Carbon fiber sucker rod prestress combination joint and using method thereof

Abstract

The invention discloses a carbon fiber sucker rod prestress combination joint and a using method thereof. The carbon fiber sucker rod prestress combination joint comprises a bonding sleeve and further comprises a prestress loading pipe; the number of the bonding sleeves is at least two, and the bonding sleeves are connected with the carbon fiber sucker rod through adhesives. And a prestress loading pipe is arranged between every two bonding sleeves. The at least two bonding sleeves comprise a first bonding sleeve and at least one second bonding sleeve. According to the invention, two or more than two bonding sleeves are arranged, the stress of the single bonding sleeve is adjusted by using the prestress loading pipe, and the stress of the joint is distributed to the plurality of bonding sleeves, so that the stress of the single bonding sleeve during use in an oil well is reduced, and the effect of prolonging the service life of the joint in the oil well can be achieved. The invention solves the bottleneck technology in the application of the carbon fiber sucker rod, and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of oil production machinery, and particularly to a prestressed combined joint for a carbon fiber sucker rod and a using method thereof. Background Art

[0002] A carbon fiber sucker rod generally refers to a continuous carbon fiber sucker rod. The carbon fiber sucker rod is applied in a pumping well, with its upper end connected to a polished rod and its lower end connected to a weight rod, and a special joint is used for connection at the connection part. Due to the easy failure of the joint, for the carbon fiber sucker rod used in an oil well, generally the number of joints is minimized, usually only one carbon fiber sucker rod is used in a well, and it is stored, transported and constructed by winding. With the increasing number of carbon fiber sucker rods applied in the oil field, the problem of connection failure of carbon fiber sucker rods becomes more and more prominent.

[0003] The carbon fiber sucker rod is made of non-metallic material, and the strength of threaded connection cannot meet the strength requirements for use in an oil well, and the threaded connection of steel sucker rods cannot be adopted. Currently, there are two common connection principles. One is adhesive connection, where an adhesive is used to bond the carbon fiber sucker rod and the joint. The other is clamp ring and ferrule connection, where the clamp ring tightly holds the rod body, and the tapered ferrule applies pressure to the clamp ring. As the tensile force increases, the clamping force of the clamp ring on the carbon fiber sucker rod becomes greater. Whether it is adhesive connection or clamp ring and ferrule connection, the greater the tensile force borne by the connection part, the easier the joint connection fails. The failure form of the adhesive type is mainly cracking at the adhesive part, and the failure of the clamp ring and ferrule type is mainly in the form of rod body crushing, pulverization, longitudinal cracks, etc. at the clamping part.

[0004] If threaded connection is adopted, due to its low strength, it cannot meet the force requirements of the sucker rod in an oil well. Therefore, there is currently no carbon fiber sucker rod with threaded connection put into use. The connection technology has become a bottleneck technology restricting the service life of carbon fiber sucker rods.

[0005] The present invention adopts a device for applying prestress to the joint part, distributes the force to multiple bonding sleeves, reduces the force borne by a single bonding sleeve part during use in an oil well, and improves the service life of the joint in the oil well.

[0006] Publication (Announcement) Number: CN108286415B, which discloses a connection joint between a carbon fiber sucker rod and a steel sucker rod, including: a connection sleeve, which is threadedly connected to a half-moon type slip joint and a polished rod; a compression sleeve, which is threadedly connected to the half-moon type slip joint; a half-moon type slip joint, one end of which is threadedly connected to the connection sleeve, and the other end of the half-moon type slip joint is threadedly connected to the compression sleeve. The carbon fiber sucker rod is connected to the inner wall of the other end of the half-moon type slip joint through a high-temperature resin, and a pair of the half-moon type slip joints are connected in pairs. The beneficial effects of this invention are as follows: it greatly increases the connection strength, improves the reliability of the joint, and effectively avoids the problem of breakage and disconnection of the sucker rod; it adopts a modular connection method, has good structural properties, is convenient for on-site installation and replacement, and solves the current situation that the existing joints are complex to install and not convenient to replace.

[0007] However, the prior art cannot adjust the magnitude of the force on the joint.

