A pressurized injection water flow control device, an application string and a method of use

Abstract

The application discloses a pressure drive water injection flow control device, an applied pipe column and a use method, relates to the technical field of downhole tools of oil fields, and the device comprises a main body, the main body is tubular, the main body is provided with a half-through injection channel, and one port of the half-through injection channel is a water nozzle; the water nozzle comprises a water nozzle large-displacement water passing section with an unchanged width in the circumferential direction, and the water nozzle comprises a water nozzle small-displacement water control section with a gradually reduced width in the circumferential direction; the main body is connected with an injection channel opening mechanism, and the main body is connected with a water nozzle opening degree control mechanism. The half-through injection channel in the device is designed with a flow regulation structure combined with the large-displacement water passing section and the small-displacement water control section, the flow during pressure drive and conventional water injection can be accurately controlled through the water nozzle opening degree control mechanism, and the flow regulation requirements during large-displacement pressure drive and small-displacement conventional water injection can be met.

Description

Technical Field

[0001] This invention relates to the field of oilfield downhole tool technology, specifically to a pressure-driven water injection flow control device, its application string, and its usage method. Background Technology

[0002] The common problems in water-drive development of low-permeability reservoirs include water wells being unable to inject water and oil wells being unable to produce oil. To address these issues, hydraulic fracturing water injection technology has been developed. This technology utilizes hydraulic fracturing equipment (or a dedicated hydraulic pump) to inject water at pressure exceeding (or near) the fracturing pressure of the oil layer, significantly improving the reservoir's water injection capacity, replenishing reservoir energy in a short period of time, establishing an efficient water-drive reservoir system, and greatly improving oil well productivity and recovery rate.

[0003] The existing stratified pressure-driven water injection uses a single-layer, step-by-step pressure-driven injection method from bottom to top, which has a long injection cycle and a long well occupation period for pressure-driven equipment. After pressure-driven water injection in multi-stage stratified pressure-driven wells, it is not possible to directly switch to conventional stratified water injection. Overflow operations are required for inspection and replacement, which increases operating costs, tool costs, and energy waste.

[0004] Announcement No. CN112814634B discloses an injection device that, through the installation of a riser pipe and a movable water nozzle, achieves concentric docking with a bridge-type concentric sealing and adjustment integrated testing instrument during downhole positioning and water volume adjustment. This results in a high docking success rate and meets the needs of layered water distribution in highly deviated and deep wells. The unique structural design of the rectangular metering orifice ensures accurate and calculable flow rate measurement. When used in conjunction with the bridge-type concentric sealing and adjustment integrated testing instrument, the next run of the instrument enables simultaneous operation of water injection volume adjustment and packer sealing verification.

[0005] Announcement No. CN217538665U discloses a sand-proof bridge-type concentric water distributor. The rotating cylinder moves up and down under the action of the threaded pair, changing the overlap between the water distribution hole and the annular groove to adjust the water injection flow. A square water distribution hole is provided. The relationship between the lifting and lowering of the rotating cylinder and the overlap between the water distribution hole and the annular groove is a linear function, resulting in high accuracy of flow adjustment. The valve core is sealed by pressing against the outer end face of the water passage under the action of the compression spring. The water injection channel can only be opened under the push of water injection pressure.

[0006] Announcement No. CN108915651B discloses a bridge-type concentric constant pressure water distributor. It utilizes a balance spring and a loading spring in the regulating mechanism for pressure control. When the pressure inside the distributor decreases slightly, the balance spring contracts and the loading spring extends, thereby increasing the pressure before the outlet and reducing the throttling effect. Conversely, when the pressure increases, the balance spring extends and the loading spring contracts, thereby reducing the pressure before the outlet and increasing the throttling effect. This achieves automatic adjustment of downhole flow and overcomes the stratified flow changes caused by small pressure fluctuations.

[0007] The aforementioned existing technologies are not precise enough in controlling the water nozzle opening, and cannot meet the requirements of large-displacement pressure drive and small-displacement conventional water injection.

