A tubing scraper

Abstract

The present application belongs to the technical field of oil pipe cleaning tools, and particularly relates to an oil pipe scraper. The oil pipe scraper comprises a center rod, a mechanical scraping structure is arranged on the center rod, and the mechanical scraping structure is used for scraping sulfur or wax on the inner wall of the oil pipe when the center rod moves up and down. A chemical solvent releasing device is arranged on the top of the center rod. The chemical solvent releasing device comprises a main body with a solvent cavity. A liquid outlet is arranged on the chemical solvent releasing device and is used for communicating with the solvent cavity to release the chemical solvent. A center rod connector is arranged below the solvent cavity and is used for connecting with the center rod to move up and down with the center rod. The chemical solvent releasing device further comprises a valve structure corresponding to the center rod connector, which is used for opening the liquid outlet when the center rod is blocked and pushes the center rod connector. A spiral spring is arranged between the main body and the center rod connector.

Description

Technical Field

[0001] This invention belongs to the technical field of oil pipe cleaning tools, specifically relating to an oil pipe scraper. Background Technology

[0002] Scale buildup in oil and gas wells is a common occurrence during oil and gas extraction, especially in high-sulfur gas wells and high-wax oil wells. As oil and gas flow from the formation into the tubing and then to the surface, the solubility of sulfur or wax in the oil and gas gradually decreases with the drop in wellbore pressure and temperature, causing them to precipitate and adhere to the inner wall of the tubing due to viscosity. With prolonged production, the amount and thickness of sulfur or wax adhering to the tubing wall increase, narrowing the tubing cavity and potentially blocking the tubing passage, leading to reduced or even halted production.

[0003] Currently, the technical means to remove sulfur or wax from the inner wall of oil pipes include two types: chemical removal and mechanical removal.

[0004] Chemical removal involves pumping or injecting a sulfur or wax solvent into the tubing while the well or well is shut down to soak the sulfur or wax residue on the inner wall of the tubing. Once the chemical reaction is complete and the sulfur or wax residue on the inner wall of the tubing is removed, the well can be reopened for production. However, the chemical reaction time of the sulfur or wax solvent is short and the effect is poor. This requires a large amount of sulfur or wax solvent and the soaking time is also long, which not only affects production efficiency and has high costs, but is also prone to waste.

[0005] Mechanical removal methods are further divided into hydraulic jetting and mechanical scraping. Hydraulic jetting involves lowering coiled tubing from a winding drum into the tubing while the gas or oil well is shut down. A high-pressure pump at the surface injects water or chemical solvents into the coiled tubing. Through a nozzle at the lower end of the coiled tubing, water is jetted onto the inner wall of the tubing to remove the sulfur or wax deposits. This method requires a large amount of equipment at the surface (coiled tubing, drum frame, coiled tubing blowout preventer, high-pressure injection pump), and a high-pressure nozzle downhole. It involves numerous pieces of equipment, complex operation, and relatively poor reliability. Mechanical scraping, such as the wax scraping device disclosed in patent document CN110280547A, includes a central rod (i.e., the connecting rod in this patent) for connection with a steel wire rope. Two positioning columns are slidably mounted on the central rod, arranged vertically. The device also includes two scraping blades, each with a blade tip at both ends. The two blades are symmetrically arranged, with the upper part connected to the upper positioning column and the lower part connected to the lower positioning column. This allows the blades to move up and down along the axial direction of the central rod with the positioning columns, enabling the blade tips to remove sulfur or wax from the inner wall of the oil pipe. However, to effectively remove the wax or sulfur from the oil pipe wall, the blade tips need to be relatively thin. When the scraping device descends and collides with the harder sulfur or wax on the oil pipe wall, the thin blade tips will be damaged. Frequent replacement of the scraping blades will increase costs.

[0006] Chemical and mechanical methods of cleaning each have their own advantages, but their functions are relatively limited, and neither can guarantee the smooth progress of the cleaning operation when used alone. Summary of the Invention

[0007] The purpose of this invention is to provide an oil pipe scraper to solve the technical problem that existing chemical and mechanical cleaning methods are limited in function and cannot guarantee the smooth progress of cleaning operations.