[0008] Publication (Announcement) Number: CN106761459B, which discloses a fixed-length carbon fiber continuous sucker rod joint with carbon fiber as the carrier, including a corrosion-resistant and wear-resistant thermoplastic, carbon fiber filaments, a composite material, a carbon fiber continuous sucker rod, a metal sleeve, a metal pull ring, and a standard adapter. The carbon fiber filaments are located inside the corrosion-resistant and wear-resistant thermoplastic, and the composite material is filled between the corrosion-resistant and wear-resistant thermoplastic and the carbon fiber filaments. The carbon fiber continuous sucker rod is integrally formed by pultrusion of the corrosion-resistant and wear-resistant thermoplastic, carbon fiber filaments, and the composite material. The carbon fiber continuous sucker rod is connected to the metal sleeve, the carbon fiber filaments pass through the metal sleeve and are connected to the metal pull ring, the metal pull ring is connected to the metal sleeve, and the standard adapter is connected to the metal sleeve. This invention changes the composite material as the force-bearing carrier at the joint, and the two-stage connection strengthens the connection strength of the carbon fiber continuous sucker rod joint. Using carbon fiber with high tensile strength, high fatigue strength, and high load-bearing capacity as the force-bearing carrier prolongs the life of the joint.

[0009] However, the prior art cannot adjust the magnitude of the force on the joint.

[0010] Publication (Announcement) Number: CN218376351U, which discloses a carbon fiber continuous sucker rod connection joint. This utility model includes a connection end head, a shrinkage groove is provided in the inner cone sleeve, and the taper of the inner wall of the outer cone sleeve matches the taper of the outer wall of the inner cone sleeve. The connection end head is connected to the outer cone sleeve, and the carbon fiber continuous sucker rod connection joint is connected to both ends of the carbon fiber continuous sucker rod. This utility model is connected to both ends of the carbon fiber continuous sucker rod. There is no need to use special resin to naturally solidify and bond firmly between the carbon fiber continuous sucker rod and the ordinary steel sucker rod, and the tighter it is pulled. It solves the problems that the connection between the carbon fiber continuous sucker rod and the carbon fiber continuous sucker rod joint is currently connected by a bonding method, with long drying and solidification time and the connection strength being easily affected by humid weather, etc., and improves the construction efficiency.

[0011] The crimp joint of the prior art is threadedly connected to the adhesive joint. The threaded connection only combines and connects the two parts, and the force borne by the two joints cannot be adjusted.

[0012] In summary, the technical solutions, the technical problems to be solved, and the beneficial effects of the above-disclosed technologies are all different from those of the present invention. For more technical features, technical problems to be solved, and beneficial effects of the present invention, there is no technical inspiration in the above-disclosed technical documents. Summary of the Invention

[0013] In view of the above-mentioned defects existing in the prior art, the object of the present invention is to provide a prestressed combined joint for a carbon fiber sucker rod and its use method. By using two or more adhesive sleeves and a prestress loading pipe, the force is distributed to multiple adhesive sleeves, so as to reduce the force on a single adhesive sleeve part during use in an oil well and improve the service life of the joint in the oil well.

[0014] To achieve the above object, the present invention adopts the following technical solutions:

[0015] A prestressed combined joint for a carbon fiber sucker rod includes an adhesive sleeve and a prestress loading pipe; at least two adhesive sleeves are provided, and the adhesive sleeves are connected to the carbon fiber sucker rod through an adhesive; a prestress loading pipe is arranged between every two adhesive sleeves.

[0016] Further, the at least two adhesive sleeves include a first adhesive sleeve and at least one second adhesive sleeve.

[0017] Further, a blind hole is provided at the center of the upper end of the first adhesive sleeve, and a first wavy diameter-changing section is provided on the inner wall of the blind hole;

[0018] Specifically, a first external thread is provided on the outer wall of the upper end of the first adhesive sleeve, and a joint thread is provided on the outer wall of the lower end of the first adhesive sleeve;

[0019] Specifically, a wrench flat is provided on the outer wall of the first adhesive sleeve.

[0020] Further, a through hole is provided at the center of the second adhesive sleeve, and a second wavy diameter-changing section is provided on the inner wall of the through hole;

[0021] Specifically, a second external thread is provided on the outer wall of the lower end of the second adhesive sleeve.

[0022] Further, the aperture of the blind hole of the first adhesive sleeve and the aperture of the through hole of the second adhesive sleeve are both larger than the carbon fiber sucker rod;

[0023] Specifically, the first external thread and the second external thread have opposite helix directions.

