Gap bridge series feedback oil well pump

Abstract

The utility model provides a gap bridge series feedback oil well pump which comprises a pump cylinder assembly and a plunger assembly, the plunger assembly is located in the pump cylinder assembly and reciprocates, the pump cylinder assembly comprises an upper pump cylinder assembly and a lower pump cylinder assembly which are connected in series, and an annular oil inlet valve mechanism is arranged between the upper pump cylinder assembly and the lower pump cylinder assembly; the pump cylinder assembly comprises an upper coupling, an upper gap bridge pipe, a lower gap bridge pipe, a two-way joint, an outer pipe and a lower coupling which are connected in sequence; the plunger assembly comprises an upper plunger, an oil passing connector and a lower plunger which are sequentially connected, the upper portion of the upper plunger is connected with a sucker rod string, a plurality of oil outlet valves are arranged in the upper plunger, the upper plunger moves in the upper pump cylinder, and the lower plunger moves in the lower pump cylinder and the pump cylinder lengthening cylinder. The pump is good in structural reliability, high in well condition adaptability, high in pump efficiency, long in service life and capable of effectively improving the comprehensive exploitation benefits of an oil field, and integrates the functions of large-displacement liquid extraction, well washing, gas injection and thin oil mixing and viscosity reduction of a heavy oil well.

Description

Technical Field

[0001] The utility model relates to the field of oil extraction pumps, and particularly relates to a cross-bridge series feedback oil extraction pump. Background Art

[0002] With the development of heavy oil blocks in some domestic oilfields entering the middle and late stages, the comprehensive water cut of the underground oil reservoir gradually increases. To improve the oil recovery rate, increasing the liquid production of oil wells is one of the important measures to make up for the decline of oilfield production. The series feedback oil extraction pump has many advantages such as generating a downward hydraulic feedback force when the plunger moves downward, being conducive to the downward movement of the rod string, having a high pump efficiency, and being strongly resistant to heavy oil, and is widely used in the pumping well exploitation of heavy oil reservoirs. However, for the conventional series feedback oil extraction pump, since the small plunger needs to be used as a flow passage, the diameter of the small plunger cannot be reduced, which reduces the annular pump chamber space and results in a small displacement, unable to meet the liquid-lifting requirements of large-displacement heavy oil wells. Due to the structural size limitations of the upper and lower pump barrels, the load-bearing capacity is poor, and it cannot be equipped with a long tail pipe that needs to extend to the bottom of the well, unable to meet the process requirements of well flushing, gas injection, or dilution with light oil to reduce viscosity. Content of the Utility Model

[0003] The main purpose of the utility model is to provide a cross-bridge series feedback oil extraction pump to solve the problems in the above background art.

[0004] To solve the above technical problems, the technical solution adopted by the utility model is: it includes a pump barrel assembly and a plunger assembly. The plunger assembly reciprocates inside the pump barrel assembly. The pump barrel assembly includes a series-connected upper pump barrel assembly and a lower pump barrel assembly, and an annular oil inlet valve mechanism is arranged between the upper pump barrel assembly and the lower pump barrel assembly;

[0005] The pump barrel assembly includes a upper coupling, an upper cross-bridge pipe, a lower cross-bridge pipe, a double-pass joint, an outer pipe, and a lower coupling connected in sequence. The upper part of the upper coupling is connected to the tubing string, and the lower part of the lower coupling is connected to the tail pipe and the screen pipe;

[0006] An upper pump barrel is arranged inside the upper cross-bridge pipe, and the end of the upper pump barrel is connected to the upper cross-bridge pipe through a support ring. A lower pump barrel and a pump barrel extension cylinder are arranged inside the lower cross-bridge pipe;

[0007] The plunger assembly includes a upper plunger, an oil passing joint, and a lower plunger connected in sequence. The upper part of the upper plunger is connected to the sucker rod string. A plurality of oil outlet valves are arranged inside the upper plunger. The upper plunger moves inside the upper pump barrel, and the lower plunger moves inside the lower pump barrel and the pump barrel extension cylinder;

[0008] A pump chamber with an annular chamber is formed between the upper plunger and the lower plunger and the upper pump barrel. The upper part of the upper plunger is a tubing chamber.

[0009] Preferably, the annular oil inlet valve mechanism is arranged between the upper pump barrel and the lower pump barrel. The annular oil inlet valve mechanism includes an intermediate coupling, an annular valve ball, an annular valve seat, a sealing cylinder, and a sealing joint;

[0010] The annular valve ball is fixed on the end of the sealing cylinder and moves together with the sealing cylinder;

[0011] The annular valve seat is fixed inside the intermediate coupling and is used to confine the annular valve ball inside the intermediate coupling;

[0012] The outer surface of the sealing cylinder abuts against the inner wall of the sealing joint and rubs, which is used to play a supporting role when the sealing cylinder moves up and down;

[0013] The circumferential side of the sealing joint is provided with a flow-through channel.