[0008] In summary, the technical solutions, technical problems to be solved, and beneficial effects of the above-disclosed technologies are all different from those of the present invention. For more technical features, technical problems to be solved, and beneficial effects of the present invention, the above-disclosed technical documents do not provide any technical inspiration. Summary of the Invention

[0009] In view of the above-mentioned defects in the existing technology, the purpose of this invention is to provide a pressure-driven water injection flow control device, its application tubing, and its usage method.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] On one hand, the present invention provides a pressure-driven water injection flow control device, comprising a main body, the main body being tubular, the main body being provided with a semi-through injection channel, one port of the semi-through injection channel being a water nozzle; the water nozzle comprising a water nozzle large-displacement water passage section with a constant width in the circumferential direction, and a water nozzle small-displacement water control section with a gradually decreasing width in the circumferential direction; the main body is connected to an injection channel opening mechanism, and the main body is connected to a water nozzle opening control mechanism.

[0012] Furthermore, the semi-through injection channel connects the lower end face of the main body with the side wall;

[0013] Specifically, the port of the semi-through injection channel located on the lower end face of the main body is a water nozzle;

[0014] Specifically, the upper end of the main body is connected to an injection channel opening mechanism, and the lower end of the main body is provided with a water nozzle opening control mechanism.

[0015] Furthermore, the injection channel opening mechanism includes a spring seat, an outer spring, and a piston;

[0016] Specifically, the spring seat is cylindrical, and the outer wall of the spring seat is provided with a downward-facing spring positioning step through a reduced diameter. The lower end of the reduced diameter outer wall of the spring seat is connected to the upper inner wall of the main body.

[0017] Specifically, a pressure ring is provided on the inner wall of the upper end of the piston, the piston is sleeved on the outer wall of the main body, the piston covers and seals the port of the semi-through injection channel located on the side wall of the main body, and the pressure ring is located above the upper end face of the main body;

[0018] Specifically, the outer spring is disposed between the spring positioning step and the compression ring, and the outer spring is in a compressed state;

[0019] Specifically, the pressure ring is sealed to the reduced-diameter outer wall of the spring seat by a first sealing ring, the reduced-diameter outer wall of the spring seat is sealed to the main body by a second sealing ring, and the spring seat is provided with a radially penetrating pressure transmission hole between the first sealing ring and the second sealing ring.

[0020] Furthermore, the faucet opening control mechanism includes a centrally connected connecting pipe, an adjusting core, a friction pad, an inner spring, and a stop cap;

[0021] Specifically, the inner wall of the upper end of the connecting pipe is connected to the outer wall of the lower end of the main body, and the outer wall of the baffle cap is connected to and sealed to the inner wall of the connecting pipe;

[0022] Specifically, the upper end of the stop cap is provided with a first positioning countersunk hole, in which an inner spring and a friction pad are placed; the upper end of the friction pad is provided with a second positioning countersunk hole, and the lower end of the adjusting core is locked in the second positioning countersunk hole.

[0023] Specifically, the side wall of the adjusting core is provided with a rotating groove, the upper side wall of the adjusting core is provided with a water-blocking block, the water-blocking block can contact and seal with the lower end face of the main body, and the inner spring is in a compressed state.

[0024] Furthermore, the main body has an axially continuous, normally open pressure transmission channel in its pipe wall.

[0025] Furthermore, a third sealing ring is provided above the semi-through injection channel port on the main body sidewall, and a fourth sealing ring is provided below it;

[0026] Specifically, the piston is fixedly connected to the main body sidewall below the fourth sealing ring by a shear pin.

[0027] Furthermore, the upper inner wall of the main body is provided with a large inner diameter wall and a small inner diameter wall, the spring seat is connected to the large inner diameter wall, the small inner diameter wall is threadedly connected to an anti-rotation sleeve, and the anti-rotation sleeve is provided with a positioning hole.

