Fully-coated sucker rod

Abstract

The utility model relates to a fully-coated sucker rod, which is characterized in that the outer surface of a rod body is coated with a corrosion-resistant and wear-resistant ultra-high molecular layer, the outer surface of a rod head is coated with a modified engineering plastic layer, and two sides of the modified engineering plastic layer are respectively coated and combined on the outer surfaces of a circular bead and a part of the corrosion-resistant and wear-resistant ultra-high molecular layer. A first dovetail groove is formed in the outer surface of the shoulder in the circumferential direction, the inner surface of the modified engineering plastic layer extends outwards to form a first limiting protrusion matched with the first dovetail groove, the first limiting protrusion is combined in the first dovetail groove in a wrapped mode, and a second dovetail groove is formed in the outer surface of the anti-corrosion and anti-wear ultra-high molecular layer in the circumferential direction. The inner surface of the modified engineering plastic layer extends outwards to form a second limiting protrusion matched with the second dovetail groove, and the second limiting protrusion is combined in the second dovetail groove in a wrapped mode. Due to the arrangement of the first dovetail groove and the second dovetail groove, the reliability of the coating layer on the outer side of the sucker rod base body is improved, and the anti-corrosion and anti-wear performance of the sucker rod is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of sucker rods, in particular to a fully covered sucker rod. Background Art

[0002] The sucker rod is an important component required in the process of oil drilling and production. At present, most of my country's oil fields have entered the middle and late stages of development, with increasingly high water content. Water injection and other production-increasing measures are often used, and the oil field reinjection water is basically sewage directly reinjected, resulting in a very harsh working environment for the sucker rod. Highly mineralized well fluids contain various corrosive media and corrosive microorganisms, especially those rich in Cl - , which greatly increases the corrosion rate of the pump rod. At the same time, the associated gas contains corrosive gases such as CO2 and H2S, which make the well fluid weakly acidic. As we all know, the treatment of Cl - Corrosion caused by CO2, H2S, and other factors has always been a global challenge in oil production. Furthermore, friction between the sucker rod and the inner wall of the tubing generates heat, activating the rod's surface. Under the influence of corrosive produced fluids, the rate of corrosion on the rod surface is significantly accelerated. Furthermore, factors such as sand content, wax and scaling in the well, and produced fluid viscosity can also contribute to corrosion and eccentric wear on the rod surface. In short, the long-term exposure of sucker rods to alternating loads and the combined effects of oil, gas, water, and corrosive media, coupled with eccentric wear, makes them the least reliable equipment in mechanical oil production and prone to breakage accidents.

[0003] The Chinese utility model disclosed in publication number CN218563600U provides an extruded fully covered sucker rod, which includes a sucker rod base and a metal sleeve. The middle part of the sucker rod base is the rod body, and the two end parts are rod heads, and the two ends are symmetrically arranged. The rod head includes a threaded joint, a shoulder and a wrench square. The outer surface of the rod body is covered with an anti-corrosion non-metallic material layer. The metal sleeve is extruded to tightly fit the outer surfaces of the shoulder and the wrench square and completely cover the shoulder and the wrench square and partially cover the anti-corrosion non-metallic material layer. The shape formed at the corresponding position of the outer surface of the metal sleeve and the shoulder and the wrench square is the same as the shape of the outer surface of the shoulder and the wrench square. The sucker rod has the following defects: on the one hand, the metal sleeve is expensive, the extrusion and bonding process is complicated, and gaps are likely to exist between the metal sleeve and the sucker rod base, resulting in reduced anti-corrosion effect; on the other hand, the metal sleeve is directly coated on the outside of the anti-corrosion non-metallic material layer, and the anti-corrosion non-metallic material layer is easily elongated or shortened due to changes in temperature and other factors, resulting in poor reliability of the combination of the two.

[0004] Therefore, the present invention proposes a fully covered sucker rod to solve the above problems. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a fully covered sucker rod, thereby improving the reliability of the outer covering layer of the sucker rod base and enhancing the corrosion and wear resistance of the sucker rod.

[0006] In order to solve the above technical problems, the technical solution of the utility model is: a fully covered sucker rod, including a sucker rod base, the middle part of the sucker rod base is the rod body, and the two end parts are rod heads and are symmetrically arranged, and the rod head includes a shoulder. Its innovation lies in: the outer surface of the rod body is covered with an anti-corrosion and wear-resistant ultra-high molecular layer, and the outer surface of the rod head is covered with a modified engineering plastic layer, and the two sides of the modified engineering plastic layer are respectively covered and bonded to the outer surface of the shoulder and part of the anti-corrosion and wear-resistant ultra-high molecular layer, the outer surface of the shoulder is provided with a first dovetail groove along the circumferential direction, the inner surface of the modified engineering plastic layer extends outward to form a first limiting protrusion matching the first dovetail groove, the first limiting protrusion is covered and bonded in the first dovetail groove, the outer surface of the anti-corrosion and wear-resistant ultra-high molecular layer is provided with a second dovetail groove along the circumferential direction, the inner surface of the modified engineering plastic layer extends outward to form a second limiting protrusion matching the second dovetail groove, and the second limiting protrusion is covered and bonded in the second dovetail groove.