[0008] To achieve the above objectives, the technical solution for the oil pipe scraper provided by the present invention is as follows: an oil pipe scraper includes a central rod, on which a mechanical scraping structure is provided for scraping sulfur or wax on the inner wall of the oil pipe when the central rod moves up and down. A chemical solvent release device is provided at the top of the central rod. The chemical solvent release device includes a main body having a solvent chamber. The chemical solvent release device is provided with a drain port for communicating with the solvent chamber to release the chemical solvent. A central rod connector is provided below the solvent chamber for connecting to the central rod and moving up and down with the central rod. The chemical solvent release device also includes a valve structure corresponding to the central rod connector, which is used to open the drain port when the central rod is obstructed and pushes the central rod connector upward. A helical spring is provided between the main body and the central rod connector.

[0009] The beneficial effects are as follows: Compared with the prior art, which uses only chemical or mechanical methods for cleaning, the oil pipe scraper provided by this invention has a chemical solvent release device above the center rod. In addition to the mechanical scraping structure on the center rod scraping off sulfur or wax on the inner wall of the oil pipe when the center rod moves up and down, the chemical solvent release device can release chemical solvent into the oil pipe to dissolve and remove sulfur or wax on the inner wall of the oil pipe when the center rod is obstructed from descending. Combining chemical and mechanical cleaning methods can ensure the smooth progress of the cleaning operation. Furthermore, the helical spring can generate a downward tendency for the center rod to move, preventing the center rod from rising to open the drain port when it comes into contact with sulfur or wax of any hardness, thus avoiding waste of chemical solvent.

[0010] As a further improvement, the valve structure includes a drain head connected to the bottom of the main body. The drain head is a hollow structure and includes a cylindrical section and a conical section. The drain port is located on the conical section. The valve structure also includes a sealing piston connected to a central rod. The sealing piston has a conical mating section for sealing with the conical section. The maximum outer diameter of the conical mating section is smaller than the inner diameter of the cylindrical section, so as to form a gap between the sealing piston and the drain head for the passage of chemical solvent when the sealing piston moves upward.

[0011] The beneficial effects are: the drain port can be sealed by the outer circumferential surface of the conical mating section of the sealing piston and the conical section of the drain head. The structure is simple and easy to manufacture.

[0012] As a further improvement, the bottom of the solvent chamber is provided with a spring seat for supporting the helical spring, and the spring seat is provided with a channel for communicating the solvent chamber with the inner cavity of the drain head.

[0013] The beneficial effects are: the spring seat can provide effective support for the helical spring, and can also reduce the diameter of the channel for chemical solvent flow, and increase the pressure when the chemical solvent enters the drain head.

[0014] As a further improvement, the bottom of the main body is closed to form a spring seat, and the solvent cavity is formed above the spring seat. The spring seat is provided with a flow hole for communicating the solvent cavity with the inner cavity of the drain head.

[0015] The beneficial effects are: the bottom of the main body is closed, and a flow hole is set on the spring seat, which can increase the pressure of the chemical solvent entering the drain head, making it easier for the chemical solvent to be discharged.

[0016] As a further improvement, the main body is provided with an injection hole that is opened when chemical solvent is injected into the solvent chamber and closed after the chemical solvent injection is completed.

[0017] The beneficial effect is that operators can inject chemical solvents into the main body through the injection hole, allowing for multiple uses.

[0018] As a further improvement, an upper piston is provided in the solvent chamber, and the outer peripheral surface of the upper piston is sealed to the inner wall of the solvent chamber. The main body is provided with a balance vent that pushes out the air in the solvent chamber when the upper piston moves upward, so as to balance the pressure between the solvent chamber and the outside.

