A method of manufacturing a fully-coated sucker rod

Abstract

The present application relates to a kind of methods for manufacturing full-coated sucker rod, step one, sucker rod matrix is manufactured by machining method, the middle part of the finished sucker rod matrix is rod body, two end parts are rod head and two ends are symmetrically arranged, the rod head is from the end of sucker rod matrix towards rod body in turn threaded joint, unloading groove, shoulder, wrench square and flange, the outer surface of the rod body is covered with anticorrosive non-metal material layer;Step two, metal sleeve is made by machining method, and the finished metal sleeve is cylindrical;Step three, by extrusion, the metal sleeve is tightly attached to the outer surface of the shoulder, wrench square and flange, and completely covers the shoulder, wrench square and flange, and the anticorrosive non-metal material layer is covered, and the metal sleeve outer surface and the corresponding position of the shoulder, wrench square and flange form the same shape as the shape of the outer surface of the shoulder, wrench square and flange.The present application can reduce the cost and workload of machining, and facilitate on-site operation, improve work efficiency.

Description

A method for manufacturing a fully enclosed sucker rod Technical Field

[0001] This invention relates to the field of oil drilling and production, and specifically to a method for manufacturing a fully enclosed sucker rod. Background Technology

[0002] Sucker rods are crucial components in oil drilling and production. However, most oilfields in my country are currently in the mid-to-late stages of development, with increasingly higher overall water cuts. Water injection and other production enhancement measures are frequently employed, and the reinjected water is often directly recycled from wastewater, creating an extremely harsh working environment for the sucker rods. High-salinity well fluids contain various corrosive media and microorganisms, especially rich in Cl. - This significantly increases the corrosion rate of the sucker rod. Simultaneously, the associated gas contains corrosive gases such as CO2 and H2S, making the well fluid weakly acidic. As is well known, treating Cl... - CO2 and H2S corrosion have always been global challenges in oilfield engineering. Furthermore, the friction between the sucker rod and the tubing inner wall generates heat, activating the surface and significantly accelerating corrosion rates under the influence of corrosive produced fluids. Additionally, factors such as sand content, oil well wax and scale formation, and produced fluid viscosity also contribute to surface corrosion and uneven wear on the sucker rod. In short, due to the long-term exposure to alternating loads and the combined effects of oil, gas, water, and corrosive media, coupled with uneven wear, the sucker rod is the least reliable piece of equipment in mechanical oilfield production, highly susceptible to breakage accidents.

[0003] Studies have shown that when the water content in an oil well exceeds 74.02%, the produced fluid undergoes phase change, transforming from a water-in-oil type to an oil-in-water type. The tubing surface loses the protection of crude oil, and the produced water directly contacts the metal, increasing the corrosion rate. The lubricant changes from crude oil to produced water, losing the lubricating effect of crude oil. As the water content of the well fluid increases, its specific gravity also increases, while the lubrication coefficient of the tubing contact surface decreases significantly. This leads to a marked increase in upward load and an increased downward resistance, exacerbating the stress and deformation of the sucker rod, increasing frictional resistance, and accelerating tubing wear. Uneven wear on the tubing generates heat, activating its surface. Under the influence of highly corrosive produced fluid, the unevenly worn areas are preferentially corroded, increasing surface roughness and frictional resistance, resulting in more severe wear. Furthermore, factors such as sand content, oil well wax and scale formation, and produced fluid viscosity also promote corrosion and uneven wear on the sucker rod surface. Corrosion and mechanical wear are not simply additive but interact and promote each other; the combination of the two has a greater destructive effect. Oilfield sites widely use anti-wear measures such as centralizers, anti-wear pairs, and weighted rods. Although these measures can extend the service life of pipes and rods, they cannot completely solve the problem.

[0004] To address the challenges of corrosion and wear resistance, current preventative measures for sucker rods mainly include using conventional methods such as electroplating or chemical plating to process chrome-plated sucker rods, nickel-plated sucker rods, tungsten-plated sucker rods, as well as semi-encased and fully encased anti-corrosion and wear-resistant sucker rods.