[0028] Furthermore, at least two semi-through injection channels are provided and are evenly distributed along the circumference of the main body. The water-blocking block corresponds one-to-one with the semi-through injection channel. At least two normally open pressure transmission channels are provided and are evenly distributed along the circumference of the main body.

[0029] Furthermore, the upper inner wall of the spring seat is provided with an upper connector thread; the lower inner wall of the connecting pipe is connected to the lower connector through a reverse thread.

[0030] Secondly, the present invention provides a tubing string for a pressure-driven water injection flow control device, including tubing, a well-washing valve at the bottom end of the tubing, and at least two layered well-washing units on the tubing, each layered well-washing unit corresponding to an oil layer; the layered well-washing unit includes a packer and the pressure-driven water injection flow control device described in one aspect, arranged sequentially.

[0031] Thirdly, the present invention provides a method for using a tubing string in a pressure-driven water injection flow control device, comprising the following steps:

[0032] S1. Set the number of well-washing unit stages according to the number of oil layers, connect the packer, pressure-driven water injection flow control device, and well-washing valve through the tubing, and run them into the casing; after the well is in place, the packer is set.

[0033] S2. Lower the measuring and adjusting instrument, start the injection pump, and use the measuring and adjusting instrument to adjust the opening of each level of water nozzles. Close or fully open the small discharge control section, and only adjust the opening of the large discharge water passage section of the water nozzles to control the flow rate of each layer to meet the large discharge geological injection of the stratified pressure-driven water injection.

[0034] After the adjustment is completed, shut down the injection pump and take out the measuring and adjusting instruments; then start the injection pump again to complete the stratified pressure drive.

[0035] S3. After the pressure drive is completed, stop the pump and inject water; lower the measuring and adjusting instrument, use the measuring and adjusting instrument to adjust the opening of each level of water nozzle, close the large discharge water passage section, and only adjust the opening of the small discharge water control section of the water nozzle to control the flow rate of each layer to meet the small discharge geological injection of conventional layered water injection.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] 1. The annular channel in the device of the present invention is designed with independent normally open pressure transmission channel and semi-open injection channel. The semi-open injection channel is designed with a flow regulation structure that combines a large-displacement water passage section and a small-displacement water control section. By adjusting the core to control the flow rate during pressure drive and conventional water injection, the flow rate regulation requirements during large-displacement pressure drive and small-displacement conventional water injection can be met.

[0038] 2. The device of the present invention adopts a dual-channel design, which has a main channel for measurement, adjustment and flow control, as well as an annular channel for pressure transmission and water injection, to prevent large-volume injection under pressure and damage to the instrument during measurement and adjustment.

[0039] 3. The device of the present invention is equipped with shear pins, which enables direct pressure setting of the hydraulic compression packer after it is lowered into the well, followed by pressure opening of the injection channel, and the pre-opening of the piston effectively prevents damage during high-displacement pressure drive.

[0040] 4. The lower connector and connecting pipe of the device of the present invention adopt reverse thread connection. When encountering jamming during operation, it should be disengaged first to avoid the special parts such as springs, stop caps, and friction pads in the pressure-driven flow control device from randomly falling apart, which would cause difficulties in retrieval and improve the efficiency of operation.

[0041] 5. The tubing of this invention integrates setting, pressure driving, and water injection, while also improving the efficiency of subsequent operations. The structure is simple and reliable. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of a pressure-driven water injection flow control device according to the present invention;

[0043] Figure 2 This is a schematic diagram of the main structure of the present invention;

[0044] Figure 3 This is a schematic diagram of the structure of the adjusting core in this invention;

[0045] Figure 4 This is a schematic diagram of the tubing used in the pressure-driven water injection flow control device.