[0019] The beneficial effect is that, due to the long length of the main body, when the oil pipe scraper is assembled and chemical solvent is injected into the main body, the upper piston can discharge the gas in the solvent chamber through the balance vent, avoiding the formation of a dead space in the solvent chamber and facilitating the injection of chemical solvent.

[0020] As a further improvement, multiple scraping gears are arranged sequentially from top to bottom on the central rod. As a mechanical scraping structure, the scraping gears have arc-shaped cutting edges at their tooth tips that are adapted to the arc-shaped inner wall surface of the oil pipe.

[0021] The beneficial effects are: the scraping gear has a larger thickness, greater strength, and is less prone to damage.

[0022] As a further improvement, the central rod is provided with multiple rods, the diameter of each rod decreasing from top to bottom, and the diameter of the scraping gears on different rods decreasing from top to bottom.

[0023] The beneficial effects are: the diameter of each rod decreases from top to bottom, and the diameter of the scraping gear decreases from top to bottom, which can remove sulfur or wax from smaller gaps and improve the applicability.

[0024] As a further improvement, the number of scraping gears on different stages of the rod increases sequentially from top to bottom.

[0025] The beneficial effect is that the more scraping gears on the lower rod, the better the cleaning effect on the inner wall of the oil pipe with small gaps.

[0026] As a further improvement, the arc-shaped cutting edges of each scraping gear on the same level rod can completely cover the inner wall of the oil pipe in the circumferential direction.

[0027] The beneficial effect is that the arc-shaped cutting edge of the scraping gear on the same stage of the rod completely covers the inner wall of the oil pipe, improving the cleaning effect. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the oil pipe scraper provided by the present invention;

[0029] Figure 2 This is a structural schematic diagram of a primary rod.

[0030] Figure 3 This is a structural schematic diagram of a secondary rod.

[0031] Figure 4 This is a schematic diagram of a three-stage rod structure;

[0032] Figure 5 This is a structural schematic diagram of the smallest stage rod;

[0033] Figure 6 for Figure 1 Schematic diagram of the chemical solvent release device;

[0034] Figure 7 for Figure 2 AA cross-section view;

[0035] Figure 8 for Figure 2 BB cross-section.

[0036] Explanation of reference numerals in the attached drawings: 1. Chemical solvent release device; 2. Upper connector; 3. Main body; 4. Drain head; 5. Central rod connector; 6. Central rod; 7. First-stage rod; 8. Second-stage rod; 9. Third-stage rod; 10. Minimum-stage rod; 11. Conical blade; 12. Scraping gear; 13. Mounting groove; 14. Connector; 15. Gear shaft; 16. Gear shaft mounting hole; 17. Gear mounting hole; 18. Upper connector mounting groove; 19. Upper piston; 20. Upper... 21. Piston seal ring; 22. Solvent chamber; 23. Spring seat; 24. Flow hole; 25. Injection hole; 26. Helical spring; 27. Upper spring mounting groove; 28. Lower spring mounting groove; 29. ​​Cylindrical section; 20. Conical section; 31. Drain port; 32. Sealing piston; 33. Steel frame; 34. Rubber seal; 35. Steel frame sealing ring; 36. Drain head sealing ring; 37. Stop head; 38. Shoulder; 39. Limiting step; 30. Balancing vent. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that, in specific embodiments of the present invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply such an actual relationship or order between these entities or operations. Furthermore, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the use of phrases such as "comprising a…" to define an element does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] In the description of this invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] In the description of this invention, unless otherwise explicitly specified and limited, the term "provided with" should be interpreted broadly. For example, the object "provided with" can be a part of the body, or it can be separately arranged from the body and connected to the body. This connection can be a detachable connection or a non-detachable connection. Those skilled in the art can understand the specific meaning of the above terms in this invention through specific circumstances.

[0042] The present invention will be further described in detail below with reference to embodiments.

