Hollow rod packing box for screw pump

Abstract

The invention discloses a hollow rod packing box for a screw pump, and relates to the technical field of mechanical oil extraction equipment. Comprising an upper pressing connector, a polished rod, a main body, a welding short connector, a special short connector and a lower pressing connector, wherein the polished rod is connected with the special short connector through a screw thread; a communicating hole is formed in one side of the middle of the body, sealing cavities are formed in the two sides of the communicating hole, and sealing rings are arranged in the sealing cavities. The hollow polished rod is sealed through the upper pressing connector, the lower pressing connector and the extrusion sealing ring, the special short connector is a cylinder with the small middle and is communicated with the welding short connector through the vertical through hole, during rotation, the liquid flowing resistance is small, liquid flowing is not affected, and the sealing effect is good. The end of the upper pressing connector and the end of the lower pressing connector are in geometrical shapes, the sealing ring can be conveniently pressed through a tool, the sealing ring is made of materials good in elasticity and abrasion resistance, and the welding short connector is connected with an external liquid pipeline and used for injecting working liquid into a well.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical oil production equipment, and particularly to a stuffing box for a hollow rod of a screw pump. Background Art

[0002] At present, for the development of oil and gas fields in China, especially for shale gas and coalbed methane drainage and gas production, due to the settlement of sand particles and fly ash during the mining process, downhole pumps are often stuck. The screw pump method can better solve the problems of sand and fly ash settlement and lifting. There are usually two methods: surface-driven screw pump and electric submersible screw pump. These two methods have their own advantages and disadvantages: The advantages of the surface-driven screw pump are that it can start at low speed and is used for high-viscosity, high-sand, and fly ash drainage and gas production wells; the rotation speed can be adjusted arbitrarily to meet the requirements of oil and gas wells with a displacement of 1-150 m 3 / d. However, for directional wells and horizontal wells, due to the problem of rod string eccentric wear, the working life is relatively short.

[0003] The electric submersible screw pump is suitable for use in wells with a relatively high sand content (sand content less than 3%, particle size less than 0.25), has a short transmission chain, good energy-saving effect, and high pump efficiency, and is suitable for oil and gas wells with a displacement of 15-300 m 3 / d. However, it is not suitable for oil and gas wells with a displacement of less than 15 m 3 / d and oil and gas wells with a sand content greater than 3% and a particle size greater than 0.25 mm.

[0004] The displacement of shale gas and coalbed methane drainage and gas production wells is less than 15 m 3 / d, and most wells are 1-5 m 3 / d. Due to the slow flow rate, the critical flow rate is often not reached. In this way, fly ash and pressure sand settle above the pump, causing the pump to be stuck or work abnormally, or due to other reasons on the ground to stop the machine, and the particle components in the well fluid settle above the screw pump, jamming the pump rotor and the tubing. Injecting liquid into the well through a hollow rod is one of the most effective methods at present, but there is a problem of leakage between the rotating polished rod on the ground and the external fluid. Summary of the Invention

[0005] The purpose of the present invention is to provide a stuffing box for a hollow rod of a screw pump to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A stuffing box for a hollow rod of a screw pump, including an upper compression joint, a polished rod, a main body, a welded short joint, a special short joint, and a lower compression joint. The polished rod is connected to the special short joint by a thread; One side of the middle of the main body is provided with a communication hole, and sealing cavities are arranged on both sides of the communication hole, and sealing rings are arranged in the sealing cavities.

[0007] As a specific embodiment of the technical solution of the present application, the end of the upper compression joint is a polygonal structure.

[0008] As a specific embodiment of the technical solution of the present application, the end of the lower compression joint is a polygonal structure.

[0009] As a specific embodiment of the technical solution of the present application, the welding short joint is connected to an external liquid pipeline through a flange and is used for injecting working fluid into the well.

[0010] As a specific embodiment of the technical solution of the present application, the sealing ring has elasticity and wear resistance.

[0011] As a specific embodiment of the technical solution of the present application, the upper compression joint, the lower compression joint and the sealing ring achieve the sealing of the special short joint.

