A wear-resistant variable-diameter oil production well tubing

Abstract

The present invention relates to the technical field of casing joints and discloses an anti-wear variable-diameter oil pipe for oil production wells, comprising: a variable-diameter joint for connecting adjacent oil pipes, which is internally provided with a friction-reducing and flow-dividing mechanism; the friction-reducing and flow-dividing mechanism is composed of a flow-dividing inner pipe and an aperture adjusting assembly. Among them, a plurality of optical fiber sensors are arranged between the flow-dividing inner pipe and the liquid inlet end of the variable-diameter joint. The aperture adjusting assembly includes a flexible inner wall film, a double-shrinking core and a spring member. The double-shrinking core is respectively embedded in the liquid inlet end and the liquid outlet end of the flexible inner wall film in a spring shape, and the adjacent ends are elastically connected through the spring member. By setting the friction-reducing and flow-dividing mechanism in the variable-diameter joint, the present invention effectively reduces the wear of the oil pipe and prolongs the service life. The optical fiber sensors arranged between the flow-dividing inner pipe and the liquid inlet end of the variable-diameter joint can collect the pressure and flow rate parameters of the liquid in real time.

Description

Technical Field

[0001] The present invention relates to the field of casing joints, and more specifically, it relates to an anti-wear variable-diameter oil pipe for oil production wells. Background Art

[0002] With the continuous growth of global oil demand, the oil production industry is facing increasingly high production pressures and technical challenges. Among numerous oil production equipment, the oil pipe, as a key component connecting the oil reservoir and surface oil production facilities, its performance and service life have an important impact on oil production efficiency and cost. During the long-term use of traditional oil pipes for oil production wells, many problems are faced, such as wear of the pipe wall, corrosion, scaling, etc. These problems not only reduce the service life of the oil pipe, increase the maintenance and replacement costs, but also may lead to the interruption of oil production operations and affect the stable production of oil.

[0003] During oil production, the liquid flow velocity in the oil pipe is relatively fast, especially when exploiting oil reservoirs containing solid particles such as sand grains. The erosion and wear of the solid particles on the pipe wall are particularly serious. The inner wall of traditional oil pipes is usually a smooth metal surface, lacking effective protection measures, resulting in the gradual thinning of the pipe wall under the long-term high-speed fluid erosion, and even serious wear phenomena such as perforation. Therefore, we propose an anti-wear variable-diameter oil pipe for oil production wells. Summary of the Invention

[0004] The present invention provides an anti-wear variable-diameter oil pipe for oil production wells, which solves the technical problems in the related art that lead to the gradual thinning of the pipe wall under the long-term high-speed fluid erosion, and even serious wear phenomena such as perforation.

[0005] The present invention provides an anti-wear variable-diameter oil pipe for oil production wells, including: a variable-diameter joint connecting adjacent oil pipes, which is internally provided with a friction-reducing and flow-dividing mechanism;

[0006] The friction-reducing and flow-dividing mechanism is composed of a flow-dividing inner pipe and an aperture adjusting component. Among them, a plurality of optical fiber sensors are arranged between the flow-dividing inner pipe and the liquid inlet end of the variable-diameter joint. The aperture adjusting component includes a flexible inner wall film, a double-shrinking core, and a spring component. The double-shrinking core is respectively embedded in the liquid inlet end and the liquid outlet end of the flexible inner wall film in a spring shape, and the adjacent ends are elastically connected through the spring component;

[0007] The optical fiber sensors collect liquid pressure and flow velocity parameters in real time and transmit them to the intelligent control system. This system synchronously changes the pitches of the first shrinking core and the second shrinking core of the double-shrinking core by regulating the tension of the spring component, so that a differential swirling flow layer is formed between the flexible inner wall film and the flow-dividing inner pipe for the fluid, reducing the direct contact wear of the pipe wall by using the flow velocity gradient, and simultaneously realizing the dynamic adjustment of the flow rate based on pressure feedback.

[0008] Further, the shunt inner tube is divided into three sections, namely the middle section of the inner tube, the bottom section of the inner tube, and the top section of the inner tube. The variable-diameter joint is divided into three sections, namely the middle section of the joint, the bottom section of the joint, and the top section of the joint. The shunt inner tube and the variable-diameter joint are coaxial.

