Hydraulically-driven underground motor pump for deep coal and rock gas exploitation

Abstract

The invention discloses a hydraulic drive underground motor pump for deep ground coal and rock gas exploitation, and belongs to the technical field of deep ground (the pump hanging depth is 2000-3800 m) coal and rock gas exploitation equipment. The hydraulic drive underground motor pump comprises a setting pipe head, the setting pipe head is connected with a setting connector in a sealing mode through setting, an outer pipe of a double-layer pipe column is in threaded connection with an upper connector, and a lower pipe of the double-layer pipe column is in threaded connection with a lower connector. Then the plunger is in threaded connection with an outer pipe short joint to separate power liquid pipelines of upper and lower cavities of the plunger; the interior of the upper end of the flow guide connector is in threaded connection with the setting connector, the exterior of the upper end of the flow guide connector is in threaded connection with the outer pipe short connector, the interior of the lower end of the flow guide connector is in threaded connection with the motor plunger pump cylinder, and the exterior of the lower end is in threaded connection with the motor outer pipe. The buffers are arranged at the upper end and the lower end of the motor plunger and installed at the upper end and the lower end of the motor plunger, impact and vibration generated when the plunger reaches an upper dead point and a lower dead point are reduced, the anti-impact distance of the pump plunger is greatly reduced, the operation stroke of the plunger is guaranteed, and meanwhile the service life of an underground motor pump is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of deep-earth (pump setting depth of 2,000 - 3,800 meters) coalbed methane extraction equipment, and specifically to a hydraulic-driven downhole motor pump for deep-earth coalbed methane extraction. Background Technique

[0002] Currently, for deep-earth (pump setting depth of 2,000 - 3,800 meters) coalbed methane extraction, mechanical drainage is mainly carried out using equipment such as pumping units, progressing cavity pumps, and jet pumps, which basically ensures the normal production of coalbed methane. However, new geological conditions (such as high salinity, easy corrosion, easy scaling, and eccentric wear in inclined wells), high maintenance costs, difficult control of liquid production volume, and other characteristics, as well as the existing downhole horse pumps during operation, have insufficient running stroke stability of the plunger, and the motor is easily damaged due to frequent impacts, with a short service life. At the same time, the pump barrel and plunger structure of the existing equipment are not reasonably designed, and the intermediate pull rod has insufficient stiffness and is easily broken during use, affecting the normal operation of the equipment. Therefore, there is an urgent need for a new type of hydraulic-driven downhole motor pump for deep-earth (pump setting depth of 2,000 - 3,800 meters) coalbed methane extraction to solve the above problems.

[0003] Therefore, the applicant considers providing a hydraulic-driven downhole motor pump for deep-earth coalbed methane extraction, which can meet the requirements of extending the service life of the device, preventing the plunger from getting stuck during work, scaling between the valve ball and valve seat, and being able to be used for drainage in different deep wells (pump setting depth of 2,000 - 3,800 meters). Summary of the Invention

[0004] The purpose of the present invention is to provide a hydraulic-driven downhole motor pump for deep-earth coalbed methane extraction to solve the problems raised in the above background technique.

[0005] To achieve the above purpose, the present invention provides the following technical solution:

[0006] A hydraulic-driven downhole motor pump for deep-earth (pump setting depth of 2,000 - 3,800 meters) coalbed methane extraction, including a setting packer head, the setting packer head is sealed with the setting joint through setting, the outer pipe of the double-layer pipe string is threadedly connected to the upper joint, and then threadedly connected to the outer pipe nipple, separating the power fluid pipelines of the upper and lower chambers of the plunger; the upper end inside of the diversion joint is threadedly connected to the setting joint, the upper end outside is threadedly connected to the outer pipe nipple, the lower end inside of the diversion joint is threadedly connected to the motor plunger pump barrel, the lower end outside is threadedly connected to the motor outer pipe, and the upper buffer seat is connected directly below.

[0007] As a further solution of the present invention: wherein, the upper end of the motor plunger is threadedly connected to the upper buffer, a downward start port is formed on the upper buffer, the lower end is threadedly connected to the upper traveling valve, the upper traveling valve ball is located inside the upper traveling valve, the upper traveling valve is threadedly connected to the pump long plunger, and the lower buffer is connected directly below.

[0008] As a further solution of the present invention: wherein, the pump long plunger is threadedly connected to the lower traveling valve seat, the lower traveling valve ball is located inside the lower traveling valve seat, the upper end of the intermediate joint is respectively threadedly connected to the motor outer tube and the motor plunger pump barrel, the lower end is respectively threadedly connected to the short pump barrel and the pump outer tube, the pump outer tube is threadedly connected to the lower joint, and the short pump barrel is threadedly connected to the fixed valve connecting pipe.