[0043] Example 1 of the oil pipe scraper provided in this invention:

[0044] like Figure 1 As shown, the tubing scraper includes a central rod 6 and a chemical solvent release device 1. The central rod 6 is equipped with a scraping gear 12, which serves as a mechanical scraping structure and can rotatably remove sulfur or wax from the inner wall of the tubing. The chemical solvent release device 1 is connected to the central rod 6 and is used to discharge chemical solvent when the central rod 6 is obstructed from moving upward, so as to dissolve the sulfur or wax on the inner wall of the tubing.

[0045] like Figure 1As shown, the central rod 6 comprises, from top to bottom, a primary rod 7, a secondary rod 8, a tertiary rod 9, ... and a minimum rod 10. Each rod has a mounting groove 13 at its upper end, with internal threads on the groove wall. Each rod has a connector 14 at its lower end, with external threads on its outer circumference to allow for threaded connection between adjacent rods. The mounting groove 13 at the upper end of the primary rod 7 is used to connect to the chemical solvent release device 1. Figure 5 As shown, the lower end of the minimum stage rod 10 is provided with a tapered blade 11 at a 45° angle to the axis of the minimum stage rod 10.

[0046] Each level of the rod body is provided with multiple gear mounting holes 17. The gear mounting holes 17 are rectangular through holes on the rod body. These rectangular through holes on the same level of rod body 7 are arranged sequentially up and down along the axial direction of their respective rod bodies and are evenly distributed along the circumference of their respective rod bodies, for mounting the scraping gears 12. Figures 2 to 5 As shown, the scraping gears 12 on each stage of the rod are evenly distributed around their respective circumference to more effectively remove sulfur or wax from the inner wall of the oil pipe.

[0047] The assembly method of the scraping gears 12 on each level of the rod is consistent. In this embodiment, the first-level rod 7 is used as an example for explanation. Figure 7 and Figure 8 As shown, the first-stage rod 7 is provided with a gear mounting hole 17, the length direction of which is consistent with the axial direction of the first-stage rod 7. A gear shaft mounting hole 16 is provided on the first-stage rod 7 in the width direction of the gear mounting hole 17, and the gear shaft mounting hole 16 passes through the gear mounting hole 17. After the scraping gear 12 is installed into the gear mounting hole 17, the gear shaft 15 is connected through the first-stage rod 7 and the scraping gear 12 for assembly, so that the scraping gear 12 can rotate around the gear shaft 15. The tooth ends of each scraping gear 12 are provided with arc-shaped cutting edges adapted to the arc surface of the inner wall of the oil pipe. Furthermore, the sum of the arc lengths of two opposite teeth on the same scraping gear 12 on the same stage rod is not less than 1 / n of the circumference of the inner wall of the oil pipe (n is the number of scraping gears 12 on that stage rod), so that the arc-shaped cutting edges of each scraping gear 12 on the same stage rod can completely cover the inner wall of the oil pipe circumferentially.

[0048] To facilitate the removal of sulfur or wax from smaller gaps in the tubing, the diameters of the rods arranged from top to bottom decrease sequentially, the diameters of the scraping gears 12 on different rods decrease sequentially from top to bottom, and the number of scraping gears 12 on different rods increases sequentially.

[0049] like Figure 1 and Figure 6 As shown, the chemical solvent release device 1 includes a main body 3, and a valve structure is provided at the lower end of the main body 3, through which the chemical solvent in the main body 3 can be discharged.

[0050] like Figure 6As shown, the main body 3 is provided with a solvent chamber 21 for holding chemical solvents. The top of the main body 3 is provided with an upper connector mounting groove 18 for threaded connection of an upper connector 2 to the main body 3. The upper connector 2 is used to connect to a wire rope, allowing the oil pipe scraper to be raised or lowered via the wire rope. The upper connector 2 is provided with two symmetrically arranged balancing vents 39, which are used to introduce air from outside the solvent chamber 21 into the solvent chamber 21 to balance the pressure between the solvent chamber 21 and the outside, facilitating the injection of chemical solvents into the solvent chamber 21. An upper piston 19 is also provided in the solvent chamber 21. The outer diameter of the upper piston 19 is adapted to the inner diameter of the solvent chamber 21. It is sealed to the solvent chamber 21 by an upper piston sealing ring 20 and can be axially guided within the solvent chamber 21. This allows the air in the solvent chamber 21 to be discharged through the balancing vents 39, facilitating the upward movement of the sealing piston 31.