[0005] Conventional wear-resistant and corrosion-resistant coatings for sucker rods are limited by the large diameter ratio and complex shape of the rod head and body in upset forged sucker rods. The coating has low bonding strength with the substrate, and in the complex well conditions described above, it is prone to peeling, flaking, and wear, forming a weakness in corrosion and wear resistance. The effect is not ideal, and the cost is high. For example, Chinese invention patent application CN108798537A discloses a corrosion-resistant and wear-resistant smooth rod, including a rod body with a first external threaded joint and a second external threaded joint at both ends. The outer side of the rod body is coated with a corrosion-resistant and wear-resistant alloy coating, and the non-upset section of the rod body near the second external threaded joint is coated with a cathodic protection corrosion-resistant alloy coating. Another example is a novel corrosion-resistant and wear-resistant spray-welded sucker rod disclosed in Chinese invention patent application CN108798538A, including a rod body with a first upset section of the rod head and a first threaded section connected sequentially to one end. The other end of the rod body... The rod body is sequentially connected to a second upset rod head and a second threaded rod head section. A first arc transition zone and a first flange are sequentially provided between the rod body and the first upset rod head. A first push-bearing shoulder and a first unloading groove are sequentially provided between the first upset rod head and the first threaded rod head section. A second arc transition zone and a second flange are sequentially provided between the rod body and the second upset rod head. A second push-bearing shoulder and a second unloading groove are sequentially provided between the second upset rod head and the second threaded rod head section. The outer sides of the rod body, the first upset rod head, and the second upset rod head are coated with an anti-corrosion and wear-resistant alloy coating. Both of the aforementioned patent applications enhance the anti-corrosion and wear-resistant properties of sucker rods through coatings, but they also inevitably suffer from problems such as low bonding strength between the coating and the substrate, easy peeling, and wear.

[0006] The bonding strength between the sprayed coating and the substrate of the semi-coated anti-corrosion and wear-resistant sucker rod is greatly improved, resulting in good anti-corrosion and wear-resistant performance. However, after the anti-corrosion alloy coating is sprayed onto the rod head, a secondary solution strengthening process is required. The high temperature will substantially reduce the substrate performance of the coated anti-corrosion and wear-resistant sucker rod head, which will substantially reduce the overall anti-corrosion and wear-resistant performance and reliability of the sucker rod, and the cost will be high.