[0009] As a further solution of the present invention: wherein, the fixed valve connecting pipe is threadedly connected to the fixed valve seat, and the fixed valve is located inside the fixed valve seat.

[0010] As a further solution of the present invention: wherein, starting small holes are provided at the upper and lower ends of the motor.

[0011] As a further solution of the present invention: wherein, a sand settling cavity of 400 - 800 mm is provided below the motor plunger, and anti-scaling films are sprayed on both the valve seat and the valve cover.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] 1. In the present invention, buffers are provided at the upper and lower ends of the plunger, which are installed at the upper and lower ends of the motor plunger, reducing the impact and vibration of the plunger reaching the top and bottom dead points, greatly reducing the anti-surge distance of the pump plunger, ensuring the operating stroke of the plunger, and at the same time extending the service life of the motor;

[0014] 2. The present invention provides the use of a long plunger and a short pump barrel, increasing the stiffness of the intermediate tie rod to prevent breakage during use;

[0015] 3. In the present invention, upper and lower starting small holes are separately machined on the buffer. During the up and down strokes of the motor plunger, the contact area between the power fluid and the plunger buffer can be increased through the small holes, preventing problems such as the motor plunger getting stuck or unable to start due to insufficient contact area between the plunger and the power fluid when reaching the dead point.

[0016] 4. In the present invention, a sand settling cavity is provided below the motor plunger to prevent particles such as sand grains in the power fluid from entering the gap between the motor plunger and the pump barrel, causing problems such as the motor plunger jamming the pump and wear.

[0017] 5. The present invention can select the size of the motor plunger according to needs. Different plunger sizes can be applied to different well types. Larger pump plungers are selected for large displacements, and smaller pump plungers are selected for small displacements. Currently, there are series models of 70 / 38, 70 / 44, and 57 / 32.

[0018] 6. The present invention sprays anti-scaling films on all valve seats and valve covers or performs PVD treatment, which increases the wear resistance of the device, prevents scaling, and extends the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural sectional view of the hydraulic-driven downhole motor pump device for deep coalbed methane extraction in the present invention;

[0020] Figure 2 It is a schematic diagram of the liquid flow direction when the gas drainage and production device of the present invention performs the upstroke and downstroke;

[0021] The corresponding relationship between the labels of each attached drawing in the figure and the component names is as follows:

[0022] 1. Setting packer head; 2. Upper joint; 3. Setting packer joint; 4. Setting packer seal; 5. Outer pipe nipple; 6. Diverting joint; 7. Motor outer pipe; 8. Upper buffer seat; 9. Motor plunger pump barrel; 10. Upper buffer; 11. Motor plunger; 12. Upper floating valve; 13. Upper floating valve ball; 14. Lower buffer; 15. Intermediate joint; 16. Long pump plunger; 17. Short pump barrel; 18. Motor pump outer pipe; 19. Lower floating valve; 20. Fixed valve cover; 21. Lower joint; 22. Fixed valve seat; 23. Fixed valve connecting pipe; 24. Lower floating valve cover; 25. Fixed valve. DETAILED DESCRIPTION OF THE INVENTION

[0023] Please refer to Figure 1 and Figure 2: The present invention is a hydraulic-driven downhole motor pump device for deep coalbed methane extraction, and its structural features are as follows: The setting packer head and the setting joint 3 are sealed by the setting seal 4. The outer pipe of the double-layer pipe string is threadedly connected to the upper joint 2, and then threadedly connected to the outer pipe short joint 5. The upper joint 2 is threadedly connected to the outer pipe short joint 5. The inner upper end of the diversion joint 6 is threadedly connected to the setting joint 3, and the outer upper end is threadedly connected to the outer pipe short joint 5. The inner lower end of the diversion joint is threadedly connected to the motor plunger pump barrel 9, and the outer lower end is threadedly connected to the motor outer pipe 7, and the upper buffer seat 8 is connected directly below. The upper end of the motor plunger 11 is threadedly connected to the upper buffer 10. The upper buffer 10 is provided with a downward starting port, and the lower end is threadedly connected to the upper floating valve 1. The upper floating valve ball 13 is located inside the upper floating valve 12. The upper floating valve 12 is threadedly connected to the pump long plunger 16, and the lower buffer 14 is connected directly below. The upper surface of the lower buffer 14 is provided with an upward starting port. The pump long plunger 16 is threadedly connected to the lower floating valve seat 19. The lower floating valve ball 20 is located inside the lower floating valve seat 19. The upper end of the intermediate joint 15 is respectively threadedly connected to the motor outer pipe 7 and the motor plunger pump barrel 9. The upper end of the intermediate joint 15 and the motor outer pipe 7 form a sand settling cavity. The lower end is respectively threadedly connected to the short pump barrel 17 and the motor pump outer pipe 18. The motor pump outer pipe 18 is threadedly connected to the lower joint 21. The short pump barrel 17 is threadedly connected to the fixed valve connecting pipe 23. The fixed valve connecting pipe 23 is threadedly connected to the fixed valve seat 22. The fixed valve 25 is located inside the fixed valve seat 22. The screen pipe joint is threadedly connected to the lower joint 21 through the lower pipe joint.

