Integrated fracturing fluid flowback and throttling drainage and mining downhole tool

Abstract

The invention relates to an integrated fracturing fluid flowback and throttling drainage and production downhole tool which comprises a water drainage and gas production assembly, a fracturing fluid flowback assembly and a throttling production assembly from top to bottom, the water drainage and gas production assembly comprises an upper barrel and an expansion alloy upper connector, a silicon-chromium alloy spring and an upper sliding sleeve are arranged in the upper barrel, and a lower sliding sleeve is arranged in the lower barrel. The top end of the silicon-chromium alloy spring is fixed to the bottom end of the expansion alloy upper connector, and the bottom end of the silicon-chromium alloy spring is fixed to the top end of the upper sliding sleeve. The integrated fracturing fluid flow-back and throttling drainage and production downhole tool integrates three functions of fracturing fluid flow-back, throttling production and drainage gas production, is arranged at the tail end of a continuous oil pipe, can sequentially complete three procedures of fracturing fluid flow-back, throttling production and drainage gas production through single-trip continuous oil pipe operation, meets the requirements of rapid pipe lifting, convenient tool replacement and the like, and is suitable for large-scale popularization and application. The current situation that the function of a current downhole tool is single is improved, the tedious steps of frequently pulling a tubular column and replacing the downhole tool are reduced, manpower and material resources are saved, and the natural gas development cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas drilling and production downhole tools, and in particular to an integrated fracturing fluid return and throttling production downhole tool. Background Art

[0002] There are many processes from the completion to the production of a natural gas well, such as the return of fracturing fluid, the throttling production, and the drainage and gas production stage. In addition, the downhole tools involved in different stages have single functions and the steps for replacing downhole tools are cumbersome. In the return of fracturing fluid stage of a natural gas well, the fracturing fluid is mostly returned by lifting the pipe and lowering the return pump, and the fracturing fluid is pumped to the ground by the pump production method. The process of lifting the pipe and equipping the return pump is time-consuming and labor-intensive, which prolongs the completion cycle of the natural gas well. In the throttling production stage in the early stage of natural gas well development, the pipe needs to be lifted again to replace the return pump with a downhole throttle, which has low completion efficiency and wastes a lot of time and manpower. In the drainage and gas production stage in the middle and late stages of natural gas well development, the underground liquid accumulation has a serious impact on the production of the natural gas well. A large amount of bottom-well liquid accumulates above the throttling nozzle, causing the natural gas well to stop spraying and production. At this time, a drainage and gas production device needs to be lowered again. The above-mentioned single-function downhole tools and cumbersome procedures lead to a wide variety of downhole tools and the need to frequently lift and lower the tubing to replace the tools, which greatly consumes manpower and material resources, prolongs the completion cycle of natural gas wells, and increases the development cost of natural gas. Therefore, the development of integrated multifunctional downhole tools is of great significance to the development of natural gas wells.

[0003] For example, the invention with the publication number CN 111927400 A discloses a downhole throttling vortex drainage and gas production integrated tool, the main components of which include a center tube, a salvage neck, a vortex shaft, an axis tube sleeve, an upper rubber tube connecting pipe, a lower rubber tube connecting pipe, a sand cover, a rubber tube assembly and a throttling component. This invention integrates the vortex tool and the throttle into one. In essence, the purpose is only for drainage and gas production. It is not a multifunctional integrated tool. It simply improves the efficiency of drainage and gas production and increases the recovery rate. Moreover, it is not used in conjunction with continuous oil pipes, and the construction period is long, and the operation is complicated and laborious. There are also many patents that use drainage and gas production integrated pipe strings, but compared with the present invention, none of them have achieved downhole tools that integrate the return of fracturing fluid, throttling production, and drainage and gas production.

