Sand prevention device for drainage gas production unit protector

Abstract

The utility model relates to the technical field of submersible screw pumps for coal bed gas exploitation, and discloses a sand prevention device for a drainage and gas production unit protector, which comprises a connector, a filter device is fixedly connected in the connector, a protector output shaft is rotatably connected in the connector, and the protector output shaft is rotatably connected with the filter device. A sand prevention cap is fixedly connected to the outer side of the protector output shaft, a mechanical seal is arranged on the outer side of the protector output shaft, and a mechanical seal mounting base is arranged at the bottom of the mechanical seal. According to the utility model, most of sand grains are filtered through the filtering device, and the filtered sand grains are discharged into the sand setting cavity through the sand discharging inclined hole of the connecting joint due to high-speed rotational flow of the sand prevention cap; during shutdown, a small part of sand grains are deposited on the upper part of the sand prevention cap, and after startup, the sand prevention cap swirls to discharge the sand grains into the sand setting cavity through the sand discharging channel of the sand discharging connector, so that the sand grains are prevented from entering the sand prevention device, and shaft abrasion or breakage caused by relative movement between the sand prevention cap and the output shaft of the protector due to blockage is avoided.

Description

Technical Field

[0001] This utility model relates to the field of submersible screw pump technology for coalbed methane extraction, and in particular to a sand prevention device for a protective device of a drainage gas extraction unit. Background Technology

[0002] The submersible screw pump drainage and gas production device utilizes a downhole submersible motor to directly drive a screw pump to lift liquid and achieve coalbed methane extraction. It combines the advantages of rodless oil production systems, downhole motor drives, and screw pumps. Compared with rod pumps, it can save 30% to 60% of energy and can exceed the pumping depth of rod pumps. It can be applied to heavy oil wells, sand-producing wells, gas-bearing wells, deviated wells, and horizontal wells.

[0003] Due to the unique well conditions of coalbed methane wells, submersible screw pump drainage gas production systems require excellent sand and gas prevention capabilities. Existing protectors for these systems simply remove the sand discharge hole from the original oil-producing submersible screw pump protector to ensure adequate gas prevention. However, when the sand discharge hole is blocked, sand particles in the well fluid accumulate and cannot be discharged, eventually causing the sand cap to become completely clogged. During operation, the sand cap rotates connected to the protector's output shaft. If the sand cap becomes clogged, relative movement between the cap and shaft occurs, leading to severe wear and failure or breakage of the protector's output shaft due to the abrasion caused by sand particles. Therefore, a new sand prevention device for drainage gas production system protectors is proposed to address these issues. Utility Model Content

[0004] To overcome the above deficiencies, this utility model provides a sand-proof device for the protector of a drainage gas extraction unit, aiming to improve the problem in the prior art where the sand particles deposited by the sand-proof device of the protector cannot be discharged, causing relative movement between the sand-proof cap and the output shaft of the protector, resulting in shaft wear or breakage.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a sand-proof device for a protector of a drainage gas extraction unit, comprising a connecting joint, a filter device fixedly connected inside the connecting joint, a protector output shaft rotatably connected inside the connecting joint, a sand-proof cap fixedly connected to the outside of the protector output shaft, a mechanical seal provided on the outside of the protector output shaft, a mechanical seal mounting base provided at the bottom of the mechanical seal, a sand discharge joint threadedly connected to the bottom of the connecting joint, multiple sand discharge oblique holes opened on the outside of both the connecting joint and the sand discharge joint, a sand discharge channel opened inside the sand discharge joint, a sand settling chamber shell fixedly connected to the outside of the connecting joint, a sand settling chamber opened inside the sand settling chamber shell, and a small flat cable fixedly connected to the outside of the connecting joint.

[0006] As a further description of the above technical solution:

[0007] The output shaft of the protector is rotatably connected inside the sand discharge joint.

[0008] As a further description of the above technical solution:

[0009] The sand-proof cap is located inside the sand discharge joint.

[0010] As a further description of the above technical solution:

[0011] The mechanical seal is located inside the sand cap and above the sand discharge joint.

[0012] As a further description of the above technical solution:

[0013] The sand discharge joint and the mechanical seal mounting base are interference-fitted.

[0014] As a further description of the above technical solution:

[0015] The outer shell of the sedimentation chamber is fixedly connected to the outside of the sand discharge connector, and the small flat cable is fixedly connected to the outside of the sand discharge connector.

