Production process of lining oil pipe

Abstract

The invention provides a production process of a lining oil pipe, which comprises the following steps of: providing an oil pipe and a lining pipe, reducing the diameter of the lining pipe, penetrating the reduced diameter of the lining pipe into the oil pipe, assembling the lining oil pipe, putting the assembled lining oil pipe into a heat preservation chamber, heating, and cooling to obtain the lining oil pipe. The two ends of the lining pipe are cut in the heat preservation chamber, the two ends of the lining pipe are subjected to opening baking and edge sealing treatment in the heat preservation chamber, so that the two ends of the lining pipe are buckled to the two ends of the oil pipe, and the heat preservation chamber has a constant interval temperature; therefore, the problem of elongation after well descending is solved.

Description

Technical Field

[0001] This application relates to the field of oil pipe processing technology, and more specifically, to a manufacturing process for oil pipes with internal lining. Background Technology

[0002] The main causes of tubing failure are wear and corrosion. Wear is primarily uneven wear, which exacerbates electrochemical corrosion. Other substances, mainly wax, easily adhere to the inner wall of the tubing. Frequent wellhead mobilization and cleaning reduce production efficiency and increase costs. To address these tubing problems, an isolation principle is employed: a plastic inner liner is installed inside the tubing, forming an inner-lined tubing. This effectively solves the problems of wax buildup, corrosion, and wear in well tubing that hinder production, thereby reducing costs.

[0003] Lined tubing is made by inserting an inner liner into a regular tubing. By using techniques such as diameter reduction, the inner liner is made to fit tightly with the tubing, forming a "tube-in-tube" structure. This transforms the steel-to-steel wear between the sucker rod and the tubing into wear between the steel of the sucker rod and the inner liner.

[0004] Plastic-lined tubing has a wide range of applications in oilfields. However, long-term practical use has revealed that the plastic liner of the tubing expands and elongates with increasing well depth and temperature. This expansion causes adjacent liner sections to press and squeeze against each other, leading to deformation and, in severe cases, blockage of the tubing diameter, thus affecting oil production operations. Furthermore, in hot summer weather, existing plastic-lined tubing also experiences liner protrusion during both surface placement and downhole use. The protrusion length varies with ambient temperature, and excessive protrusion renders the tubing unusable. Therefore, this paper proposes a manufacturing process for plastic-lined tubing. Summary of the Invention

[0005] This application aims to provide a manufacturing process for inner-lined tubing, which addresses the problem that as the depth and temperature of the tubing change, the plastic inner liner expands and elongates due to increased temperature, causing adjacent inner liners to press against each other and deform under pressure.

[0006] This application provides a manufacturing process for an inner-lined oil pipe, comprising the following steps:

[0007] An oil pipe and an inner liner are provided. The inner liner is reduced in diameter and then inserted into the oil pipe to complete the assembly of the inner liner oil pipe.

[0008] The assembled inner lining oil pipe is placed in an insulated chamber and heated until the inner lining pipe expands due to heat and extends outward to the end of the oil pipe, thereby achieving pre-stretching of the inner lining oil pipe.

[0009] The two ends of the inner lining tube are cut inside the insulation chamber;

[0010] Inside the insulation chamber, the two ends of the inner lining tube are heated and sealed so that the two ends of the inner lining tube are snapped into the two ends of the oil pipe.

[0011] The insulated room has a constant temperature range.

[0012] Optionally, the insulation chamber is equipped with a power module, a probe temperature control sensor, a PID temperature controller, a SCR regulator, and a heating module;

[0013] The probe temperature control sensor, the PID temperature controller, the SCR regulator, and the heating module are respectively connected to the power module. The probe temperature control sensor, the PID temperature controller, the SCR regulator, and the heating module are electrically connected in sequence to ensure that the temperature range inside the insulation chamber is constant.

[0014] Optionally, the temperature range is 60℃ to 85℃.

[0015] Optionally, the heating time of the inner lining oil pipe placed in the insulation chamber is greater than or equal to 2 hours.