[0004] For example, the invention with publication number CN 113090231 A discloses a gas lift water drainage gas production integrated velocity string and its operation process, which is composed of a coiled tubing, a bridge-type eccentric high-pressure gas lift valve, a plugging sleeve, a screen pipe and a guide head. This invention patent also uses a coiled tubing, but it only solves the problem of gas wells being shut down and stopped due to the increase of bottom-hole liquid accumulation in the late production period of the gas well. It does not achieve a multifunctional, integrated, and integrated bottom-hole tool. It is a tool that simply improves the efficiency of water drainage and gas production, and has a single function.

[0005] For example, the invention with publication number CN 115749627 A discloses a downhole tool with a high-temperature trigger sleeve, which uses a spring made of memory alloy. The application field of the downhole tool is oil extraction. The spring pushes the sleeve as a connector to connect the oil well. It is not a multifunctional downhole tool. Moreover, the memory alloy spring of the invention needs to be heated by a resistance wire. The working environment downhole is harsh, and the stability of the electronic control will be affected.

[0006] Problems solved by the present invention: There are many processes from the completion to the production stage of natural gas wells, and the functions of the downhole tools involved in different stages are single, resulting in a variety of downhole tools and the need to frequently pull up and down the pipe to replace the tools, which greatly consumes manpower and material resources, prolongs the completion cycle of natural gas wells, and increases the development cost of natural gas. The integrated fracturing fluid return and throttling drainage downhole tool integrates three functions of returning fracturing fluid, throttling production, and drainage and gas production. Through a single continuous oil pipe operation, the three processes of fracturing fluid return, throttling production, and drainage and gas production can be completed in sequence, which can effectively solve the problems of the existing downhole completion operation and subsequent production tools being too complicated, not centralized in function, and frequently pulling up and down the pipe to replace the tools.

[0007] Therefore, an integrated fracturing fluid flowback and throttling drainage downhole tool is designed to solve the above problems. Summary of the invention

[0008] In order to overcome the above shortcomings and solve the above problems, the present invention integrates the three functions of returning fracturing fluid, throttling production, and draining gas production, and is configured at the very end of the continuous oil pipe. Through a single continuous oil pipe operation, the three processes of returning fracturing fluid, throttling production, and draining gas production can be completed in sequence, meeting the needs of rapid pipe lifting and convenient tool replacement, improving the current situation of single function of downhole tools, reducing the tedious steps of frequently lifting and lowering the pipe string to replace downhole tools, saving manpower and material resources, shortening the development cycle of natural gas wells from completion to production, and greatly reducing the cost of natural gas development.

[0009] The present invention provides an integrated fracturing fluid flowback and throttling drainage and production downhole tool, which includes a drainage and gas production assembly, a flowback fracturing fluid assembly and a throttling production assembly from top to bottom;

[0010] The drainage and gas production assembly comprises an upper cylinder and an expansion alloy upper joint, wherein a silicon-chromium alloy spring and an upper sliding sleeve are arranged in the upper cylinder, wherein the top end of the silicon-chromium alloy spring is fixed to the bottom end of the expansion alloy upper joint, and the bottom end of the silicon-chromium alloy spring is fixed to the top end of the upper sliding sleeve; the upper sliding sleeve compresses the silicon-chromium alloy spring and is fixed to the middle of the upper cylinder with a matching shear pin;

[0011] The upper cylinder is provided with a plurality of drainage and air collection side windows in the circumferential direction thereof;

[0012] The return fracturing fluid assembly includes an intermediate cylinder, an intermediate joint and a lower joint, wherein the middle and upper end of the intermediate joint is fixed to the bottom end of the upper cylinder by means of matching pins and threaded connections, a memory alloy spring and a lower slide sleeve are arranged inside the intermediate cylinder, the top end of the memory alloy spring is fixed to the bottom end of the intermediate joint, the bottom end of the memory alloy spring is fixed to the top end of the lower slide sleeve, the lower slide sleeve compresses the memory alloy spring and is fixed to the inside of the intermediate cylinder by means of an additionally arranged shear pin, the bottom end of the intermediate cylinder is fixed to the middle and upper end of the lower joint by means of pins and threaded connections; a pressure holding head assembly is arranged inside the lower joint, the pressure holding head assembly is fixed to the inside of the lower joint by means of shear pins, and the middle and lower end of the lower joint is fixed to the top end of the lower cylinder by means of pins and threaded connections;