[0046] In the diagram: 1-Spring seat; 2-Anti-rotation sleeve; 3-Outer spring; 4-Piston; 5-Main body; 6-Shear pin; 7-Connecting pipe; 8-Adjusting core; 9-Friction pad; 10-Inner spring; 11-Block cap; 12-Lower connector; 13-Main channel; 14-Annular channel; 15-Pressure transmission hole; 16-Semi-open injection channel; 17-Normal open pressure transmission channel; 18-Large displacement water passage section; 19-Small displacement water control section; 20-Rotating groove.

[0047] A-Tubing; B-Casing; C-First Packer; D-First Pressure-Driven Water Injection Flow Control Device; E-Second Packer; F-Second Pressure-Driven Water Injection Flow Control Device; G-Well Washing Valve. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Example 1:

[0050] Please see Figures 1 to 3 The present invention provides a pressure-driven water injection flow control device, comprising a main body 5, wherein the main body 5 is provided with a semi-open injection channel 16 and a normally open pressure transmission channel 17, the upper end of the main body 5 is connected to an injection channel opening mechanism, and the lower end of the main body 5 is provided with a water nozzle opening control mechanism.

[0051] The main body 5 is tubular, the semi-through injection channel 16 connects the lower end face of the main body 5 with the side wall, and the normally open pressure transmission channel 17 axially penetrates the tube wall of the main body 5.

[0052] Specifically, the port of the semi-through injection channel 16 located on the lower end face of the main body 5 is a water nozzle. The water nozzle includes a large-volume water passage section 18 and a small-volume water control section 19. The width of the large-volume water passage section 18 remains constant in the circumferential direction, while the width of the small-volume water control section 19 gradually decreases in the circumferential direction. This allows for simultaneous stratified flow control during both pressure-driven large-volume injection and conventional small-volume water injection, enabling simultaneous injection of each layer in a stratified pressure-driven well, and allowing for direct transition to conventional stratified water injection without further operation after pressure-driven injection. This improves the efficiency of pressure-driven injection, shortens well occupation time, reduces construction costs, and accelerates well production.

[0053] The injection channel opening mechanism includes a spring seat 1, an outer spring 3, and a piston 4. The spring seat 1 is cylindrical, and its outer wall has a downward-facing spring positioning step with a reduced diameter. The lower end of the reduced-diameter outer wall of the spring seat 1 is threaded to the upper inner wall of the main body 5. The upper inner wall of the piston 4 has a protruding pressure ring. The piston 4 is fitted onto the outer wall of the main body 5, covering and sealing the port of the semi-through injection channel 16 located on the side wall of the main body 5. The pressure ring is located above the upper end face of the main body 5. The outer spring 3 is positioned between the spring positioning step and the pressure ring and is in a compressed state. The pressure ring is sealed to the reduced-diameter outer wall of the spring seat 1 by a first sealing ring, and the reduced-diameter outer wall of the spring seat 1 is sealed to the main body 5 by a second sealing ring. The spring seat 1 has a radially penetrating pressure transmission hole 15 between the first and second sealing rings. Pressure is transmitted through the pressure transmission hole 15, causing the piston 4 to move upward and compress the outer spring 3, thus opening the semi-through injection channel 16.

[0054] The faucet opening control mechanism includes a centrally connected connecting pipe 7, an adjusting core 8, a friction pad 9, an inner spring 10, and a stop cap 11. The upper inner wall of the connecting pipe 7 is threaded to the lower outer wall of the main body 5. The outer wall of the stop cap 11 is threaded to the inner wall of the connecting pipe 7 and sealed by a sealing ring. A first positioning countersunk hole is provided at the upper end of the stop cap 11, in which the inner spring 10 and the friction pad 9 are placed. A second positioning countersunk hole is provided at the upper end of the friction pad 9. The lower end of the adjusting core 8 is engaged in the second positioning countersunk hole. The core 8 has a rotating groove 20 on its side wall. The upper side wall of the adjusting core 8 is provided with a water-blocking block, which can contact and seal with the lower end face of the main body 5. The inner spring 10 is in a compressed state. Under the action of the inner spring 10, the friction pad 9 is in close contact with the adjusting core 8 to prevent the adjusting core 8 from rotating. The adjusting core 8 is in close contact and sealed with the lower end face of the main body 5. The measuring and adjusting instrument rotates the adjusting core 8 through the rotating groove 20, so that the opening of the port of the semi-through injection channel 16 located on the lower end face of the main body 5 changes. The rotating groove 20 also serves as a liquid flow channel.