[0016] Optionally, the inner diameter of the oil pipe is 62 mm, and the outer diameter of the inner liner is 65 mm.

[0017] Optionally, the two ends of the inner liner tube are left with a 20mm allowance extending beyond both sides of the oil pipe during cutting.

[0018] Optionally, the wall thickness of the oil pipe is 11 mm.

[0019] Optionally, the wall thickness of the inner liner is 3.4 mm.

[0020] Optionally, the inner liner may be made of polyethylene or polyamide.

[0021] Beneficial effects:

[0022] In the manufacturing process of the inner-lined tubing of this application, the outer surface of the inner liner is compressed to reduce its outer diameter, allowing it to be inserted into the tubing. The inner liner is then heated in an insulated chamber to accelerate its rebound from the contracted state, ensuring a tight fit between the inner liner and the tubing. Subsequently, the two ends of the inner liner are cut, heated, and sealed (i.e., flanged) to secure them to the tubing, forming the finished inner-lined tubing. The inner liner undergoes a pre-stretching treatment (fully elongating the inner liner under insulated conditions, leaving it with a certain stress after processing, so it returns to its natural state during well operation; this is called "pre-stretching treatment"). This allows the inner liner to fully elongate within the insulated chamber. During production, this pre-stretching method is used, with the inner liner being produced under a certain temperature and elongated state. After the finished product cools to room temperature, the inner liner retains a certain amount of pre-stretched material, which is released after well operation, thus solving the elongation problem after well operation.

[0023] The manufacturing process of the tubing liner in this application is simple, requiring no adhesive to tightly connect the liner to the tubing. The tubing manufactured using this process, made of thermoplastic engineering plastic, effectively solves the problems of tubing corrosion prevention, waxing prevention, and scaling prevention, significantly reducing well rod string load and wear, improving pumping unit efficiency, and exhibiting strong mechanical properties and durability with a long service life. Furthermore, cutting the liner after heating eliminates the need for processing excess material after flanging, saving labor costs. Simultaneously, the liner is less prone to elongation and detachment during operation and at room temperature, demonstrating stable performance. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a process flow diagram of a manufacturing process for an inner-lined oil pipe according to an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the production process and structure of an inner-lined oil pipe according to an embodiment of this application;

[0027] Figure 3 This is a connection diagram of the temperature control components of a greenhouse in a production process for an inner-lined oil pipe according to an embodiment of this application;

[0028] Figure 4This is a schematic diagram of a diameter reduction machine structure for a production process of an inner-lined oil pipe according to an embodiment of this application;

[0029] Figure 5 This is a schematic diagram of a cutting machine structure for a production process of an inner-lined oil pipe according to an embodiment of this application;

[0030] Figure 6 This is a schematic diagram of the blade holder, centrifugal counterweight, and cutting blade of a cutting machine for a production process of an inner-lined oil pipe according to an embodiment of this application;

[0031] Figure 7 This is a schematic diagram of the structure of a flanging machine for a production process of an inner-lined oil pipe according to an embodiment of this application;

[0032] Figure 8 yes Figure 7 Cross-sectional view at point B in the middle;

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Oil pipe; 2. Inner liner pipe; 3. Power module; 4. Probe temperature control sensor; 5. PID temperature controller; 6. Thyristor regulator; 7. Heating module; 8. Reduction machine; 80. Frame; 81. Drive motor; 82. Belt drive assembly; 83. Multi-layer gear assembly; 84. Roller assembly; 9. Head cutter; 90. Housing; 90. Waste collection chamber; 90. Mounting chamber; 90. Cutting motor; 91. Knife holder; 92. Centrifugal counterweight; 93. Cutting blade; 94. Flanging machine; 11. Flanging base; 111. Three-jaw chuck; 112. Flanging die; 113. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] In related technologies, the manufacturing process of the inner-lined oil pipe is as follows:

[0037] Necking and inserting tube: Provide an inner liner tube and an outer tube. The outer diameter of the inner liner tube is larger than the inner diameter of the outer tube. Compress the outer circumference of the inner liner tube to reduce its outer diameter. Insert the inner liner tube with the reduced outer diameter into the outer tube.

