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 invention relates to the technical field of mechanical oil production equipment, in particular to a hollow rod packing box for a screw pump. Background Art

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

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

[0004] The drainage capacity of shale gas and coalbed methane wells is 15m 3 / d or less, most wells are 1-5m 3 / d, due to the slow flow rate, the critical flow rate is often not reached, so fly ash and pressure sand settle on the upper part of the pump, causing the pump to get stuck or malfunction, or shut down due to other reasons on the ground, and the particles in the well fluid settle on the top of the screw pump, blocking the pump rotor and oil pipe. Injecting liquid into the well through a hollow rod is one of the most effective methods at present, but there are problems of rotating bare rods and external fluid leakage on the ground. Summary of the invention

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

[0006] To achieve the above object, the present invention provides the following technical solution: a hollow rod packing box for a screw pump, comprising an upper clamping joint, a polished rod, a main body, a welding short joint, a special short joint and a lower clamping joint, wherein the polished rod and the special short joint are connected by threads; A communication hole is opened on one side of the middle part of the main body, and sealing cavities are arranged on both sides of the communication hole, and a sealing ring is arranged in the sealing cavity.

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

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

[0009] As a specific solution of the technical solution of the present application, the welded short joint is connected to an external liquid pipeline through a flange to inject working fluid into the well.

[0010] As a specific solution of the technical solution of the present application, the sealing ring is elastic and wear-resistant.

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

[0012] Compared with the prior art, the present invention has the following beneficial effects: The hollow rod packing box for the screw pump is provided with an upper compression joint and a lower compression joint, and a sealing ring is squeezed to achieve sealing of the hollow bare rod. The special short joint adopts a small cylinder in the middle, which is connected to the welded short joint through a vertical through hole. When rotating, the liquid flow resistance is small and the liquid flow is not affected. The ends of the upper compression joint and the lower compression joint adopt a geometric shape, which is convenient for pressing the sealing ring with a tool. The sealing ring is made of a material with good elasticity and wear resistance. The welded short joint is connected to an external liquid pipeline 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 cross-sectional structural schematic diagram of the present invention; Figure 3 For the present invention Figure 2 A is an enlarged schematic diagram.

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

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] It should be noted that, in the description of the present invention, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0017] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

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

[0019] like Figure 1-Figure 3 As shown, the present invention provides a technical solution: a hollow rod packing box for a screw pump, comprising an upper clamping joint 7, a polished rod 2, a main body 3, a welding short joint 5, a special short joint 6 and a lower clamping joint 1, wherein the polished rod 2 is connected to the special short joint 6 by a threaded connection; A connecting hole is provided on one side of the middle of the main body 3, and sealing cavities are provided on both sides of the connecting hole, and a sealing ring 4 is provided in the sealing cavity. 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 welding short joint 5 is connected to the external liquid pipeline through a flange, which is used to inject working fluid into the well. The sealing ring 4 is elastic and wear-resistant. The upper compression joint 7, the lower compression joint 1 and the sealing ring 4 realize the sealing of the special short joint 6.

[0020] It should be clear that in the embodiment of the present application, the special short connector 6 is a geometric body with a hollow center and sealed ends, through the middle hole, such as Figure 2As shown, it is connected to the outside, and the middle of the special short joint 6 is more than 5mm smaller than the diameter of the two ends. When the special short joint 6 rotates with the light rod 2, the liquid can flow into the inside of the welded short joint along the small cylinder without being affected. A connecting hole is opened on one side of the middle part of the main body 3, and there is a sealing cavity on both sides of the connecting hole. A sealing ring 4 is installed in the sealing cavity. The sealing ring 4 is squeezed by the upper clamping joint 7 and the lower clamping joint 1 to achieve the sealing of the special short joint 6. It should also be clear that in this application, there is no restriction on the shape of the ends of the upper clamping joint 7 and the lower clamping joint 1, such as triangle, quadrilateral, pentagon, etc. Since it is a prior art, it will not be repeated again. The ends of the upper clamping joint 7 and the lower clamping joint 1 adopt a geometric shape, and the sealing ring can be conveniently 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 welded short joint 5 is connected to the liquid pipeline of the external device by means of threads, flanges or clamps, etc., for injecting working fluid into the well.

[0021] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the attached embodiments and their equivalents.

Claims

1. A hollow rod packing box for a screw pump, characterized in that: It comprises an upper clamping joint (7), a polished rod (2), a main body (3), a welding short joint (5), a special short joint (6) and a lower clamping joint (1), wherein the polished rod (2) and the special short joint (6) are connected via a threaded connection; A communication hole is provided on one side of the middle of the main body (3), and sealing cavities are provided on both sides of the communication hole, and a sealing ring (4) is provided in the sealing cavity.

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

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

4. The hollow rod packing box for a screw pump according to claim 1, characterized in that: The welded short joint (5) is connected to an external liquid pipeline via a flange and is used to inject working fluid into the well.

5. The hollow rod packing box for a screw pump according to claim 1, characterized in that: The sealing ring (4) is elastic and wear-resistant.

6. The hollow rod packing box for a 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 sealing of the special short joint (6).

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