[0007] Fully encapsulated sucker rods, by completely encapsulating the rod head and body, possess excellent corrosion resistance and wear resistance. For example, an improved fully encapsulated sucker rod disclosed in Chinese Utility Model Patent CN210564384U includes a sucker rod base and a clamp. The sucker rod base has shoulders and a rod body at both ends, from the outside in. The shoulders are provided with a thrust plate and clamp threads from the outside in for tight clamping. The connection between the shoulders and the rod body includes a wrench-shaped square and a flange, with the diameters of the wrench-shaped square and the flange reduced, while the diameter of the shoulders is larger than that of the flange. A corrosion-resistant polymer plastic layer is provided on the connection between the shoulders and the rod body and on the outer wall of the rod body. The clamp includes a connector, the inner ring of which has a thrust port and internal threads corresponding to the shoulders, ensuring a tight fit between the clamp and the sucker rod base. An injection molding channel is formed between the sucker rod base encapsulated with the corrosion-resistant polymer plastic layer and the inner cavity of the clamp, where high-pressure injection molding of the polymer plastic is performed. The aforementioned patent forms a complete encapsulation of the sucker rod through a clamp, a polymer plastic layer, and a high-pressure injection-molded polymer plastic layer inside the clamp. This patent has good anti-corrosion and wear-resistant properties, but it requires processing the thrust plate and clamp threads on the shoulder of the sucker rod base, processing the thrust port and internal threads on the clamp, and high-pressure injection molding of the clamp cavity. The increase in processing steps leads to a corresponding increase in processing costs and workload. For example, Chinese utility model patent CN212454282U discloses a novel sucker rod, comprising a sucker rod base and a threaded sleeve. The two ends of the sucker rod base are symmetrically arranged. From the end to the center, the sucker rod base is provided with a first external threaded connector, an unloading groove, a second external threaded shoulder, a wrench square, and a rod body. The threaded sleeve is fitted onto the second external threaded shoulder of the sucker rod base and partially covers the rod body. The end of the second external threaded shoulder that abuts against the threaded sleeve is provided with a thrust plate and a thrust port, respectively. The outer wall of the rod body is covered with a corrosion-resistant polymer plastic layer, and the outer surface of the threaded sleeve is provided with a corrosion-resistant coating. Wear-resistant coating; A novel sucker rod disclosed in Chinese Utility Model Patent CN212454283U includes a sucker rod base and a conical sleeve. The two ends of the sucker rod base are symmetrically arranged. From the end to the center, the sucker rod base is provided with an external threaded joint, an unloading groove, a conical shoulder, a wrench square, and a rod body. The conical sleeve is fitted onto the conical shoulder of the sucker rod base and partially covers the rod body. The ends of the conical shoulder that abut against the conical sleeve are respectively provided with a conical thrust plate and a conical thrust port. The outer wall of the rod body is covered with an anti-corrosion polymer plastic layer, and the outer surface of the conical sleeve is provided with an anti-corrosion and wear-resistant coating. The two patents mentioned above are similar to CN210564384U. They all involve covering the rod head with clamps / sleeves and covering the rod body with a polymer plastic layer. However, they also require the machining of the sleeve and shoulder with threads, thrust ports and thrust plates, which increases the amount of machining work and cost.Furthermore, the standard API sucker rod design with a square wrench is intended to eliminate directional selection during on-site operations, allowing for quick alignment from any direction. However, the aforementioned Chinese utility model patents CN210564384U, CN212454282U, and CN212454283U, because the wrench square is covered by a clamp / sleeve, and the clamp / sleeve is circular in shape, have two symmetrical wrench square grooves milled at 180 degrees on the outer surface of the clamp / sleeve for the convenience of on-site operations. This creates directional selection, causing inconvenience to on-site operations. Moreover, due to the limited wall thickness of the clamp / sleeve, the milling depth of the wrench square groove is very small, which in turn affects the efficiency of on-site operations.

[0008] In view of this, the present invention provides a method for manufacturing a fully enclosed sucker rod. By improving the sleeve structure and the way the sleeve and rod head are enclosed, the invention solves the technical problem of high machining costs and workload caused by the need to process threads, thrust plates and thrust ports in existing fully enclosed sucker rods. It also ensures that the rod head of the fully enclosed sucker rod still forms a square four-sided wrench according to API specifications, thereby improving the efficiency of on-site operations. Summary of the Invention

[0009] The present invention aims to provide a method for manufacturing a fully enclosed sucker rod to overcome the shortcomings of the prior art. The technical problem to be solved by the present invention is achieved through the following technical solution.

[0010] An improvement in a method for manufacturing a fully enclosed sucker rod is that:

[0011] Step 1: The sucker rod base is manufactured by machining. The middle part of the finished sucker rod base is the rod body, and the two ends are rod heads, which are symmetrically arranged at both ends. The rod head consists of a threaded joint, unloading groove, shoulder, wrench square and flange in sequence from the end of the sucker rod base toward the rod body. The outer surface of the rod body is covered with a layer of anti-corrosion non-metallic material.

[0012] Step 2: The metal sleeve is manufactured by machining. The finished metal sleeve is cylindrical.

[0013] Step 3: By squeezing, the metal sleeve is made to fit tightly against the outer surface of the shoulder, wrench square and flange, completely covering the shoulder, wrench square and flange, and covering part of the anti-corrosion non-metallic material layer. The outer surface of the metal sleeve forms the same shape as the outer surface of the shoulder, wrench square and flange at the corresponding positions.

[0014] Preferably, in step one, the outer surface of the rod is coated with a layer of anti-corrosion non-metallic material by heating, injection molding, and curing the anti-corrosion non-metallic material.

[0015] Preferably, the inner wall of the metal sleeve produced in step two has at least one groove near the end.