[0038] Cutting the inner liner: After the inner liner is inserted into the outer tube, cut both ends of the inner liner so that both ends of the inner liner protrude from both ends of the outer tube.

[0039] Heating inner liner tube: The outer tube with the inner liner tube is placed in a hot water tank for heating. The inner liner tube expands when heated and is then interference-fitted into the outer tube.

[0040] Flanging: Take the outer tube with the inner liner tube through it out of the hot water tank, fold the two ends of the inner liner tube, and form annular grooves at the two ends of the inner liner tube. The annular grooves are fastened to the ends of the outer tube.

[0041] In long-term practical use, it has been found that the plastic inner liner tubes manufactured using the above process tend to expand and elongate with increasing temperature. This causes adjacent inner liner tubes to press and squeeze each other after thermal expansion and elongation, resulting in the inner liner tubes being squeezed, bulging and deformed, rendering the inner liner tubes unusable.

[0042] In view of this, this application proposes a manufacturing process for an inner-lined oil pipe.

[0043] Example

[0044] Reference Figure 1 The image shows a manufacturing process for an inner-lined oil pipe disclosed in an embodiment of this application. The manufacturing process for the inner-lined oil pipe includes the following steps:

[0045] Step S1: Provide an oil pipe 1 and an inner liner 2, wherein the inner diameter of the oil pipe 1 is 62mm and the wall thickness of the oil pipe 1 is 11mm, the outer diameter of the inner liner 2 is 65mm and the wall thickness of the inner liner 2 is 3.4mm, the inner liner 2 is reduced in diameter, and the reduced diameter inner liner 2 is inserted into the oil pipe 1 to complete the assembly of the inner liner oil pipe, wherein the inner liner 2 is made of compressible plastic material;

[0046] Specifically, the material of the inner liner tube 2 is polyethylene or polyamide.

[0047] like Figure 2 As shown, it is quite difficult to directly insert the inner liner tube 2 into the oil pipe 1 because the inner wall of the oil pipe 1 is not smooth and has a deviation in straightness. Therefore, the inner liner tube needs to be reduced in diameter before inserting it into the oil pipe. However, the inner liner tube has a spring-like characteristic. If the existing three sets of rollers are used to reduce the diameter, the inner liner tube 2 will quickly spring back after entering the oil pipe 1, resulting in poor insertion. If there are impurities or coatings inside the oil pipe 1, the inner liner tube 2 is very likely to get stuck during the insertion process, causing the inner liner tube 2 to be scrapped.

[0048] like Figure 4 As shown, in order to solve the problem of low success rate of inner lining tube insertion, in one optional embodiment, a diameter reduction machine 8 is provided. The diameter reduction machine 8 adopts multiple sets of rollers to reduce the diameter multiple times in order to delay its rebound time, and the inner lining tube expands and rebounds through the subsequent heat preservation process.

[0049] The reducing machine 8 includes: a frame 80, a drive motor 81, a belt drive assembly 82, a multi-layer gear assembly 83, and a roller assembly 84.

[0050] Specifically, the drive motor 81 is mounted on the frame 80, one end of the belt drive assembly 82 is connected to the output end of the drive motor 81, and the other end of the belt drive assembly 82 is connected to the input end of the multi-layer gear assembly 83. The multi-layer gear assembly 83 is disposed between the belt drive assembly 82 and the roller assembly 84, and the output end of the multi-layer gear assembly 83 is connected to the roller assembly 84.

[0051] The roller assembly 84 is provided with multiple sets of rollers, each set of rollers is arranged side by side along the entry direction of the inner liner tube 2, and each set of rollers is provided with two rollers. When the inner liner tube 2 enters the reducing machine 8, it will be located between the two rollers of each set, and thus be squeezed to reduce its diameter. In this embodiment, the roller assembly 82 is provided with at least eight sets of rollers.