[0012] Compared with the prior art, the beneficial effects of the present invention are: For the stuffing box of the hollow rod of the screw pump, by arranging the upper compression joint and the lower compression joint, the sealing ring is extruded to achieve the sealing of the hollow polished rod. The special short joint adopts a small cylinder in the middle and is connected to the welding short joint through a vertical through hole. When rotating, the liquid flow resistance is small and does not affect the liquid flow. The ends of the upper compression joint and the lower compression joint adopt geometric shapes, which are convenient for using tools to compress the sealing ring. The sealing ring is made of a material with good elasticity and wear resistance. The welding short joint is connected to an external liquid pipeline and is used for injecting working fluid into the well. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic cross-sectional structure diagram of the present invention; Figure 3 For the present invention Figure 2 The enlarged schematic diagram of A in.

[0014] In the figure: 1. Lower compression joint; 2. Polished rod; 3. Main body; 4. Sealing ring; 5. Welding short joint; 6. Special short joint; 7. Upper compression joint. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] 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. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0016] It should be noted that in the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0017] In addition, it should be understood that for the convenience of description, the sizes of the various components shown in the drawings are not drawn in actual proportional relationships. For example, the thickness or width of some layers may be exaggerated relative to other layers.

[0018] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined or described in one drawing, further specific discussion and description thereof will not be required in the description of the subsequent drawings.

[0019] As Figures 1-3 shown, the present invention provides a technical solution: a stuffing box for a hollow rod of a screw pump, including an upper compression joint 7, a polished rod 2, a main body 3, a welded nipple 5, a special nipple 6, and a lower compression joint 1. The polished rod 2 is connected to the special nipple 6 by a thread. A communication hole is provided on one side of the middle of the main body 3. Sealing cavities are provided on both sides of the communication hole, and sealing rings 4 are provided in the sealing cavities. The end of the upper compression joint 7 is a triangular structure. The end of the lower compression joint 1 is a quadrilateral structure. The welded nipple 5 is connected to an external liquid pipeline through a flange for injecting working fluid into the well. The sealing ring 4 has elasticity and wear resistance. The upper compression joint 7, the lower compression joint 1, and the sealing ring 4 achieve the sealing of the special nipple 6.

[0020] It should be clearly understood that in the embodiments of the present application, the special nipple 6 is a geometric body with a hollow middle and a sealed end. Through the middle hole, such as Figure 2As shown, it is connected to the outside. The diameter of the middle part of the special adapter 6 is more than 5 mm smaller than that of both ends. When the special adapter 6 rotates with the polished rod 2, the liquid can flow into the welding adapter along the small cylinder without being affected. A communication hole is provided on one side of the middle part of the main body 3, and there is a sealing cavity on each side of the communication hole. A sealing ring 4 is installed in the sealing cavity. By pressing the upper pressing joint 7 and the lower pressing joint 1 against the sealing ring 4, the sealing of the special adapter 6 is achieved. It should also be clear that in this application, the end shapes of the upper pressing joint 7 and the lower pressing joint 1 are not restricted in any way, such as triangles, quadrilaterals, pentagons, etc. Since this is prior art, it will not be elaborated again. The ends of the upper pressing joint 7 and the lower pressing joint 1 adopt geometric shapes, and the sealing ring 4 can be easily tightened or loosened by tools. The sealing ring 4 is made of a material with good lubricity, elasticity and wear resistance. At the same time, the welding adapter 5 is connected to the external liquid pipeline by means of threads, flanges or clamps, etc., for injecting working fluid into the well.

[0021] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended embodiments and their equivalents.

Claims

1. A stuffing box for a hollow rod of a screw pump, characterized in that It includes an upper compression joint (7), a polished rod (2), a main body (3), a welded nipple (5), a special nipple (6) and a lower compression joint (1). The polished rod (2) is connected to the special nipple (6) by threads; One side in the middle of the main body (3) is provided with a communication hole, and sealing cavities are arranged on both sides of the communication hole. A sealing ring (4) is arranged in the sealing cavity.

2. The stuffing box for the hollow rod of a screw pump according to claim 1, characterized in that: The end of the upper compression joint (7) is of a polygonal structure.

3. The stuffing box for hollow rod of screw pump according to claim 1, characterized in that: The end of the lower compression joint (1) is of a polygonal structure.

4. A stuffing box for a hollow rod of a screw pump according to claim 1, characterized in that: The welded nipple (5) is connected to an external liquid pipeline through a flange and is used for injecting working fluid into the well.

5. The stuffing box for hollow rod of screw pump according to claim 1, characterized in that: The sealing ring (4) has elasticity and wear resistance.

6. The stuffing box for hollow rod of screw pump according to claim 1, characterized in that: The upper compression joint (7), the lower compression joint (1) and the sealing ring (4) achieve the sealing of the special nipple (6).

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