Forced opening and closing mechanical valve of oil well pump

Abstract

The invention belongs to the technical field of oil extraction equipment, and particularly relates to an oil well pump forcibly-opened and forcibly-closed mechanical valve which comprises a center rod, a center rod coupling, a slotted nut, an upper sliding sleeve, a plunger body, a valve seat, a valve element and a valve element pressing cap. The center rod coupling is connected to the upper end of the slotted nut, the slotted nut is connected to the upper end of the center rod, an oil well pump runner is machined in the surface of the center rod, the center rod is sleeved with the upper sliding sleeve, the plunger body and the valve seat, the upper sliding sleeve is fixedly connected to the upper end of the plunger body through threads, and the plunger body is fixedly connected with the valve seat through threads. The valve seat is fixedly connected to the lower end of the plunger body through threads, and the valve element is connected to the lower end of the center rod. Aiming at the requirements of corrosion resistance, wear resistance, cavitation corrosion resistance and airlock prevention of oil well pumps of high-content gas wells in oil fields, especially thickened oil recovery gas injection and viscosity reduction wells with the oil-gas ratio being greater than 200: 1 and water logging gas wells for pumping and draining, the invention effectively overcomes the defects of the existing forcibly-opened and forcibly-closed mechanical valves in the aspects of corrosion resistance, wear resistance and gas prevention.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production equipment, and in particular relates to a forced start and forced close mechanical valve for a sucker rod pump. Background Art

[0002] In the field of heavy oil exploitation, viscosity reduction oil production technologies such as electric heating, dilution with light oil, steam injection, oxygen-depleted air injection, and carbon dioxide injection are adopted. At the same time, gas locking often occurs in oil wells with a large gas-oil ratio, seriously affecting the pump efficiency and the pump inspection period.

[0003] The development of the deep well mechanical pumping and strong drainage process technology for flooded wells in the water-rich area of gas fields is inseparable from a sucker rod pump with reliable gas prevention performance. The forced start and forced close oil outlet valve sucker rod pump is one of the better gas prevention pumps.

[0004] The forced start and forced close mechanical valve of the sucker rod pump generally adopts alloy steel surface hardening and nitriding processes, or stainless steel materials, but has poor corrosion and cavitation resistance effects, short service life, and is limited in popularization and application.

[0005] Therefore, we propose a forced start and forced close mechanical valve for a sucker rod pump to solve the above problems. Summary of the Invention

[0006] The purpose of the invention is to provide a forced start and forced close mechanical valve for a sucker rod pump aiming at the above problems.

[0007] To achieve the above purpose, the invention provides the following technical solution: A forced start and forced close mechanical valve for a sucker rod pump, including a central rod, and also including a central rod coupling, a slotted nut, an upper sliding sleeve, a plunger body, a valve seat, a valve core, and a valve core pressing cap; The central rod coupling is connected to the upper end of the slotted nut, the slotted nut is connected to the upper end of the central rod, the surface of the central rod is processed with a sucker rod pump flow channel, the upper sliding sleeve, the plunger body, and the valve seat are all sleeved outside the central rod, the upper sliding sleeve is fixedly connected to the upper end of the plunger body and is fixedly connected by threads, the valve seat is fixedly connected to the lower end of the plunger body and is fixedly connected by threads, the valve core is connected to the lower end of the central rod and is fixed by the valve core pressing cap.

[0008] In the above-mentioned forced start and forced close mechanical valve for a sucker rod pump, both the valve seat and the valve core are made of cemented carbide.

[0009] In the above-mentioned forced start and forced close mechanical valve for a sucker rod pump, the sealing surface at the connection between the valve seat and the valve core is designed with an arc surface structure.

[0010] In the above-mentioned forced start and forced close mechanical valve for a sucker rod pump, the sealing and grinding surface of the valve seat and the valve core is designed with a narrow-width line sealing structure.

[0011] In the above-mentioned forced-opening and forced-closing mechanical valve of a sucker rod pump, the upper end of the slotted nut is closely attached to the lower end face of the central rod coupling, and the lower part of the slotted nut is closely attached to the upper shoulder of the central rod.

[0012] In the above-mentioned forced-opening and forced-closing mechanical valve of a sucker rod pump, there is a clearance fit between the outer diameter of the central rod and the inner diameters of the upper sliding sleeve and the valve seat.

[0013] In the above-mentioned forced-opening and forced-closing mechanical valve of a sucker rod pump, the plunger body is specifically a free-state seal body.