[0051] The lower end of the main body 3 is provided with a liquid injection section, which is a solid structure. The liquid injection section has two flow holes 23, which are symmetrically arranged and extend along the axial direction of the main body 3 to connect the solvent chamber 21 of the main body 3 with the inner cavity of the discharge head 4. The circumferential sidewall of the liquid injection section is provided with an injection hole 24, which is perpendicular to and communicates with the flow holes 23, for injecting chemical solvent into the solvent chamber 21 of the main body 3 through the injection hole 24 and the flow holes 23. The lower end of the liquid injection section is provided with an end cap, the outer circumferential surface of which is provided with external threads for connection to a valve structure.

[0052] The valve structure includes a drain head 4, such as Figure 6 As shown, the drain head 4 has a hollow structure, including a cylindrical section 28 and a conical section 29. The cylindrical section 28 is located above the conical section 29. The inner wall of the upper end of the cylindrical section 28 is provided with internal threads for threaded connection to the end of the main body 3. The circumferential sidewall of the conical section 29 is provided with two sets of drain ports 30, each set containing two drain ports 30. The two drain ports 30 in the same set are arranged in parallel and obliquely on the drain head 4 for the discharge of chemical solvents. The bottom end of the conical section 29 is provided with a through hole for the central rod connector 5 in the valve structure to pass through. The circumferential direction of the through hole forms a seat for the sealing piston 31 to be seated.

[0053] The valve structure also includes a sealing piston 31 and a central rod connector 5. The sealing piston 31 is integrally molded from a steel frame 32 and a rubber seal 33. The steel frame 32 has a through hole at its center for the central rod connector 5 to pass through. The overall size of the steel frame 32 is larger than that of the rubber seal 33 to enclose it. Multiple mating grooves are provided on the steel frame 32 at the joint with the rubber seal 33 so that the rubber seal 33 can enter the mating grooves during molding, thereby increasing the mating area between the rubber seal 33 and the steel frame 32 and improving the mating strength. Sealing ring mounting grooves are provided on the wall of the through hole for the central rod connector 5 on the steel frame 32 and on the wall of the hole for the central rod connector 5 on the drain head 4. A steel frame sealing ring 34 is installed in the sealing ring mounting groove of the steel frame 32, and a drain head sealing ring 35 is installed in the sealing ring mounting groove of the drain head 4, so as to achieve sealing between the central rod connector 5 and the steel frame 32, and between the steel frame 32 and the drain head 4, respectively.

[0054] The upper end face of the steel frame 32 is provided with a lower spring mounting groove 27, which is located directly above the perforation. The lower end face of the liquid injection section of the main body 3 is provided with an upper spring mounting groove 26, which is arranged opposite to the lower spring mounting groove 27 for the installation of the helical spring 25. The liquid injection section forms a spring seat 22, which is used to block the helical spring 25 when the sealing piston 31 moves upward.

[0055] The center rod connector 5 has a columnar structure and a shoulder 37 for stopping the assembly with the sealing piston 31. Specifically, the perforation of the steel frame 32, from top to bottom, includes a small-diameter section, a medium-diameter section, and a large-diameter section with a sealing ring mounting groove. A limiting step 38 is formed between the small-diameter section and the medium-diameter section for stopping the assembly with the shoulder 37. The valve structure also includes a stop head 36, which is threaded to the underside of the shoulder 37 on the center rod connector 5. The outer circumferential surface of the stop head 36 has external threads for threaded connection in the large-diameter section, so as to stop the assembly of the center rod connector 5 onto the sealing piston 31.

