High-temperature-resistant sealed hollow sucker rod

Abstract

The utility model relates to a high-temperature-resistant sealed hollow sucker rod, and belongs to the technical field of sucker rods. Every two adjacent hollow rod units are connected through a sealing connector with threaded structures at the two ends of the inner wall, annular sealing bins used for installing sealing pieces are formed between the ends of every two adjacent hollow rods and the inner wall of the sealing connector, and therefore sealing connection of every two adjacent hollow rod units is achieved. In the actual operation process, only the hollow rods need to be installed at the two ends of the sealing connector in a threaded mode, operation is easy, leakage risk points are few, the effect is reliable, the sealing connector and the hollow rods are detachably connected, and maintenance or regular replacement of components is convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of sucker rods, in particular to a high temperature resistant sealed hollow sucker rod. Background Art

[0002] During the heavy oil production process, due to its high viscosity and high freezing point, the lifting load is heavy and the alternating load is large during pumping, resulting in serious lag of the bare rod. In severe cases, the sucker rod breaks frequently and the lifting is difficult. Therefore, the lifting process is often supplemented by the wellbore viscosity reduction process to solve this problem. The hollow sucker rod can form a working channel in the oil pipe of the production string, through which heat carriers such as hot water, hot oil, chemicals, steam and cables can be injected into the well to reduce the viscosity of the crude oil in the well and make the crude oil smoothly extracted from the ground. However, the existing hollow sucker rod sealing method mostly uses ordinary rubber ring sealing, which has a maximum temperature resistance of 150°C and cannot meet the on-site needs.

[0003] In order to solve the above problems, the invention patent CN107869313A published in April 2018 discloses a high-temperature sealing connection device and connection method for a hollow sucker rod, wherein the device includes an upper joint and a lower joint connected to each other from top to bottom, and a closed annulus is formed between the outer wall of the upper section of the lower joint and the inner wall of the lower section of the upper joint, and a seal is installed in the annulus. The inner cavity of the upper joint is provided with an enlarged diameter hole section and a reduced diameter hole section from the lower end to the top, wherein the inner wall of the reduced diameter hole section is provided with an internal thread, and the outer wall of the lower joint is provided with a small diameter pipe section and a large diameter pipe section from the upper end to the bottom, wherein the outer wall of the small diameter pipe section is provided with an external thread, and the small diameter pipe section is inserted into the reduced diameter hole section and connected through the threads of the two. The seal includes a metal compensation seal and a non-metal compensation seal which are axially arranged in the closed annulus from top to bottom. Thereby, the high temperature resistance of the hollow sucker rod sealing connection device is improved.

[0004] However, the above-mentioned prior art requires that at each connection, an upper joint be installed at one end of a hollow sucker rod, a lower joint be installed at one end of another corresponding hollow sucker rod, and finally the upper and lower joints be connected, which complicates the on-site operation process and affects the installation progress of the sucker pipe. In addition, the connection between the upper and lower joints and the hollow sucker rod itself requires high temperature resistant sealing treatment, which increases the risk of leakage. Utility Model Content

[0005] The utility model aims to provide a high temperature resistant sealed hollow sucker rod to solve the technical problems in the prior art of complicated operation and many subsequent leakage risk points when connecting adjacent hollow sucker rods.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A high-temperature resistant sealed hollow sucker rod comprises at least two hollow rod units, wherein two adjacent hollow rod units are connected via a sealing joint, wherein the upper and lower ends of the inner wall of the sealing joint are provided with internal threads, and the ends of the hollow rods are provided with external threads which match the internal threads on the inner walls at both ends of the sealing joint; an annular sealing chamber is formed between the two adjacent hollow rod ends and the inner wall of the sealing joint, and a sealing member is installed in the annular sealing chamber.

[0008] Furthermore, the hollow rod has a constant diameter section and a reduced diameter section, and the reduced diameter section is located at the top of the hollow rod thread; the reduced diameter section and the inner wall of the sealing joint constitute the annular sealing chamber.

[0009] Furthermore, an annular convex ring for abutting against the peripheral surface of the reduced diameter section of the hollow rod is provided in the middle of the sealing joint.

[0010] Furthermore, the sealing member includes a metal sealing member and a non-metallic high-temperature sealing ring; the metal sealing member is located on a side of the non-metallic high-temperature sealing ring close to the sealing joint port.