[0016] Preferably, step three includes the following steps: Step three-one: heating the metal sleeve; Step three-two: fitting the metal sleeve into the rod head, making the end face of the metal sleeve near the end of the sucker rod base flush with the end face of the shoulder near the unloading groove; Step three-three: pressing the metal sleeve with a press, so that the metal sleeve fits tightly against the outer surface of the shoulder, wrench square, and flange, completely covering the shoulder, wrench square, and flange, and the outer surface of the metal sleeve forms the same shape as the outer surface of the shoulder, wrench square, and flange; Step three-four: cooling; Step three-five: cold-pressing the metal sleeve with a press, so that the metal sleeve is covered with a partial anti-corrosion non-metallic material layer.

[0017] Preferably, in step 3, medium-high frequency induction heating is used, and the heating temperature is controlled between 200-500℃.

[0018] Preferably, the extrusion pressure in step 3 is 800-1300kN.

[0019] Preferably, the pressure of cold extrusion in step three is 300-800kN.

[0020] Preferably, in step three and five, before cold extrusion, at least two O-rings are fitted into the area of ​​the anti-corrosion non-metallic material layer that will be covered by the metal sleeve.

[0021] Preferably, the metal sleeve is made of stainless steel.

[0022] Preferably, the anti-corrosion non-metallic material layer is made of anti-corrosion polymer plastic material.

[0023] This invention achieves full corrosion protection for a single sucker rod by forming a corrosion-resistant non-metallic material layer on the outer surface of the rod and using a metal sleeve to cover part of the rod head with the same layer. Multiple sucker rods are connected by butt joints (such as standard spray-welded collars) and threaded joints, using preload to achieve a compression seal between the butt joint and the metal sleeve, effectively preventing corrosive media from entering the rod head. Compared with existing technologies, this invention covers the shoulder, wrench square, and flange of the rod head with a partial corrosion-resistant non-metallic material layer by compressing the metal sleeve, thus eliminating the need for machining threads, thrust blocks, and thrust ports, thereby reducing machining costs and workload. Furthermore, since the outer surface of the metal sleeve forms the same shape as the shoulder, wrench square, and flange—that is, the metal sleeve retains the API standard four-sided wrench square structure—it facilitates on-site operations and improves operational efficiency. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the structure of the fully enclosed sucker rod manufactured according to the present invention;

[0025] Figure 2 is a schematic diagram of the structure of the sucker rod base in this invention;

[0026] Figure 3 is a schematic diagram of the structure of the metal sleeve in this invention (the metal sleeve shown in the figure is a schematic diagram of the structure when it is not extruded and covered with the sucker rod base);

[0027] The reference numerals in the attached figures are as follows: 1. Sucker rod base, 11. Threaded joint, 12. Unloading groove, 13. Shoulder, 14. Wrench square, 15. Flange, 16. Rod body, 2. Metal sleeve, 21. Groove, 3. Anti-corrosion non-metallic material layer. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] Example 1:

[0030] Referring to Figures 1 to 3, an improvement in a method for manufacturing a fully enclosed sucker rod is as follows:

[0031] Step 1: The sucker rod base 1 is manufactured by machining. The middle part of the finished sucker rod base 1 is the rod body 16, and the two ends are rod heads, which are symmetrically arranged. The rod head consists of a threaded joint 11, a relief groove 12, a shoulder 13, a wrench square 14 and a flange 15 from the end of the sucker rod base 1 toward the rod body 16. The outer surface of the rod body 16 is covered with a non-metallic anti-corrosion material layer 3.

[0032] Step 2: The metal sleeve 2 is manufactured by machining. The finished metal sleeve 2 is cylindrical.

[0033] Step 3: By squeezing, the metal sleeve 2 is made to fit tightly against the outer surfaces of the shoulder 13, the wrench square 14, and the flange 15, and completely cover the shoulder 13, the wrench square 14, and the flange 15, and cover part of the anti-corrosion non-metallic material layer 3. The outer surface of the metal sleeve 2 forms the same shape as the outer surface of the shoulder 13, the wrench square 14, and the flange 15 at the corresponding positions.