[0013] The intermediate cylinder is provided with a plurality of gas injection side windows in the circumferential direction thereof;

[0014] The pressure holding head assembly is composed of a connecting rod, a rubber barrel body, and a cap; the connecting rod and the cap both have threaded holes in the axial direction, the rubber barrel body is cylindrical and hollow inside, the top of the rubber barrel body is installed on the step at the bottom of the connecting rod, the top of the cap presses the bottom of the rubber barrel body, and the connecting rod and the cap are connected with screws to fix the rubber barrel body;

[0015] The throttling production assembly includes a lower cylinder, a throttling component and a filtering component;

[0016] The throttling assembly includes a throttling air nozzle, an air nozzle pressure cap, and a diffuser air nozzle seat. The top end of the diffuser air nozzle seat is fixed to the bottom end of the lower cylinder by means of a pin and a threaded connection. The bottom end of the diffuser air nozzle seat is fixed to the top end of the screen tube by means of a pin. The air nozzle pressure cap is threadedly connected to fix the throttling air nozzle inside the diffuser air nozzle seat.

[0017] The filter assembly includes a screen tube and a screen mesh, wherein a prism is provided inside the screen tube, and the screen mesh is provided with grooves, and the prism of the screen tube is embedded in the groove of the screen mesh, so that the screen mesh is fixed inside the screen tube;

[0018] The middle and lower end of the lower joint is fixed to the top of the lower cylinder by means of pins and threads, the top of the throttling assembly is fixed to the bottom of the lower cylinder by means of pins and threads, and the bottom of the throttling assembly is fixed to the top of the screen tube by means of pins;

[0019] Preferably, an O-ring is provided at the lower end of the expansion alloy upper joint, both ends of the upper sliding sleeve, both ends of the middle joint, both ends of the lower sliding sleeve, and the lower end of the lower joint.

[0020] Preferably, the connecting rod portion of the pressure holding head assembly is provided with an O-ring.

[0021] Preferably, O-rings are provided at both ends of the diffuser valve seat.

[0022] Preferably, the upper cylinder and the middle cylinder are respectively provided with 6 drainage and air collection side windows and 6 air injection side windows in the circumferential direction thereof.

[0023] Preferably, the memory alloy spring and the silicon-chromium alloy spring are both rectangular springs.

[0024] Preferably, the memory alloy spring and the silicon-chromium alloy spring are both springs with two ends tightened.

[0025] Preferably, the outlet of the diffusion-type air nozzle seat is designed as a diffusion-type curve.

[0026] Preferably, the material of the memory alloy spring is NiTi memory alloy material, and the material of the silicon-chromium alloy spring is CrSi alloy material.

[0027] Preferably, the material of the expansion alloy upper joint is Cu with a high thermal expansion coefficient. 60 Zn 40 High expansion alloy.

[0028] The beneficial effects of the present invention are:

[0029] The integrated fracturing fluid flowback and throttling downhole tool of the present invention has the following advantages:

[0030] 1. The integrated downhole tool of the present invention integrates three functions of returning fracturing fluid, throttling production, and draining water and gas production. It is arranged at the very end of the coiled tubing and can complete the three processes of returning fracturing fluid, throttling production, and draining water and gas production in sequence through a single coiled tubing operation.