[0052] The frame 80 is used to support and carry components such as the drive motor 81, the multi-layer gear assembly 83, and the roller assembly 84. The drive motor 81 is used to drive the multi-layer gear assembly 83 to rotate. The belt drive assembly 82 is used to connect the drive motor 81 and the multi-layer gear assembly 83, thereby transmitting the kinetic energy of the drive motor 81 to the multi-layer gear assembly 83. The multi-layer gear assembly 83 is used to drive the roller assembly 84 to rotate. The roller assembly 84 is used to extrude and compress the inner liner tube 2.

[0053] During operation, the drive motor 81 is started, which drives the multi-layer gear assembly 83 to mesh and transmit power through the belt transmission assembly 82. The multi-layer gear assembly 83 then transmits power to the roller assembly 84, which places the inner liner tube 2 into the roller assembly. The roller assembly 84 then squeezes the outer diameter of the inner liner tube 2 to reduce its diameter, making the outer diameter of the inner liner tube 2 smaller than the inner diameter of the oil pipe 1. The inner liner tube 2 is then inserted into the oil pipe 1, completing the assembly of the inner liner oil pipe.

[0054] The reducing machine 8 uses bidirectional extrusion rollers and a gear transmission mode to increase the speed of the reducing machine. During the lining process, the extrusion time of the inner liner tube 2 is shortened, which is conducive to the springback of the liner tube and changes the compression amount of the inner liner tube, so that its reduction success rate reaches more than 95% (specific statistics are shown in Table 1). By increasing and stabilizing the springback amount, the compression amount is increased, which means that the friction between the springback and the tube wall is increased, making it fit more tightly with the tube wall and reducing the occurrence of elongation problems.

[0055] Table 1. Inner Diameter Parameters of Lining Machine Rollers

[0056]

[0057] Step S2: Place the assembled inner lining oil pipe into the heat preservation chamber and heat it until the inner lining pipe 2 expands and extends outward to the end of the oil pipe 1 to achieve pre-stretching of the inner lining oil pipe.

[0058] In order to ensure the heating effect of the inner lining tube 2 and the subsequent processing effect, the insulation chamber has a constant temperature range.

[0059] like Figure 3 As shown, specifically, the insulation chamber is equipped with a power module 3, a probe temperature control sensor 4, a PID temperature controller 5, a SCR regulator 6, and a heating module 7.

[0060] Among them, multiple probe temperature control sensors 4 are set and installed in different areas of the insulation room. The probe temperature control sensors 4, PID temperature controller 5, SCR regulator 6 and heating module 7 are respectively connected to the power supply module. The probe temperature control sensors 4, PID temperature controller 5, SCR regulator 6 and heating module 7 are electrically connected in sequence.

[0061] Temperature sensor 4 is used to monitor the temperature inside the insulation chamber and transmit the monitored temperature information to PID temperature controller 5. PID temperature controller 5 outputs a control signal to SCR regulator 6, which controls heating module 7 to adjust the temperature inside the insulation chamber.

[0062] Multiple temperature sensors 4 are installed in different areas of the insulation chamber to collect signals multiple times and compare temperature changes in different areas. This ensures uniform temperature throughout the chamber. The temperature control system of the insulation chamber is modified and optimized by replacing relays with SCR regulators 6 and using PID temperature controllers 5 for precise temperature control. The use of SCR regulators 6, PID temperature controllers 5, and other equipment improves the accuracy of temperature control, enabling a constant temperature range within the insulation chamber. This allows for customized production by setting different production parameters for different conditions.

[0063] Specifically, depending on production needs, the temperature range of the insulation chamber is 60℃~85℃.