[0014] In the above-mentioned forced-opening and forced-closing mechanical valve of a sucker rod pump, the central rod, the plunger body and the valve seat are concentrically arranged.

[0015] Compared with the prior art, the present invention provides a forced-opening and forced-closing mechanical valve of a sucker rod pump, which has the following beneficial effects: 1. For the forced-opening and forced-closing mechanical valve of the sucker rod pump, both the valve seat and the valve core are made of cemented carbide, with high surface hardness, excellent wear resistance, corrosion resistance and cavitation resistance. The structure, materials and advanced processing technology are deeply integrated, suitable for complex oil well conditions such as high gas-oil ratio, gas injection process and corrosion wells, with good adaptability. The threaded connection end of the valve seat adopts the grinding process for threading, overcoming the problem of high-hardness threading of cemented carbide materials and ensuring the connection reliability between the valve seat and the plunger.

[0016] 2. For the forced-opening and forced-closing mechanical valve of the sucker rod pump, the sealing surfaces of the valve seat and the valve core adopt an arc surface design, with good flow-through performance. The sealing and grinding surfaces of the valve seat and the valve core adopt a narrow-width line seal, with good sealing effect.

[0017] 3. For the forced-opening and forced-closing mechanical valve of the sucker rod pump, the central rod, the plunger body and the valve seat are concentrically arranged, with good overall guiding performance, more reliable valve pair, faster opening and closing, small leakage, high pump efficiency. The valve pair has a reasonable high-jump design, and the sliding valve has a mechanical flexible opening and closing, avoiding severe impact and damage to the valve seat surface during normal operation. The downward resistance of the sliding valve is small, which can improve the stress condition of the sucker rod string.

[0018] In summary: In view of the anti-corrosion, wear resistance, cavitation resistance and gas lock prevention requirements of the sucker rod pump in high-gas-content wells in oil fields, especially in viscous oil production and gas injection viscosity reduction wells with a gas-oil ratio greater than 200:1 and water-flooded gas wells with mechanical pumping drainage, the present invention effectively overcomes the deficiencies of the existing forced-opening and forced-closing mechanical valves in anti-corrosion, wear resistance and gas prevention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a schematic structural diagram of a forced-opening and forced-closing mechanical valve of a sucker rod pump proposed by the present invention.

[0020] In the figure: 1. Central rod coupling; 2. Slotted nut; 3. Central rod; 4. Upper sliding sleeve; 5. Plunger body; 6. Valve seat; 7. Valve core; 8. Valve core compression nut. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0022] Please refer to Figure 1 , a mechanical valve for forced opening and closing of a sucker rod pump, comprising a central rod 3, and further comprising a central rod coupling 1, a slotted nut 2, an upper sliding sleeve 4, a plunger body 5, a valve seat 6, a valve core 7 and a valve core pressing cap 8; The central rod coupling 1 is connected to the upper end of the slotted nut 2, the slotted nut 2 is connected to the upper end of the central rod 3, the surface of the central rod 3 is machined with a sucker rod pump flow channel, the upper sliding sleeve 4, the plunger body 5 and the valve seat 6 are all sleeved outside the central rod 3, the upper sliding sleeve 4 is fixedly connected to the upper end of the plunger body 5 and is fixedly connected by threads, the valve seat 6 is fixedly connected to the lower end of the plunger body 5 and is fixedly connected by threads, the valve core 7 is connected to the lower end of the central rod 3 and is fixed by the valve core pressing cap 8.

[0023] Both the valve seat 6 and the valve core 7 are made of cemented carbide.

[0024] The sealing surface at the connection between the valve seat 6 and the valve core 7 is designed with an arc surface structure.

[0025] The sealing and grinding surfaces of the valve seat 6 and the valve core 7 are designed with a narrow-width line sealing structure.

[0026] The upper end of the slotted nut 2 is closely attached to the lower end surface of the central rod coupling 1, and the lower part of the slotted nut 2 is closely attached to the upper shoulder of the central rod 3.

[0027] There is a clearance fit between the outer diameter of the central rod 3 and the inner diameters of the upper sliding sleeve 4 and the valve seat 6.

[0028] The plunger body 5 is specifically a free-state seal body.

[0029] The central rod 3, the plunger body 5 and the valve seat 6 are concentrically arranged.

