Anti-overflow pump for oil and gas well

Abstract

The utility model relates to a special pump type pumping device for lifting fluid, in particular to an anti-overflow pump for an oil-gas well, which comprises a pump cylinder and a pump valve, and the pump cylinder comprises an upper pump cylinder and a lower pump cylinder which are in threaded connection. A pump valve capable of automatically opening and closing the overflowing channel under the action of internal and external pressure difference of the tubular column is arranged in the upper pump cylinder, and a fixed valve seat is arranged in the lower pump cylinder. The anti-overflow pump not only solves the problem of well mouth overflow in the process that an oil well pump descends into a well, but also solves the problem that in the prior art, due to the fact that large pressure difference exists inside and outside an upper pipe column, the screw thread connecting position of the upper pipe column is damaged.

Description

Technical Field

[0001] The utility model relates to a pump type pumping device specially used for lifting fluid, in particular to an anti-overflow pump for oil and gas wells. Background Art

[0002] The oil pump is a downhole device driven by a pumping unit and used to lift crude oil or other liquids in the well to the ground. It is generally composed of a pump barrel, a downhole joint, a plunger and a fixed valve. The fixed valve is the core component of the oil pump, which is generally composed of a fixed valve cover, a valve ball and a fixed valve seat. During the process of the oil pump going down the well, if the annular pressure of the oil casing is higher than the pressure in the wellbore above the fixed valve, the valve ball will be pushed off the fixed valve seat by the well fluid, causing the well fluid to spray out of the wellhead along the pipe string, resulting in overflow at the wellhead or even blowout, causing environmental pollution and affecting the operation.

[0003] In order to solve the above problems, a Chinese utility model with authorization announcement number CN208885489U and authorization announcement date of May 21, 2019 discloses a blowout-proof oil pump, which includes a pump barrel coupling, a fixed valve cover, a valve ball, a valve seat, a spring, a reducer, a plug, a sealing ring, a pin and a pump barrel, wherein the pump barrel, the pump barrel coupling, the fixed valve cover and the reducer are all connected by threads; the plug is located in the reducer, and the reducer and the plug are fixed by pins, and the reducer and the plug are sealed by a sealing ring; an annular mounting groove is provided between the bottom valve cover and the reducer, the valve seat is fixedly installed in the mounting groove, the valve ball is placed between the bottom valve cover and the valve seat, and the spring is sleeved outside the plug. In the prior art blowout-proof oil pump, the plug provided by the reducer is abutted against the bottom of the fixed valve cover, so that the high-pressure well fluid in the well is blocked at the lower part of the pipe string, which effectively prevents the oil pump from overflowing during the process of going down the well.

[0004] Although the prior art has a plugging core of a reducer abutting against the bottom of the fixed valve cover, so that the flow channel of the pipe string is always in a closed state during the lowering process of the well, and overflow will not occur, but because the upper pipe string of the prior art is hollow inside and filled with well fluid outside, the annular pressure of the oil casing will be greater than the pressure inside the pipe string, causing the pipe string to be compressed and the threaded connection to be damaged. Utility Model Content

[0005] The utility model aims to provide an anti-overflow pump for oil and gas wells, which is used to solve the problem of oil pump overflow during the well running process and the problem that the existing technology may cause damage to the pipe thread due to the large pressure difference between the inside and outside of the pipe.

[0006] In order to achieve the above-mentioned purpose, an anti-overflow pump for oil and gas wells of the utility model adopts the following technical solutions:

[0007] An anti-overflow pump for oil and gas wells includes a pump barrel and a pump valve. The pump barrel includes an upper pump barrel and a lower pump barrel connected by bolts. The upper pump barrel is provided with a pump valve that automatically opens and closes a flow channel under the action of a pressure difference between the inside and outside of a pipe column, and the lower pump barrel is provided with a fixed valve seat.

[0008] Beneficial effects: The utility model is an improved invention. The existing oil pump uses a plugging core set by a reducer to block the high-pressure well fluid in the well outside the plugging core. However, after the pipe string is lowered into the well, the upper pipe string is hollow inside and filled with well fluid outside, causing the oil casing annulus pressure to be greater than the internal pressure of the pipe string, making the threaded connection of the pipe string easily damaged. The pump valve of the utility model can automatically open and close under the pressure difference between the inside and outside of the pipe string. When the pressure difference between the inside and outside of the pipe string is large and the pressure of the oil casing annulus is greater than the force required to open the pump valve, the pump valve opens, and the well fluid can enter the upper pump barrel through the pump valve, so that the pressure difference between the inside and outside of the pipe string gradually tends to balance, and there will be no large pressure difference between the inside and outside of the pipe string, and the threaded connection of the pipe string will not be damaged. When the pressure of the oil casing annulus is less than the force required to open the pump valve, the pump valve automatically closes, so that the utility model also has an anti-overflow function.