[0064] After the inner liner pipe is assembled, it is placed in a heating chamber at 60°C to 85°C. In this embodiment, the temperature of the heating chamber is 80°C and the heating time is greater than or equal to 2 hours, so that the oil pipe 1 and the inner liner pipe 2 are fully heated. At this time, the inner liner pipe 2 expands due to heat, and the compressed outer diameter of the inner liner pipe 2 expands and rebounds due to heat, so that the inner liner pipe 2 fits better with the inner wall of the oil pipe 1, increasing the bonding strength. At the same time, the inner liner pipe 2 also extends and stretches to both ends of the oil pipe 1 due to heat expansion, so that the inner liner pipe 2 is in a state of pre-stretch due to heat expansion. The oil pipe 1 is also in a state of pre-stretch due to heat expansion and stretching. However, compared with the plastic inner liner pipe 2, the stretching range of the alloy oil pipe 1 is smaller, and the entire inner liner pipe is also in a state of pre-stretch.

[0065] Step S3: Cut both ends of the inner lining tube 2 inside the insulation chamber.

[0066] Within the constant temperature of the insulation chamber, the two ends of the inner liner tube 2 are cut, that is, the two ends of the inner liner tube 2 are cut while the inner liner tube 2 is in a pre-stretched state, so that the two ends of the inner liner tube 2 retain a 20mm allowance extending out of the oil pipe 1 on both sides during the cutting.

[0067] Furthermore, the existing method for cutting the inner lining tube 2 is manual cutting. The tools used in manual cutting vary, basically divided into three types: handheld electric saw, toothed saw, and homemade handheld tool. All three methods of cutting the inner lining tube have certain drawbacks. First, manual cutting requires one person to stand on each side of the tube to operate, requiring two workers, which increases labor costs. Second, burrs are left after cutting, which need to be manually polished. Third, the length of the cut is not fixed, and manual trimming is required after the flanging process.

[0068] like Figure 5 and Figure 6 As shown, in order to solve the defects of the existing manual cutting method for the inner lining tube 2 and the problem that workers cannot work in the high-temperature environment of the insulation room, this application embodiment provides a cutting machine 9. The cutting machine 9 cuts the inner lining tube 2, replacing manual cutting, and the cutting accuracy is higher. The cutting machine 9 includes a housing 90, a cutting motor 91, a blade holder 92, a centrifugal counterweight 93, and a cutting blade 94. The housing 90 is divided into a waste collection chamber 901 and an installation chamber 902 by a partition plate.

[0069] A cutting motor 91 is fixedly installed in the mounting cavity 902 of the housing 90. A tool holder 92 is installed in the mounting cavity 902 of the housing 90 and is connected to the output end of the cutting motor 91. The tool holder 92 has a hollow structure inside and is used to place the pre-stretched inner lining oil pipe.

[0070] Centrifugal counterweight 93 is slidably mounted on both sides of the tool holder 92;

[0071] The cutting blade 94 is located at the front end of the blade holder 92 and is connected to the centrifugal counterweight 93 via a linkage mechanism.

[0072] The housing 90 is used to support components such as the cutting motor 91 and the tool holder 92. The waste collection chamber 901 is used to collect waste generated during cutting. The mounting chamber 902 is used to support and mount the cutting motor 91. The cutting motor 91 is used to drive the tool holder 92 to rotate. The tool holder 92 is used to place the pre-stretched inner liner oil pipe that needs to be cut. When the tool holder 92 rotates, the centrifugal counterweight 93 is thrown outward by the centrifugal force. Then, through the linkage mechanism, the cutting blade 94 moves towards the rotation center of the tool holder 92, thereby cutting the inner liner 2 of the inner liner oil pipe located at the rotation center of the tool holder 92.

[0073] During operation, the pre-stretched inner liner tube is placed in the cutter holder 92. The cutting motor 91 is started and drives the cutter holder 92 to rotate via belt drive components. The rotation of the cutter holder 92 causes the centrifugal counterweight 93 to be thrown outward under centrifugal force. At the same time, the force of the centrifugal counterweight 93 being thrown outward will drive the blade in the cutter 94 to extend inward by the linkage mechanism. The blade in the cutter 94 rotates and cuts the two ends of the inner liner tube 2, cutting off the inner liner tube ends. The cut-off tube ends will be collected into the waste collection chamber 901.