[0055] The upper inner wall of the spring seat 1 is provided with an upper connector thread.

[0056] The lower end of the connecting pipe 7 is connected to the lower connector 12 by a reverse thread, and the lower connector and the stop cap are sealed by a sealing ring.

[0057] Example 2:

[0058] Based on Example 1, this example provides a more specific pressure-driven water injection flow control device.

[0059] Specifically, a third sealing ring is provided above the semi-through injection channel 16 port on the side wall of the main body 5, and a fourth sealing ring is provided below it. The piston 4 is fixedly connected to the side wall of the main body 5 below the fourth sealing ring by a shear pin 6. The shear pin 6 gives the injection channel opening mechanism opening pressure to prevent accidental opening during insertion.

[0060] Specifically, the upper inner wall of the main body 5 is provided with a large inner diameter wall and a small inner diameter wall. The spring seat 1 is connected to the large inner diameter wall, and the small inner diameter wall is threadedly connected to an anti-rotation sleeve 2. The anti-rotation sleeve 2 is provided with a positioning hole for positioning of the positioning claw of the measuring and adjusting instrument.

[0061] The anti-rotation sleeve 2, the main body 5, and the adjusting core 8 form the main channel 13; the annular space between the anti-rotation sleeve 2 and the spring seat 1 is the annular channel 14.

[0062] Specifically, at least two semi-through injection channels 16 are provided and are evenly distributed along the circumference of the main body 5. The water-blocking block corresponds one-to-one with the semi-through injection channel 16. At least two normally open pressure transmission channels 17 are provided and are evenly distributed along the circumference of the main body 5.

[0063] In this embodiment, two semi-open injection channels 16, two water-blocking blocks, and two normally open pressure transmission channels 17 are used as examples.

[0064] Example 3:

[0065] Please see Figure 4 Based on Example 2, this example provides a tubing string for a pressure-driven water injection flow control device, including tubing A, a well-washing valve G at the bottom end of tubing A, and at least two layered well-washing units on tubing A.

[0066] The layered well washing unit includes a packer and a pressure-driven water injection flow control device as described in Example 2, arranged in sequence. One layered well washing unit corresponds to one oil layer.

[0067] In this embodiment, two layered well-washing units are set up. From top to bottom on tubing A, there are the first packer C, the first pressure-driven water injection flow control device D, the second packer E, the second pressure-driven water injection flow control device F, and the well-washing valve G.

[0068] Specifically, the packer is a washable high-pressure packer. Both the packer and the wash valve G are existing technologies, and those skilled in the art are aware of their structure.

[0069] Example 4:

[0070] Based on Example 3, this example provides a method for using a tubing string in a pressure-driven water injection flow control device, including the following steps:

[0071] S1. Set the number of well-washing unit stages according to the number of oil layers, connect the packer, pressure-driven water injection flow control device, and well-washing valve G through the tubing, and run them into the casing B; when running them into the well, the nozzle of one of the pressure-driven water injection flow control devices is in the closed state; after running them into the well, set them according to the packer setting method.

[0072] S2, Layered Pressure Drive:

[0073] S2.1. The measuring and adjusting instrument is lowered in, and its positioning claw engages with the positioning hole of the anti-rotation sleeve 2. Its adjusting manipulator enters the rotating groove 20 of the adjusting core 8 of the pressure-driven water injection flow control device and adjusts the water nozzles of each stage of the pressure-driven water injection flow control device (including the large-displacement water passage section 18 and the small-displacement water control section 19) to open.