[0016] As a further description of the above technical solution:

[0017] The sedimentation chamber is located outside the connecting joint, and the sedimentation chamber is located outside the sand discharge joint.

[0018] As a further description of the above technical solution:

[0019] The outlet of the sand discharge oblique hole is located inside the sand settling chamber.

[0020] This utility model has the following beneficial effects:

[0021] In this invention, most of the sand particles are filtered by a filtration device. The sand-proof cap is used to protect the output shaft of the protector. Under the action of the high-speed rotation of the sand-proof cap, the filtered sand particles are discharged into the sand settling chamber through the sand discharge oblique hole on the connecting joint. If the unit stops due to a malfunction, a small portion of the sand particles from the filtration device will settle on the upper part of the sand-proof cap and cannot directly enter the mechanical seal mating surface. When the unit restarts, the sand-proof cap rotates at high speed, and the sand particles settled on the upper part of the sand-proof cap are discharged into the sand discharge channel on the sand discharge joint under the action of the swirling flow, and finally enter the sand settling chamber. This prevents sand particles and other impurities in the well fluid from entering the sand-proof device and avoids the problem of the sand-proof cap becoming blocked, causing relative movement with the protector's output shaft, resulting in wear or breakage of the output shaft. Attached Figure Description

[0022] Figure 1 This is a front cross-sectional view of a sand-prevention device for a drainage gas extraction unit protector proposed in this utility model;

[0023] Figure 2 This is a top cross-sectional view of the sand-proof cavity of a sand-proof device for a drainage gas extraction unit protector proposed in this utility model.

[0024] Legend:

[0025] 1. Connecting joint; 2. Filter device; 3. Sand cap; 4. Mechanical seal; 5. Mechanical seal mounting base; 6. Sand discharge joint; 7. Sand discharge channel; 8. Sand settling chamber; 9. Protector output shaft; 10. Sand settling chamber shell; 11. Small flat cable; 12. Sand discharge oblique hole. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Reference Figures 1-2This utility model provides an embodiment of a sand-proof device for a gas drainage unit protector, comprising a connecting joint 1, a filter device 2 fixedly connected inside the connecting joint 1, a protector output shaft 9 rotatably connected inside the connecting joint 1, a sand-proof cap 3 fixedly connected to the outside of the protector output shaft 9, a mechanical seal 4 provided on the outside of the protector output shaft 9, a mechanical seal mounting base 5 provided at the bottom of the mechanical seal 4, a sand discharge joint 6 threadedly connected to the bottom of the connecting joint 1, multiple sand discharge oblique holes 12 opened on the outside of both the connecting joint 1 and the sand discharge joint 6, a sand discharge channel 7 opened inside the sand discharge joint 6, a sand settling chamber shell 10 fixedly connected to the outside of the connecting joint 1, a sand settling chamber 8 opened inside the sand settling chamber shell 10, a small flat cable 11 fixedly connected to the outside of the connecting joint 1, and a flange connection at the top of the connecting joint 1 for connecting the unit's flexible shaft shell, which is a hollow structure. The filter device 2 is installed inside the connecting joint 1 and is connected to the protector output shaft 9. A certain gap allows for the filtration of most sand particles in the well fluid. The protector output shaft 9 is installed inside the connecting joint 1 and serves as the transmission component of the unit, transmitting motor torque to the screw pump to drive its operation. The sand cap 3 is connected to the protector output shaft 9 via fixing bolts. The device discharges the filtered sand particles from the connecting joint 1 through the high-speed rotation of the sand cap 3. The mechanical seal 4 is installed on the protector output shaft 9 via a moving ring and moves together with the protector output shaft 9 during unit operation. The mechanical seal 4 is fixed to the mechanical seal mounting base 5 via a stationary ring. The lower part of the connecting joint 1 is a threaded connection sand discharge joint 6, through which sand particles are discharged via the sand discharge inclined hole 12. The sand discharge channel 7 guides the sand particles on the sand discharge joint 6. The outer shell 10 of the sand settling chamber is a three-quarter arc shape, with its opening for the passage of the small flat cable 11. The sand settling chamber 8 is used for the sedimentation and collection of sand particles. The small flat cable 11 transmits electricity from underground to the motor at the bottom of the well and is externally bound to the connecting joint 1.

[0028] The protector output shaft 9 is rotatably connected inside the sand discharge connector 6, and the protector output shaft 9 is installed inside the sand discharge connector 6.

[0029] The sand cap 3 is located inside the sand discharge joint 6 and is used to protect the mechanical seal 4.