[0074] The head cutter 9 is simple in operation and novel in design, and can quickly cut the inner liner tube 2 with high cutting precision.

[0075] Step S4: In the insulation chamber, bake and seal both ends of the inner lining tube 2 so that the two ends of the inner lining tube 2 are snapped onto the two ends of the oil pipe 1.

[0076] Under constant temperature in the insulation chamber, the two ends of the inner lining tube 2 are heated and sealed so that the two ends of the inner lining tube 2 are snapped onto the two ends of the oil pipe 1 in the pre-stretched state. This ensures that the cutting process of the inner lining tube 2, the heating and sealing of the two ends of the inner lining tube 2 are all carried out under constant temperature in the insulation chamber, so that the inner lining tube can be processed in the pre-stretched state and adapt to the high-temperature underground environment during processing.

[0077] Specifically, in one optional embodiment, a seaming machine is used to heat both ends of the inner lining tube 2 in the cut inner lining oil pipe to achieve seaming treatment of the inner lining tube 2. The seaming machine uses an electric heater and a PID temperature control system, which is conducive to controlling the baking temperature of both ends of the inner lining tube 2 to ensure a suitable temperature during edge forming. The PID temperature control system can achieve continuous and adjustable temperature control.

[0078] Furthermore, the existing lining tube flanging process involves manually aligning and installing the mold, and then using a hydraulic cylinder to press and tighten the flanging. This flanging method has three main drawbacks: firstly, the sealing may be uneven, resulting in a rough sealing quality; secondly, it requires manual operation and is dependent on the worker's skill level; and thirdly, the temperature changes rapidly after baking, and the inconsistent speed of manual operation makes it difficult to guarantee the flanging quality.

[0079] like Figure 7 and Figure 8 As shown, in order to solve the defects of the existing inner lining pipe flanging process and the problem that workers cannot work in the high-temperature environment inside the insulation room, this application embodiment provides a flanging machine 11, which realizes the edge sealing treatment of the cut inner lining oil pipe.

[0080] The flanging machine 11 includes a flanging base 111, a three-jaw chuck 112, a flanging mold 113, and a hydraulic cylinder mounted on the flanging base 111.

[0081] The three-jaw chuck 112 is used to clamp the inner lining oil pipe. The flanging die 113 has a guide rod and a flanging part. The guide rod is used to guide the inner lining oil pipe to be aligned with the three-jaw chuck 112. The flanging part is connected to the telescopic end of the hydraulic cylinder to achieve flanging of the end of the inner lining pipe 2.

[0082] The inner lining tube 2 is heated at both ends by a heating machine after cutting, thus achieving a heating treatment. A three-jaw chuck 112 then clamps the inner lining tube, ensuring concentricity between the tube and the clamp for high-quality flanging. Next, a flanging die 113 with a guide rod guides the tube to align with the chuck 112. A hydraulic cylinder then drives the flanging section of the die 113 to compact and flange the inner lining tube 2. Since the inner lining tube 2 has been cut to a fixed length, there is no excess material after flanging, eliminating the need for trimming and saving labor costs. Furthermore, the coordinated operation of the cutting machine 9, the heating machine, and the flanging machine 11 achieves a series of automated operations on the inner lining tube, eliminating the need for manual labor and enhancing safety.

[0083] The overall workflow is as follows: First, the drive motor 81 is started, which drives the multi-layer gear assembly 83 to mesh and transmit power through the belt transmission assembly 82. The multi-layer gear assembly 83 then transmits power to the roller assembly 84. The inner liner tube 2 is placed into the roller assembly, and the rollers in the roller assembly 84 squeeze the outer diameter of the inner liner tube 2 to achieve the diameter reduction process of the inner liner tube 2, so that the outer diameter of the inner liner tube 2 is smaller than the inner diameter of the oil pipe 1. Then, the inner liner tube 2 is inserted into the oil pipe 1 to complete the assembly of the inner liner oil pipe.

