediate injection process of the powder thickener for fracturing fluid according to claim 1, characterized in that, A liquid addition pump set is arranged in the space below the mixer (41) and / or the powder storage device (2). The liquid addition pump set is used to convey a liquid thickening agent and other additives to the fracturing fluid.

9. The on-line mixing, immediate preparation and immediate injection process of the powder thickener for fracturing fluid according to claim 1, characterized in that, After step S40, the following steps are further included: S50: Stop the construction operation, and close the butterfly valve and the screw conveyor (3); Gradually reduce the discharge of the water pump 3 to 15 seconds after closing the screw conveyor (3), and then turn off the water pump; Close the powder storage bin (21), the liquid flow device (5) and the mixer (41); Check the operating status of the discharge bin of the screw conveyor (3), check the powder feeding pipeline connecting the mixer (41), and observe whether the remaining powder in the powder storage bin (21) needs powder replenishment work.

10. An on-line mixing, immediate preparation and immediate injection device for powder thickener for fracturing fluid, characterized in that, It includes the online mixing, immediate preparation and immediate injection process of the powder thickening agent for fracturing fluid according to any one of claims 1-9.

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