Tubing injection device

Abstract

The present application relates to a kind of oil pipe dosing device, to solve the problem of traditional dosing method medicament uniform dispersion to the bottom of oil pipe.The device includes oil pipe, adjacent oil pipe male oil pipe joint and female oil pipe joint are threadedly connected;N connection flat tubes, which are closely attached to the outer wall of the oil pipe, the n connection flat tubes are connected into a complete annular sleeve in the circumferential direction of the oil pipe, and n is an even number;Wherein, from the female oil pipe joint to the extension direction of the oil pipe body, the width of the inner cavity of the connection flat tube gradually decreases along the radial direction of the oil pipe, so that the inner cavity of the connection flat tube forms an expanded diameter structure at the connection of the upper and lower adjacent oil pipes;The connection flat tube is made of wear-resistant and corrosion-resistant composite material, and an antistatic coating is provided on the outer side wall of the connection flat tube.The present application does not need to modify the existing oil pipe structure, and the modular design improves the installation efficiency, is suitable for thick oil, high sulfur / wax oil well, can reduce the load of pumping equipment, and prolong the service life of oil pipe.

Description

Oil pipe dosing device Technical Field

[0001] This invention relates to the field of oil extraction. More specifically, this invention relates to a pipeline chemical dosing device. Background Technology

[0002] In the oil extraction industry, oil well tubing serves as a crucial channel for transporting crude oil from the bottom of the well to the surface, and its structural design is closely linked to the efficiency and stability of extraction operations. As extraction activities advance into deeper and more complex geological areas, higher demands are placed on the chemical additive processes in oil well production.

[0003] Currently, the most common method for chemical dosing in oil extraction is simple and direct injection. While easy to implement, this method has serious drawbacks. Crude oil exhibits a complex physical state within the tubing, with significant density stratification; lighter components typically reside in the upper layer, while heavier components concentrate in the lower layer. This is especially true under high pressure and low temperature conditions at the wellbore, where oil properties become even more complex and variable. Directly injected chemicals face numerous obstacles during their transport from the wellhead to the bottom. The high viscosity of crude oil creates strong viscous resistance, slowing the chemicals' descent. The complex flow field within the tubing, alternating between turbulent and laminar flow, makes it difficult for the chemicals to maintain a stable downward trajectory, leading to deviation and dispersion. Furthermore, the surface tension of the chemicals themselves, as well as the interfacial tension with the crude oil, further increases the difficulty of diffusion and descent. Ultimately, this results in chemicals failing to penetrate sufficiently and uniformly to the bottom of the oil well.

[0004] This problem is particularly prominent in heavy oil extraction scenarios. Heavy oil has poor fluidity; if there is insufficient viscosity-reducing agent at the bottom of the oil well, the load on the pumping equipment will increase significantly, energy consumption will surge, equipment wear will accelerate, and pump failures will occur frequently, severely impacting extraction efficiency and economic benefits. In high-sulfur, high-wax oil wells, if the bottom of the oil well is not effectively protected by anti-corrosion and anti-wax agents, the bottom of the tubing is highly susceptible to corrosion and perforation. Excessive wax deposition leads to tubing blockage, not only shortening tubing lifespan and increasing maintenance costs, but also potentially causing reduced well production or even well abandonment.

[0005] However, improving chemical dosing effectiveness by modifying the tubing structure is no easy task. Currently, tubing connections using joints are widely used in various oil wells, and the corresponding laying tools and equipment are highly mature. Significant adjustments to the tubing structure require redesigning suitable joints and matching laying tools and equipment. This not only necessitates substantial investment in the research and development and manufacturing of new equipment but also requires retraining of construction personnel to master the new laying techniques. More importantly, the new tubing structure and its associated equipment must undergo a series of rigorous performance tests and safety assessments before being put into use to ensure stable and reliable operation in harsh mining environments such as high pressure and high temperature, which undoubtedly further increases time and economic costs.

[0006] Therefore, developing a brand-new tubing dosing device that can effectively overcome the drawbacks of existing dosing methods, ensure that the chemicals accurately reach the bottom of the oil, and achieve uniform and efficient dosing, without requiring major modifications to the existing tubing structure, has become a key issue that urgently needs to be addressed in the oil extraction field. Summary of the Invention

[0007] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0008] Another objective of this invention is to provide a pipeline chemical dosing device that can guide the chemical agent to be evenly dispersed to the bottom of the oil, optimize the dosing effect, and save costs without altering the existing pipeline structure.

[0009] To achieve these objectives and other advantages according to the present invention, a tubing dosing device is provided, comprising:

[0010] The tubing includes a tubing body, a male tubing connector located at one end of the tubing body, and a female tubing connector located at the other end of the tubing body. The male tubing connectors of adjacent tubings are threadedly connected to the female tubing connectors.

[0011] n connecting flat tubes are tightly fitted to the outer wall of the oil pipe. Any connecting flat tube covers the main oil pipe joint and the oil pipe body along the axial direction of the oil pipe. The n connecting flat tubes are connected in the circumferential direction of the oil pipe to form a complete annular sleeve, where n is an even number.

[0012] In particular, in the direction extending from the main oil pipe joint to the oil pipe body, the width of the inner cavity of the connecting flat tube gradually decreases along the radial direction of the oil pipe, so that the inner cavity of the connecting flat tube forms an enlarged diameter structure at the connection of the upper and lower adjacent oil pipes; the connecting flat tube is made of wear-resistant and corrosion-resistant composite material, and the outer wall of the connecting flat tube is provided with an antistatic coating.

[0013] Preferably, the connecting flat tube is a single-section or two-section type, wherein the two-section type includes a joint section adapted to the main oil pipe joint and an oil pipe section adapted to the oil pipe body. From the main oil pipe joint to the oil pipe body, the width of the inner cavity of the connecting flat tube of the joint section and the oil pipe section gradually decreases along the radial direction of the oil pipe, so that the inner cavity of the connecting flat tube of the joint section and the oil pipe section forms an enlarged diameter structure at their connection.

[0014] Preferably, along the axial direction of the oil pipe, an O-ring is provided at the connection point of adjacent connecting flat tubes, and the O-ring is located close to the outer wall of the connecting flat tube; along the circumferential direction of the oil pipe, both ends of the connecting flat tube are provided with downwardly extending grooves, and when adjacent connecting flat tubes are connected, sealant is applied to the edge of the groove.

[0015] Preferably, the connecting flat tube is provided with a reinforcing rib along the axial direction of the oil pipe. The reinforcing rib is a zigzag or S-shaped reinforcing rib, and the reinforcing rib is set below the end face of the connecting flat tube.

[0016] Preferably, the connecting flat tube has multiple guide vanes arranged from top to bottom, each guide vane being spirally arranged, and:

[0017] When the viscosity of the agent is ≤20mPa·s, the spacing of the guide vanes is 20~25mm and the helix angle is 30~35°.

[0018] When 20 mPa·s < reagent viscosity < 100 mPa·s, the spacing of the guide vanes is 15~19 mm, and the helix angle is 36~40°;

[0019] When the viscosity of the agent is ≥100mPa·s, the spacing between the wafers is 8~14mm and the helix angle is 41~48°.