[0031] 2. During the fracturing fluid return stage of natural gas wells, the fracturing fluid is returned to the ground by gas lift, which reduces the pollution of groundwater resources and production layers by fracturing fluid;

[0032] 3. In the throttling production stage of natural gas wells, there is no need to frequently trip the pipe string to replace the downhole production tools, which can enter the throttling production stage, saving the time of tripping the pipe string and improving the completion efficiency;

[0033] 4. During the drainage and gas production stage of natural gas wells, the amount of liquid accumulated underground increases and submerges the throttling components, resulting in low production efficiency or even dead wells. At this time, the pressure of the natural gas well is difficult to maintain normal throttling production. The upper sliding sleeve is pushed by throwing balls to hold the pressure, and the drainage and gas production side window is opened to connect the continuous oil pipe. The continuous oil pipe is used to carry liquid and produce gas for large-diameter production.

[0034] 5. It improves the current status of single function of downhole tools, reduces the cumbersome steps of frequent tripping and replacing of downhole tools, saves manpower and material resources, shortens the development cycle of natural gas wells from completion to production, and greatly reduces the cost of natural gas development;

[0035] 6. When the present invention is applied to coiled tubing operations, compared with the common tubing operations that require well killing and single-piece connection, which have the problems of long construction period, secondary pollution to the reservoir, high safety risk, and difficulty in implementing measures, the coiled tubing operation speed is fast and can be continuously tripped, which effectively reduces the downtime of the production well and improves the efficiency of the construction; BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall assembly of the integrated fracturing fluid flowback and throttling drainage downhole tool;

[0037] Figure 2 It is an external schematic diagram of the integrated fracturing fluid flowback and throttling drainage downhole tool of the present invention;

[0038] Figure 3 It is a schematic diagram of the internal structure of the water drainage and gas production assembly of the integrated fracturing fluid flowback and throttling drainage and production downhole tool of the present invention;

[0039] Figure 4 It is a schematic diagram of the internal structure of the flowback fracturing fluid assembly of the integrated fracturing fluid flowback and throttling drainage downhole tool of the present invention;

[0040] Figure 5 It is a schematic diagram of the internal structure of the throttling production assembly of the integrated fracturing fluid flowback and throttling drainage downhole tool of the present invention;

[0041] Figure 6 It is a schematic structural diagram of a pressure holding head assembly of the integrated fracturing fluid flowback and throttling drainage downhole tool of the present invention;

[0042] Figure 7 It is a schematic diagram of the structure of the throttling assembly of the integrated fracturing fluid flowback and throttling drainage downhole tool of the present invention;

[0043] Figure 8 It is a schematic diagram of the structure of the filter assembly of the integrated fracturing fluid flowback and throttling drainage downhole tool of the present invention.

[0044] in:

[0045] 1- expansion alloy upper joint; 2- silicon-chromium alloy spring; 3- upper cylinder; 4- upper sliding sleeve; 5- middle joint; 6- middle cylinder; 7- memory alloy spring; 8- lower sliding sleeve; 9- lower joint; 11- lower cylinder; 14- pin; 15- O-ring; 16- steel ball; 17- shear pin; 18- drainage and gas collection side window; 19- soluble magnesium ball; 21- gas injection side window;

[0046] 10-pressure holding head assembly; 20-connecting rod; 22-rubber cartridge body; 23-cap;

[0047] 12-throttle assembly; 24-throttle air nozzle; 25-air nozzle pressure cap; 26-diffusion type air nozzle seat;

[0048] 13-filter assembly; 27-screen; 28-screen tube. DETAILED DESCRIPTION

[0049] like Figure 1 and Figure 2 As shown, the integrated fracturing fluid flowback and throttling drainage and production downhole tool includes, from top to bottom, a drainage and gas production assembly, a fracturing fluid flowback assembly, and a throttling production assembly;