[0009] Furthermore, a limiting shoulder is provided at the upper portion of the central through hole of the upper pump barrel, an annular stop surface is provided at the top end of the lower pump barrel, and the pump valve is clamped and fixed between the limiting shoulder and the annular stop surface.

[0010] Furthermore, the pump valve comprises a valve cylinder with an annular inner shoulder at its lower portion, and a rubber support ring, a valve ball, a movable valve cover, and an elastic pressure piece are arranged on the annular inner shoulder in sequence from bottom to top.

[0011] Furthermore, an inner pressure plate for limiting the movement of the rubber support ring is provided on the rubber support ring, and a pressure ring for pressing the elastic pressure piece is provided on the elastic pressure piece.

[0012] Furthermore, the upper end surface of the movable valve cover is provided with flow holes which penetrate vertically, and the flow holes are evenly distributed on the upper end surface of the movable valve cover in the circumferential direction.

[0013] Furthermore, the movable valve cover is also provided with a center hole for pressing and aligning the valve ball on the rubber support ring under the action of the elastic pressure piece.

[0014] Furthermore, a telescopic claw is provided at the lower end of the valve cylinder to limit the travel of the valve ball when the oil pump works normally.

[0015] Furthermore, an outer bushing for enhancing the sealing performance of the pump barrel is arranged outside the valve barrel, and a sealing copper gasket for sealing the annulus is arranged between the limit shoulder and the outer bushing.

[0016] Furthermore, a stop shoulder is provided at the bottom of the outer bushing, and the stop shoulder extends obliquely downward to form a telescopic claw that limits the travel of the valve ball when the oil pump works normally.

[0017] Furthermore, the telescopic claw is composed of at least three elastic cards that shrink inwardly, and the inner diameter of the elastic card when shrinking is smaller than the outer diameter of the valve ball. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the fourth embodiment of the present utility model;

[0020] Figure 3 This is a state diagram of the pump barrel of the utility model when pumping;

[0021] Figure 4 This is a state diagram of the pump barrel of the utility model during normal production.

[0022] Figure 1-4 In: 1. Upper pump barrel; 2. Pump valve; 3. Lower pump barrel; 4. Valve ball; 5. Telescopic claw; 6. Stop shoulder; 101. External thread of upper pump barrel; 102. Sealing copper gasket; 103. Limit shoulder; 104. Internal thread of upper pump barrel; 201. Pressing ring; 202. Valve barrel; 203. Spring; 204. Movable valve cover; 205. Rubber support ring; 206. Inner pressure plate; 207. Annular inner shoulder; 208. Flow hole; 209. Outer bushing; 301. External thread of lower end of lower pump barrel; 302. External thread of upper end of lower pump barrel; 303. Fixed valve seat. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model, that is, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] The fixed valve of the oil well pump is generally composed of a fixed valve seat, a valve ball and a fixed valve cover. The valve ball sits on the fixed valve seat by its own weight to close the upward well fluid channel. However, during the pumping process, due to the existence of the casing annulus pressure, the valve ball will be pushed open from the fixed valve seat by the well fluid, causing the well fluid to spray out of the wellhead along the tubing, causing overflow, which seriously affects the construction working environment.

[0025] In view of the above problems, the prior art discloses a blowout-proof oil pump device, which has a plug for closing the well fluid passage abutted against the fixed valve cover, so that the high-pressure liquid in the well is blocked outside the plug, thereby effectively preventing the overflow and blowout of the high-pressure fluid in the well during operation.

[0026] Although the existing technology solves the problem of oil well overflow, when the device is lowered into the well, due to the large pressure difference between the inside and outside of the pipe string, irreparable damage is caused to the threaded connection of the pipe string.

[0027] In view of the above problems, the utility model designs an anti-overflow pump device for oil and gas wells. The core concept of the device is that a pump valve that can automatically open and close the flow channel under the pressure difference between the inside and outside of the pipe column is provided in the upper pump barrel, and an elastic pressure piece and a movable valve cover are provided in the pump valve. The movable valve cover can control the opening and closing of the pump valve under the joint action of the pressure difference between the inside and outside of the pipe column and the elastic pressure piece. When the annular pressure of the oil casing is greater than the elastic force of the elastic pressure piece, the well fluid pushes the valve ball and the movable valve cover upward, and the well fluid enters the pipe column through the flow hole of the movable valve cover, so that the pressure difference between the inside and outside of the pipe column gradually tends to balance, thereby solving the problem of damage to the pipe column thread due to the large pressure difference between the inside and outside of the pipe column, and when the annular pressure of the oil casing is less than the liquid column pressure of the pipe column and the elastic force of the elastic pressure piece, the valve ball re-seats on the rubber support ring, and the well fluid in the well will no longer overflow upward, so that the device of the utility model also realizes the function of preventing oil well overflow.