[0020] Preferably, the wear-resistant and corrosion-resistant composite material comprises the following components by weight percentage:

[0021] Low alloy steel matrix: carbon C 0.15%~0.25%, silicon Si 0.3%~0.6%, manganese Mn 0.8%~1.2%, with the balance being iron Fe;

[0022] Alloy strengthening elements: Chromium (Cr) 12%~15%, Nickel (Ni) 3%~5%, Molybdenum (Mo) 1%~2%;

[0023] Dispersed reinforcing phase: 8%~12% titanium carbide particles with a particle size of 0.48~0.52μm, and 3%~5% vanadium carbide particles with a particle size of 12~14μm.

[0024] Preferably, the wear-resistant and corrosion-resistant composite material provides the connecting flat tube with a wear-resistant and corrosion-resistant functional layer, which is prepared by the following method:

[0025] S10. Take the powder of each component according to the proportion and put it into a planetary ball mill. Add zirconia grinding balls at a ball-to-material ratio of 3 to 8:1 and mix thoroughly at a speed of 200 to 300 rpm for 4 to 6 hours. During this period, add 0.3% to 0.5% of zinc stearate as a lubricant according to the total weight of the powder.

[0026] S20. Place the powder mixed in step S10 into a mold and press it under a pressure of 150~200MPa for 2~3 minutes to form a blank.

[0027] S30. Place the green body obtained in step S20 into a vacuum sintering furnace. First, heat it to 800℃ at a heating rate of 10~15℃ / min and hold it at that temperature for 30~60min. Then, heat it to 1250~1300℃ at a heating rate of 5~10℃ / min and hold it at that temperature for 1.5~2.5h. During the sintering process, the vacuum degree inside the furnace should always be ≤5×10⁻⁶. -3 Pa;

[0028] After sintering in steps S40 and S30, the furnace is cooled to 400-500°C, then removed from the furnace and air-cooled. Next, tempering is performed at 600-650°C. After holding at this temperature for 2-3 hours, the material is air-cooled to room temperature to obtain the wear-resistant and corrosion-resistant composite material.

[0029] Preferably, the mixing step of each component powder in step S10 includes two stages, specifically:

[0030] In the first stage, the mixing time is 1~2 hours, the rotation speed is 200~250 rpm, the ball-to-material ratio is 3~5:1, and the particle size of the grinding balls is 1~5 mm.

[0031] Second stage: Mixing time is 3~4 hours, rotation speed is 280~300 rpm, ball-to-material ratio is 6~8:1, and grinding ball particle size is 1~5 mm;

[0032] In the second stage, zinc stearate, accounting for 0.3% to 0.5% of the total powder weight, is added to the mixing system as a lubricant and sprayed evenly through the atomizing nozzle built into the ball mill. After mixing, the particle size distribution D50 of the powder is 10 to 20 μm and the agglomeration index is ≤5%.

[0033] Preferably, an antistatic coating is formed on the outer wall of the connecting flat tube. The antistatic coating has a gradient structure and comprises the following components by mass percentage:

[0034] Polypyrrole 30%~40%; mixed nano-carbon material 10%~20%, which is composed of carbon nanotubes and graphene nanosheets in a mass ratio of 1~2:1, wherein the diameter of the carbon nanotubes is 10~50nm and the length is 1~10μm, and the diameter of the graphene nanosheets is 5~20μm and the thickness is 1~5nm; anti-aging agent 5%~10%, wherein the anti-aging agent is a hindered amine anti-aging agent; plasticizer 3%~5%, wherein the plasticizer is dioctyl phthalate; the balance is polymer matrix;

[0035] Among them, the antistatic coating adopts a gradient structure. In the coating bottom layer near the outer wall of the connecting flat tube, the mixed nano-carbon material accounts for 30-40% of the total mixed nano-carbon material, and the remaining mixed nano-carbon material is enriched in the coating surface layer.

[0036] Preferably, the antistatic coating of the gradient mechanism is achieved by the following spraying method:

[0037] S11. Pyrrole monomer, carbon nanotubes, graphene nanosheets, anti-aging agent and plasticizer are added to an aqueous solution containing surfactant in proportion and fully dispersed under ultrasonic treatment. The ultrasonic power is 200~300W and the ultrasonic time is 30~60min. The bottom layer solution and the top layer solution of the coating are prepared respectively.

[0038] S12. An oxidant is added to the coating underlayer solution and the coating surface solution respectively to initiate the in-situ polymerization reaction of pyrrole monomer. The reaction is continuously stirred during the reaction, the reaction temperature is controlled at 20~30℃, and the reaction time is 6~12h to obtain the antistatic coating underlayer solution and the antistatic coating surface solution.

[0039] S13. The antistatic coating underlayer solution and antistatic coating surface solution obtained in step S12 are uniformly sprayed onto the outer wall of the connecting flat tube by passing them sequentially through a high-pressure airless spraying device. The spraying pressure is 10~15MPa and the spraying thickness is 50~100μm. The thickness ratio of the antistatic coating underlayer to the antistatic coating surface layer is 1:1.

[0040] S14. After spraying, the coating is heat-treated. First, dry it at 60~80℃ for 2~4 hours, and then heat-treat it at 120~150℃ for 1~2 hours.

[0041] The present invention has at least the following beneficial effects:

[0042] Firstly, the oil dosing device provided by this invention, based on the original oil pipe structure, opens an annular cavity on the oil pipe joint and connects it with n connecting flat pipes set on the outer wall of the oil pipe, so as to deliver the agent from the outside of the oil pipe to the bottom of the oil at low cost, optimize the dosing effect, and complete the laying in the oil well without changing the laying tools and equipment.

[0043] Secondly, the present invention further improves upon the invention by setting guide vanes inside the connecting flat tube and adjusting the spacing and spiral angle of the guide vanes according to the viscosity of the agent, thereby creating a stable spiral flow field during the transport process and uniformly transporting the agent to the bottom of the oil product. This can reduce the load on the pumping equipment by more than 30%, especially in heavy oil extraction.

[0044] Thirdly, the annular cavity of the present invention is provided with a zigzag / S-shaped reinforcing rib, which not only ensures the compressive strength of the male and female oil pipe joints, but also, in conjunction with the connecting flat pipe made of wear-resistant and corrosion-resistant material, extends the service life of the oil pipe dosing device in terms of erosion and corrosion resistance, making it suitable for the delivery of various agents.

[0045] Fourth, the present invention designs a dual sealing system of O-ring and groove sealant, combined with the matching design of the outer diameter of the annular sleeve and the oil pipe joint (male oil pipe joint, female oil pipe joint), which improves the pressure resistance of the connection part and effectively prevents the leakage of the agent.

[0046] Fifth, the surface resistivity of the polypyrrole / carbon nanotube / graphene gradient coating provided by this invention is ≤10. 6 With a density of Ω·cm, the material achieves rapid dissipation of static electricity through a gradient distribution of 30-40% nano-carbon material at the bottom layer and 60-70% at the surface layer, which can reduce the risk of static-induced combustion and explosion in highly volatile oil and gas environments.

[0047] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0048] Figure 1 is a schematic diagram of the connection structure of an oil pipe in the prior art;

[0049] Figure 2 is a schematic diagram of the tubing dosing device according to one technical solution of the present invention;

[0050] Figure 3 is a schematic diagram of the structure of an oil pipe dosing device with an O-ring in another technical solution of the present invention;

[0051] Figure 4 is a schematic diagram of the connection structure of the oil pipe-level connecting flat pipe in another technical solution of the present invention;

[0052] 1. Tubing body; 2. Female tubing connector; 3. Male tubing connector; 4. Inner cavity of connecting flat tube; 41. Inner cavity of connector section; 42. Inner cavity of tubing section; 5. Connecting flat tube; 51. Connector section; 52. Tubing section; 6. O-ring; 7. Groove. Detailed Implementation

[0053] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0054] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0055] As shown in Figures 1-4, the present invention provides a tubing chemical dosing device, comprising:

[0056] The oil pipe includes an oil pipe body 1, a male oil pipe connector 3 located at one end of the oil pipe body 1, and a female oil pipe connector 2 located at the other end of the oil pipe body. The male oil pipe connector 3 of the adjacent oil pipe is threadedly connected to the female oil pipe connector 2.