[0074] Start the injection pump, and the injection water enters from the oil pipe and enters the formation through the pressure-driven water injection flow control devices at each stage.

[0075] Specifically, the injected water enters through the pressure transmission hole 15 on the main body 5, pushing the piston 4 to cut the shear pin 6, compressing the outer spring 3 to move upward and open the semi-through injection channel 16; at this time, the injected water enters the formation through the adjusting core 8, the water nozzle of the main body 5, and the semi-through injection channel 16.

[0076] S2.2 Adjust the opening of the nozzles of the pressure-driven water injection flow control devices at each level through ground control and adjustment instruments, close or fully open the small-displacement water control section 19, and only adjust the opening of the large-displacement water passage section 18 of the nozzles to control the flow of each layer to meet the large-displacement geological injection of the stratified pressure-driven water injection.

[0077] During the adjustment process, the measuring instrument enters the main channel 13 of the pressure-driven water injection flow control device, partially blocking the main channel 13. At this time, the injected water passes through the annular channel 14 and the rotating tank 20 to the main channel 13 below the pressure-driven water injection flow control device, so that the pressure above and below the measuring instrument is consistent, reducing the impact force of the large-volume injection on the measuring instrument during pressure-driven adjustment and preventing damage to the instrument.

[0078] After the adjustment is completed, shut down the injection pump and take out the measuring and adjusting instruments.

[0079] S2.3 Start the injection pump. The injection water is injected into the formation through the pressure drive water flow control device at each stage until the stratified pressure drive is completed.

[0080] S3, Layered Water Injection:

[0081] After the pressure drive is completed, the pump is stopped, and water is injected using the surface water injection process;

[0082] The measuring and adjusting instrument is lowered in, and its robotic arm enters the rotating groove of the adjusting core 8 of the pressure-driven water injection flow control device. It adjusts the opening of the water nozzles of each stage of the pressure-driven water injection flow control device, closes the large-displacement water passage section 18, and only adjusts the opening of the small-displacement water control section 19 of the water nozzle to control the flow of each layer to meet the small-displacement geological distribution of conventional stratified water injection.

[0083] It should be noted that the measuring and adjusting instrument is existing technology, and it has a robotic arm and a positioning gripper. The robotic arm is rotatable, which is clear to those skilled in the art.

[0084] All components not discussed in detail in this application, as well as the connection methods of these components, are well-known technologies in this field. They can be directly applied and will not be elaborated further.

[0085] In this invention, the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0086] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0087] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pressure-driven water injection flow control device, comprising a main body, wherein the main body is tubular, characterized in that, The main body is provided with a semi-through injection channel, and one port of the semi-through injection channel is a water tap; The water nozzle includes a large-displacement water passage section with a constant width in the circumferential direction, and a small-displacement water control section with a gradually decreasing width in the circumferential direction. The main body is connected to the injection channel opening mechanism, and the main body is connected to the water nozzle opening control mechanism.

2. The pressure-driven water injection flow control device according to claim 1, characterized in that, The semi-through injection channel connects the lower end face of the main body with the side wall; The port of the semi-through injection channel located on the lower end face of the main body is a water nozzle; The upper end of the main body is connected to an injection channel opening mechanism, and the lower end of the main body is provided with a water nozzle opening control mechanism.

3. The pressure-driven water injection flow control device according to claim 2, characterized in that, The injection channel opening mechanism includes a spring seat, an outer spring, and a piston; The spring seat is cylindrical, and the outer wall of the spring seat is provided with a downward-facing spring positioning step through a reduced diameter. The lower end of the reduced diameter outer wall of the spring seat is connected to the upper inner wall of the main body. A pressure ring is provided on the inner wall of the upper end of the piston. The piston is sleeved on the outer wall of the main body. The piston covers and seals the port of the semi-through injection channel located on the side wall of the main body. The pressure ring is located above the upper end face of the main body. The outer spring is disposed between the spring positioning step and the compression ring, and the outer spring is in a compressed state; The pressure ring is sealed to the reduced-diameter outer wall of the spring seat by a first sealing ring, and the reduced-diameter outer wall of the spring seat is sealed to the main body by a second sealing ring. A radially penetrating pressure transmission hole is provided between the first sealing ring and the second sealing ring.