[0028] Based on the above invention concept, Figure 1 As shown, an anti-overflow pump device for oil and gas wells of the utility model comprises a pump barrel and a pump valve 2, wherein the pump barrel comprises a cylindrical upper pump barrel 1 and a lower pump barrel 3; the pump valve 2 can be automatically opened and closed under the pressure difference between the inside and outside of the pipe column.

[0029] Embodiment 1, as Figure 1 As shown, a limiting shoulder 103 is provided on the upper part of the central through hole of the upper pump barrel 1, and an annular stop surface is provided on the top of the lower pump barrel 3. The pump valve 2 is clamped between the limiting shoulder 103 of the upper pump barrel 1 and the annular stop surface at the top of the lower pump barrel 3.

[0030] Specifically, the upper pump barrel 1 is a hollow cylinder, with an external thread 101 on the upper part and an internal thread 104 on the bottom; the lower pump barrel 3 is also a hollow cylinder, with external threads on both the upper and lower ends, and a fixed valve seat 303 inside. The upper end external thread 101 of the upper pump barrel is connected to the pipe column, the lower end internal thread 104 is connected to the upper end external thread 302 of the lower pump barrel 3, and the lower end external thread 301 of the lower pump seat 3 is connected to the tail pipe of the oil pump. The pump valve 2 is provided with a rubber support ring 205 for supporting the valve ball 4, the valve ball 4, a movable valve cover 204 that can move up and down with the elastic pressure piece, and an elastic pressure piece that controls the opening and closing of the pump valve 2 from bottom to top. After the lower pump barrel 3 and the upper pump barrel 1 are threadedly connected, the lower pump barrel 3 presses against the pump valve 2, so that all the components in the pump valve 2 are clamped between the limit shoulder 103 and the annular stop surface.

[0031] Embodiment 2, as Figure 1 As shown, different from the first embodiment, in this embodiment, a valve cylinder for enhancing the working stability of the pump valve 2 is additionally provided in the upper pump cylinder 1, and an annular inner shoulder 207 is provided at the lower part of the valve cylinder. The rubber support ring 205, the valve ball 4, the movable valve cover 204 and the elastic pressure piece are arranged in sequence from bottom to top on the annular inner shoulder 207, and an inner pressure plate 206 for limiting the movement of the rubber support ring 205 is provided on the rubber support ring 205, and a pressure ring 201 for pressing the elastic pressure piece is provided on the elastic pressure piece.

[0032] Specifically, the movable valve cover 204 is concave, with a flow hole 208 extending from top to bottom on the top surface, and a center hole in the middle for pressing the valve ball against the rubber support ring under the action of the elastic pressure piece. In this embodiment, the movable valve cover 205 can maintain balance when the well fluid flows through the flow hole 208. The flow holes 208 are evenly distributed on the upper end surface of the movable valve cover 205 in the circumferential direction, but in other embodiments, the number and position of the flow holes 208 do not have to be limited to this, and can be flexibly opened according to the working environment. In addition, in this embodiment, the spring 203 is selected as the elastic pressure piece of this embodiment, but in other embodiments, elastic components such as elastic push rods can also be selected.

[0033] Embodiment three, as Figure 1 As shown, different from the second embodiment, in this embodiment, a telescopic claw 5 is additionally provided at the lower end of the valve cylinder to ensure the pumping efficiency of the anti-overflow pump and limit the stroke of the valve ball 4 when the oil pump works normally.

[0034] Specifically, the telescopic claw 5 is composed of at least three elastic cards that shrink inwards, and the inner diameter of the elastic card after shrinking is smaller than the diameter of the valve ball 4. When the telescopic claw 5 is hit by the valve ball 4 from top to bottom, the spring card of the telescopic claw 5 will expand outwards, and the spring card can shrink to the original state after the valve ball 5 passes. In addition, in this embodiment, a space is provided at the bottom of the valve cylinder to avoid the expansion of the telescopic claw 5, but in other embodiments, it is not necessary to stick to this. As long as the telescopic claw 5 does not touch the valve cylinder wall after expanding outwards, the avoidance space may not be provided.

[0035] Embodiment 4, as Figure 2 As shown, different from the third embodiment, in this embodiment, an outer bushing 209 is additionally provided outside the valve cylinder 202 for enhancing the sealing performance of the device, and a sealing copper gasket 102 for sealing the annulus is provided between the limit shoulder 103 of the upper pump cylinder 1 and the outer bushing.