[0007] Furthermore, a transition chamfer is provided at the end of the modified engineering plastic layer where it is wrapped with the anti-corrosion and anti-wear ultra-high molecular weight layer, and the inclined surface of the transition chamfer is inclined from the side close to the shoulder toward the direction close to the central axis of the rod body.

[0008] Furthermore, there are two second dovetail grooves and two second limiting protrusions, which correspond to each other one by one, and the second limiting protrusions are covered and combined in the corresponding second dovetail grooves.

[0009] Furthermore, the rod head also includes a wrench square and a flange, the wrench square is located on the side of the shoulder close to the rod body, and the flange is located on the side of the wrench square close to the rod body. The modified engineering plastic layer is coated on the outer surfaces of the shoulder, the wrench square and the flange, and the shape formed on the outer surface of the modified engineering plastic layer at the corresponding positions of the shoulder, the wrench square and the flange is the same as the shape of the shoulder, the wrench square and the flange.

[0010] Furthermore, the end surface of the joint between the modified engineering plastic layer and the shoulder is flush with the end surface of the shoulder on the side away from the wrench.

[0011] The advantages of the present invention are:

[0012] The fully covered sucker rod of the utility model is coated with an anti-corrosion and anti-wear ultra-high molecular layer on the sucker rod body and a modified engineering plastic layer on the rod head, thereby blocking the sucker rod from H2S, CO2, Cl -The contact with downhole corrosive media such as salt water and the inner wall of the oil pipe can effectively avoid the surface corrosion and eccentric wear of the sucker rod. Both the modified engineering plastic layer and the anti-corrosion and anti-wear ultra-high molecular layer can be tightly wrapped and fitted on the surface of the sucker rod due to their material properties, ensuring the anti-corrosion effect of the sucker rod.

[0013] The utility model provides an axial limit to the modified engineering plastic layer by opening a first dovetail groove along the circumferential direction on the outer surface of the shoulder, and provides a second dovetail groove at the junction of the outer surface of the anti-corrosion and anti-wear ultra-high molecular layer and the modified engineering plastic layer, thereby ensuring a firm connection between the two and preventing the plastic material from being elongated or shortened due to changes in temperature and other factors, thereby affecting the reliability of the connection between the two.

[0014] The utility model provides a transition chamfer at the junction of the modified engineering plastic layer and the anti-corrosion and anti-wear ultra-high molecular layer, thereby preventing damage caused by scraping against the oil pipe during underground work.

[0015] The modified engineering plastic layer of the utility model is coated on the outer surface of the shoulder, the wrench square and the flange, and the shape of the outer surface of the modified engineering plastic layer at the corresponding positions of the shoulder, the wrench square and the flange is the same as the shape of the shoulder, the wrench square and the flange. On the one hand, the wrench square of the sucker rod retains its original shape well, which is convenient for on-site operations. On the other hand, the protection strength of various parts of the sucker rod head is the same, ensuring the consistency of service life of various parts, thereby avoiding the problem of waste caused by excessive thickness of the modified engineering plastic layer in a certain place.

[0016] The end face of the modified engineering plastic layer at the junction with the shoulder of the utility model is flush with the end face of the shoulder away from the wrench side, which will not cause adverse effects on the connection sealing when the sucker rods are spliced together. Moreover, the modified engineering plastic layer can use the shoulder end face as a reference surface during injection molding, which simplifies the injection molding operation and improves the molding accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0018] Figure 1 This is a schematic structural diagram of the fully covered sucker rod of the present utility model.

[0019] Figure 2 It is a partial schematic diagram of the fully covered sucker rod of the present utility model. DETAILED DESCRIPTION

[0020] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the following is a detailed description of the specific implementation method, structure, characteristics and effects of the present invention in combination with the accompanying drawings and preferred embodiments.

[0021] This embodiment provides a fully covered sucker rod, including a sucker rod base, the middle part of the sucker rod base is the rod body 2, and the two ends are rod heads and are symmetrically arranged. The rod head includes a threaded joint, a shoulder 21, a wrench square 22 and a flange 23. The threaded joint is located on the side of the shoulder 21 away from the rod body 2, the wrench square 22 is located on the side of the shoulder 21 close to the rod body 2, and the flange 23 is located on the side of the wrench square 22 close to the rod body 2.