[0057] n connecting flat tubes 5 are tightly attached to the outer wall of the oil pipe. Any one of the connecting flat tubes 5 covers the main oil pipe joint 2 and the oil pipe body 1 along the axial direction of the oil pipe. The n connecting flat tubes 5 are connected in the circumferential direction of the oil pipe to form a complete annular sleeve, where n is an even number.

[0058] In the direction extending from the main oil pipe joint 2 to the oil pipe body 1, the width of the inner cavity 4 of the connecting flat tube gradually decreases along the radial direction of the oil pipe, so that the inner cavity of the connecting flat tube 5 forms an enlarged diameter structure at the connection of adjacent upper and lower oil pipes; the connecting flat tube 5 is made of wear-resistant and corrosion-resistant composite material, and the outer wall of the connecting flat tube 5 is provided with an antistatic coating.

[0059] As shown in Figure 1, the existing oil pipe structure includes an oil pipe body 1 and male oil pipe joint 3 and female oil pipe joint 2 set at both ends of the oil pipe, wherein adjacent oil pipes are connected by threaded connection of male oil pipe joint 3 and female oil pipe joint 2.

[0060] In the above technical solution, the tubing dosing device includes a tubing and n connecting flat tubes 5. The tubing is an existing tubing structure, with a male tubing connector 3 and a female tubing connector 2 at each end. Adjacent tubings are connected by threaded connections between the male tubing connector 3 and the female tubing connector 2, i.e., the external thread of the male tubing connector 3 matches the internal thread of the female tubing connector 2. Threaded connection is a common and mature tubing connection method, and its laying tools are also relatively mature, eliminating the need to develop new laying equipment and tools. The n connecting flat tubes 5 are tightly installed on the outer wall of the existing tubing, forming annular sleeves around the circumference of the tubing. That is, the connecting flat tubes 5 are directly and tightly installed on the outer wall of the existing tubing structure. The inner cavity 4 of the connecting flat tubes serves as the dosing chamber, allowing the tubing dosing device to be laid without new laying tools.

[0061] In the above technical solution, n (n is an even number) connecting flat tubes 5 are attached to the outer wall of the oil pipe. The n connecting flat tubes 5 form a ring-shaped sleeve through a sealing connection, and the agent flows directly within the inner cavity of the ring-shaped sleeve (i.e., the inner cavity of the connecting flat tubes). Even if the connecting flat tubes 5 do not perfectly align axially with the oil pipe due to slight variations in the laying tools during installation, it will not affect the normal flow of the agent. The sealing connection between the n connecting flat tubes 5 can be achieved using sealant. Sealant is applied to the joints of adjacent connecting flat tubes 5 along the circumference of the oil pipe, and a seal is achieved after the sealant cures. The inner cavity 4 of the connecting flat tube gradually decreases in width from top to bottom along its radial direction, thus forming an expanded diameter structure at the connection of the connecting flat tube 5 of adjacent oil pipes. That is, during the delivery process, the agent is always delivered from the small diameter oral cavity to the large diameter oral cavity at the connection, avoiding the risk of leakage. The structure of the inner cavity 4 of the connecting flat tube gradually decreasing in width from top to bottom along its radial direction can be achieved by using a specific mold during the manufacturing of the connecting flat tube 5.

[0062] According to the above technical solution, the upper and lower oil pipes are connected by rotating the male and female oil pipe joints through threads. The dosing pipe (connecting flat tube) is attached to the outer wall of the oil pipe, and n connecting flat tubes are connected by a sealing loop to form a ring sleeve. As the upper and lower oil pipes are gradually tightened by rotating the threads, the male and female oil pipe joints gradually align and approach under the guidance of the threads until they are fully tightened. Since the connecting flat tubes are attached and fixed to the outer wall of the oil pipe, as the oil pipe joints are tightened, the end faces of the upper and lower connecting flat tubes 5 will also gradually align and approach (the connecting flat tubes move together with the oil pipes and do not need to be aligned independently). When the oil pipe joints are fully tightened: the inner cavities of the connecting flat tubes are aligned, thereby forming a continuous agent channel. To ensure reliable connection and sealing, this application designs an expansion structure. The inner cavity of the connecting flat tubes decreases in width from top to bottom, so that the inner cavities of the connecting flat tubes of adjacent oil pipes form an expansion structure at their connection, guiding the agent flow and reducing the risk of leakage. At the same time, O-rings are set at the connection between the connecting flat tubes. When the joint is tightened, the O-rings are compressed to achieve further sealing.

[0063] In the above technical solution, the connecting flat tube 5 is made of wear-resistant and corrosion-resistant composite material, which can resist the corrosion and wear of chemicals in the agent, extend the service life of the connecting flat tube 5, and reduce maintenance costs.

[0064] Based on the above technical solution, the present invention has at least the following beneficial effects:

[0065] 1. The oil pipe dosing device still uses oil pipe thread connection for connection, which is not only tight and reliable, but also able to withstand certain pressure and tension, ensuring the normal delivery of crude oil in the oil pipe and chemical agent outside the oil pipe;

[0066] 2. The n connecting flat tube ring sleeves provide a channel for the delivery of the agent, and there is no need to consider the error of the thread rotation. The special structure of the expanded diameter can not only prevent leakage, but also buffer and adjust the flow rate of the agent when it enters the connecting flat tube, which is conducive to more uniform distribution and delivery of the agent.

[0067] 3. The connecting flat tube 5 is made of wear-resistant and corrosion-resistant composite material, which can resist the corrosion and wear of chemicals in the agent, extend the service life of the connecting flat tube 5, reduce the maintenance cost of the oil pipe dosing device, and prevent static electricity accumulation during the agent transportation process, avoid safety accidents caused by static electricity, and greatly improve the safety of the device.

[0068] In one technical solution, the connecting flat tube is either a single-section or a two-section type. The two-section type includes a connector section 51 adapted to the main oil pipe connector and an oil pipe section 52 adapted to the oil pipe body. From the main oil pipe connector towards the oil pipe body, the width of the inner cavity of both the connector section and the oil pipe section gradually decreases radially, creating an expanded diameter structure at their connection point. This two-section structure accurately matches the different external contours of the main oil pipe connector and the oil pipe body 1, improving the stability of the fitting section and the structure, while also reducing overall processing difficulty. The inner cavity 41 of the connector section and the inner cavity 42 of the oil pipe section both gradually narrow from the main oil pipe connector towards the oil pipe body, forming a continuous expanded diameter structure at the connection point. This facilitates smooth flow and distribution of the reagent, reducing resistance and deposition.

[0069] In one of the technical solutions, along the axial direction of the oil pipe, an O-ring 6 is provided at the connection of adjacent connecting flat tubes, and the O-ring 6 is located close to the outer wall of the connecting flat tube 5; along the circumference of the oil pipe, the two ends of the connecting flat tube are provided with downwardly extending grooves 7, and when adjacent connecting flat tubes are connected, sealant is applied to the edge of the groove.