[0050] like Figure 3 As shown, the drainage and gas production assembly includes an upper cylinder 3 and an expansion alloy upper joint 1, wherein a silicon-chromium alloy spring 2 and an upper sliding sleeve 4 are arranged in the upper cylinder 3, wherein the top end of the silicon-chromium alloy spring 2 is fixed to the bottom end of the expansion alloy upper joint 1, and the bottom end of the silicon-chromium alloy spring 2 is fixed to the top end of the upper sliding sleeve 4; the upper sliding sleeve 4 compresses the silicon-chromium alloy spring 2 and is fixed to the middle of the upper cylinder 3 by a matching shear pin 17;

[0051] The upper cylinder 3 is provided with six drainage and air collection side windows 18 in the circumferential direction thereof;

[0052] like Figure 4 As shown, the flowback fracturing fluid assembly includes an intermediate cylinder 6, an intermediate joint 5 and a lower joint 9, the middle and upper end of the intermediate joint 5 is fixed to the bottom end of the upper cylinder 3 by means of a matching pin 14 and a threaded connection, a memory alloy spring 7 and a lower sleeve 8 are arranged inside the intermediate cylinder 6, the top end of the memory alloy spring 7 is fixed to the bottom end of the intermediate joint 5, the bottom end of the memory alloy spring 7 is fixed to the top end of the lower sleeve 8, the lower sleeve 8 compresses the memory alloy spring and is fixed to the inside of the intermediate cylinder 6 by an additionally configured shear pin 17, the bottom end of the intermediate cylinder 6 is fixed to the middle and upper end of the lower joint 9 by means of a pin 14 and a threaded connection; a pressure holding head assembly 10 is arranged in the lower joint 9, the pressure holding head assembly 10 is fixed to the inside of the lower joint 9 by means of a shear pin 17, and the middle and lower end of the lower joint 9 is fixed to the top end of the lower cylinder 11 by means of a pin 14 and a threaded connection;

[0053] The middle cylinder 6 is provided with six gas injection side windows 21 in its circumferential direction;

[0054] like Figure 6 As shown, the pressure holding head assembly 10 is composed of a connecting rod 20, a rubber barrel body 22, and a cap 23; the connecting rod 20 and the cap 23 have threaded holes in the axial direction, and the rubber barrel body 22 is cylindrical and hollow inside. The top of the rubber barrel body 22 is installed on the step at the bottom of the connecting rod 20, and the top of the cap 23 presses the bottom of the rubber barrel body 22, and the connecting rod 20 and the cap 23 are connected by screws to fix the rubber barrel body 22;

[0055] like Figure 5As shown, the throttling production assembly includes a lower cylinder 11, a throttling component 12 and a filter component 13;

[0056] like Figure 7 As shown, the throttling assembly 12 includes a throttling air nozzle 24, an air nozzle pressure cap 25, and a diffuser air nozzle seat 26. The top of the diffuser air nozzle seat 26 is fixed to the bottom of the lower cylinder 11 by means of a pin 14 and a threaded connection. The bottom of the diffuser air nozzle seat 26 is fixed to the top of the screen tube 28 by means of a pin 14. The air nozzle pressure cap 25 is threadedly connected to fix the throttling air nozzle 24 inside the diffuser air nozzle seat 26.

[0057] like Figure 8 As shown, the filter assembly 13 includes a screen tube 28 and a screen mesh 27. Four prisms are provided inside the screen tube 28. The screen mesh 27 is provided with four grooves. The prisms of the screen tube 28 are embedded in the grooves of the screen mesh 27 to fix the screen mesh 27 inside the screen tube 28.

[0058] The filter assembly 13 includes a screen tube 28 and a screen mesh 27. The screen tube 28 is used to filter larger impurities, such as gravel and rocks, etc.; the screen mesh 27 is used to filter smaller impurities, such as gravel and silt, etc.; the erosion and damage to the throttling assembly are reduced, and the service life of the throttling air nozzle is extended;

[0059] The middle and lower end of the lower joint 9 is fixed to the top end of the lower cylinder 11 by means of a pin 14 and a threaded connection, the top end of the throttling assembly 12 is fixed to the bottom end of the lower cylinder 11 by means of a pin 14 and a threaded connection, and the bottom end of the throttling assembly 12 is fixed to the top end of the screen tube 28 by means of a pin 14;