[0014] Preferably, the intermediate coupling is connected to the sealing joint. The upper part of the intermediate coupling is connected to the upper crossover pipe and the upper pump barrel, and the lower part of the sealing joint is connected to the lower crossover pipe.

[0015] Preferably, the double-pass joint is provided with two channels for gas-liquid flow that do not affect each other, which are respectively communicated with the inner side and the outer side of the pump barrel extension. The lower part of the double-pass joint is provided with an oil inlet valve, and the oil inlet valve is communicated with the pump chamber through the outer channel of the pump barrel extension and the annular oil inlet valve mechanism.

[0016] Preferably, the lower plunger is designed as a solid plunger and a hollow plunger according to the displacement of the pump;

[0017] When it is a high-displacement pump, the lower plunger is a solid plunger with a small diameter, which is used to increase the volume of the pump chamber;

[0018] When it is a low-displacement pump, the lower plunger is a hollow plunger with a large diameter and a sealing end.

[0019] The utility model provides a crossover series feedback oil extraction pump, and the beneficial effects are as follows:

[0020] 1. The small plunger of the crossover series feedback oil extraction pump is no longer used as a flow-through channel. Without increasing the pump diameter of the large pump, by reducing the diameter of the small plunger and increasing the volume of the pump chamber, the displacement of the pump can be increased without affecting the lower pump depth of the pump, meeting the liquid lifting requirements of high-displacement wells with requirements for lower pump depth.

[0021] 2. The oil inlet valve is designed at the bottom of the small plunger, avoiding the problem that the eccentric valve type series feedback oil extraction pump designs the oil inlet valve on the side of the connection part between the upper and lower pump barrels, increasing the outer diameter of the whole pump and resulting in its inability to meet the requirements of conventional casing running into the well. At the same time, an annular valve is designed between the upper and lower pump barrels, which can reduce the clearance in the pump chamber when the plunger assembly moves downward, reduce the gas interference in the well fluid, and is beneficial to the timely opening of the outlet valve, enabling it to have the same pump efficiency as the conventional series feedback oil extraction pump and the eccentric valve type series feedback oil extraction pump.

[0022] 3. Since the lower plunger is not an over - flow channel, the lower plunger can be flexibly selected as a solid plunger or a hollow plunger structure according to the displacement requirements of the pump. When making a large - displacement pump, the lower plunger can be made into a solid plunger with a small diameter to increase the volume of the pump chamber; when making a small - displacement pump, the lower plunger can be made into a hollow plunger with a larger diameter and a sealed end to reduce the processing cost.

[0023] 4. The special annular valve design between the upper and lower pump barrels not only reduces the clearance in the pump chamber and improves the pump efficiency during the normal pumping operation of the sucker rod pump, but also seals the annular flow - channel space outside the lower pump barrel during gas injection, well flushing or dilution operation, preventing scale, sand particles or heavy - oil asphalt in the tubing from falling in, blocking the liquid - inlet channel, and affecting the normal operation of the standing valve during the next pumping operation, thus improving the adaptability of the pump.

[0024] 5. Load - bearing pipes are designed outside the upper and lower pump barrels and the inlet valve, so that the relatively weak - strength pump barrel does not need to bear the tubing liquid - column load and the additional loads of anchoring devices such as the tail pipe and packer, reducing the risk of fatigue fracture or overload breakage of the pump barrel. At the same time, according to the load - bearing requirements of the dilution pipe string, by selecting appropriate materials, the bridge - pipe assembly composed of the upper cross - over pipe, the lower cross - over pipe and the outer pipe has sufficient tensile strength, ensuring that the suspended tail pipe can extend to the designed depth, enabling the diluted oil injected from the wellhead to reach the bottom of the well directly and improving the dilution and mixing effect of heavy - oil wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present utility model will be further described below in conjunction with the drawings and embodiments:

[0026] Figure 1 is the front - sectional view of the overall structure of the present utility model;

[0027] Figure 2 is the schematic diagram of the up - stroke of the present utility model;

[0028] Figure 3 is the schematic diagram of the down - stroke of the present utility model;

[0029] Figure 4 is the schematic diagram of gas injection or well flushing of the present utility model;