[0022] The outer surface of the rod body 2 is covered with an anti-corrosion and wear-resistant ultra-high molecular layer 3, which is formed by extrusion. The outer surface of the rod head is covered with a modified engineering plastic layer 1, which is formed by injection molding. The two sides of the modified engineering plastic layer 1 are respectively covered and bonded to the outer surface of the shoulder 21 and part of the anti-corrosion and wear-resistant ultra-high molecular layer 3. The outer surface of the shoulder 21 is provided with a first dovetail groove 211 along the circumferential direction. The inner surface of the modified engineering plastic layer 1 extends outward to form a first dovetail groove 211 that matches the first dovetail groove 211. The limiting protrusions, the first limiting protrusions are coated and combined in the first dovetail groove 211, to axially limit the modified engineering plastic layer 1, the outer surface of the anti-corrosion and wear-resistant ultra-high polymer layer 3 has two second dovetail grooves 31 along the circumferential direction, the inner surface of the modified engineering plastic layer 1 extends outward to form two second limiting protrusions that match the second dovetail grooves and correspond one to one, the second limiting protrusions are coated and combined in the corresponding second dovetail grooves 31, to ensure that the two are firmly combined, to prevent the plastic material from elongating or shortening due to changes in temperature and other factors, which affects the reliability of the combination of the two.

[0023] In this embodiment, a transition chamfer 11 is provided at the end of the modified engineering plastic layer 1 where it is wrapped around the anti-corrosion and anti-wear ultra-high polymer layer 3. The slope of the transition chamfer 11 slopes from the side near the shoulder toward the center axis of the rod body 2, effectively preventing damage caused by scraping against the oil pipe during underground operation. The modified engineering plastic layer 1 is coated on the outer surface of the shoulder 21, the wrench square 22, and the flange 23. The shape of the outer surface of the modified engineering plastic layer 1 at the corresponding positions of the shoulder 21, the wrench square 22, and the flange 23 is the same as the shape of the shoulder 21, the wrench square 22, and the flange 23. This design not only allows the wrench square of the sucker rod to retain its original shape, facilitating on-site operations, but also provides the same level of protection at all locations on the sucker rod head, ensuring consistent service life at all locations, thereby avoiding the problem of waste caused by excessive thickness of the modified engineering plastic layer at a certain location. The end face of the modified engineering plastic layer 1 at the junction with the shoulder 21 is flush with the end face of the shoulder 21 on the side away from the wrench square 22, which will not adversely affect the connection sealing when the sucker rods are spliced together using threaded joints. Moreover, when the modified engineering plastic layer 1 is injection molded, the end face of the shoulder 21 can be used as the reference surface, which simplifies the injection operation and improves the molding accuracy.

[0024] The fully covered sucker rod is coated with an anti-corrosion and anti-wear ultra-high molecular layer on the sucker rod body and a modified engineering plastic layer on the rod head, thereby blocking the sucker rod from H2S, CO2, Cl - The contact with downhole corrosive media such as salt water and the inner wall of the oil pipe can effectively avoid the surface corrosion and eccentric wear of the sucker rod. Both the modified engineering plastic layer and the anti-corrosion and anti-wear ultra-high molecular layer can be tightly wrapped and fitted on the surface of the sucker rod due to their material properties, ensuring the anti-corrosion effect of the sucker rod.

[0025] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A fully covered sucker rod, comprising a sucker rod base, wherein the middle portion of the sucker rod base is a rod body, and the two ends are rod heads that are symmetrically arranged, and the rod heads include shoulders, characterized in that: The outer surface of the rod body is covered with an anti-corrosion and wear-resistant ultra-high molecular layer, and the outer surface of the rod head is covered with a modified engineering plastic layer. The two sides of the modified engineering plastic layer are respectively coated and bonded to the outer surface of the shoulder and part of the anti-corrosion and wear-resistant ultra-high molecular layer. The outer surface of the shoulder is provided with a first dovetail groove along the circumferential direction, and the inner surface of the modified engineering plastic layer extends outward to form a first limiting protrusion matching the first dovetail groove. The first limiting protrusion is coated and bonded in the first dovetail groove. The outer surface of the anti-corrosion and wear-resistant ultra-high molecular layer is provided with a second dovetail groove along the circumferential direction. The inner surface of the modified engineering plastic layer extends outward to form a second limiting protrusion matching the second dovetail groove. The second limiting protrusion is coated and bonded in the second dovetail groove.

2. The fully covered sucker rod according to claim 1, characterized in that: The end of the modified engineering plastic layer and the anti-corrosion and anti-wear ultra-high molecular weight layer is provided with a transition chamfer, and the inclined surface of the transition chamfer is inclined from the side close to the shoulder to the direction close to the central axis of the rod body.

3. The fully covered sucker rod according to claim 1, characterized in that: There are two second dovetail grooves and two second limiting protrusions, which correspond to each other one by one. The second limiting protrusions are covered and combined in the corresponding second dovetail grooves.

4. The fully covered sucker rod according to claim 1, characterized in that: The rod head also includes a wrench square and a flange, the wrench square is located on the side of the shoulder close to the rod body, and the flange is located on the side of the wrench square close to the rod body. The modified engineering plastic layer is coated on the outer surfaces of the shoulder, the wrench square and the flange, and the shape formed on the outer surface of the modified engineering plastic layer at the corresponding positions of the shoulder, the wrench square and the flange is the same as the shape of the shoulder, the wrench square and the flange.

5. The fully covered sucker rod according to claim 4, characterized in that: The end surface of the joint between the modified engineering plastic layer and the shoulder is flush with the end surface of the shoulder on the side away from the wrench.

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