[0070] In the above technical solution, an annular groove for installing the O-ring 6 is pre-machined at the connection point of the connecting flat tubes 5. The annular groove is located close to the outer wall of the connecting flat tube 5, and its size matches the size of the O-ring 6, ensuring that the O-ring 6 can be tightly embedded in the annular groove. When the connecting flat tubes 5 are joined, the O-ring 6 is always positioned within the annular groove, subjected to a certain compressive force, thereby achieving a sealed connection between the connecting flat tubes 5. Due to the good elasticity of the O-ring 6, after the connecting flat tubes are compressed, it can fit tightly between the contact surfaces, effectively filling tiny gaps and preventing leakage of the agent from the connection. The O-ring 6's location close to the outer wall of the connecting flat tube 5 also serves as a buffer and isolation mechanism, reducing direct friction and wear between the connecting flat tubes 5, helping to extend the service life of the connection and improve the reliability and stability of the entire device.

[0071] In the above technical solution, downward-extending grooves 7 are machined at both ends of the connecting flat tube 5 (referring to the two ends of one end of the connecting flat tube 5, i.e., the two ends along the circumference of the oil pipe). The preferred depth of the grooves 7 is 5-10 mm, and the width is less than the width of the connecting flat tube 5. When adjacent connecting flat tubes 5 are connected to form a ring sleeve, sealant is applied to the edge of the grooves 7. The sealant can be an oil-resistant and chemically resistant polyurethane sealant or a silicone sealant. The sealant in the grooves 7 can fill the tiny gaps caused by processing errors or installation deformation of the connecting flat tubes 5, especially under vibration conditions, ensuring the sealing between the connecting flat tubes 5, effectively controlling the leakage rate of the agent, and further improving the sealing performance of the entire device. Moreover, the synergistic effect of the sealant and the wear-resistant and corrosion-resistant composite material can effectively resist the erosion of chemicals in the agent and extend the sealing life.

[0072] In one technical solution, a reinforcing rib is provided along the axial direction of the oil pipe inside the connecting flat tube. The reinforcing rib is a zigzag or S-shaped reinforcing rib, and the reinforcing rib is set below the end face of the connecting flat tube.

[0073] In the above technical solution, the zigzag or S-shaped reinforcing rib is integrally cast with the connecting flat tube 5. During casting, it is ensured that the reinforcing rib is lower than the end face of the connecting flat tube, meaning that the inner cavity of the connecting flat tube at both ends of the reinforcing rib remains a complete annulus, effectively preventing the problem of obstruction points during drug delivery. The zigzag or S-shaped reinforcing rib can disperse and bear external forces in multiple directions, effectively enhancing the structural strength of the connecting flat tube and improving its resistance to pressure and deformation, allowing the connecting flat tube to remain stable even under high pressure and complex working conditions. The reinforcing rib is set lower than the end face of the connecting flat tube to avoid interfering with the delivery of the drug and will not hinder the flow of the drug, ensuring the stability of the drug dosing process. In the above technical solution, the reinforcing rib can also be set in a wavy or honeycomb shape.

[0074] In one technical solution, the connecting flat tube 5 is provided with multiple guide vanes from top to bottom, each guide vane being arranged in a spiral shape, and:

[0075] When the viscosity of the agent is ≤20mPa·s, the spacing of the guide vanes is 20~25mm and the helix angle is 30~35°.

[0076] When 20 mPa·s < reagent viscosity < 100 mPa·s, the spacing of the guide vanes is 15~19 mm, and the helix angle is 36~40°;

[0077] When the viscosity of the agent is ≥100mPa·s, the spacing between the wafers is 8~14mm and the helix angle is 41~48°.

[0078] In the above technical solution, based on the wear-resistant and corrosion-resistant requirements of the connecting flat tube 5, a material compatible with the connecting flat tube 5 is selected to manufacture the guide vanes, such as using the same material as the connecting flat tube 5. The guide vanes are sheet-like or rib-like structures protruding from the inner wall of the connecting flat tube towards the center of the cavity. They are usually integrally formed with the connecting flat tube body, and their cross-sectional shape can be streamlined (such as an airfoil section) or rectangular, designed to guide the fluid and reduce flow resistance. Each guide vane does not extend straight along the long axis of the connecting flat tube (i.e., the oil pipe axis), but rather extends along the inner wall in a spiral trajectory. Multiple guide vanes within the entire connecting flat tube form a set of multi-headed spirals with equal pitch. All guide vanes are fixed to the side wall of the connecting flat tube and extend towards the center of the cavity. Their spiral directions are consistent, collectively causing the liquid to generate a stable tangential velocity while flowing downwards, thus forming a downward-falling flow field. The connecting flat tube 5, with its varying guide vane arrangement, is selected based on the viscosity of the chemical agent. For low-viscosity agents (viscosity ≤ 20 mPa·s), a larger guide vane spacing and a smaller helical angle allow for smoother flow of the agent within the connecting flat tube 5, reducing flow resistance. Simultaneously, the helical guide vanes still guide the agent to form a certain helical flow, facilitating better agent delivery. For medium-viscosity agents (20 mPa·s < viscosity < 100 mPa·s), a suitable guide vane spacing and helical angle increase the contact area and time between the agent and the guide vanes, enhancing the guiding effect. For high-viscosity agents (viscosity ≥ 100 mPa·s), a smaller guide vane spacing and a larger helical angle provide greater resistance and stronger guiding force, overcoming the high viscosity of the agent and ensuring smooth flow within the connecting flat tube 5 and uniform addition to the crude oil. By selecting connecting flat tubes 5 with different guide vane arrangements based on agent viscosity, the tubing dosing device can be adapted to agents of varying viscosities, improving its versatility and applicability.

[0079] In one of the technical solutions, the wear-resistant and corrosion-resistant composite material comprises the following components by weight percentage:

[0080] Low alloy steel matrix: carbon C 0.15%~0.25%, silicon Si 0.3%~0.6%, manganese Mn 0.8%~1.2%, balance iron Fe;

[0081] Alloy strengthening elements: Chromium (Cr) 12%~15%, Nickel (Ni) 3%~5%, Molybdenum (Mo) 1%~2%;

[0082] Dispersed reinforcing phase: 8%~12% titanium carbide particles with a particle size of 0.48~0.52μm, and 3%~5% vanadium carbide particles with a particle size of 12~14μm.

[0083] In the above technical solution, the wear-resistant and corrosion-resistant composite material is mainly composed of Fe. The low-alloy steel matrix is ​​supplemented with C to increase hardness, Si to enhance toughness, and Mn to improve hardenability. Among the alloying strengthening elements, Cr is used to form a dense oxide film to improve corrosion resistance, Ni is used for solid solution strengthening and to enhance low-temperature toughness, and Mo is used to suppress temper brittleness. In the dispersed reinforcing phase, TiC particles pin grain boundaries through nanoparticles, improving the material's hardness and wear resistance, while VC particles are used to form a second phase for strengthening, improving the material's erosion resistance. This invention utilizes the synergistic effect of the Cr-Ni-Mo system to improve the corrosion resistance of the connecting flat tube 5. The VC-TiC gradient strengthening mechanism optimizes the wear resistance of the connecting flat tube 5. VC particles form a skeleton structure, extending the erosion wear life to 2-3 times that of traditional materials. The grain boundary strengthening of TiC drastically increases the hardness of the connecting flat tube 5, improving its anti-adhesive wear capability by at least 40%. Finally, by controlling the C content, impact toughness is improved, preventing brittle fracture.