[0060] O-rings 15 are provided at the lower end of the expansion alloy upper joint 1, the two ends of the upper sliding sleeve 4, the two ends of the middle joint 5, the two ends of the lower sleeve 8, the lower end of the lower joint 9, the connecting rod 20 of the pressure holding head assembly 10, and the two ends of the diffuser valve seat 26;

[0061] The connecting rod 20 is provided with an O-ring, which cooperates with the main body of the rubber tube 22 to achieve better sealing and pressure holding effects. At the same time, the pressure holding head assembly 10 isolates the throttling production assembly and the return fracturing fluid assembly into two independent spaces that are not interconnected, thereby avoiding the problem of fracturing fluid flowing back from the throttling production assembly to the bottom of the well;

[0062] The present invention application needs to cooperate with the steel ball 16 and the soluble magnesium ball 19 to operate; when the steel ball 16 is put into operation, the steel ball 16 is located on the upper sliding sleeve 4, and when the soluble magnesium ball 19 is put into operation, the soluble magnesium ball 19 is located on the lower sliding sleeve 8.

[0063] The material of the memory alloy spring 7 is NiTi memory alloy material. When the high-temperature fracturing fluid is returned, the memory alloy spring is deformed by the high temperature, and a certain shear force is generated on the shear pin, which reduces the time and pressure of the wellhead pressure holding, and avoids the problem that the sliding sleeve cannot be opened after the shear pin is cut off during the wellhead pressure holding. The material of the silicon-chromium alloy spring 2 is CrSi alloy material, which has good corrosion resistance and high temperature resistance, and has good elasticity and toughness. Even if it is subjected to a large load for a long time, it will not fatigue.

[0064] The memory alloy spring 7 and the silicon-chromium alloy spring 2 are both rectangular springs. Compared with ordinary circular cross-section springs, rectangular springs have high load-bearing capacity, stability and durability. Their rectangular cross-sections increase the force-bearing area of ​​the spring, thereby more evenly distributing the load, which can improve material utilization and durability. In order to facilitate installation, the memory alloy spring 7 and the silicon-chromium alloy spring 2 are both springs with both ends tightened;

[0065] The outlet of the diffusion type nozzle seat 26 is designed as a diffusion curve. Compared with the traditional straight nozzle, the nozzle design of the diffusion curve can produce a wall attachment effect, and the high-speed fluid at the outlet diffuses to a larger diameter, and the energy is rapidly dissipated, so that the flow rate of the fluid after throttling slows down, reducing the impact on the throttling component and extending the service life of the throttling component. At the same time, by adopting the downhole throttling process, the pressure in the wellbore can be effectively controlled, and the change of the formation temperature can be used to make the temperature of the gas flow consistent with the temperature of the formation, so as to achieve the purpose of saving energy and reducing the formation of hydrates, improve the liquid carrying capacity of the natural gas well, reduce the pressure loss of the oil pipe, and achieve the effect of improving the recovery rate.

[0066] The material of the expansion alloy upper joint 1 is Cu with a high thermal expansion coefficient. 60 Zn 40 High expansion alloy. The expansion alloy upper joint is configured at the end of the coiled tubing by threaded connection. Since the expansion alloy upper joint 1 is made of Cu with a high thermal expansion coefficient, 60 Zn 40 High expansion alloy, so under the conditions of high temperature and high pressure in natural gas wells, the internal thread of the expansion alloy upper joint 1 and the external thread of the coiled tubing are closely matched, ensuring the sealing of the expansion alloy upper joint 1 and the coiled tubing. At the same time, the high expansion alloy material also has good corrosion resistance and easy processing;

[0067] Directions:

[0068] 1. Flowback fracturing fluid stage

[0069] The top end of the expansion alloy upper joint 1 is connected to the end of the coiled tubing through a thread, and is quickly lowered into the well along with the coiled tubing. Nitrogen is pumped into the bottom of the well through the gas injection side window 21 through the coiled tubing, and the pressure difference between the bottom of the well and the wellhead is used to quickly return the fracturing fluid. The fracturing fluid is returned to the ground from the annular space between the coiled tubing and the production string.