[0036] Specifically, the outer bushing 209 is a cylinder with an internal thread on the top and a stop shoulder 6 on the bottom. The internal thread is connected to the pressure ring 201, and the stop shoulder 6 is seated on the annular stop surface of the lower pump barrel 3. Different from the first embodiment, in this embodiment, the telescopic claw 5 and the stop shoulder 6 of the outer bushing 209 are of an integrated design, and the stop shoulder 6 of the outer bushing 209 has a telescopic claw 5 extending obliquely downward.

[0037] The following describes the working process in combination with the above embodiments:

[0038] When the oil pump is lowered: Figure 3 As shown, as the depth of the pump gradually increases, the annular pressure of the oil casing gradually exceeds the elastic force of the spring 203. After the well fluid enters from the lower pump barrel 3, it pushes the valve ball 4 and the movable valve cover 204 to move upward, opening the flow channel, and the well fluid enters the pump upper pipe string; as the well fluid continues to flow into the pump upper pipe string, the pressure difference between the inside and outside of the pipe string gradually decreases, and the pipe string thread of the oil pipe will no longer be damaged due to the large pressure difference between the inside and outside of the pipe string. When the annular pressure of the oil casing is less than the elastic force of the spring 203 and the pressure of the liquid column in the pump upper pipe string, the valve ball 4 re-seats on the rubber support ring 205 under the joint action of the elastic force and the hydraulic pressure of the pump upper pipe string, closing the well fluid channel, so that the utility model has the function of realizing overflow prevention.

[0039] During normal production: Figure 4 As shown, when the oil pump is lowered to the designed well depth, water is poured into the pump barrel to pressurize the pump, so that the valve ball 4 is driven by the hydraulic pressure to force the rubber support ring 205 to deform, and then the valve ball 4 falls and sits on the fixed valve seat 303 through the telescopic claw 5. At this time, the oil well can achieve normal production.

Claims

1. An anti-overflow pump for oil and gas wells, comprising a pump barrel and a pump valve, characterized in that: The pump barrel comprises an upper pump barrel and a lower pump barrel connected by threads, wherein a pump valve which automatically opens and closes a flow channel under the action of a pressure difference between the inside and outside of the pipe column is arranged in the upper pump barrel; and a fixed valve seat is arranged in the lower pump barrel.

2. The anti-overflow pump for oil and gas wells according to claim 1, characterized in that: A limiting shoulder is provided at the upper portion of the central through hole of the upper pump barrel, an annular stop surface is provided at the top end of the lower pump barrel, and the pump valve is clamped and fixed between the limiting shoulder and the annular stop surface.

3. The anti-overflow pump for oil and gas wells according to claim 2, characterized in that: The pump valve comprises a valve cylinder with an annular inner shoulder at the lower part thereof, and a rubber support ring, a valve ball, a movable valve cover and an elastic pressing piece are arranged in sequence from bottom to top on the annular inner shoulder.

4. The anti-overflow pump for oil and gas wells according to claim 3, characterized in that: An inner pressure plate for limiting the movement of the rubber support ring is arranged on the rubber support ring, and a pressure ring for pressing the elastic pressure piece is arranged on the elastic pressure piece.

5. The anti-overflow pump for oil and gas wells according to claim 4, characterized in that: The upper end surface of the movable valve cover is provided with flow holes which penetrate up and down, and the flow holes are evenly distributed on the upper end surface of the movable valve cover in the circumferential direction.

6. The anti-overflow pump for oil and gas wells according to claim 5, characterized in that: The movable valve cover is also provided with a center hole for pressing and aligning the valve ball on the rubber support ring under the action of the elastic pressure piece.

7. The anti-overflow pump for oil and gas wells according to claim 3, characterized in that: A telescopic claw is provided at the lower end of the valve cylinder to limit the stroke of the valve ball when the oil pump works normally.

8. The anti-overflow pump for oil and gas wells according to claim 3, characterized in that: An outer bushing for enhancing the sealing performance of the pump barrel is arranged outside the valve barrel, and a sealing copper gasket for sealing the annulus is arranged between the limit shoulder and the outer bushing.

9. The anti-overflow pump for oil and gas wells according to claim 8, characterized in that: A stop shoulder is provided at the bottom of the outer bushing, and the stop shoulder extends obliquely downward to form a telescopic claw for limiting the travel of the valve ball when the oil pump works normally.

10. The anti-overflow pump for oil and gas wells according to claim 7 or 9, characterized in that: The telescopic claw is composed of at least three elastic cards that shrink inwardly, and the inner diameter of the elastic card when shrinking is smaller than the outer diameter of the valve ball.

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