[0084] In the above technical solution, the mass fraction of Cr can be reduced to 8-10%, and the missing mass fraction of Cu can be supplemented to form a Cu2O film resistant to CO2 corrosion, which can be applied to carbon dioxide flooding wells. To further improve the wear resistance of the connecting flat tube 5, some TiC particles can be replaced with WC particles.

[0085] In one of the technical solutions, the wear-resistant and corrosion-resistant composite material gives the connecting flat tube a wear-resistant and corrosion-resistant functional layer, which is prepared by the following method:

[0086] S10. Take the powder of each component according to the proportion and put it into a planetary ball mill. Add zirconia grinding balls at a ball-to-material ratio of 3 to 8:1 and mix thoroughly at a speed of 200 to 300 rpm for 4 to 6 hours. During this period, add 0.3% to 0.5% of zinc stearate as a lubricant according to the total weight of the powder.

[0087] S20. Place the powder mixed in step S10 into a mold and press it under a pressure of 150~200MPa for 2~3 minutes to form a blank.

[0088] S30. Place the green body obtained in step S20 into a vacuum sintering furnace. First, heat it to 800℃ at a heating rate of 10~15℃ / min and hold it at that temperature for 30~60min. Then, heat it to 1250~1300℃ at a heating rate of 5~10℃ / min and hold it at that temperature for 1.5~2.5h. During the sintering process, the vacuum degree inside the furnace should always be ≤5×10⁻⁶. -3 Pa;

[0089] After sintering in steps S40 and S30, the furnace is cooled to 400-500°C, then removed from the furnace and air-cooled. Next, tempering is performed at 600-650°C. After holding at this temperature for 2-3 hours, the material is air-cooled to room temperature to obtain the wear-resistant and corrosion-resistant composite material.

[0090] In the above technical solution, according to the mass percentage requirements of each component of the wear-resistant and corrosion-resistant composite material, the powders of the low-alloy steel matrix (carbon, silicon, manganese, iron), alloying reinforcing elements (chromium, nickel, molybdenum), and dispersed reinforcing phases (titanium carbide particles, vanadium carbide particles) are accurately weighed. The weighed powder is placed in the grinding jar of a planetary ball mill, and zirconia grinding balls are added at a ball-to-powder ratio of 3~8:1. Zirconia grinding balls have high hardness and good wear resistance, and can effectively grind and mix the powder. The planetary ball mill is started and ball milling is performed at a speed of 200~300 rpm for 4~6 hours. During the ball milling process, when the ball milling reaches a certain stage, zinc stearate is added as a lubricant at 0.3%~0.5% of the total weight of the powder. Zinc stearate can reduce the friction between the powder and the grinding jar and grinding balls, prevent powder agglomeration, and improve the uniformity of mixing.

[0091] In the above technical solution, the mixed powder from step S10 is uniformly filled into a mold. A press is used to apply a pressure of 150-200 MPa to the powder in the mold and maintain it for 2-3 minutes, allowing the powder to bind tightly under pressure, thus forming a green body with a certain shape and strength. The green body obtained in step S20 is then placed in a vacuum sintering furnace. The furnace is started, and the temperature is first raised to 800℃ at a heating rate of 10-15℃ / min and held for 30-60 minutes. This step is mainly to remove impurities such as lubricant and moisture from the green body. Then, the temperature is further raised to 1250-1300℃ at a rate of 5-10℃ / min and held for 1.5-2.5 hours. During this high-temperature stage, diffusion and fusion occur between the powder particles, gradually densifying the green body. Throughout the sintering process, the vacuum level inside the furnace is maintained at ≤5×10⁻⁵ using a vacuum pump and other equipment. -3 Pa prevents oxidation of the green body at high temperatures, ensuring sintering quality. After sintering, the green body is allowed to cool in the furnace to 400-500℃. Furnace cooling allows for a uniform transformation of the internal microstructure of the green body, reducing internal stress. When the furnace temperature drops to 400-500℃, the green body is removed from the furnace and cooled in air. The air-cooled green body is then placed in a tempering furnace, heated to 600-650℃, held for 2-3 hours, and then air-cooled again to room temperature. Tempering eliminates residual stress in the green body, improving the toughness and stability of the material.

[0092] In the above technical solution, a planetary ball mill with appropriate ball-to-powder ratio, rotation speed, and milling time ensures thorough mixing of the powder components, guaranteeing a uniform distribution of the composite material composition. The addition of zinc stearate further enhances the mixing effect, preventing powder agglomeration and allowing for better interaction between components during subsequent sintering, thus improving material properties. Pressing the green body under high pressure ensures close contact between powder particles, increasing the density and strength of the green body and laying a solid foundation for further densification during sintering, while reducing shrinkage and defects. Simultaneously, a staged heating and holding method gradually removes impurities and ensures uniform heating of the green body, preventing cracking or other defects caused by excessively rapid heating. Sintering in a vacuum environment prevents oxidation, ensuring the performance of alloying elements and reinforcing phases, and improving material purity and quality. Finally, a combination of furnace cooling and air cooling controls the material's microstructure transformation process and reduces internal stress. Tempering further eliminates residual stress, improves the material's toughness and fatigue resistance, resulting in superior overall performance and extending the material's service life in practical applications.

[0093] In one technical solution, the mixing step of the component powders in step S10 includes two stages, specifically:

[0094] In the first stage, the mixing time is 1~2 hours, the rotation speed is 200~250 rpm, the ball-to-material ratio is 3~5:1, and the particle size of the grinding balls is 1~5 mm.

[0095] Second stage: Mixing time is 3~4 hours, rotation speed is 280~300 rpm, ball-to-material ratio is 6~8:1, and grinding ball particle size is 1~5 mm;

[0096] In the second stage, zinc stearate, accounting for 0.3% to 0.5% of the total powder weight, is added to the mixing system as a lubricant and sprayed evenly through the atomizing nozzle built into the ball mill. After mixing, the particle size distribution D50 of the powder is 10 to 20 μm and the agglomeration index is ≤5%.

[0097] In the above technical solution, the mass percentages of each component in the corrosion-resistant composite material are determined by accurately weighing the powders of the low-alloy steel matrix (carbon, silicon, manganese, iron), alloying reinforcing elements (chromium, nickel, molybdenum), and dispersed reinforcing phases (titanium carbide particles, vanadium carbide particles). These powders are placed in the grinding jar of a planetary ball mill, and zirconia grinding balls with a particle size of 1-5 mm are added at a ball-to-powder ratio of 3-5:1. The planetary ball mill is set to a speed of 200-250 rpm and mixed for 1-2 hours. This stage primarily aims to initially disperse and allow the powder components to come into contact with each other, laying the foundation for more uniform mixing in the subsequent stages. At the beginning of the second stage, zinc stearate, accounting for 0.3%-0.5% of the total powder weight, is uniformly sprayed into the mixing system as a lubricant through the atomizing nozzle built into the ball mill. The atomizing nozzle ensures that the zinc stearate is evenly distributed in the powder, better exerting its lubricating effect. Adjust the ball mill speed to 280-300 rpm and the ball-to-powder ratio to 6-8:1, and continue mixing for 3-4 hours. At higher speeds and ball-to-powder ratios, the impact and grinding action of the grinding balls on the powder is stronger, further refining the powder and ensuring uniform distribution of the components. Staged mixing allows for adjustment of ball mill parameters according to the needs of different stages. The lower speed and ball-to-powder ratio in the first stage prevent excessive powder agglomeration, allowing the powder components to initially disperse. The higher speed and ball-to-powder ratio in the second stage further refine the powder and enhance the mixing effect, resulting in a more uniform distribution of the components throughout the system. Simultaneously, zinc stearate is added in the second stage. At this point, the powder already has a certain degree of dispersion; uniform spraying through an atomizing nozzle allows for better coating of the powder particles, reducing friction between powder particles, preventing agglomeration, and further improving the uniformity of mixing. The different ball milling parameter settings in the two stages help to precisely control the particle size distribution of the powder. The first stage is for initial refinement, and the second stage further refines and makes the particle size more uniform, ultimately achieving a particle size distribution D50 of 10-20 μm and an agglomeration index ≤5%. A suitable particle size distribution is beneficial to the subsequent pressing and sintering processes, improving the density and performance of the material.