[0030] In the figure: upper coupling 1; support ring 2; upper cross - over pipe 3; upper pump barrel 4; intermediate coupling 5; annular valve ball 6; annular valve seat 7; sealing cylinder 8; sealing joint 9; lower pump barrel 10; lower cross - over pipe 11; pump - barrel extension 12; two - way joint 13; inlet valve 14; outer pipe 15; lower coupling 16; outlet valve 17; upper plunger 18; oil - passing joint 19; lower plunger 20; pump chamber A; tubing chamber B. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] As Figures 1 to 4As shown in the figure, a cross-bridge series-feedback oil extraction pump includes a pump barrel assembly and a plunger assembly. The plunger assembly reciprocates within the pump barrel assembly. The pump barrel assembly includes an upper pump barrel assembly and a lower pump barrel assembly connected in series, and an annular oil inlet valve mechanism is provided between the upper pump barrel assembly and the lower pump barrel assembly.

[0032] The pump barrel assembly includes an upper coupling 1, an upper cross-bridge pipe 3, a lower cross-bridge pipe 11, a double-pass joint 13, an outer pipe 15, and a lower coupling 16 connected in sequence. The upper part of the upper coupling 1 is connected to the tubing string, and the lower part of the lower coupling 16 is connected to an anchoring device such as a tail pipe, a screen pipe, or a packer.

[0033] An upper pump barrel 4 is provided inside the upper cross-bridge pipe 3. The end of the upper pump barrel 4 is connected to the upper cross-bridge pipe 3 through a support ring 2. A lower pump barrel 10 and a pump barrel extension tube 12 are provided inside the lower cross-bridge pipe 11.

[0034] The plunger assembly includes an upper plunger 18, an oil-passing joint 19, and a lower plunger 20 connected in sequence. The upper part of the upper plunger 18 is connected to the sucker rod string. A plurality of oil outlet valves 17 are provided inside the upper plunger 18. The upper plunger 18 moves inside the upper pump barrel 4, and the lower plunger 20 moves inside the lower pump barrel 10 and the pump barrel extension tube 12. Driven by the sucker rod string, the plunger assembly reciprocates up and down inside the pump barrel assembly to realize the oil suction and oil discharge of the pump. The upper plunger 18 is a short plunger and always moves inside the upper pump barrel 4. The lower plunger 20 is a long plunger. The sealing cylinder 8 and the lower pump barrel 10 respectively form a sealing pair with the lower plunger 20 to realize the sealing of the lower small pump.

[0035] An annular chamber pump chamber A is formed between the upper plunger 18 and the lower plunger 20 and the upper pump barrel 4. The upper part of the upper plunger 18 is a tubing chamber B. During the up and down movement of the plunger assembly, the bottom oil in the well enters the pump chamber A through the oil inlet valve 17 and the annular oil inlet valve mechanism, and then enters the tubing chamber B through the oil outlet valve 14. When the plunger assembly moves downward, due to the pressure in the pump chamber A being higher than the submerged pressure of the oil-casing annulus, a downward hydraulic feedback force will be formed on the upper and lower parts of the lower plunger, helping the plunger assembly overcome the viscous oil resistance and move downward, thus ensuring the synchronous operation of the sucker rod string and the pumping unit. Since the inner hole of the lower plunger 20 is not used as an oil inlet flow channel, the diameter of the lower plunger 20 can be reduced to increase the pump chamber volume and improve the pump displacement. Therefore, this pump can meet the production requirements of high-viscosity oil wells with large displacements.

[0036] Cross-bridge pipes are designed outside both the upper pump barrel 4 and the lower pump barrel 10, and an outer pipe 15 is designed outside the oil outlet valve 14. The liquid column load, the tail pipe load, and the loads of anchoring devices such as packers all act on the cross-bridge pipes and the outer pipe, avoiding the increase in pump leakage or plastic fracture due to elastic deformation of the pump barrel under large loads. Therefore, the strength of the cross-bridge pipe can be improved by selecting appropriate materials to improve the tail pipe suspension capacity of the pump, meet the technological requirements of extending the tail pipe string in high-viscosity oil wells, and improve the injection gas or dilution mixing effect.

[0037] A double inlet valve structure with a conventional inlet valve 17 and an annular inlet valve mechanism is adopted. The annular inlet valve mechanism is designed between the upper pump barrel 4 and the lower pump barrel 10. When the plunger assembly moves downward, the annular valve closes, which can reduce the clearance in the pump chamber, reduce the gas interference in the well fluid, help the outlet valve 17 to open in time, and improve the pump efficiency. During well flushing, gas injection or dilution operation, the plunger assembly is lifted out of the pump barrel assembly, the tubing cavity B is communicated with the annulus between the tubing and the casing, and the gas-liquid mixture reaches the bottom of the well directly through the liquid passage composed of the upper pump barrel 4 and the lower pump barrel 10. At the same time, the annular inlet valve closes, and the annular flow passage space between the inlet valve 14 and the annular valve is sealed. Along with the flow of the liquid, the scale, sand particles or heavy oil asphalt in the tubing will also be washed and carried to the bottom of the well together, and will not fall into the annular flow passage space to affect the normal operation of the inlet valve.