[0011] Furthermore, the metal seal is a copper pad.

[0012] Furthermore, a transition slope is provided between the reduced diameter section and the constant diameter section.

[0013] Furthermore, a protrusion is provided in the middle of the inner wall of the sealing joint, and the end surface of the hollow rod cooperates with the step surface stop formed between the protrusion and the inner wall of the sealing joint.

[0014] Furthermore, chamfers are provided at both axial ends of the inner wall of the sealing joint.

[0015] The high temperature resistant sealed hollow sucker rod in the utility model is an improved invention, and has the beneficial effect of connecting two adjacent hollow rod units through a sealing joint with threaded structures at both ends of the inner wall, and forming an annular sealing chamber with sealing components installed between the ends of the two adjacent hollow rods and the inner wall of the sealing joint, thereby realizing the sealed connection of the two adjacent hollow rod units. In the actual operation process, it is only necessary to thread the two hollow rods at both ends of the sealing joint, which is simple to operate, has few leakage risk points, and has a reliable effect. In addition, the sealing joint and the hollow rod are detachably connected, which is convenient for maintenance or regular replacement of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a high temperature resistant sealed hollow sucker rod in an embodiment of the utility model;

[0017] Figure 2 It is an enlarged view of the connection between two adjacent hollow rods in the embodiment of the utility model.

[0018] Explanation of the reference numerals: 1. hollow rod; 2. sealing joint; 3. copper pad; 4. high-temperature sealing ring; 5. bump; 6. annular convex ring; 7. transition slope; 8. chamfer. DETAILED DESCRIPTION

[0019] The technical concept of the utility model is to connect two adjacent hollow rod units through a sealing joint with threaded structures at both ends of the inner wall, and an annular sealing chamber for installing sealing components is formed between the ends of the two adjacent hollow rods and the inner wall of the sealing joint, thereby realizing the sealed connection of the two adjacent hollow rod units. In the actual operation process, it is only necessary to thread the two hollow rods at both ends of the sealing joint, which is simple to operate; there are only two connection points, fewer leakage risk points, and reliable effects; the sealing joint and the hollow rod are detachably connected, which is convenient for maintenance or regular replacement of parts.

[0020] The features and performance of the present invention are further described in detail below in conjunction with specific embodiments.

[0021] High temperature resistant sealed hollow sucker rod, such as Figure 1 As shown, it includes a plurality of hollow rod units, and two adjacent hollow rods 1 are sealed and connected via a sealing joint 2. The inner walls at both ends of the sealing joint 2 are provided with internal threads, and correspondingly, the ends of the adjacent hollow rods 1 are provided with external threads adapted to the internal threads on the inner walls at both ends of the sealing joint, so that the two hollow rods can be connected.

[0022] like Figure 2 As shown, a protrusion 5 is provided in the middle of the inner wall of the sealing joint 2, and a step surface is formed between the protrusion 5 and the inner wall of the sealing joint 2. During the connection process between the hollow rod 1 and the sealing joint 2, the step surface cooperates with the stopper on the top surface of the hollow rod 1 to form a stopper surface. The protrusion can be a plurality of protrusions arranged at intervals around the inner wall of the sealing joint 2 in the circumferential direction, or it can be a whole ring, as long as it plays a stopper role to prevent the hollow rod 1 from being screwed in excessively.

[0023] In this embodiment, the end of the hollow rod 1 has a constant diameter section and a reduced diameter section, wherein the reduced diameter section is arranged at the top of the thread, i.e., near the end of the hollow rod, wherein the external thread is arranged on the constant diameter section, and the reduced diameter section cooperates with the inner wall of the sealing joint 2 to form an annular sealing chamber. The annular sealing chamber is arranged near the end of the hollow rod, and the sealing member in the annular sealing chamber can effectively prevent the high temperature carrier in the hollow rod from reaching the threaded part, thereby protecting the thread and extending the service life of the sealing joint 2 and the hollow rod 1. It is only necessary to replace the sealing member regularly, thereby reducing the cost.