[0024] Its working method features are as follows: The hydraulic-driven downhole motor pump device for deep coalbed methane extraction overcomes the deficiencies and disadvantages existing in the existing extraction technology in terms of design. The entire drainage and production device consists of the following parts: power fluid delivery device, downhole motor plunger pump group, buffer device, etc. The drainage and production process of the entire device can be divided into two states: the upstroke and the downstroke.

[0025] Upstroke: The power fluid is pressurized into high-pressure power fluid by the ground power device and injected from the central oil pipe of the double-layer pipe string. After passing through the annular space formed by the upper end of the diversion joint 6 and the motor plunger pump barrel 9 and the motor outer pipe 7, it enters through the upward starting port and pushes the motor plunger 11 upward. When the upper buffer 10 enters the upper buffer seat 8 and the downhole motor pump reaches the top dead center, the upstroke ends. At this time, the fixed valve 25 of the downhole motor pump opens, the lower floating valve 19 closes, the upper floating valve 12 closes, and the downhole motor pump completes the liquid suction process. The liquid above the upper floating valve 12 is drained to the ground through the annulus of the double-layer pipe string channel. The ground production phenomenon is the liquid output state.

[0026] Downstroke: The power fluid is pressurized into high-pressure power fluid by the surface power device and injected into the annular space of the double-layer pipe string. It enters the downward starting port at the upper end of the motor plunger 11 through the side of the diversion joint 6 and pushes the motor plunger 11 downward. When the lower buffer 14 enters the buffer seat of the intermediate joint 15 and the downhole motor pump reaches the bottom dead center, the downstroke ends. At this time, the fixed valve 25 of the downhole motor pump closes, the upper floating valve 12 opens, the lower floating valve 19 opens, and the produced fluid enters the pump chamber between the upper floating valve 12 and the lower floating valve 19. Then, the upstroke behavior is repeated. After the produced fluid and the exhausted power fluid in the pump chamber of the motor plunger pump with double floating valves are mixed, they flow back to the ground through the annulus of the double-layer pipe string.

[0027] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A hydraulic-driven downhole motor pump for deep coalbed methane extraction, characterized in that, It includes a setting packer head, which is sealed with a setting joint through setting. The outer pipe of the double-layer pipe string is threadedly connected to the upper joint, and then threadedly connected to the outer pipe short joint, separating the power fluid pipelines of the upper and lower chambers of the plunger. The upper end inside of the diversion joint is threadedly connected to the setting joint, and the upper end outside is threadedly connected to the outer pipe short joint. The lower end inside of the diversion joint is threadedly connected to the motor plunger pump barrel, and the lower end outside is threadedly connected to the motor outer pipe. The upper buffer seat is connected directly below.

2. The hydraulic-driven downhole motor pump for deep coalbed methane extraction according to claim 1, wherein The upper end of the motor plunger is threadedly connected to the upper buffer, and a downward starting port is opened on the upper buffer. The lower end is threadedly connected to the upper traveling valve. The upper traveling valve ball is located inside the upper traveling valve. The upper traveling valve is threadedly connected to the long pump plunger, and the lower buffer is connected directly below.

3. The hydraulic-driven downhole motor pump for deep coalbed methane extraction according to claim 2, characterized in that, The long pump plunger is threadedly connected to the lower traveling valve seat, and the lower traveling valve ball is located inside the lower traveling valve seat. The upper end of the intermediate joint is respectively threadedly connected to the motor outer pipe and the motor plunger pump barrel, and the lower end is respectively threadedly connected to the short pump barrel and the pump outer pipe. The pump outer pipe is threadedly connected to the lower joint, and the short pump barrel is threadedly connected to the fixed valve connecting pipe.

4. The hydraulic-driven downhole motor pump for deep coalbed methane extraction according to claim 3, characterized in that, The fixed valve connecting pipe is threadedly connected to the fixed valve seat, and the fixed valve is located inside the fixed valve seat.

5. The hydraulic-driven downhole motor pump for deep coalbed methane extraction according to claim 1, wherein Starting small holes are provided at the upper and lower ends of the motor.

6. The hydraulic-driven downhole motor pump for deep coalbed methane extraction according to claim 1, wherein A sand settling chamber of 400 - 800 mm is provided below the motor plunger, and anti-scaling films are sprayed on both the valve seat and the valve cover.

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