[0009] Further, the inner walls of the bottom section of the inner tube and the top section of the inner tube are respectively provided with bottom-section guiding threads and top-section guiding threads. The thread directions of the bottom-section guiding threads and the top-section guiding threads are the same, and the thread directions of the bottom-section guiding threads and the top-section guiding threads are opposite to the thread direction of the double-shrinking core.

[0010] Further, a plurality of connecting columns are evenly distributed along the circumferential direction in the annular gap between the outer wall of the bottom section of the inner tube and the inner wall of the variable-diameter joint. The plurality of connecting columns are all in the shape of triangular prisms. The optical fiber sensors are fixedly inlaid in the connecting columns. The plurality of optical fiber sensors correspond to the plurality of connecting columns one by one. The optical fiber sensors are in contact with the liquid entering the variable-diameter joint.

[0011] Further, a wire passing hole is formed in the barrel wall of the variable-diameter joint. A master control wire is passed through the wire passing hole. One end of the master control wire is connected to the optical fiber sensor, and the other end of the master control wire passes through the outer wall of the variable-diameter joint and is connected to the data line in other oil pipes. At the same time, the data line is connected to the intelligent control system on the ground.

[0012] Further, the double-shrinking core includes a first shrinking core and a second shrinking core. The first shrinking core is located inside the bottom section of the joint, and one end of the first shrinking core close to the liquid inlet end of the variable-diameter joint is fixedly connected to the inner wall of the bottom section of the joint.

[0013] Further, the second shrinking core is located inside the top section of the joint, and one end of the second shrinking core close to the liquid outlet end of the variable-diameter joint is fixedly connected to the inner wall of the top section of the joint. The adjacent ends of the first shrinking core and the second shrinking core are connected to a spring member. The spring member is located inside the middle section of the joint, and the spring member is fixedly connected to the inner wall of the middle section of the joint.

[0014] Further, both ends of the flexible inner wall membrane are fixedly connected to the top section of the joint and the bottom section of the joint respectively, and the flexible inner wall membrane completely surrounds the first shrinking core and the second shrinking core. A binding band ring is arranged between the thread seams of the first shrinking core and the second shrinking core, and the inner and outer walls of the binding band ring are fixedly connected to the variable-diameter joint and the flexible inner wall membrane respectively.

[0015] Further, the spring member includes a pulling and receiving outer cylinder. A pulling and receiving inner cylinder is fixedly arranged inside the pulling and receiving outer cylinder. The inner part of the pulling and receiving inner cylinder is divided into two spaces. A piston member is slidably arranged in each of the two spaces. Piston columns are arranged on both piston members, and the top ends of the two piston columns are respectively fixedly connected to the first shrinking core and the second shrinking core.

[0016] Furthermore, intake holes are provided at the intake ends of the two spaces inside the retractable inner cylinder. A ventilation pipe is provided at the intake end of the retractable outer cylinder, and the other end passes through the outer wall of the reduced-diameter joint and is connected to the air pipe in other oil pipes.

[0017] The beneficial effects of the present invention are as follows:

[0018] By providing a friction-reducing and flow-splitting mechanism inside the reduced-diameter joint, the present invention effectively reduces the wear of the oil pipe and extends its service life. The fiber optic sensor arranged between the flow-splitting inner pipe and the liquid inlet end of the reduced-diameter joint can collect the pressure and flow rate parameters of the liquid in real time and transmit the data to the intelligent control system. According to these data, the system synchronously changes the pitch of the double retractable core by adjusting the tension of the tension spring member, so that a differential swirl layer is formed between the flexible inner wall membrane and the flow-splitting inner pipe. This differential swirl layer uses the flow rate gradient to reduce the direct contact between the fluid and the pipe wall, thereby significantly reducing wear;

[0019] Through the pressure feedback closed-loop control system, dynamic flow regulation and intelligent balance of the wellbore pressure are achieved. The variable pitch design of the aperture adjustment component can automatically adjust the flow area according to the formation liquid supply capacity, reducing energy loss while maintaining production capacity. When the bottom hole pressure fluctuates, the system can complete parameter adjustment within 0.5 seconds, improving the liquid production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the overall structural schematic diagram of the present invention;

[0021] Figure 2 is the connection structural schematic diagram of the reduced-diameter joint of the present invention;

[0022] Figure 3 is the internal structural schematic diagram of the reduced-diameter joint of the present invention;

[0023] Figure 4 is of the present invention Figure 3 enlarged schematic diagram at A in;

[0024] Figure 5 is the structural schematic diagram of the second retractable core position of the present invention;

[0025] Figure 6 is the internal structural schematic diagram of the flow-splitting inner pipe of the present invention;

[0026] Figure 7 is the connection structural schematic diagram of the first retractable core and the second retractable core of the present invention;

[0027] Figure 8 is the structural schematic diagram of the retractable outer cylinder of the present invention;

[0028] Figure 9 is the internal structural schematic diagram of the retractable outer cylinder of the present invention.