[0038] Preferably, the annular inlet valve mechanism is arranged between the upper pump barrel 4 and the lower pump barrel 10. The annular inlet valve mechanism includes an intermediate coupling 5, an annular valve ball 6, an annular valve seat 7, a sealing cylinder 8 and a sealing joint 9;

[0039] The annular valve ball 6 is fixed at the end of the sealing cylinder 8 and moves together with the sealing cylinder 8;

[0040] The annular valve seat 7 is fixed inside the intermediate coupling 5 and is used to restrict the annular valve ball 6 inside the intermediate coupling 5;

[0041] The outer surface of the sealing cylinder 8 abuts against the inner wall of the sealing joint 9 and rubs, which is used to support when the sealing cylinder 8 moves up and down;

[0042] The sealing joint 9 is provided with a flow passage on its periphery.

[0043] When the plunger assembly is lifted out of the pump barrel assembly for well flushing, gas injection or dilution operation, the annular valve ball 6 seats on the annular valve seat 7, sealing the annular flow passage space outside the lower pump barrel 10, preventing scale, sand particles or heavy oil asphalt in the tubing from falling in and blocking the liquid inlet passage, affecting the normal operation of the fixed valve.

[0044] Preferably, the intermediate coupling 5 is connected to the sealing joint 9. The upper part of the intermediate coupling 5 is connected to the upper crossover pipe 3 and the upper pump barrel 4, and the lower part of the sealing joint 9 is connected to the lower crossover pipe 11.

[0045] Preferably, the double-pass joint 13 is provided with two channels for gas-liquid flow that do not affect each other, which are respectively connected to the inner and outer sides of the pump barrel extension 12. The passage formed by its connection with the pump barrel extension 12 can be directly connected to the lower tubing-casing annulus. When the plunger assembly moves downward, this passage enables a downward hydraulic feedback force to be generated above the lower plunger 20, helping the plunger assembly overcome the viscous oil resistance and move downward, thus ensuring the synchronous operation of the sucker rod string and the pumping unit. However, the oil fluid cannot enter the pump chamber A through this passage. The passage formed by the connection of the double-pass joint 13 and the lower inlet valve 14 communicates with the tubing chamber B at its upper part and is the only channel for the oil fluid to enter the pump chamber A. When the plunger assembly moves up and down, the oil fluid in the tubing-casing annulus can flow into the pump chamber A through the inlet valve 14, realizing the oil suction process of the oil pump.

[0046] Preferably, the lower plunger 20 is designed as a solid plunger and a hollow plunger according to the displacement of the pump;

[0047] When it is a high-displacement pump, the lower plunger 20 is a solid plunger with a small diameter, which is used to increase the volume of the pump chamber A;

[0048] When it is a low-displacement pump, the lower plunger 20 is a hollow plunger with a large diameter and a sealed end.

[0049] Working principle:

[0050] During the downhole operation, first connect the upper end of the pump barrel assembly to the tubing, and the lower end to an anchoring device such as a tail pipe, a screen pipe or a packer, and lower it into the designed position in the oil well together with the tubing string. Then connect the upper end of the plunger assembly to the sucker rod and lower it into the bottom of the tubing together with the sucker rod string to complete the pump bumping with the pump barrel assembly.

[0051] During the pumping operation, the plunger assembly makes an up-and-down reciprocating motion in the pump barrel assembly driven by the sucker rod string.

[0052] During the upstroke, the plunger assembly moves upward, the volume of the pump chamber increases, the pressure drops, the outlet valve closes under the action of the pressure in the tubing chamber, the liquid above the upper plunger is lifted to the ground. At the same time, the inlet valve and the annular valve open under the action of the submerged pressure in the tubing-casing annulus, and the pump chamber is connected to the tubing-casing annulus, and the downhole liquid flows into the pump chamber.

[0053] During the downstroke, the plunger assembly moves downward, the volume of the pump chamber decreases, the pressure increases, the outlet valve opens under the action of the pressure in the pump chamber, the pump chamber is connected to the tubing chamber, and the liquid in the pump chamber is discharged into the tubing chamber. At the same time, the inlet valve and the annular valve close under the action of the pressure in the pump chamber. Since the pressure in the pump chamber is higher than the submerged pressure in the tubing-casing annulus at this time, a downward hydraulic feedback force will be generated under the differential pressure between the upper and lower parts of the lower plunger, helping the plunger assembly overcome the viscous oil resistance and move downward.