[0034] In this embodiment, the two ends of the sucker rod base 1 are symmetrically arranged, firstly for ease of processing and production, and secondly for ease of assembly, as the structures at both ends are identical, eliminating the need to specify the direction during assembly, thus saving time and effort. After the threaded joint 11 and the butt joint (not shown in the diagram) are connected by threads, the butt joint and the metal sleeve 2 abut tightly, achieving a sealing effect through pre-tightening force. The unloading groove 12 reduces the stress on the sucker rod base 1. The outer surface of the rod body 16 is covered with a layer of anti-corrosion non-metallic material 3, which can prevent corrosive media from corroding the rod body 16. The metal sleeve 2 completely covers the shoulder 13, the wrench square 14, and the flange 15, sealing the shoulder 13, the wrench square 14, and the flange 15, thereby preventing corrosive media from corroding the shoulder 13, the wrench square 14, and the flange 15. The metal sleeve 2 covering part of the anti-corrosion non-metallic material layer 3 achieves a sealed connection between the two, preventing corrosive media from corroding the sucker rod base 1.

[0035] It is worth noting that in this embodiment, the reason why the shape formed by the outer surface of the metal sleeve 2 after covering the shoulder 13, the wrench square 14, and the flange 15 is the same as the shape of the outer surface of the shoulder 13, the wrench square 14, and the flange 15 is because the wrench square 14 on the sucker rod base 1 is designed to facilitate on-site operations. The standard API sucker rod is designed with a four-sided wrench square so that there is no directional selection during on-site operations, and the wrench can be used to quickly align the sucker rod in any direction. However, the fully enclosed sucker rods in the prior art mostly use a circular clamp / sleeve to cover the rod head, which makes it impossible to effectively correct the sucker rod during on-site operations. To solve this problem, the prior art mills two 180-degree symmetrical wrench square grooves on the outer surface of the clamp / sleeve, which creates directional selection, causing inconvenience to on-site operations. Moreover, due to the wall thickness of the clamp / sleeve, the milling depth of the wrench square groove is very small, which affects the efficiency of on-site operations. In this embodiment, the shape of the outer surface of the extruded metal sleeve 2 is made to match the shape of the sucker rod head, so that the fully enclosed sucker rod still retains the square structure of the API standard four-sided wrench, which facilitates on-site operation and improves work efficiency.

[0036] This embodiment achieves full corrosion protection for a single sucker rod by forming a non-metallic anti-corrosion material layer 3 on the outer surface of the rod body 16 and covering the rod head portion with a metal sleeve 2, partially covering the non-metallic anti-corrosion material layer 3. Multiple sucker rods are connected by butt joints such as standard spray-welded ferrules and threaded joints 11. Pre-tightening force is used to achieve a compression seal between the butt joint and the metal sleeve 2, which can effectively prevent corrosive media from entering the rod head.

[0037] Compared with the prior art, this embodiment achieves the covering of the shoulder 13, wrench square 14 and flange 15 of the rod head and the partial covering of the anti-corrosion non-metallic material layer 3 by extruding the metal sleeve 2, thereby eliminating the need to process threads, thrust plates and thrust ports, thus reducing the cost and workload of machining. At the same time, since the outer surface of the metal sleeve 2 forms the same shape as the shoulder 13, wrench square 14 and flange 15, that is, the metal sleeve 2 still retains the API standard four-sided wrench square structure, which facilitates on-site operation and improves work efficiency.

[0038] Furthermore, in step one, the outer surface of the rod 16 is coated with a layer 3 of anti-corrosion non-metallic material through heating, injection molding, and curing processes. Even further, the anti-corrosion non-metallic material layer 3 is made of anti-corrosion polymer plastic material.

[0039] In this embodiment, the anti-corrosion polymer plastic layer is formed on the outer surface of the rod 16 through processes such as heating, medium-low pressure injection molding, and curing of the polymer plastic. The polymer plastic possesses high chemical stability, high toughness, certain wear resistance, and self-lubricating properties. Its advantages mainly include high mechanical strength, good toughness, impact resistance, fatigue resistance, smooth surface, low coefficient of friction, heat resistance (long-term use within 180℃), corrosion resistance, light weight, easy molding, and reliable dimensional stability. Coating the rod 16 of the sucker rod substrate 1 with the anti-corrosion polymer plastic layer isolates the rod 16 from corrosive media, thereby ensuring that the rod 16 is not damaged by corrosive media and enhancing the fatigue strength of the rod 16.