[0024] Further, the prestressed loading tube includes a first prestressed loading tube;

[0025] Specifically, the first external thread and the second external thread are connected by a first prestressed loading tube;

[0026] Specifically, the inner wall of the upper end of the first prestressed loading tube is provided with a second internal thread, and the rotation direction and specification of the second internal thread match the second external thread;

[0027] Specifically, the inner wall of the lower end of the first prestressed loading tube is provided with a first internal thread, and the rotation direction and specification of the first internal thread match the first external thread.

[0028] Furthermore, the first external thread is also provided with a first locking nut, and the second external thread is also provided with a second locking nut. After the first prestressed loading tube is adjusted into place, the first locking nut and the second locking nut are used to lock the first prestressed loading tube.

[0029] Furthermore, a third external thread is provided at the upper end of the second bonding sleeve;

[0030] Specifically, the third external thread has a rotation direction opposite to that of the second external thread, and a third locking nut is provided on the third external thread;

[0031] Specifically, the prestressed loading tube further includes at least one second prestressed loading tube; the structure of the second prestressed loading tube is completely the same as that of the prestressed loading tube;

[0032] Specifically, the third external thread is connected to the adjacent second external thread through a second prestressed loading tube.

[0033] In order to achieve the above object, the present invention adopts the following technical solutions:

[0034] A method for using a carbon fiber sucker rod prestressed combined joint comprises the following steps:

[0035] S1, using adhesive to fix the carbon fiber sucker rod head in the first adhesive sleeve 3, and using adhesive to fix at least one second adhesive sleeve on the rod head;

[0036] S2, using the first prestressed loading tube to connect the first bonding sleeve and the second bonding sleeve with threads; by adjusting the rotation angle of the first prestressed loading tube, tighten or relax the tensioning prestress between the first bonding sleeve and the second bonding sleeve;

[0037] If the number of the second bonding sleeves is greater than or equal to two, the second bonding sleeves are threadedly connected using a second prestressed loading tube, and the tensioning prestress between the second bonding sleeves is tightened or relaxed by adjusting the rotation angle of the second prestressed loading tube;

[0038] S3. Lock the threaded connection with a lock nut.

[0039] Further, the distance from the second bonding sleeve at the bottom to the rod head is 0.3 m - 1 m; the distance between the second bonding sleeves is the same as the distance from the second bonding sleeve at the bottom to the rod head.

[0040] The present invention has the following beneficial effects compared with the prior art:

[0041] 1. By providing two or more bonding sleeves and using a prestress loading tube to adjust the force on a single bonding sleeve, the present invention distributes the joint force to multiple bonding sleeves, reduces the force on a single bonding sleeve during use in an oil well, and can improve the service life of the joint in the oil well.

[0042] 2. The prestressed combined joint of the present invention is applicable to the connection of non-metallic sucker rods such as carbon fiber sucker rods, carbon fiber - glass hybrid sucker rods, and glass fiber sucker rods, achieving the purpose of improving the service life of the joint.

[0043] 3. The present invention solves the bottleneck technology in the application of carbon fiber sucker rods and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic structural diagram of a prestressed combined joint of a carbon fiber sucker rod according to the present invention;

[0045] Figure 2 is a schematic internal structural diagram of a prestressed combined joint of a carbon fiber sucker rod according to the present invention;

[0046] Figure 3 is a schematic structural diagram of a first bonding sleeve of a prestressed combined joint of a carbon fiber sucker rod according to the present invention;

[0047] Figure 4 is a schematic structural diagram of a second bonding sleeve of a prestressed combined joint of a carbon fiber sucker rod according to the present invention;

[0048] Figure 5 is a schematic structural diagram of a first prestress loading tube of a prestressed combined joint of a carbon fiber sucker rod according to the present invention;

[0049] In the figure: 1. Joint thread; 2. Wrench square; 3. First bonding sleeve; 4. First external thread; 5. First lock nut; 6. Second bonding sleeve; 7. Second external thread; 8. Second lock nut; 9. First prestress loading tube; 10. First internal thread; 11. Second internal thread; 12. Carbon fiber sucker rod. DETAILED DESCRIPTION OF THE INVENTION