[0056] When removing sulfur or wax from the inner wall of the tubing, chemical solvent is injected into the main body 3 through the injection hole 24 and the flow hole 23. The main body 3, now filled with the solution, is then pressurized. The first-stage rod 7, second-stage rod 8, third-stage rod 9, ..., and the smallest-stage rod 10 are then connected sequentially. The first-stage rod 7 is threaded onto the lower end of the central rod connector 5. The upper connector 2, installed on the upper end of the main body 3, is then connected to the lower end of the rope cap or weight rod. If the thickness or condition of the scale on the inner wall of the tubing is unknown before installation, the smallest-stage rod 10 can be connected to the central rod connector 5 separately first. Then, the number of rod stages or the combined connection can be gradually increased according to the actual situation.

[0057] The tubing scraper is lowered into the oil and gas test blowout preventer using a wire rope cap and weighted rod. The other end of the wire rope is connected to a test vehicle. The wire rope not lowered into the well is wound around the drum of the test vehicle. Without stopping the well, the tubing scraper is lowered into the scaled tubing using the wire rope cap and weighted rod. Under the weight and inertia of the wire rope cap, weighted rod, and tubing scraper, it impacts downwards and is lifted upwards by the power of the test vehicle. During the downward impact or upward lift, the scraping gears 12 on the first-stage rod 7, second-stage rod 8, third-stage rod 9, ... and the smallest rod 10 will move up and down or rotate to remove sulfur or wax from different radial ranges of the inner wall of the tubing.

[0058] When the tubing scraper encounters resistance during its downward movement, the central rod 6, under the influence of resistance or impact force, drives the central rod connector 5 upward, compressing the helical spring 25 and moving the sealing piston 31 upward. This causes the sealing piston 31 to open the drain port 30, forming an annular gap between the sealing piston 31 and the drain head 4. At this time, the chemical solvent flows out from the drain port 30 through the flow hole 23 and the annular gap. It is important to note that the upward stroke of the central rod connector 5 (i.e., the gap between the upper end face of the sealing piston 31 and the lower end face of the spring seat 22) is less than the upward distance of the steel frame 32 of the sealing piston 31 relative to the drain head 4, to prevent the chemical solvent from leaking between the steel frame 32 and the drain head 4, thus flushing or dissolving the sulfur or wax at the obstructed location. The deposits cut or flushed off will rise with the oil and gas flow and be carried to the ground, thereby achieving the purpose of removing sulfur or wax from different radial ranges inside the tubing. Furthermore, the faster the lifting and lowering speed, the greater the impact force, the better the cutting effect, and the cleaner the inner surface of the tubing.

[0059] After the oil pipe is cleaned, disassemble and soak the high-pressure chemical solvent release device 1, first-stage rod 7, second-stage rod 8, third-stage rod 9, ... and the smallest rod 10 one by one, and clean the sulfur or wax deposits adhering to the rods or scraping gears 12, and apply grease for reuse.

[0060] The tubing scraper provided by this invention, compared with the prior art which uses only chemical or mechanical methods for cleaning, features a chemical solvent release device above the center rod. In addition to the mechanical scraping structure on the center rod scraping away sulfur or wax from the inner wall of the tubing as the center rod moves up and down, the chemical solvent release device releases chemical solvent into the tubing when the center rod is obstructed from descending, dissolving and removing the sulfur or wax from the inner wall. This combination of chemical and mechanical cleaning methods ensures smooth cleaning operations. Furthermore, the helical spring tends to move the center rod downwards, preventing it from rising to open the drain port when in contact with sulfur or wax of any hardness, thus avoiding waste of chemical solvent.

[0061] Embodiment 2 of the oil pipe scraper provided in this invention:

[0062] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the valve structure includes a sealing piston 31, with a conical seal between the sealing piston 31 and the drain head 4, and the sealing piston 31 moves upward to open the drain port 30 on the drain head 4. In this embodiment, the top end of the central rod connector 5 extends upward into the solvent chamber 21, and the valve structure includes a sealing cap at the top end of the central rod connector 5. The sealing cap sits on the upper end face of the spring seat 22 to block the flow hole 23. When the central rod 6 is obstructed from moving downward and pushes the central rod connector 5 upward, the sealing cap moves upward to open the flow hole 23, allowing the chemical solvent to flow out sequentially through the flow hole 23, the gap between the sealing piston 31 and the drain head 4, and the drain port 30.