[0098] In one technical solution, an antistatic coating is formed on the outer wall of the connecting flat tube. The antistatic coating has a gradient structure and includes the following components by mass percentage:

[0099] Polypyrrole 30%~40%; mixed nano-carbon material 10%~20%, which is composed of carbon nanotubes and graphene nanosheets in a mass ratio of 1~2:1, wherein the diameter of the carbon nanotubes is 10~50nm and the length is 1~10μm, and the diameter of the graphene nanosheets is 5~20μm and the thickness is 1~5nm; anti-aging agent 5%~10%, wherein the anti-aging agent is a hindered amine anti-aging agent; plasticizer 3%~5%, wherein the plasticizer is dioctyl phthalate; the balance is polymer matrix;

[0100] Among them, the antistatic coating adopts a gradient structure. In the coating bottom layer near the outer wall of the connecting flat tube 5, the mixed nano-carbon material accounts for 30-40% of the total mixed nano-carbon material, and the remaining mixed nano-carbon material is enriched in the coating surface layer.

[0101] In the above technical solution, the antistatic coating adopts a gradient structure. In the coating bottom layer near the outer wall of the connecting flat tube 5, the mixed nano-carbon material accounts for 30-40% of the total mixed nano-carbon material, while in the coating surface layer away from the outer wall of the connecting flat tube 5, the mixed nano-carbon material accounts for 60-70% of the total mixed nano-carbon material, forming a gradient antistatic grid. This improves the antistatic ability by 2-5 times compared to a uniform coating. Among them, the 60-70% mixed nano-carbon material in the surface layer forms a dense conductive network. When the agent flows and generates static electricity, the high concentration of nano-carbon in the surface layer can quickly capture and conduct away the charge, reducing the surface resistivity to 10. 6 ~10 8 The coating, with a thickness of Ω·cm, features a bottom layer of 30-40% nano-carbon that enhances adhesion between the coating and the substrate through mechanical interlocking, preventing coating peeling due to vibration and ensuring the continuity of the conductive network. Simultaneously, carbon nanotubes in the mixed nano-carbon material form long-range conductive channels spanning the micropores within the coating, while graphene nanosheets cover a larger surface area, filling the conductive gaps between carbon nanotubes. The synergistic effect of these two materials drastically reduces the permeation threshold, lowering costs while improving conductivity, thus enhancing the coating's antistatic properties. Polypyrrole, as a conductive polymer, forms delocalized π bonds after doping, creating a "conductive polymer-nano-carbon" composite conductive system with the nano-carbon material. The bottom layer of polypyrrole forms an interfacial conductive layer with the nano-carbon, while the surface layer of polypyrrole forms a rapid conductive path with the high concentration of nano-carbon, improving charge migration rate. Dioctyl phthalate (DAPI) increases the coating's elongation at break to 20-30%, maintaining the integrity of the conductive network even under pipe vibration and preventing electrostatic accumulation due to cracking. High-pressure atomization ensures uniform dispersion of the nano-carbon material within the coating, reducing agglomeration.

[0102] In one of the technical solutions, the antistatic coating of the gradient mechanism is achieved through the following spraying method:

[0103] S11. Pyrrole monomer, carbon nanotubes, graphene nanosheets, anti-aging agent and plasticizer are added to an aqueous solution containing surfactant in proportion and fully dispersed under ultrasonic treatment. The ultrasonic power is 200~300W and the ultrasonic time is 30~60min. The bottom layer solution and the top layer solution of the coating are prepared respectively.

[0104] S12. An oxidant is added to the coating underlayer solution and the coating surface solution respectively to initiate the in-situ polymerization reaction of pyrrole monomer. The reaction is continuously stirred during the reaction, the reaction temperature is controlled at 20~30℃, and the reaction time is 6~12h to obtain the antistatic coating underlayer solution and the antistatic coating surface solution.

[0105] S13. The antistatic coating underlayer solution and antistatic coating surface solution obtained in step S12 are uniformly sprayed onto the outer wall of the connecting flat tube 5 by passing them sequentially through a high-pressure airless spraying device. The spraying pressure is 10~15MPa and the spraying thickness is 50~100μm. The thickness ratio of the antistatic coating underlayer to the antistatic coating surface layer is 1:1.

[0106] S14. After spraying, the coating is heat-treated. First, dry it at 60~80℃ for 2~4 hours, and then heat-treat it at 120~150℃ for 1~2 hours.

[0107] In the above technical solution, the surfactant can be sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, Tween-80, or polyethylene glycol octylphenyl ether. The surfactant improves the dispersion effect of each component by means of good emulsifying and dispersing properties, electrostatic adsorption, or by reducing the surface tension of the solution, which helps to disperse and stabilize each component.

[0108] In the above technical solution, pyrrole monomer, carbon nanotubes, graphene nanosheets, anti-aging agent, and plasticizer are accurately weighed according to the required mass percentage of the antistatic coating components. Simultaneously, an aqueous solution containing surfactants is prepared, as surfactants can improve the dispersibility of each component in water. The weighed raw materials are added to the surfactant-containing aqueous solution and placed in an ultrasonic device. The ultrasonic power is set to 200-300W, and the ultrasonic time is 30-60 minutes. Under ultrasonic action, particles such as carbon nanotubes and graphene nanosheets are dispersed, preventing agglomeration and forming a uniform dispersion system. A bottom layer solution and a top layer solution are prepared separately, with the bottom layer solution containing 30-40% of the mixed carbon nanomaterials, and the top layer solution containing the remainder. An oxidant (such as ferric chloride) is added to the bottom layer solution and the top layer solution prepared in step S11. The oxidant initiates the in-situ polymerization reaction of pyrrole monomers to generate polypyrrole. During the reaction, the solution is continuously stirred using a stirring device to ensure uniform reaction. Meanwhile, the reaction temperature is controlled at 20~30℃, and the reaction time is 6~12h. Suitable temperature and time ensure the polymerization reaction proceeds fully, generating polypyrrole with good properties. After the reaction, an antistatic coating underlayer solution and an antistatic coating surface solution are obtained. The antistatic coating underlayer solution and the antistatic coating surface solution obtained in step S12 are then uniformly sprayed onto the outer wall of the connecting flat tube 5 using a high-pressure airless spraying device. The spraying pressure is set to 10~15MPa, which allows the solution to be sprayed onto the tube wall in a good atomized state, ensuring the uniformity of the coating. The spraying thickness is controlled at 50~100μm, and the thickness ratio of the antistatic coating underlayer to the antistatic coating surface is 1:1. After spraying, the coated connecting flat tube 5 is placed in a heating device and dried at 60~80℃ for 2~4h. This process removes moisture and solvent from the coating, allowing the coating to initially cure. Then, the temperature is raised to 120~150℃ for 1~2h of heat treatment. High-temperature heat treatment can promote further cross-linking and curing of polypyrrole, and improve the performance of the coating, such as hardness, adhesion and conductivity.