[0084] After the inner lining pipe is assembled, it is placed in a heating chamber at 60°C to 85°C. In this embodiment, the temperature of the heating chamber is 80°C and the heating time is greater than or equal to 2 hours, so that the oil pipe 1 and the inner lining pipe 2 are fully heated. At this time, the inner lining pipe 2 expands due to heat, and the compressed outer diameter of the inner lining pipe 2 expands and rebounds due to heat, so that the inner lining pipe 2 fits better with the inner wall of the oil pipe 1, increasing the bonding strength. At the same time, the inner lining pipe 2 also extends and stretches to both ends of the oil pipe 1 due to heat expansion, so that the inner lining pipe 2 is in a state of pre-stretch due to heat expansion. The oil pipe 1 is also in a state of pre-stretch due to heat expansion and stretching. However, compared with the plastic inner lining pipe 2, the stretching range of the alloy oil pipe 1 is smaller, and the entire inner lining pipe is also in a state of pre-stretch.

[0085] Then, the pre-stretched inner liner tube is placed into the cutter holder 92. The cutting motor 91 is started and drives the cutter holder 92 to rotate through the belt drive and other components. The rotation of the cutter holder 92 causes the centrifugal counterweight 93 to be thrown outward under the action of centrifugal force. At the same time, the force of the centrifugal counterweight 93 being thrown outward will drive the blade in the cutter 94 to extend inward. The blade in the cutter 94 rotates and cuts the two ends of the inner liner tube 2, cutting off the inner liner tube ends. The cut-off tube ends will be collected into the waste collection chamber 901.

[0086] Then, the ends of the inner lining tube 2 in the cut inner lining tube are heated by a seaming machine to achieve seaming treatment. A three-jaw chuck 112 is then used to clamp the inner lining tube. The three-jaw chuck 112 has a centering function, ensuring concentricity between the tube and the clamp, resulting in good flanging quality. Next, the flanging die 113, equipped with a guide rod, guides the tube to align with the three-jaw chuck 112. Then, a hydraulic cylinder drives the flanging section of the flanging die 113 to compact and flanging the inner lining tube 2. Since the cut end of the inner lining tube 2 has already been set to a fixed length, there is no excess material after flanging, eliminating the need for trimming and saving labor costs. Furthermore, the coordinated operation of the cutter 9, seaming machine, and flanging machine 11 achieves a series of automated operations on the inner lining tube, eliminating the need for manual labor and making the operation safer.

[0087] In the manufacturing process of the inner-lined oil pipe of this application, the outer surface of the inner-lined tube 2 is compressed to reduce the outer diameter of the inner-lined tube 2, which is then inserted into the oil pipe 1. The inner-lined oil pipe is heated by a heat preservation chamber to accelerate the rebound of the contracted state, so that the inner-lined tube 2 and the oil pipe 1 can fit together tightly. Then, the two ends of the inner-lined tube are cut, baked, and sealed (i.e., flanged) so that the two ends of the inner-lined tube 2 are snapped onto the two ends of the oil pipe 1, forming the finished inner-lined oil pipe. The inner tubing is pre-stretched (the inner tubing 2 is fully elongated under heat preservation, and after processing, it is subjected to a certain stress, which is then restored to its natural state during well application; this is called "pre-stretching treatment"). The inner tubing 2 is fully elongated in the heat preservation chamber. During the production process, the pre-stretching method is used, and the production is carried out under the elongated state of the inner tubing 2 at a certain temperature. After the finished product cools down to room temperature, the inner tubing 2 has a certain amount of reserved stretching. This amount of shrinkage is released after the tubing is run into the well, thereby solving the elongation problem after the tubing is run into the well.