[0070] 2. Saving production stage

[0071] After the fracturing fluid is returned, a soluble magnesium ball 19 is dropped into the wellhead and seated on the sliding sleeve 8, and the wellhead is pressurized. The shear pin 17 on the sliding sleeve 8 is sheared off, and the memory alloy spring 7 pushes the sliding sleeve 8 to move and close the gas injection side window 21. Then, a solvent is poured in to dissolve the soluble magnesium ball 19, and then the wellhead is pressurized. The shear pin 17 of the pressure holding head assembly 10 is sheared off, and the pressure holding head assembly 10 falls into the cavity of the diffusion type gas nozzle 10, connecting the throttling production assembly and the continuous oil pipe. The throttling assembly 12 starts to work, and enters the throttling production stage.

[0072] 3. Drainage and gas production stage

[0073] As the natural gas well enters the low-pressure period, the liquid accumulation at the bottom of the well increases and the pressure of the natural gas well decreases. The natural gas is covered by the liquid at the bottom of the well and cannot be produced. At this time, the steel ball 16 is inserted and sits on the upper sleeve 4 and the pressure is held. Under the action of pressure, the shear pin 17 on the upper sleeve 4 is sheared off, and the silicon-chromium alloy spring 2 pushes the upper sleeve 4 to open the drainage and gas production side window 18, starting the large-diameter drainage and gas production stage.

[0074] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0075] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An integrated fracturing fluid flowback and throttling downhole tool, characterized in that: From top to bottom, it includes the drainage and gas production assembly, the flowback fracturing fluid assembly and the throttling production assembly; The drainage and gas production assembly comprises an upper cylinder (3) and an expansion alloy upper joint (1), wherein a silicon-chromium alloy spring (2) and an upper sliding sleeve (4) are arranged in the upper cylinder (3), wherein the top end of the silicon-chromium alloy spring (2) is fixed to the bottom end of the expansion alloy upper joint (1), and the bottom end of the silicon-chromium alloy spring (2) is fixed to the top end of the upper sliding sleeve (4); the upper sliding sleeve (4) compresses the silicon-chromium alloy spring (2) and is fixed to the middle of the upper cylinder (3) by a matching shear pin (17); The upper cylinder (3) is provided with a plurality of drainage and air collection side windows (18) in the circumferential direction thereof; The flowback fracturing fluid assembly comprises an intermediate cylinder (6), an intermediate joint (5) and a lower joint (9); the upper end of the intermediate joint (5) is fixed to the lower end of the upper cylinder (3) by means of a matching pin (14) and a threaded connection; a memory alloy spring (7) and a lower sleeve (8) are arranged inside the intermediate cylinder (6); the top end of the memory alloy spring (7) is fixed to the bottom end of the intermediate joint (5); the bottom end of the memory alloy spring (7) is fixed to the top end of the lower sleeve (8); the lower sleeve (8) is pressed After the memory alloy spring is compressed, it is fixed inside the middle cylinder (6) by an additionally configured shear pin (17), and the bottom end of the middle cylinder (6) is fixed to the middle and upper end of the lower joint (9) by a pin (14) and a threaded connection; a pressure holding head assembly (10) is arranged inside the lower joint (9), and the pressure holding head assembly (10) is fixed inside the lower joint (9) by a shear pin (17), and the middle and lower end of the lower joint (9) is fixed to the top end of the lower cylinder (11) by a pin (14) and a threaded connection; The intermediate cylinder (6) is provided with a plurality of gas injection side windows (21) in the circumferential direction thereof; The pressure holding head assembly (10) is composed of a connecting rod (20), a rubber barrel body (22), and a cover cap (23); the connecting rod (20) and the cover cap (23) are both provided with threaded holes in the axial direction, the rubber barrel body (22) is cylindrical and hollow inside, the top end of the rubber barrel body (22) is installed at the bottom step of the connecting rod (20), the top end of the cover cap (23) presses the bottom end of the rubber barrel body (22), and the connecting rod (20) and the cover cap (23) are connected by screws to fix the rubber barrel body (22); The throttling production assembly comprises a lower barrel (11), a throttling component (12) and a filtering component (13); The throttling assembly (12) comprises a throttling air nozzle (24), an air nozzle pressure cap (25), and a diffuser air nozzle seat (26); the top end of the diffuser air nozzle seat (26) is fixed to the bottom end of the lower cylinder (11) by means of a pin (14) and a threaded connection; the bottom end of the diffuser air nozzle seat (26) is fixed to the top end of the screen tube (28) by means of a pin (14); the air nozzle pressure cap (25) is threadedly connected to fix the throttling air nozzle (24) inside the diffuser air nozzle seat (26); The filter assembly (13) comprises a screen tube (28) and a screen mesh (27), wherein the screen tube (28) is provided with (4) prisms, and the screen mesh (27) is provided with (4) grooves, wherein the prisms of the screen tube (28) are embedded in the grooves of the screen mesh (27), and the screen mesh (27) is fixed inside the screen tube (28); The lower middle end of the lower joint (9) is fixed to the top end of the lower cylinder (11) by means of a pin (14) and a threaded connection, the top end of the throttling assembly (12) is fixed to the bottom end of the lower cylinder (11) by means of a pin (14) and a threaded connection, and the bottom end of the throttling assembly (12) is fixed to the top end of the screen tube (28) by means of a pin (14).