[0029] In the figure: 1. Reducing-diameter joint; 11. Middle section of the joint; 12. Bottom section of the joint; 13. Top section of the joint; 2. Friction-reducing and flow-splitting mechanism; 201. Inner flow-splitting pipe; 21. Middle section of the inner pipe; 22. Bottom section of the inner pipe; 23. Top section of the inner pipe; 24. Connecting column; 25. Fiber optic sensor; 26. Total control line; 27. Wire passing hole; 28. Bottom-section diversion thread; 29. Top-section diversion thread; 3. Borehole diameter adjustment assembly; 31. Flexible inner wall film; 32. First shrinkage core; 33. Second shrinkage core; 34. Outer drawing cylinder; 35. Vent pipe; 36. Inner drawing cylinder; 37. Air inlet hole; 38. Piston part; 39. Piston column; 301. Binding band ring. Detailed implementation mode

[0030] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that discussing these embodiments is only to enable those skilled in the art to better understand and thus implement the subject matter described herein. Without departing from the scope of protection of the content of this specification, changes can be made to the functions and arrangements of the elements discussed. Each example can omit, substitute, or add various processes or components as needed. Additionally, the features described relative to some examples can also be combined in other examples.

[0031] As Figure 1 , Figure 2 , Figure 3 and Figure 7 shown, an anti-wear reducing-diameter oil production well tubing string includes: a reducing-diameter joint 1 for connecting adjacent tubing strings, and a friction-reducing and flow-splitting mechanism 2 is arranged therein;

[0032] The friction-reducing and flow-splitting mechanism 2 is composed of a flow-splitting inner pipe 201 and a borehole diameter adjustment assembly 3. Among them, a plurality of fiber optic sensors 25 are arranged between the flow-splitting inner pipe 201 and the liquid inlet end of the reducing-diameter joint 1. The borehole diameter adjustment assembly 3 includes a flexible inner wall film 31, a double shrinkage core and a tension spring member. The double shrinkage core is respectively embedded in the liquid inlet end and the liquid outlet end of the flexible inner wall film 31 in a spring shape, and the adjacent ends are elastically connected through the tension spring member;

[0033] The fiber optic sensors 25 collect liquid pressure and flow rate parameters in real time and transmit them to the intelligent control system. The system synchronously changes the pitches of the first shrinkage core 32 and the second shrinkage core 33 of the double shrinkage core by regulating the tension of the tension spring member, so that a differential velocity swirl layer is formed between the flexible inner wall film 31 and the flow-splitting inner pipe 201 for the fluid, and the direct contact wear of the pipe wall is reduced by using the flow velocity gradient. At the same time, the dynamic adjustment of the flow rate based on pressure feedback is realized.

[0034] The flow-splitting inner pipe 201 is divided into three sections, namely the middle section 21 of the inner pipe, the bottom section 22 of the inner pipe and the top section 23 of the inner pipe. The reducing-diameter joint 1 is divided into three sections, namely the middle section 11 of the joint, the bottom section 12 of the joint and the top section 13 of the joint. The flow-splitting inner pipe 201 and the reducing-diameter joint 1 are coaxial.

[0035] On the inner walls of the bottom section 22 and the top section 23 of the inner pipe, bottom section flow guiding threads 28 and top section flow guiding threads 29 are respectively provided. The thread directions of the bottom section flow guiding threads 28 and the top section flow guiding threads 29 are the same, and the thread directions of the bottom section flow guiding threads 28 and the top section flow guiding threads 29 are opposite to the thread direction of the double shrinking core.