4. The pressure-driven water injection flow control device according to claim 3, characterized in that, The faucet opening control mechanism includes a centrally connected connecting pipe, an adjusting core, a friction pad, an inner spring, and a stop cap; The upper inner wall of the connecting pipe is connected to the lower outer wall of the main body, and the outer wall of the baffle cap is connected to and sealed to the inner wall of the connecting pipe. The upper end of the stop cap is provided with a first positioning countersunk hole, in which an inner spring and a friction pad are placed. The upper end of the friction pad is provided with a second positioning countersunk hole, and the lower end of the adjusting core is locked in the second positioning countersunk hole. The adjusting core has a rotating groove on its side wall, and a water-blocking block is provided on the upper side wall of the adjusting core. The water-blocking block can contact and seal with the lower end face of the main body, and the inner spring is in a compressed state.

5. The pressure-driven water injection flow control device according to claim 4, characterized in that, The main body has an axially continuous, normally open pressure transmission channel in its pipe wall.

6. The pressure-driven water injection flow control device according to claim 4, characterized in that, The main body sidewall is provided with a third sealing ring above the semi-through injection channel port and a fourth sealing ring below it; The piston is fixedly connected to the main body sidewall below the fourth sealing ring by a shear pin.

7. The pressure-driven water injection flow control device according to claim 4, characterized in that, The upper inner wall of the main body is provided with a large inner diameter wall and a small inner diameter wall. The spring seat is connected to the large inner diameter wall, and the small inner diameter wall is threadedly connected to an anti-rotation sleeve, which is provided with a positioning hole.

8. The pressure-driven water injection flow control device according to claim 4, characterized in that, At least two semi-through injection channels are provided and are evenly distributed along the circumference of the main body. Each water-blocking block corresponds to a semi-through injection channel. At least two normally open pressure transmission channels are provided and are evenly distributed along the circumference of the main body.

9. The pressure-driven water injection flow control device according to claim 4, characterized in that, The upper inner wall of the spring seat is provided with an upper connector thread; the lower inner wall of the connecting pipe is connected to the lower connector through a reverse thread.

10. A pressure-driven water injection flow control device using a tubing string, comprising tubing, wherein a well-washing valve is provided at the bottom end of the tubing, characterized in that, At least two layered well-washing units are provided on the oil pipe, and one layered well-washing unit corresponds to one oil layer; The layered well washing unit includes a packer and a pressure-driven water injection flow control device as described in claim 1, arranged in sequence.

11. A method for using a tubing string in a pressure-driven water injection flow control device, characterized in that, Using the tubing string of claim 10 includes the following steps: S1. Set the number of well-washing unit stages according to the number of oil layers, connect the packer, pressure-driven water injection flow control device, and well-washing valve through the tubing, and run them into the casing; after the well is in place, the packer is set. S2. Lower the measuring and adjusting instrument, start the injection pump, and use the measuring and adjusting instrument to adjust the opening of each level of water nozzles. Close or fully open the small discharge control section, and only adjust the opening of the large discharge water passage section of the water nozzles to control the flow rate of each layer to meet the large discharge geological injection of the stratified pressure-driven water injection. After the adjustment is completed, shut down the injection pump and take out the measuring and adjusting instruments; then start the injection pump again to complete the stratified pressure drive. S3. After the pressure drive is completed, stop the pump and inject water; lower the measuring and adjusting instrument, use the measuring and adjusting instrument to adjust the opening of each level of water nozzle, close the large discharge water passage section, and only adjust the opening of the small discharge water control section of the water nozzle to control the flow rate of each layer to meet the small discharge geological injection of conventional layered water injection.

Images