[0054] When well washing, gas injection or dilution operation is required, the plunger assembly is lifted out of the pump barrel assembly, the tubing cavity is communicated with the annulus between the tubing and the casing, and the gas and liquid reach the bottom of the well directly through the liquid passage formed by the upper and lower pump barrels. At the same time, the annular inlet valve closes, and the annular flow passage space between the inlet valve and the annular valve is sealed. Along with the flow of the liquid, the scale, sand particles or viscous oil asphalt in the tubing will also be washed and carried to the bottom of the well together, and will not fall into the annular flow passage space to affect the normal operation of the inlet valve.

[0055] The above embodiments are only the preferred technical solutions of the present invention, and should not be regarded as a limitation to the present invention. The protection scope of the present invention should be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, the equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A bridge series feedback oil well pump, characterized by: It includes a pump barrel assembly and a plunger assembly. The plunger assembly is located in the pump barrel assembly and moves back and forth. The pump barrel assembly includes an upper pump barrel assembly and a lower pump barrel assembly connected in series. An annular oil inlet valve mechanism is provided between the upper pump barrel assembly and the lower pump barrel assembly. The pump barrel assembly comprises an upper coupling (1), an upper bridge pipe (3), a lower bridge pipe (11), a two-way joint (13), an outer pipe (15) and a lower coupling (16) which are connected in sequence, wherein the upper portion of the upper coupling (1) is connected to the oil pipe string, and the lower portion of the lower coupling (16) is connected to the tail pipe and the screen pipe; An upper pump barrel (4) is arranged in the upper bridge pipe (3), and the end of the upper pump barrel (4) is connected to the upper bridge pipe (3) via a support ring (2). A lower pump barrel (10) and a pump barrel extension barrel (12) are arranged in the lower bridge pipe (11); The plunger assembly comprises an upper plunger (18), an oil-passing joint (19) and a lower plunger (20) which are connected in sequence. The upper portion of the upper plunger (18) is connected to a sucker rod column. A plurality of oil outlet valves (17) are arranged in the upper plunger (18). The upper plunger (18) is located in an upper pump barrel (4) and moves therein. The lower plunger (20) is located in a lower pump barrel (10) and a pump barrel extension barrel (12) and moves therein. An annular pump chamber (A) is formed between the upper plunger (18), the lower plunger (20) and the upper pump barrel (4), and the upper portion of the upper plunger (18) is an oil pipe chamber (B).

2. According to claim 1, a bridge series feedback oil pump is characterized in that: The annular oil inlet valve mechanism is arranged between the upper pump barrel (4) and the lower pump barrel (10), and comprises a middle connecting hoop (5), an annular valve ball (6), an annular valve seat (7), a sealing barrel (8) and a sealing joint (9); The annular valve ball (6) is fixed to the end of the sealing cylinder (8) and moves together with the sealing cylinder (8); The annular valve seat (7) is fixed in the middle hoop (5) and is used to restrict the annular valve ball (6) in the middle hoop (5); The outer surface of the sealing cylinder (8) rubs against the inner wall of the sealing joint (9) to provide support when the sealing cylinder (8) moves up and down; A flow passage is provided on the peripheral side of the sealing joint (9).

3. According to claim 2, a bridge series feedback oil pump is characterized in that: The middle hoop (5) is connected to the sealing joint (9), the upper part of the middle hoop (5) is connected to the upper bridge pipe (3) and the upper pump barrel (4), and the lower part of the sealing joint (9) is connected to the lower bridge pipe (11).

4. According to claim 1, a bridge series feedback oil pump is characterized in that: The two-way joint (13) is provided with two gas-liquid circulation passages which do not affect each other and are respectively connected to the inner side and the outer side of the pump barrel extension tube (12). An oil inlet valve (14) is provided at the lower part of the two-way joint (13). The oil inlet valve (14) is connected to the pump chamber (A) through the outer channel of the pump barrel extension tube (12) and the annular oil inlet valve mechanism.

5. According to claim 1, a bridge series feedback oil pump is characterized in that: The lower plunger (20) is designed as a solid plunger or a hollow plunger according to the displacement of the pump; When it is a large displacement pump, the lower plunger (20) is a solid plunger with a small diameter, which is used to increase the volume of the pump chamber (A); When the pump is of small displacement, the lower plunger (20) is a hollow plunger with a large diameter and a sealed end.

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