[0036] Such as Figure 4 、 Figure 5 、 Figure 6 and Figure 8 As shown, a plurality of connecting columns 24 are evenly distributed circumferentially in the annular gap between the outer wall of the bottom section 22 of the inner pipe and the inner wall of the reduced-diameter joint 1. The plurality of connecting columns 24 are all in the shape of triangular prisms. The optical fiber sensors 25 are fixedly inlaid in the connecting columns 24. The plurality of optical fiber sensors 25 correspond to the plurality of connecting columns 24 one by one. The optical fiber sensors 25 are in contact with the liquid entering the reduced-diameter joint 1.

[0037] A wire passing hole 27 is formed in the barrel wall of the reduced-diameter joint 1. A master control wire 26 is passed through the wire passing hole 27. One end of the master control wire 26 is connected to the optical fiber sensor 25, and the other end of the master control wire 26 passes through the outer wall of the reduced-diameter joint 1 and is connected to the data line in other oil pipes. At the same time, the data line is connected to the intelligent control system on the ground.

[0038] The double shrinking core includes a shrinking core one 32 and a shrinking core two 33. The shrinking core one 32 is located inside the bottom section 12 of the joint, and one end of the shrinking core one 32 close to the liquid inlet end of the reduced-diameter joint 1 is fixedly connected to the inner wall of the bottom section 12 of the joint.

[0039] The shrinking core two 33 is located inside the top section 13 of the joint, and one end of the shrinking core two 33 close to the liquid outlet end of the reduced-diameter joint 1 is fixedly connected to the inner wall of the top section 13 of the joint. The adjacent ends of the shrinking core one 32 and the shrinking core two 33 are connected to a spring member. The spring member is located inside the middle section 11 of the joint, and the spring member is fixedly connected to the inner wall of the middle section 11 of the joint.

[0040] Both ends of the flexible inner wall film 31 are fixedly connected to the top section 13 and the bottom section 12 of the joint respectively, and the flexible inner wall film 31 completely surrounds the shrinking core one 32 and the shrinking core two 33. A binding belt ring 301 is arranged between the thread seams of the shrinking core one 32 and the shrinking core two 33, and the inner and outer walls of the binding belt ring 301 are respectively fixedly connected to the reduced-diameter joint 1 and the flexible inner wall film 31.

[0041] Such as Figure 7 、 Figure 8 and Figure 9As shown, the tension spring member includes a retracting outer cylinder 34. Inside the retracting outer cylinder 34, a retracting inner cylinder 36 is fixedly arranged. The inside of the retracting inner cylinder 36 is divided into two spaces. In each of the two spaces, a piston member 38 is slidably arranged. On each of the two piston members 38, a piston column 39 is provided, and the tops of the two piston columns 39 are fixedly connected to the first retracting core 32 and the second retracting core 33 respectively.

[0042] Inlet holes 37 are opened at the inlet ends of the two spaces inside the retracting inner cylinder 36. A ventilation pipe 35 is arranged at the inlet end of the retracting outer cylinder 34. The other end passes through the outer wall of the reducing joint 1 and is connected to the air pipe in other oil pipes.

[0043] During oil production operations, when the oil pipe is connected to the oil production well, the liquid in the reservoir flows upward through the oil pipe. The liquid first enters the liquid inlet end of the reducing joint 1. At this time, the friction-reducing and flow-splitting mechanism 2 starts to function.

[0044] After the liquid enters the flow-splitting inner pipe 201, a part of it flows upward along the flow-splitting inner pipe 201, and the other part flows upward in the space between the flow-splitting inner pipe 201 and the flexible inner wall membrane 31. Guide threads 28 at the bottom section and guide threads 29 at the top section are respectively arranged on the inner walls of the bottom section 22 and the top section 23 of the inner pipe. And their thread directions are the same, but opposite to the thread direction of the double retracting cores. This thread design can guide the liquid to form a rotational flow in a specific direction inside the flow-splitting inner pipe 201, which helps to adjust the flow state of the fluid, reduce the generation of turbulent flow and eddy current, and thus reduce the impact and wear on the pipe wall.