[0109] In the above technical solution, ultrasonic dispersion allows carbon nanotubes and graphene nanosheets to be uniformly dispersed in the solution, avoiding agglomeration. This results in a more uniform conductive network in the final coating, improving its antistatic properties. In-situ polymerization causes polypyrrole to grow around the carbon nanotubes and graphene nanosheets, forming a tight bond and enhancing the stability of the conductive network, further improving the antistatic effect. High-pressure airless spraying equipment allows the solution to be sprayed uniformly onto the outer wall of the connecting flat tube 5, ensuring the uniformity of coating thickness and surface smoothness. Appropriate spraying pressure and thickness control help form a high-quality coating, improving its adhesion and protective performance. Separate preparation and spraying of the base and top solutions, along with a 1:1 thickness ratio, enables a gradient structure design for the coating, achieving a good balance between antistatic performance and adhesion to the substrate. The heat treatment process is carried out in stages, first with low-temperature drying to remove moisture and solvents, preventing bubbles and cracks in the coating. Then, high-temperature heat treatment promotes the cross-linking and curing of polypyrrole, improves the hardness, wear resistance and chemical stability of the coating, and extends the service life of the coating.

[0110] The following is a specific embodiment of the tubing dosing device of this application used in a heavy oil well, which aims to solve the problem that viscosity-reducing agents are difficult to disperse evenly to the bottom of the tubing during heavy oil extraction.

[0111] The connecting flat tube material is a wear-resistant and corrosion-resistant composite material with the following composition (by weight):

[0112] Low alloy steel matrix: C 0.20%, Si 0.45%, Mn 1.0%, Fe balance (65.85%); Alloying strengthening elements: Cr 13%, Ni 4%, Mo 1.5%; Dispersed reinforcing phase: TiC particles 10% (particle size 0.50μm), VC particles 4% (particle size 13μm).

[0113] Preparation method: Mixing: The above-mentioned powder components were placed in a planetary ball mill and mixed in two stages. First stage: ball-to-powder ratio 4:1, speed 230 rpm, mixing for 1.5 h; Second stage: ball-to-powder ratio 7:1, speed 290 rpm, initially spraying in 0.4% zinc stearate, mixing for 3.5 h. The final powder D50 was 15 μm, and the agglomeration index was ≤5%. Pressing: The powder was pressed at 180 MPa for 2.5 min to form a green body. Sintering: The green body was sintered under a vacuum degree ≤5×10⁻⁶. -3 Under Pa conditions, the temperature was increased to 800℃ at 12℃ / min and held for 45 min, then increased to 1280℃ at 8℃ / min and held for 2 h. Post-treatment: the furnace was cooled to 450℃ and then air-cooled, followed by tempering at 630℃ for 2.5 h, and then air-cooled to room temperature.

[0114] The antistatic coating employs a gradient structure with the following composition (by weight): polypyrrole: 35%; mixed nano-carbon materials: 15% (carbon nanotubes: graphene nanosheets = 1.5:1, carbon nanotube diameter 30nm, length 5μm; graphene sheet diameter 12μm, thickness 3nm); hindered amine anti-aging agent: 7%; dioctyl phthalate: 4%; polymer matrix: balance. The bottom layer of the coating contains 35% of the total nano-carbon materials, while the surface layer is enriched with 65%.

[0115] Spraying method: Separate primer and topcoat dispersions were prepared and ultrasonically dispersed (250W, 45min). An oxidant was then added and the mixture was stirred at 25℃ for 9h to initiate in-situ polymerization of pyrrole. The primer and topcoat solutions were sprayed sequentially using a high-pressure airless spraying device at a pressure of 12MPa, with a total thickness of 80μm (40μm for the primer and 40μm for the topcoat). After spraying, the mixture was dried at 70℃ for 3h and then heat-treated at 135℃ for 1.5h.

[0116] The tubing chemical dosing device consists of a standard tubing and six connecting flat tubes (n=6) attached to its outer wall. These connecting flat tubes are circumferentially sealed to form a complete annular casing. The standard tubing includes the tubing body, a male tubing connector, and a female tubing connector, with a structure consistent with existing oil well tubing. Adjacent tubing sections are connected by threads. The connecting flat tubes employ a two-section design, including a connector section that conforms to the shape of the female tubing connector and a tubing section that conforms to the tubing body. Extending from the female tubing connector towards the tubing body, the radial width of both the connector section and the tubing section gradually decreases, creating a widening structure at the joint of the connecting flat tubes, facilitating smooth chemical transfer and reducing residue. Along the tubing axis, the mating ends of adjacent connecting flat tubes have annular grooves with embedded fluororubber O-rings for sealing. Along the circumference of the tubing, each connecting flat tube has grooves 8mm deep machined on both sides of its edges. During installation, oil-resistant silicone sealant is applied to these grooves to achieve a circumferential seal. S-shaped reinforcing ribs are axially arranged inside the connecting flat tubes, with the height of the ribs lower than the end face of the connecting flat tubes to ensure the continuity of the reagent channel is not affected. For the viscosity-reducing reagent used in this embodiment, which has a viscosity of approximately 85 mPa·s, spiral guide vanes are installed on the inner wall of the connecting flat tubes. The vane spacing is 17mm, and the spiral angle is 38° to create a stable spiral flow field for the reagent, enhancing the delivery effect to the bottom of the well.

[0117] When implemented in a heavy oil well, the tubing dosing device of this embodiment, compared with the traditional direct dosing method, demonstrated that: viscosity-reducing agents were delivered more evenly and quickly to the bottom oil; the operating current of the pumping unit motor decreased by approximately 32%, effectively reducing equipment load and energy consumption; there were no leaks at the flat pipe joints; and the entire device operated for over 12 months in a high-pressure, high-sulfur environment downhole without significant corrosion or wear; and the surface resistivity of the antistatic coating on the outer surface of the device remained stable at 5 × 10⁻⁶. 6With a strength of approximately Ω·cm, it effectively prevents the risk of static electricity buildup in oil and gas environments.

[0118] The number of devices and processing capacity described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the tubing chemical dosing device of the present invention will be readily apparent to those skilled in the art.

[0119] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A pipeline chemical dosing device, wherein the pipeline chemical dosing device is capable of guiding the agent to be evenly dispersed to the bottom of the oil, comprising: The tubing includes a tubing body, a male tubing connector at one end of the tubing body, and a female tubing connector at the other end of the tubing body. The male and female tubing connectors of adjacent tubing are threaded together. There are n connecting flat tubes, each with an inner and outer wall, forming an inner cavity between them. When the tubing connectors are fully tightened, the inner cavities of the connecting flat tubes align, forming a continuous drug channel. The width of the inner cavity of the connecting flat tubes decreases from top to bottom, and the connecting flat tubes fit tightly against the tubing. On the outer wall of the tubing, any connecting flat tube covers the main tubing joint and the tubing body along the tubing axis. n connecting flat tubes are connected in the circumferential direction of the tubing to form a complete annular sleeve, where n is an even number. In the direction extending from the main tubing joint to the tubing body, the width of the inner cavity of the connecting flat tube gradually decreases in the radial direction of the tubing, so that the inner cavity of the connecting flat tube forms an expanded diameter structure at the connection of adjacent tubing sections. The connecting flat tube is made of wear-resistant and corrosion-resistant composite material, and an antistatic coating is provided on the outer wall of the connecting flat tube.