[0024] A metal seal and a non-metallic high-temperature sealing ring are installed in the annular sealing chamber. In the axial direction of the sealing joint, the metal seal is located on the outside of the non-metallic high-temperature sealing ring. In this embodiment, the metal seal is a copper pad 3, and the non-metallic high-temperature sealing ring is a high-temperature sealing ring 4. The copper pad 3 and the high-temperature sealing ring 4 are installed on the top of the hollow rod. As the hollow rod 1 and the sealing joint 2 are tightened by threaded connection, the high-temperature sealing ring 4 is gradually pressed into the sealing chamber formed by the rod body and the sealing joint 2, playing a primary sealing role. In this embodiment, the high-temperature sealing ring 4 adopts modified polytetrafluoroethylene, which is heat-resistant to about 350°C. At the same time, the copper pad 3 is squeezed and deformed to form a secondary seal, and the high-temperature sealing ring 4 is prevented from being crushed and lost during high-temperature and high-pressure steam injection. In other embodiments, only the copper pad 3 can be used for sealing, but the hollow rod in the well may cause the copper pad to be poorly sealed due to the tensile effect.

[0025] An annular convex ring 6 is provided in the middle of the sealing joint 2, and the inner diameter of the annular convex ring 6 is equal to the outer diameter of the reduced diameter section of the hollow rod 1. After the hollow rod 1 and the sealing joint 2 are threaded into place, the inner wall of the annular convex ring 6 abuts against the inner wall of the reduced diameter section of the hollow rod 1 to form a surface contact, forming a surface seal, thereby further enhancing the sealing effect.

[0026] There is a transition slope 7 between the reduced diameter section and the constant diameter section of the hollow rod 1. The inclined surface can provide the seal with both lateral and longitudinal extrusion forces, making the sealing effect of the seal more reliable. Of course, the transition slope 7 can also be omitted, and the reduced diameter section and the constant diameter section form a step surface. In this case, the amount of seal used can be increased, so that the annular sealing chamber can be filled by the seal's own extrusion, and finally a better sealing effect can be achieved.

[0027] Both axial ends of the inner wall of the sealing joint 2 are provided with chamfers 8 to prevent the hollow rod from colliding with the edges and corners of the inner wall of the sealing joint 2 when entering the interior of the sealing joint 2 .

[0028] The above description is only a preferred embodiment of the present utility model and is not intended to limit the patent scope of the present utility model. Other equivalent changes that apply the patent spirit of the present utility model should all fall within the patent scope of the present utility model.

Claims

1. A high temperature resistant sealed hollow sucker rod, comprising at least two hollow rod units, wherein two adjacent hollow rod units are connected by a sealing joint, characterized in that: The upper and lower ends of the inner wall of the sealing joint are provided with internal threads, and the ends of the hollow rods are provided with external threads that match the internal threads on the inner walls at both ends of the sealing joint; an annular sealing chamber is formed between the two adjacent hollow rod ends and the inner wall of the sealing joint, and a sealing member is installed in the annular sealing chamber.

2. The high temperature resistant sealed hollow sucker rod according to claim 1, characterized in that: The hollow rod has a constant diameter section and a reduced diameter section, wherein the reduced diameter section is located at the top of the thread of the hollow rod; the reduced diameter section and the inner wall of the sealing joint constitute the annular sealing chamber.

3. The high temperature resistant sealed hollow sucker rod according to claim 2, characterized in that: An annular convex ring for abutting against the peripheral surface of the reduced diameter section of the hollow rod is arranged in the middle of the sealing joint.

4. The high temperature resistant sealed hollow sucker rod according to any one of claims 1 to 3, characterized in that: The sealing member comprises a metal sealing member and a non-metal high-temperature sealing ring; the metal sealing member is located on a side of the non-metal high-temperature sealing ring close to the sealing joint port.

5. The high temperature resistant sealed hollow sucker rod according to claim 4, characterized in that: The metal sealing member is a copper pad.

6. The high temperature resistant sealed hollow sucker rod according to claim 2, characterized in that: A transition slope is provided between the reduced diameter section and the constant diameter section.

7. The high temperature resistant sealed hollow sucker rod according to claim 2 or 3, characterized in that: A convex block is arranged in the middle of the inner wall of the sealing joint, and the end surface of the hollow rod cooperates with a step surface stopper formed between the convex block and the inner wall of the sealing joint.

8. The high temperature resistant sealed hollow sucker rod according to claim 1, characterized in that: Both axial ends of the inner wall of the sealing joint are provided with chamfers.

Images