[0040] Furthermore, in step two, at least one groove 21 is machined on the inner wall of the metal sleeve 2 near the end position.

[0041] In this embodiment, the groove 21 can compress the anti-corrosion non-metallic material layer 3 when the metal sleeve 2 covers part of the anti-corrosion non-metallic material layer 3, thereby sealing the two together, achieving both a sealing effect and ensuring its firmness.

[0042] Furthermore, the metal sleeve 2 is made of stainless steel. Stainless steel was chosen for this embodiment because it has excellent corrosion resistance. In the prior art, clamps / sleeves typically have nickel-based alloy powder sprayed onto their outer surface to enhance corrosion resistance, giving them comprehensive properties such as wear resistance, corrosion resistance, and friction reduction. However, using a stainless steel sleeve eliminates the need for this alloy powder spraying.

[0043] Furthermore, the outer diameter of the threaded connector 11 is smaller than the outer diameter of the shoulder 13, the outer diameter of the flange 15 is equal to the outer diameter of the shoulder 13, and the outer diameter of the wrench square 14 is smaller than the outer diameters of the shoulder 13 and the flange 15.

[0044] Example 2:

[0045] Based on Example 1, Step 3 includes the following steps: Step 31: Heating the metal sleeve 2; Step 32: Fitting the metal sleeve 2 onto the rod head, making the end face of the metal sleeve 2 adjacent to the end of the sucker rod base 1 flush with the end face of the shoulder 13 adjacent to the unloading groove 12; Step 33: Pressing the metal sleeve 2 with a press, so that the metal sleeve 2 fits tightly against the outer surfaces of the shoulder 13, the wrench square 14, and the flange 15 and completely covers the shoulder 13, the wrench square 14, and the flange 15, and the outer surface of the metal sleeve 2 forms the same shape as the outer surface of the shoulder 13, the wrench square 14, and the flange 15; Step 34: Cooling; Step 35: Cold pressing the metal sleeve 2 with a press, so that the metal sleeve 2 is covered with a partial anti-corrosion non-metallic material layer 3.

[0046] In this embodiment, the metal sleeve 2 is first heated, and then the metal sleeve 2 is squeezed by a press to ensure that the metal sleeve 2 is tightly attached to the outer surface of the shoulder 13, the wrench square 14 and the flange 15 and completely covers the shoulder 13, the wrench square 14 and the flange 15, thereby sealing the shoulder 13, the wrench square 14 and the flange 15 to prevent corrosive media from corroding the shoulder 13, the wrench square 14 and the flange 15.

[0047] In this embodiment, the end face of the metal sleeve 2 is flush with the end face of the shoulder 13. When the joint and the metal sleeve 2 are tightly abutted, the sealing effect can be achieved by the pre-tightening force, thereby preventing the corrosive medium from corroding the unloading groove 12, the threaded joint 11 and the inside of the joint.

[0048] In this embodiment, after the metal sleeve 2 is pressed tightly against the outer surface of the shoulder 13, the wrench square 14 and the flange 15 and completely covers the shoulder 13, the wrench square 14 and the flange 15, the part of the metal sleeve 2 covered with the anti-corrosion non-metallic material layer 3 is cold-pressed, so that it is deformed and necked and then tightly pressed onto the anti-corrosion non-metallic material layer 3 to achieve a sealed connection and prevent corrosive media from corroding the sucker rod base 1.

[0049] Furthermore, in step 31, medium-high frequency induction heating is used, and the heating temperature is controlled at 200-500℃, preferably 200℃, 300℃, or 500℃; in step 33, the extrusion pressure is 800-1300kN, preferably 800kN, 900kN, 1100kN, or 1300kN; in step 35, the cold extrusion pressure is 300-800kN, preferably 300kN, 400kN, 600kN, or 800kN.