[0050] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] Embodiment 1:

[0052] Please refer to Figures 1 to 5 , a prestressed combined joint of a carbon fiber sucker rod provided by the present invention includes a first bonding sleeve 3, a second bonding sleeve 6, and a first prestressed loading tube 9;

[0053] A blind hole is provided at the center of the upper end of the first bonding sleeve 3, a first wavy reduced-diameter section is provided on the inner wall of the blind hole, a first external thread 4 is provided on the outer wall of the upper end of the first bonding sleeve 3, a joint thread 1 is provided on the outer wall of the lower end of the first bonding sleeve 3, and a wrench flat 2 is provided on the outer wall of the first bonding sleeve 3. The structures of the wrench flat 2 and the joint thread 3 are the same as those of the joint of an ordinary steel sucker rod.

[0054] A through hole is provided at the center of the second bonding sleeve 6, a second wavy reduced-diameter section is provided on the inner wall of the through hole, and a second external thread 7 is provided on the outer wall of the lower end of the second bonding sleeve 6.

[0055] The blind hole diameter of the first bonding sleeve 3 and the through hole diameter of the second bonding sleeve 6 are both larger than the carbon fiber sucker rod 12. The rotation directions of the first external thread 4 and the second external thread 7 are opposite, being left-handed and right-handed respectively.

[0056] The first external thread 4 and the second external thread 7 are connected by a first prestressed loading tube 9. A second internal thread 11 is provided on the inner wall of the upper end of the first prestressed loading tube 9, and the rotation direction and specification of the second internal thread 11 match those of the second external thread 7; a first internal thread 10 is provided on the inner wall of the lower end of the first prestressed loading tube 9, and the rotation direction and specification of the first internal thread 10 match those of the first external thread.

[0057] By adjusting the rotation angle of the first prestressed loading tube 9, the tensile prestress between the first bonding sleeve 3 and the second bonding sleeve 6 can be tightened or relaxed;

[0058] Increasing the tensile prestress can increase the tensile force borne by the second bonding sleeve 6 in the oil well use state and reduce the tensile force borne by the first bonding sleeve 3 in the oil well use state;

[0059] On the contrary, relaxing the tensile prestress can reduce the tensile force borne by the second bonding sleeve 6 in the oil well use state and increase the tensile force borne by the first bonding sleeve 3 in the oil well use state.

[0060] The first external thread 4 is also provided with a first locking nut 8, and the second external thread 7 is also provided with a second locking nut 5. After the first prestressed loading tube 9 is adjusted into place, the first locking nut 8 and the second locking nut 5 are used to lock the first prestressed loading tube 9.

[0061] Embodiment 2:

[0062] Based on Example 1, this example provides a method for using the device:

[0063] S1, fix the rod head of the carbon fiber sucker rod 12 in the first bonding sleeve 3 by using adhesive, and fix the second bonding sleeve 6 at a position 0.3m-1m away from the rod head by using adhesive;

[0064] S2. Use the first prestressed loading tube 9 to connect the first bonding sleeve 3 and the second bonding sleeve 6 by threading; by adjusting the rotation angle of the first prestressed loading tube 9, tighten or relax the tensioning prestress between the first bonding sleeve 2 and the second bonding sleeve 6;

[0065] S3. Use the first locking nut 8 and the second locking nut 5 to lock the threaded connection respectively.

[0066] Embodiment 3;

[0067] Based on Example 1, this embodiment provides a joint structure of more than two bonding sleeves, wherein a third external thread is provided on the upper end of the second bonding sleeve 6, the third external thread has a rotation direction opposite to that of the second external thread, and a third locking nut is provided on the third external thread;

[0068] At least two second bonding sleeves 6 are arranged on the carbon fiber sucker rod 12 , and a second prestressed loading tube is arranged between every two second bonding sleeves 6 . The structure of the second prestressed loading tube is completely the same as that of the first prestressed loading tube 9 .

[0069] The preload force between the second bonding sleeves 6 is adjusted by the second prestressing tube.

[0070] All existing authorized or disclosed patent technologies and public documents do not involve two or more bonding sleeves, no prestressed loading tubes, and do not involve adjustable bonding sleeves to share the bonding sleeve force technology.

[0071] All components and connection methods of components not discussed in this application belong to the known technologies in this technical field and can be directly applied without further explanation.