[0030] Mechanical seal 4 is located inside sand cap 3 and above sand discharge joint 6. Sand cap 3 covers mechanical seal 4, and mechanical seal 4 prevents sand particles from entering the interior of the protector through the gap between protector output shaft 9 and sand discharge joint 6.

[0031] There is an interference fit between the sand discharge joint 6 and the mechanical seal mounting base 5, and the mechanical seal mounting base 5 is connected to the sand discharge joint 6 through the interference fit.

[0032] The outer shell 10 of the sedimentation chamber is fixedly connected to the outside of the sand discharge connector 6, and the small flat cable 11 is fixedly connected to the outside of the sand discharge connector 6. The outer shell 10 of the sedimentation chamber is fixed to the outer shell of the sand discharge connector 6, and the small flat cable 11 is tied to the sand discharge connector 6.

[0033] The sand settling chamber 8 is located outside the connecting joint 1 and outside the sand discharge joint 6. The sand settling chamber 8 is formed by the sand settling chamber shell 10, the connecting joint 1 and the sand discharge joint 6.

[0034] The outlet of the sand discharge inclined hole 12 is located inside the sand settling chamber 8, and the filtered sand particles enter the sand settling chamber 8 through the sand discharge inclined hole 12.

[0035] Working principle:

[0036] Due to the sand particles distributed in the well fluid, the submersible screw pump drainage and gas production device is damaged. Most of the sand particles in the well fluid are filtered by the filter device 2. The sand cap 3 runs through the output shaft 9 of the protector. Under the action of the high-speed rotation of the sand cap 3, the filtered sand particles are discharged into the sand settling chamber 8 through the sand discharge inclined hole 12 on the connecting joint 1. If the unit stops due to a fault, a small amount of sand particles in the filter device 2 will settle on the upper part of the sand cap 3 and cannot directly enter the mechanical seal mating surface. When the unit is restarted, the sand cap 3 rotates at high speed and discharges the sand particles settled on the upper part of the sand cap 3 into the sand discharge channel 7 on the sand discharge joint 6 under the action of the swirling flow, and finally into the sand settling chamber 8.

[0037] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A sand-prevention device for a protective device of a drainage gas extraction unit, comprising a connecting joint (1), characterized in that: The connecting joint (1) is fixedly connected to a filter device (2), the connecting joint (1) is rotatably connected to a protector output shaft (9), the protector output shaft (9) is fixedly connected to a sand cap (3) on the outside, the protector output shaft (9) is provided with a mechanical seal (4) on the outside, the mechanical seal (4) is provided with a mechanical seal mounting base (5) at the bottom, the connecting joint (1) is threadedly connected to a sand discharge joint (6), both the connecting joint (1) and the sand discharge joint (6) are provided with multiple sand discharge oblique holes (12) on the outside, the sand discharge joint (6) is provided with a sand discharge channel (7) inside, the connecting joint (1) is fixedly connected to a sand settling chamber shell (10) on the outside, the sand settling chamber shell (10) is provided with a sand settling chamber (8) inside, and a small flat cable (11) is fixedly connected to the outside of the connecting joint (1).

2. A sand-prevention device for a drainage gas extraction unit protector according to claim 1, characterized in that: The output shaft (9) of the protector is rotatably connected inside the sand discharge joint (6).

3. A sand-prevention device for a drainage gas extraction unit protector according to claim 1, characterized in that: The sand cap (3) is located inside the sand discharge joint (6).

4. A sand-prevention device for a drainage gas extraction unit protector according to claim 1, characterized in that: The mechanical seal (4) is located inside the sand cap (3) and above the sand discharge joint (6).

5. A sand-prevention device for a drainage gas extraction unit protector according to claim 1, characterized in that: The sand discharge joint (6) and the mechanical seal mounting base (5) are interference-fitted.

6. A sand-prevention device for a drainage gas extraction unit protector according to claim 1, characterized in that: The outer shell (10) of the sedimentation chamber is fixedly connected to the outside of the sand discharge connector (6), and the small flat cable (11) is fixedly connected to the outside of the sand discharge connector (6).

7. A sand-prevention device for a drainage gas extraction unit protector according to claim 1, characterized in that: The settling chamber (8) is located outside the connecting joint (1), and the settling chamber (8) is located outside the sand discharge joint (6).

8. A sand-prevention device for a drainage gas extraction unit protector according to claim 1, characterized in that: The outlet of the sand discharge oblique hole (12) is located inside the sand settling chamber (8).

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