[0050] Furthermore, in step three-five, before cold extrusion, at least two O-rings are fitted into the area of ​​the anti-corrosion non-metallic material layer 3 that will be covered by the metal sleeve 2. In this embodiment, by pre-installing O-rings, the sealing effect between the metal sleeve 2 and the anti-corrosion non-metallic material layer 3 can be further enhanced.

[0051] It should be noted that the above detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0052] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments described in this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0053] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0054] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0055] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.

[0056] In the detailed description above, reference has been made to the accompanying drawings, which form part of this document. In the drawings, similar symbols typically identify similar parts unless the context otherwise indicates otherwise. The illustrated embodiments described in the detailed specification, drawings, and claims are not intended to be limiting. Other embodiments may be used and other changes may be made without departing from the spirit or scope of the subject matter presented herein.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing a fully enclosed sucker rod, characterized in that: Step 1: The sucker rod base (1) is manufactured by machining. The middle part of the completed sucker rod base (1) is the rod body (16), and the two ends are rod heads, which are symmetrically arranged at both ends. The rod head consists of a threaded joint (11), a relief groove (12), a shoulder (13), a wrench square (14), and a flange (15) in sequence from the end of the sucker rod base (1) toward the rod body (16). The outer surface of the rod body (16) is covered with a non-metallic anti-corrosion material layer (3). Step 2: The metal rod is manufactured by machining. The metal sleeve (2) is cylindrical in shape. In step three, the metal sleeve (2) is pressed to fit tightly against the outer surface of the shoulder (13), the wrench square (14), and the flange (15) and completely cover the shoulder (13), the wrench square (14), and the flange (15), and cover part of the anti-corrosion non-metallic material layer (3). The outer surface of the metal sleeve (2) forms a corresponding position with the shoulder (13), the wrench square (14), and the flange (15). The outer surfaces of the wrench (14) and flange (15) are the same shape; Step 3 includes the following steps: Step 31, heating the metal sleeve (2); Step 32, fitting the metal sleeve (2) into the rod head and making the end face of the metal sleeve (2) near the end of the sucker rod base (1) flush with the end face of the shoulder (13) near the unloading groove (12); Step 33, pressing the metal sleeve (2) with a press to make the metal sleeve (2) The metal sleeve (2) is tightly fitted to the outer surface of the shoulder (13), the wrench square (14) and the flange (15) and completely covers the shoulder (13), the wrench square (14) and the flange (15), and the outer surface of the metal sleeve (2) forms the same shape as the outer surface of the shoulder (13), the wrench square (14) and the flange (15); Step 3 and 4: Cooling; Step 3 and 5: Cold extruding the metal sleeve (2) by a press so that the metal sleeve (2) is covered with a partial anti-corrosion non-metallic material layer (3).

2. The method for manufacturing a fully enclosed sucker rod according to claim 1, characterized in that: In step one, the outer surface of the rod (16) is covered with a layer of anti-corrosion non-metallic material (3) by heating, injection molding and curing the anti-corrosion non-metallic material.

3. The method for manufacturing a fully enclosed sucker rod according to claim 1, characterized in that: In step two, at least one groove (21) is machined on the inner wall of the metal sleeve (2) near the end.

4. The method for manufacturing a fully enclosed sucker rod according to claim 1, characterized in that: In step three, medium-high frequency induction heating is used, and the heating temperature is controlled between 200-500℃.

5. The method for manufacturing a fully enclosed sucker rod according to claim 1, characterized in that: The extrusion pressure in step 3 is 800-1300kN.

6. The method for manufacturing a fully enclosed sucker rod according to claim 1, characterized in that: The pressure of cold extrusion in step three is 300-800kN.

7. The method for manufacturing a fully enclosed sucker rod according to claim 1, characterized in that: In step three, before cold extrusion, at least two O-rings are fitted into the area of ​​the anti-corrosion non-metallic material layer (3) that will be covered by the metal sleeve (2).

8. A method for manufacturing a fully enclosed sucker rod according to any one of claims 1-7, characterized in that: The metal sleeve (2) is made of stainless steel.

9. A method for manufacturing a fully enclosed sucker rod according to any one of claims 1-7, characterized in that: The anti-corrosion non-metallic material layer (3) is made of anti-corrosion polymer plastic material.

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