[0072] In the present invention, the term "a plurality of" refers to two or more, unless otherwise clearly defined. Terms such as "mounted", "connected", "coupled", "fixed", etc. shall be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "coupled" can be a direct coupling or an indirect coupling through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0074] In the description of this specification, the descriptions of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0075] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A prestressed combined joint for a carbon fiber sucker rod, comprising an adhesive sleeve, characterized in that, it further comprises a prestress loading tube; At least two of the adhesive sleeves are provided, and the adhesive sleeves are connected to the carbon fiber sucker rod through an adhesive; A prestress loading tube is arranged between every two adhesive sleeves.

2. The prestressed combined joint for a carbon fiber sucker rod according to claim 1, characterized in that, the at least two adhesive sleeves include a first adhesive sleeve and at least one second adhesive sleeve.

3. The prestressed combined joint for a carbon fiber sucker rod according to claim 2, characterized in that, a blind hole is provided at the center of the upper end of the first adhesive sleeve, and a first wavy reduced-diameter section is provided on the inner wall of the blind hole; a first external thread is provided on the outer wall of the upper end of the first adhesive sleeve, and a joint thread is provided on the outer wall of the lower end of the first adhesive sleeve; a wrench square is provided on the outer wall of the first adhesive sleeve.

4. The prestressed combined joint for a carbon fiber sucker rod according to claim 3, characterized in that, a through hole is provided at the center of the second adhesive sleeve, and a second wavy reduced-diameter section is provided on the inner wall of the through hole; a second external thread is provided on the outer wall of the lower end of the second adhesive sleeve.

5. The prestressed combined joint for a carbon fiber sucker rod according to claim 4, characterized in that, the aperture of the blind hole of the first adhesive sleeve and the aperture of the through hole of the second adhesive sleeve are both larger than that of the carbon fiber sucker rod; the first external thread and the second external thread have opposite helix directions.

6. The prestressed combined joint for a carbon fiber sucker rod according to claim 4, characterized in that, the prestress loading tube includes a first prestress loading tube; the first external thread and the second external thread are connected by the first prestress loading tube; a second internal thread is provided on the inner wall of the upper end of the first prestress loading tube, and the helix direction and specification of the second internal thread match those of the second external thread; a first internal thread is provided on the inner wall of the lower end of the first prestress loading tube, and the helix direction and specification of the first internal thread match those of the first external thread.

7. The prestressed combined joint for a carbon fiber sucker rod according to claim 6, characterized in that, a first locking nut is further provided on the first external thread, and a second locking nut is further provided on the second external thread. After the first prestress loading tube is adjusted in place, the first prestress loading tube is locked by using the first locking nut and the second locking nut.

8. The prestressed combined joint for a carbon fiber sucker rod according to claim 6, characterized in that, a third external thread is provided at the upper end of the second adhesive sleeve; the third external thread and the second external thread have opposite helix directions, and a third locking nut is provided on the third external thread; the prestress loading tube further includes at least one second prestress loading tube; the structure of the second prestress loading tube is exactly the same as that of the prestress loading tube; the third external thread and the adjacent second external thread are connected by the second prestress loading tube.

9. A method for using a prestressed combined joint for a carbon fiber sucker rod, characterized in that, it includes the following steps, S1, using adhesive to fix the carbon fiber sucker rod head in the first adhesive sleeve 3, and using adhesive to fix at least one second adhesive sleeve on the rod head; S2, using the first prestressed loading tube to connect the first bonding sleeve and the second bonding sleeve with threads; by adjusting the rotation angle of the first prestressed loading tube, tighten or relax the tensioning prestress between the first bonding sleeve and the second bonding sleeve; If the number of the second bonding sleeves is greater than or equal to two, the second bonding sleeves are threadedly connected using a second prestressed loading tube, and the tensioning prestress between the second bonding sleeves is tightened or relaxed by adjusting the rotation angle of the second prestressed loading tube; S3. Use locking nut to lock the threaded connection.

10. A method for using a carbon fiber sucker rod prestressed composite joint, It is characterized in that The distance between the second adhesive sleeve at the bottom and the rod head is 0.3 m-1 m; the distance between the second adhesive sleeves is the same as the distance between the second adhesive sleeve at the bottom and the rod head.

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