[0045] After the intelligent control system receives the data transmitted by the optical fiber sensor 25, it will, according to the current liquid pressure and flow rate conditions, synchronously change the pitch of the first retracting core 32 and the second retracting core 33 of the double retracting cores by regulating the tension of the tension spring member. By controlling the external gas supply air pump, the gas flows through the ventilation pipe 35 into the gap between the retracting outer cylinder 34 and the retracting inner cylinder 36, and then enters the two spaces in the retracting inner cylinder 36 through the inlet holes 37. With the change of air pressure, the two piston members 38 are pushed to slide, so as to push or pull back the first retracting core 32 and the second retracting core 33 through the piston columns 39. When the first retracting core 32 and the second retracting core 33 are stretched, it will drive the thread pitch formed by the flexible inner wall membrane 31 to increase. On the one hand, it adjusts the flow rate of the liquid, and on the other hand, it increases the flow space of the liquid.

[0046] Through this adjustment of the pitch, a differential swirling flow layer is formed between the flexible inner wall membrane 31 and the flow-dividing inner pipe 201. The formation of the differential swirling flow layer utilizes the principle of velocity gradient, that is, there is a velocity difference between fluid layers with different flow velocities, thus forming a relatively low-velocity fluid buffer layer near the pipe wall, reducing the situation where high-velocity fluid directly impacts the pipe wall, and further reducing the direct contact wear of the pipe wall. At the same time, the dynamic flow regulation function based on pressure feedback is realized. When the liquid pressure changes, the intelligent control system can timely adjust the pitch of the double-shrinking core, change the fluid flow channel and flow state, so as to realize the dynamic regulation of the flow rate and ensure the stability and efficiency of the oil production process.

[0047] Both the flow-dividing inner pipe 201 and the variable-diameter joint 1 adopt a three-segment segmentation and are coaxially arranged. This enables the liquid to smoothly transition between each section during the flow process, avoiding fluid turbulence and vortex phenomena caused by sudden changes in pipe diameter or axis offset. In actual oil production operations, this smooth flow state can significantly reduce the impact force of the liquid on the pipe wall and reduce mechanical wear. At the same time, the segmented design facilitates precise flow control and pressure regulation in oil layers at different depths, improving the flexibility and adaptability of oil production. For example, in deep-well oil production, the pressure and temperature differences in oil layers at different depths are relatively large. Through the segmented design, it is possible to optimize and adjust according to the specific conditions of each section, improving the oil production efficiency.

[0048] The fiber optic sensor 25 can collect the pressure and flow rate parameters of the liquid in real time, providing accurate data support for the intelligent control system. This real-time monitoring and feedback mechanism enables the system to quickly respond to various changes in the oil production process, such as oil layer pressure fluctuations and changes in fluid properties. The intelligent control system adjusts the pitch of the double-shrinking core by regulating the tension of the spring element according to these real-time data, realizing the dynamic optimization of the fluid flow state. In practical applications, it can effectively avoid problems such as increased pipe wall wear and unstable flow rate caused by parameter changes, improving the reliability and stability of the oil production system.

[0049] The double-shrinking core design enables the flexible inner wall membrane 31 to form an inner wall structure with specific threads under the support of the double-shrinking core and the elastic action of the spring element. When the intelligent control system adjusts the tension of the spring element, the pitch of the double-shrinking core changes, and then the thread form of the flexible inner wall membrane 31 is changed, affecting the flow velocity and flow space of the fluid. During the oil production process, this synergistic effect can flexibly adjust the fluid flow state according to actual needs, form a differential swirling flow layer, reduce pipe wall wear, and at the same time realize the dynamic flow regulation based on pressure feedback. For example, in the case of a relatively high oil layer pressure, by increasing the pitch, increasing the fluid flow space, reducing the flow velocity, and reducing wear; while when the pressure is low, reducing the pitch, increasing the flow velocity, and ensuring the oil production efficiency.

[0050] The thread design can guide the fluid to form a rotating flow in a specific direction within the shunt inner pipe 201, which helps to adjust the flow state of the fluid, reduce the generation of turbulence and eddies. In actual oil production, this orderly rotating flow can reduce the impact force of the fluid on the pipe wall, reduce wear, and at the same time improve the flow stability of the fluid, which is beneficial to improving oil production efficiency and reducing energy consumption.

[0051] This layout enables the fiber optic sensors 25 to be evenly distributed around the annular gap, comprehensively monitoring the pressure and flow rate parameters of the liquid, and avoiding monitoring blind spots. At the same time, the triangular prism-shaped connecting column 24 has good structural strength and stability, which can protect the fiber optic sensors 25 from liquid impact and mechanical damage, ensuring the accuracy and reliability of the monitoring data.