[0063] Embodiment 3 of the oil pipe scraper provided in this invention:

[0064] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the bottom end of the main body 3 is closed to form a spring seat 22. In this embodiment, the spring seat 22 is a cross seat disposed on the inner wall of the solvent cavity 21 of the main body 3, and the gap between the cross seat and the main body 3 forms a flow hole 23.

[0065] Embodiment 4 of the oil pipe scraper provided in this invention:

[0066] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the top of the main body 3 is provided with a balancing vent 39. In this embodiment, the balancing vent 39 is omitted. It is necessary to first remove the central rod and lay the main body 3 down before injecting liquid into the solvent chamber 21 through the injection hole 24.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A tubing scraper, comprising a center rod (6), wherein the center rod (6) is provided with a mechanical scraping structure for scraping sulfur or wax on the inner wall of the tubing when the center rod (6) moves up and down, characterized in that, A chemical solvent release device (1) is provided at the top of the central rod (6). The chemical solvent release device (1) includes a main body (3) with a solvent chamber (21) and a central rod connector (5) located below the solvent chamber (21) and connected to the central rod (6) to move up and down with it. The main body (3) is provided with a drain port (30) that communicates with the solvent chamber (21) to release the chemical solvent. The chemical solvent release device (1) also includes a valve structure corresponding to the central rod connector (5). The valve structure includes a hollow drain head (4) connected to the bottom of the main body (3) and a sealing piston (31) that is fitted to the central rod connector. The drain head (4) includes a cylindrical section (28) and a valve structure with the aforementioned valve structure. The conical section (29) of the drain port, the sealing piston (31) has a conical mating section for sealing with the conical section (29), and the maximum outer diameter of the conical mating section is smaller than the inner diameter of the cylindrical section (28); the bottom end of the main body (3) is closed to form a spring seat (22), a helical spring (25) is provided between the spring seat (22) and the sealing piston (31), and a flow hole (23) is provided on the spring seat (22) for connecting the solvent chamber (21) and the inner cavity of the drain head (4); when the downward movement of the central rod is blocked, the central rod connector is compressed by the upward movement of the helical spring (25) and pushes the sealing piston upward, so that the sealing piston opens the drain port and forms a gap between it and the drain head for the chemical solvent to pass through.

2. The tubing scraper according to claim 1, characterized in that, The main body (3) is provided with an injection hole (24) for opening when injecting chemical solvent into the solvent chamber (21) and closing after the chemical solvent injection is completed.

3. The tubing scraper according to claim 1, characterized in that, The solvent chamber (21) is provided with an upper piston (19), and the outer peripheral surface of the upper piston (19) is sealed with the inner wall of the solvent chamber (21). The main body (3) is provided with a balance vent (39) that pushes out the air in the solvent chamber (21) when the upper piston (19) moves upward, so as to balance the pressure between the solvent chamber (21) and the external pressure.

4. The tubing scraper according to claim 1, characterized in that, Multiple scraping gears (12) are arranged from top to bottom on the central rod (6). The scraping gears (12) are mechanical scraping structures, and their tooth tips are provided with arc-shaped cutting edges that are adapted to the arc-shaped inner wall surface of the oil pipe.

5. The tubing scraper according to claim 4, characterized in that, The central rod (6) has multiple rods, and the diameter of each rod decreases from top to bottom. The diameter of the scraping gear (12) on different rods decreases from top to bottom.

6. The tubing scraper according to claim 5, characterized in that, The number of scraping gears (12) on different stages of the rod increases from top to bottom.

7. The tubing scraper according to claim 5, characterized in that, The arc-shaped cutting edges of each scraping gear (12) on the same level rod can completely cover the inner wall of the oil pipe in the circumferential direction.

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