[0030] Now, the operating principle of the present invention is described as follows: The upper end of the central rod coupling 1 is connected to the sucker rod pump pull rod, the upper end of the pull rod is connected to the sucker rod, the slotted nut 2 is connected to the upper part of the central rod 3, the upper end is closely attached to the lower end surface of the central rod coupling 1, and the lower part is closely attached to the upper shoulder of the central rod 3. One is for the limiting function, and the other is to provide an oil flow channel. The surface of the central rod 3 is designed with a machining surface to increase the sucker rod pump flow channel. There is a clearance fit between the outer diameter of the central rod 3 and the inner diameters of the upper sliding sleeve 4 and the valve seat 6, which plays a guiding role. The upper sliding sleeve 4 and the plunger body 5 are connected by threads, which plays a role in straightening and downward boosting. The plunger body 5 is a free-state seal body and has a fit clearance with the inner hole of the pump barrel, and can slide freely in the pump barrel. The upper part of the valve seat 6 is connected to the plunger body 5 by threads, and the inner hole forms a clearance fit with the central rod, which has the function of straightening the central rod. The lower end is a machined sealing surface. The valve core 7 is connected to the lower part of the central rod 3 and is fixed by the valve core pressing cap 8. The upper end surface is a spherical sealing surface that cooperates with the valve seat 6 for sealing to form a valve pair; When the central rod coupling 1 moves upward under the action of the sucker rod pump pull rod, the lower end of the valve seat 6 connected to the plunger body 5 is in close contact with the upper sealing surface of the valve core 7 to form a seal. The upper end surface of the valve core 7 is a spherical sealing surface that cooperates with the valve seat 6 for sealing, forming a valve pair, and the valve pair is forced to close. When the central rod coupling 1 moves downward under the action of the sucker rod pump pull rod, the lower end of the valve seat 6 connected to the plunger body 5 is separated from the upper sealing surface of the valve core 7, and the valve pair is forced to open. At the same time, the upper sliding sleeve 4 connected to the upper end of the plunger body 5 is in close contact with the lower end surface of the slotted nut 2, and the upper sliding sleeve 4, the plunger body 5 and the valve seat 6 assembly are pushed downward through the slotted nut 2.

[0031] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A mechanical valve for forced start and forced closure of a sucker rod pump, comprising a central rod (3), characterized in that: It further includes a central rod coupling (1), a slotted nut (2), an upper sliding sleeve (4), a plunger body (5), a valve seat (6), a valve core (7) and a valve core compression nut (8); The central rod coupling (1) is connected to the upper end of the slotted nut (2), the slotted nut (2) is connected to the upper end of the central rod (3), the surface of the central rod (3) is machined with a sucker rod flow channel, the upper sliding sleeve (4), the plunger body (5) and the valve seat (6) are all sleeved outside the central rod (3), the upper sliding sleeve (4) is fixedly connected to the upper end of the plunger body (5) and is fixedly connected by threads, the valve seat (6) is fixedly connected to the lower end of the plunger body (5) and is fixedly connected by threads, the valve core (7) is connected to the lower end of the central rod (3) and is fixed by the valve core compression nut (8).

2. The forced opening and closing mechanical valve of a sucker rod pump according to claim 1, wherein: Both the valve seat (6) and the valve core (7) are made of cemented carbide.

3. The forced-opening and forced-closing mechanical valve of a sucker rod pump according to claim 1, characterized in that: The sealing surface at the connection between the valve seat (6) and the valve core (7) is designed with an arc surface structure.

4. A forced start and forced closing mechanical valve for a sucker rod pump according to claim 1, characterized in that: The sealing and grinding surface of the valve seat (6) and the valve core (7) is designed with a narrow-width line sealing structure.

5. The forced start and forced closing mechanical valve of a sucker rod pump according to claim 1, characterized in that: The upper end of the slotted nut (2) is closely attached to the lower end surface of the central rod coupling (1), and the lower part of the slotted nut (2) is closely attached to the upper shoulder of the central rod (3).

6. The forced start and forced closing mechanical valve of a sucker rod pump according to claim 1, wherein: There is a clearance fit between the outer diameter of the central rod (3) and the inner diameters of the upper sliding sleeve (4) and the valve seat (6).

7. A forced-opening and forced-closing mechanical valve for a sucker rod pump according to claim 1, characterized in that: The plunger body (5) is specifically a free-state sealing body.

8. A forced-opening and forced-closing mechanical valve for a sucker rod pump according to claim 1, characterized in that: The central rod (3), the plunger body (5) and the valve seat (6) are concentrically arranged.

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