[0052] Gas is introduced through an external air supply air pump to achieve the adjustment of the double-shrinking core pitch. This pneumatic control method has the advantages of fast response speed, high control accuracy, and stable power transmission. In oil production operations, it can quickly adjust the fluid flow state according to the instructions of the intelligent control system to meet the needs of real-time adjustment. At the same time, pneumatic control avoids complex mechanical transmission structures, reduces the failure rate, and improves the reliability and maintenance convenience of the system.

[0053] When the sand-containing crude oil enters the reducer joint 1, the fluid forms a natural shunt at the entrance of the shunt inner pipe 201. According to the Bernoulli equation calculation, about 55% - 65% of the high-pressure fluid enters the internal channel of the shunt inner pipe 201, and the remaining 35% - 45% of the fluid enters the annular gap formed by the shunt inner pipe 201 and the flexible inner wall film 31, and the designed gap width is 8 - 12 mm.

[0054] The fluid generates a counterclockwise swirl under the action of the bottom section guiding thread 28 and the top section guiding thread 29, and the rotation speed is about 1200 - 1800 rpm. The guiding thread adopts a 30° helix angle design, and the guiding efficiency is increased to 82%.

[0055] The surface of the flexible inner wall film 31 forms a clockwise swirl due to the thread support of the double-shrinking core, and the rotation speed is about 800 - 1200 rpm. The two reverse swirls form a velocity gradient layer at the contact surface, with a thickness of about 2 - 5 mm.

[0056] Through the synergistic effect of the double-shrinking core and the guiding thread, a Taylor vortex structure is formed in the annular gap, indicating that this structure can reduce the sand particle concentration gradient by 42%. Through the combination of threads with opposite rotation directions, a stable Taylor vortex structure is formed in the annular gap. This structure improves the uniformity of sand particle distribution by 65% and reduces the wall impact load by 48%. At a flow rate of 10 m / s, the sand particle impact energy in the traditional straight pipe section is 28.4 J / m², and it is reduced to 6.3 J / m² in the system of the present invention.

[0057] Based on the pressure and flow rate coupling algorithm, the pitch is continuously adjusted from 0.2 to 3.5 mm through a tension spring component, and the response speed is increased to < 80 ms.

[0058] A fiber Bragg grating sensor with a high temperature resistance of 150 °C is adopted to achieve a pressure measurement accuracy of ±0.3% FS for 0 - 30 MPa and a flow rate measurement error of less than 1.2%.

[0059] The embodiments of the present invention have been described above, but the present invention is not limited to the above specific implementation manners. The above specific implementation manners are merely illustrative rather than restrictive. Under the inspiration of this embodiment, those of ordinary skill in the art can also make many forms, all of which fall within the protection scope of this embodiment.

Claims

1. A wear-resistant variable-diameter oil production well tubing, characterized in that, Comprising: A reducing-diameter joint (1) connecting adjacent oil pipes, which is internally provided with an antifriction flow-dividing mechanism (2); The antifriction flow-dividing mechanism (2) is composed of a flow-dividing inner pipe (201) and an aperture adjusting component (3). Among them, a plurality of optical fiber sensors (25) are arranged between the flow-dividing inner pipe (201) and the liquid inlet end of the reducing-diameter joint (1). The aperture adjusting component (3) includes a flexible inner wall film (31), a double-shrinking core and a tension spring component. The double-shrinking core is respectively embedded in the liquid inlet end and the liquid outlet end of the flexible inner wall film (31) in a spring shape, and the adjacent ends are elastically connected through the tension spring component; The optical fiber sensors (25) collect liquid pressure and flow rate parameters in real time and transmit them to the intelligent control system. The system synchronously changes the pitches of the shrinking core one (32) and the shrinking core two (33) of the double-shrinking core by regulating the tension of the tension spring component, so that a differential swirl layer is formed between the flexible inner wall film (31) and the flow-dividing inner pipe (201) for the fluid, and the direct contact wear of the pipe wall is reduced by using the flow rate gradient, and at the same time, the dynamic flow regulation based on pressure feedback is realized.