[0088] The manufacturing process of the inner-lined tubing in this application is simple, requiring no adhesive to tightly connect the inner liner 2 to the tubing 1. Furthermore, the inner liner 2, made of thermoplastic engineering plastic, effectively solves the problems of corrosion prevention, waxing prevention, and scaling prevention in tubing, significantly reducing the load and wear on the well rod string, improving pumping unit efficiency, and exhibiting strong mechanical properties and durability with a long service life. In addition, cutting the inner liner 2 after heating eliminates the need for processing excess material after flanging, saving labor costs. Simultaneously, the inner liner 2 is less prone to elongation and detachment during operation and at room temperature, demonstrating stable performance.

[0089] This application tested a sample of finished polyethylene-lined oil pipe with a diameter of 73mm and a length of 2m according to the standards QB / T2668.1-2017 "Ultra-high molecular weight polyethylene pipes" and SY / T6947-2013 "Polyethylene-lined composite oil pipes for the petroleum and natural gas industry". The test results are shown in Table 2. Simultaneously, the applicant also tested a sample of finished polyamide-lined oil pipe with a diameter of 64mm and a length of 1m according to the standard "Technical Requirements for High Temperature Resistance of Polyamide-lined Pipes (125℃) (Tender Announcement)". The test results are shown in Table 3.

[0090] Table 2 shows the inspection report for the finished inner lining oil pipe.

[0091]

[0092]

[0093] Table 3 shows the inspection report for the finished inner lining oil pipe (Part 2).

[0094]

[0095] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0096] It should also be noted that, in this document, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device 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 terminal device. In the absence of further restrictions, an element defined by the phrase "includes a..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0097] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand this application, and the content of this specification should not be construed as a limitation of this application. Furthermore, for those skilled in the art, there will be different forms of changes in the specific implementation methods and application scope based on this application. It is neither necessary nor possible to exhaustively list all implementation methods here, and obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. A manufacturing process for an inner-lined oil pipe, characterized in that, The manufacturing process of the inner-lined oil pipe includes the following steps: An oil pipe and an inner liner are provided. The inner liner is reduced in diameter and then inserted into the oil pipe to complete the assembly of the inner liner oil pipe. The assembled inner lining oil pipe is placed in an insulated chamber and heated until the inner lining pipe expands due to heat and extends outward to the end of the oil pipe, thereby achieving pre-stretching of the inner lining oil pipe. The two ends of the inner lining tube are cut inside the insulation chamber; Inside the insulation chamber, the two ends of the inner lining tube are heated and sealed so that the two ends of the inner lining tube are snapped into the two ends of the oil pipe. The insulated room has a constant temperature range.

2. The manufacturing process of an inner-lined oil pipe according to claim 1, characterized in that: The insulation chamber is equipped with a power module, a probe temperature control sensor, a PID temperature controller, a silicon controlled rectifier, and a heating module. The probe temperature control sensor, the PID temperature controller, the SCR regulator, and the heating module are respectively connected to the power module. The probe temperature control sensor, the PID temperature controller, the SCR regulator, and the heating module are electrically connected in sequence to ensure that the temperature range inside the insulation chamber is constant.

3. The manufacturing process of an inner-lined oil pipe according to claim 1, characterized in that: The temperature range is 60℃~85℃.

4. The manufacturing process of an inner-lined oil pipe according to claim 1, characterized in that: The heating time for the inner lining oil pipe placed in the insulation chamber is greater than or equal to 2 hours.

5. The manufacturing process of an inner-lined oil pipe according to claim 1, characterized in that: The inner diameter of the oil pipe is 62mm, and the outer diameter of the inner liner is 65mm.

6. The manufacturing process of an inner-lined oil pipe according to claim 1, characterized in that: During the cutting process, the two ends of the inner liner tube are left with a 20mm margin extending beyond both sides of the oil pipe.

7. The manufacturing process of an inner-lined oil pipe according to claim 1, characterized in that: The wall thickness of the oil pipe is 11 mm.

8. The manufacturing process of an inner-lined oil pipe according to claim 1, characterized in that: The wall thickness of the inner liner is 3.4 mm.

9. The manufacturing process of an inner-lined oil pipe according to claim 1, characterized in that: The inner liner is made of either polyethylene or polyamide.

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