2. The tubing dosing device as described in claim 1, characterized in that, The connecting flat tube is a single-section or two-section type. The two-section type includes a joint section adapted to the main oil pipe joint and an oil pipe section adapted to the oil pipe body. From the main oil pipe joint to the oil pipe body, the width of the inner cavity of the connecting flat tube of the joint section and the oil pipe section gradually decreases along the radial direction of the oil pipe, so that the connection between the inner cavity of the connecting flat tube of the joint section and the oil pipe section forms an enlarged diameter structure.

3. The tubing dosing device as described in claim 1, characterized in that, Along the axial direction of the oil pipe, an O-ring is provided at the connection of adjacent connecting flat tubes, and the O-ring is located near the outer wall of the connecting flat tube; along the circumference of the oil pipe, the two ends of the connecting flat tube are provided with downwardly extending grooves, and when adjacent connecting flat tubes are connected, sealant is applied to the edge of the groove.

4. The tubing dosing device as described in claim 1, characterized in that, The connecting flat tube is provided with reinforcing ribs along the axial direction of the oil pipe. The reinforcing ribs are either zigzag or S-shaped and are positioned below the end face of the connecting flat tube.

5. The tubing dosing device as described in claim 1, characterized in that, The connecting flat tube is provided with multiple guide vanes from top to bottom. Each guide vane is arranged in a spiral shape, and: when the drug viscosity is ≤20mPa·s, the spacing between the guide vanes is 20~25mm and the spiral angle is 30~35°; when 20mPa·s < drug viscosity <100mPa·s, the spacing between the guide vanes is 15~19mm and the spiral angle is 36~40°; when the drug viscosity is ≥100mPa·s, the spacing between the guide vanes is 8~14mm and the spiral angle is 41~48°.

6. The tubing dosing device as described in claim 1, characterized in that, The wear-resistant and corrosion-resistant composite material comprises the following components by weight percentage: low alloy steel matrix: carbon C 0.15%~0.25%, silicon Si 0.3%~0.6%, manganese Mn 0.8%~1.2%, with the balance being iron Fe; alloying strengthening elements: chromium Cr 12%~15%, nickel Ni 3%~5%, molybdenum Mo 1%~2%; dispersed reinforcing phase: titanium carbide particles 8%~12%, with a particle size of 0.48~0.52μm, and vanadium carbide particles 3%~5%, with a particle size of 12~14μm.

7. The tubing dosing device as described in claim 6, characterized in that, The wear-resistant and corrosion-resistant composite material provides the connecting flat tube with a wear-resistant and corrosion-resistant functional layer. It is prepared by the following method: S10, placing the powders of each component in a planetary ball mill according to the specified ratio, adding zirconia grinding balls at a ball-to-material ratio of 3-8:1, and mixing thoroughly at 200-300 rpm for 4-6 hours, during which 0.3%-0.5% of zinc stearate by weight of the total powder is added as a lubricant; S20, placing the powder mixed in step S10 into a mold and pressing it under a pressure of 150-200 MPa for 2-3 minutes to form a green body; S30, placing the green body obtained in step S20 into a vacuum sintering furnace, first heating it to 800℃ at a heating rate of 10-15℃ / min and holding it at that temperature for 30-60 minutes, then heating it to 1250-1300℃ at a rate of 5-10℃ / min and holding it at that temperature for 1.5-2.5 hours, ensuring that the vacuum degree inside the furnace remains ≤5×10⁻⁶ throughout the sintering process. -3 Pa; After sintering in steps S40 and S30, the furnace is cooled to 400~500℃, then removed from the furnace and air-cooled. Next, tempering is performed at 600~650℃, and the temperature is maintained for 2~3 hours before air-cooling to room temperature to obtain the wear-resistant and corrosion-resistant composite material.

8. The tubing dosing device as described in claim 7, characterized in that, The mixing step of each component powder in step S10 includes two stages: the first stage, the mixing time is 1-2 hours, the rotation speed is 200-250 rpm, the ball-to-powder ratio is 3-5:1, and the particle size of the grinding balls is 1-5 mm; the second stage, the mixing time is 3-4 hours, the rotation speed is 280-300 rpm, the ball-to-powder ratio is 6-8:1, and the particle size of the grinding balls is 1-5 mm; at the beginning of the second stage, zinc stearate accounting for 0.3%-0.5% of the total weight of the powder is added to the mixing system as a lubricant and is uniformly sprayed in through the atomizing nozzle built into the ball mill; after the mixing is completed, the particle size distribution D50 of the powder is 10-20 μm, and the agglomeration index is ≤5%.

9. The tubing dosing device as described in claim 1, characterized in that, An antistatic coating is formed on the outer wall of the connecting flat tube. The antistatic coating has a gradient structure and includes the following components by mass percentage: 30%~40% polypyrrole; 10%~20% mixed nano-carbon material, which is composed of carbon nanotubes and graphene nanosheets in a mass ratio of 1~2:1, with the carbon nanotubes having a diameter of 10~50nm and a length of 1~10μm, and the graphene nanosheets having a diameter of 5~20μm and a thickness of 1~5nm; 5%~10% anti-aging agent, which is a hindered amine anti-aging agent; 3%~5% plasticizer, which is dioctyl phthalate; and the balance being a polymer matrix. The antistatic coating adopts a gradient structure, with the mixed nano-carbon material accounting for 30~40% of the total mixed nano-carbon material in the bottom layer of the coating near the outer wall of the connecting flat tube, and the balance being enriched in the surface layer of the coating.

10. The tubing dosing device as described in claim 9, characterized in that, The antistatic coating of the gradient mechanism is achieved through the following spraying method: S11, pyrrole monomer, carbon nanotubes, graphene nanosheets, anti-aging agent, and plasticizer are added to an aqueous solution containing surfactant in proportion, and fully dispersed under ultrasonication. The ultrasonic power is 200~300W, and the ultrasonication time is 30~60min, to prepare the coating bottom layer solution and the coating surface layer solution respectively; S12, an oxidant is added to the coating bottom layer solution and the coating surface layer solution respectively to initiate the in-situ polymerization reaction of pyrrole monomer. During the reaction, the mixture is continuously stirred, and the reaction temperature is controlled at 20~30℃, and the reaction time is... The process takes 6-12 hours to obtain the antistatic coating underlayer solution and the antistatic coating surface layer solution; S13, the antistatic coating underlayer solution and the antistatic coating surface layer solution obtained in step S12 are uniformly sprayed onto the outer wall of the connecting flat tube by passing them sequentially through a high-pressure airless spraying device. The spraying pressure is 10-15 MPa and the spraying thickness is 50-100 μm, wherein the thickness ratio of the antistatic coating underlayer to the antistatic coating surface layer is 1:1; S14, after the spraying is completed, the coating is heat-treated by first drying at 60-80℃ for 2-4 hours, and then heat-treated at 120-150℃ for 1-2 hours.

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