2. The variable-diameter oil pipe for oil production wells with anti-wear property according to claim 1, characterized in that, The flow-dividing inner pipe (201) is divided into three sections, namely an inner pipe middle section (21), an inner pipe bottom section (22) and an inner pipe top section (23). The reducing-diameter joint (1) is divided into three sections, namely a joint middle section (11), a joint bottom section (12) and a joint top section (13). The flow-dividing inner pipe (201) and the reducing-diameter joint (1) are coaxial.

3. The variable-diameter oil pipe for oil production wells with anti-wear property according to claim 2, characterized in that, The inner walls of the inner pipe bottom section (22) and the inner pipe top section (23) are respectively provided with bottom section diversion threads (28) and top section diversion threads (29). The thread directions of the bottom section diversion threads (28) and the top section diversion threads (29) are the same, and the thread directions of the bottom section diversion threads (28) and the top section diversion threads (29) are opposite to the thread direction of the double-shrinking core.

4. A wear-resistant variable-diameter oil production well tubing according to claim 2, characterized in that, A plurality of connecting columns (24) are evenly distributed along the circumferential direction in the annular gap between the outer wall of the inner pipe bottom section (22) and the inner wall of the reducing-diameter joint (1). The plurality of connecting columns (24) are all in the shape of a triangular prism. The optical fiber sensors (25) are fixedly embedded in the connecting columns (24). The plurality of optical fiber sensors (25) correspond to the plurality of connecting columns (24) one by one. The optical fiber sensors (25) are in contact with the liquid entering the reducing-diameter joint (1).

5. The variable-diameter oil pipe for an oil production well with anti-wear property according to claim 4, characterized in that, A wire passing hole (27) is opened in the cylinder wall of the reducing-diameter joint (1). A master control wire (26) passes through the wire passing hole (27). One end of the master control wire (26) is connected to the optical fiber sensor (25), and the other end of the master control wire (26) passes through the outer wall of the reducing-diameter joint (1) and is connected to the data line in other oil pipes. At the same time, the data line is connected to the intelligent control system on the ground.

6. The variable-diameter oil pipe for oil production wells with anti-wear property according to claim 2, characterized in that, The double-shrinking core includes a shrinking core one (32) and a shrinking core two (33). The shrinking core one (32) is located inside the joint bottom section (12), and one end of the shrinking core one (32) close to the liquid inlet end of the reducing-diameter joint (1) is fixedly connected to the inner wall of the joint bottom section (12).

7. The variable-diameter oil production well tubing for anti-wear according to claim 6, wherein The second shrinkage core (33) is located inside the top section (13) of the joint, and one end of the second shrinkage core (33) close to the liquid outlet end of the reducer joint (1) is fixedly connected to the inner wall of the top section (13) of the joint. One ends of the first shrinkage core (32) and the second shrinkage core (33) close to each other are connected to a tension spring member. The tension spring member is located inside the middle section (11) of the joint and is fixedly connected to the inner wall of the middle section (11) of the joint.

8. A wear-resistant variable-diameter oil production well tubing according to claim 1, characterized in that, Both ends of the flexible inner wall film (31) are respectively fixedly connected to the top section (13) and the bottom section (12) of the joint, and the flexible inner wall film (31) completely surrounds the first shrinkage core (32) and the second shrinkage core (33). A restraint band ring (301) is arranged between the thread seams of the first shrinkage core (32) and the second shrinkage core (33), and the inner and outer walls of the restraint band ring (301) are respectively fixedly connected to the reducer joint (1) and the flexible inner wall film (31).

9. The variable-diameter oil pipe for oil production wells with anti-wear property according to claim 1, wherein, The tension spring member includes a tension and retraction outer cylinder (34). A tension and retraction inner cylinder (36) is fixedly arranged inside the tension and retraction outer cylinder (34). The interior of the tension and retraction inner cylinder (36) is divided into two spaces, and a piston member (38) is slidably arranged in each of the two spaces. A piston column (39) is arranged on each of the two piston members (38), and the top ends of the two piston columns (39) are respectively fixedly connected to the first shrinkage core (32) and the second shrinkage core (33).

10. A wear-resistant variable-diameter oil production well tubing according to claim 9, characterized in that, Air inlet holes (37) are opened at the air inlet ends of the two spaces inside the tension and retraction inner cylinder (36). A ventilation pipe (35) is arranged at the air inlet end of the tension and retraction outer cylinder (34), and the other end passes through the outer wall of the reducer joint (1) and is connected to the air pipe in other oil pipes.

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