2. The integrated fracturing fluid flowback and throttling downhole tool according to claim 1, characterized in that: An O-type sealing ring (15) is provided at the lower end of the expansion alloy upper joint (1), the two ends of the upper sliding sleeve (4), the two ends of the middle joint (5), the two ends of the lower sliding sleeve (8), and the lower end of the lower joint (9).

3. The integrated fracturing fluid flowback and throttling downhole tool according to claim 1, characterized in that: The connecting rod (20) of the pressure holding head assembly (10) is provided with an O-type sealing ring (15).

4. The integrated fracturing fluid flowback and throttling downhole tool according to claim 1, characterized in that: O-type sealing rings (15) are provided at both ends of the diffusion type air nozzle seat (26).

5. The integrated fracturing fluid flowback and throttling downhole tool according to claim 1, characterized in that: The upper cylinder (3) and the middle cylinder (6) are respectively provided with six drainage and air collection side windows and six air injection side windows in the circumferential direction thereof.

6. The integrated fracturing fluid flowback and throttling downhole tool according to claim 1, characterized in that: The memory alloy spring (7) and the silicon-chromium alloy spring (2) are both rectangular springs.

7. The integrated fracturing fluid flowback and throttling downhole tool according to claim 6, characterized in that: The memory alloy spring (7) and the silicon-chromium alloy spring (2) are both springs with two ends tightened together.

8. The integrated fracturing fluid flowback and throttling downhole tool according to claim 7, characterized in that: The material of the memory alloy spring (7) is NiTi memory alloy material, and the material of the silicon-chromium alloy spring is CrSi alloy material.

9. The integrated fracturing fluid flowback and throttling downhole tool according to claim 4, characterized in that: The outlet of the diffusion type air nozzle seat (26) is designed as a diffusion type curve.

10. The integrated fracturing fluid flowback and throttling downhole tool according to claim 2, characterized in that: The material of the expansion alloy upper joint (1) is Cu with a high thermal expansion coefficient. 60 Zn 40 High expansion alloy.

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