Water injection well booster injection device

Abstract

A kind of water injection well pressurized water injection device, including polished rod, upper four-way, lower four-way, pressurized pump cylinder, inner pump cylinder and balance pump cylinder;The upper port of upper four-way is connected with seal, the upper port of lower four-way is connected with lower four-way, the left port is connected with liquid inlet valve, the right port is connected with the right port of lower four-way by liquid outlet valve;The upper port of lower four-way is installed with hanger, the lower port of lower four-way is connected with casing;Hanger extends into casing, pressurized pump cylinder is arranged in casing and is connected on hanger, pressurized pump cylinder is provided with pressurized plunger, balance pump cylinder is connected in the lower part of pressurized pump cylinder and is provided with balance plunger;Seal is connected with inner pump cylinder in lower part;Polished rod is inserted into seal and inner pump cylinder and is connected with inner plunger arranged in inner pump cylinder;Inner plunger, pressurized plunger, communication joint and balance plunger are sequentially connected from top to bottom, and communication hole is arranged on communication joint.The balance mechanism is formed, the upstroke load of pumping unit can be reduced, and the upstroke and downstroke load difference of pumping unit is reduced.

Description

Technical Field

[0001] This invention relates to a water injection device for oil fields, suitable for water injection wells with high injection pressure, formation blockage or low permeability, and where the pressure of ordinary water injection pipelines cannot be injected normally. It belongs to the field of water injection well pressurization technology. Background Technology

[0002] For oilfields using water injection, water injection is a crucial measure for maintaining formation pressure. To achieve efficient and large-scale water injection, oilfields have established water injection networks. The injection pressure of these networks can meet the water flow needs of most wells. However, some injection wells have blocked injection zones or low formation permeability, requiring higher injection pressures. Ordinary water injection networks cannot meet the requirements of these wells, necessitating increased injection pressures for normal water injection. Because these wells are relatively dispersed, establishing a single high-pressure water injection network is inconvenient. Therefore, oilfields typically use single-well booster injection. Single-well booster injection uses a booster device to increase the pressure of existing water in the conventional water injection network to the required high-pressure injection. Currently, the booster devices used are surface plunger pumps and centrifugal pumps. These booster devices have shortcomings, primarily: stable output pressure with minimal pressure fluctuations, no impact on the formation, no ability to clear formation blockages, and inability to improve the permeability of the injection zone. Even with increased injection pressure, water may not be successfully injected. Using surface plunger pumps and centrifugal pumps for pressurized water injection presents serious sealing problems due to their high-inlet and high-outlet operation. This makes management difficult, maintenance frequent, and labor-intensive for workers. The pressurized water injection process is often interrupted, causing the well tools to expand and contract and the formation to release sand, shortening the water injection cycle and resulting in significant economic losses.

[0003] Chinese patent document CN2010101144365 discloses a "Pressurized Water Injection Device", which uses an oil pumping unit to pressurize and inject water. This pressurization scheme can overcome the above-mentioned problems. The oil pumping unit pressurizes and injects water, and the working frequency of the oil pumping unit is several times per minute. It can conduct low-frequency impact on the formation, which has the effect of unblocking and clearing the formation. After a period of low-frequency pressurized water injection to clear the formation, the water injection pressure can be reduced, and it is possible to convert it into ordinary water injection pipeline network water injection.

[0004] However, the aforementioned patent cannot be installed in wells requiring pressurized water injection. This is because when the pressurized plunger descends, it needs to overcome the friction between the polished rod, the pressurized plunger, and the pump barrel. This friction can reach several thousand Newtons. If it were lowered into a well requiring pressurized water injection, the pressure at the upper and lower ends of the pressurized plunger would be equal during descent. The area of ​​the upper end of the pressurized plunger bearing pressure is the area of ​​the pressurized plunger minus the area of ​​the polished rod, while the area of ​​the lower end bearing pressure is the area of ​​the pressurized plunger. This area difference creates an upward thrust, making it unsuitable for wells requiring pressurized water injection. Based on the above analysis, there is a friction of several thousand Newtons between the pressurized plunger and the pump barrel, while the weight of the polished rod and the pressurized plunger is less than several thousand Newtons. Therefore, even if placed in a well without pressure, it cannot descend normally. Summary of the Invention

[0005] The purpose of this invention is to provide a water injection device for boosting water pressure in injection wells, which overcomes the above-mentioned problems. It can be installed in water injection wells that require boosted water pressure, reducing the load difference between the upper and lower parts of the device, improving the operating efficiency of the equipment, reducing energy consumption, and enabling water injection wells with blocked water injection layers or low formation permeability to inject water normally.

[0006] The water injection well booster device of the present invention adopts the following technical solution:

[0007] The device includes a smooth rod, an upper four-way connector, a lower four-way connector, a booster pump cylinder, an inner pump cylinder, and a balancing pump cylinder. The upper port of the upper four-way connector is connected to a seal, and the lower port of the upper four-way connector is connected to the upper port of the lower four-way connector. The left port of the upper four-way connector is connected to an inlet valve, and the right port of the upper four-way connector is connected to the right port of the lower four-way connector via a drain valve. A hanger is installed inside the upper port of the lower four-way connector, and a sleeve is connected to the lower port of the lower four-way connector. The hanger extends into the sleeve, and the booster pump cylinder is located inside the sleeve and connected to the hanger. A [missing information - likely a device or component] is installed inside the booster pump cylinder. The booster plunger is connected to the lower part of the booster pump cylinder, and the balance pump cylinder contains the balance plunger. The lower part of the seal is connected to the inner pump cylinder, which passes through the upper four-way connector, the hanger, and the lower four-way connector in sequence to enter the booster pump cylinder. The smooth rod passes through the seal and the inner pump cylinder, and the lower end of the smooth rod is connected to the inner plunger, which is placed inside the inner pump cylinder. The inner plunger has a discharge hole. The inner plunger, booster plunger, connecting joint, and balance plunger are connected in sequence from top to bottom. The connecting joint has a connecting hole.

[0008] The seal is an existing seal on the oil well.

[0009] A pressure relief pipe is installed on the lower outer side of the seal, and the pressure relief pipe communicates with the interior of the seal. The pressure relief pipe is connected to the oil pipeline at the well site, and the oil pipeline operates at low pressure, suitable for the seal's operation. The outer side of the inner pump barrel is filled with high-pressure liquid. After the inner plunger and the inner pump barrel are sealed with a metal fit, the liquid leaking from the gap between the inner plunger and the inner pump barrel flows to the upper part of the inner pump barrel and is discharged through the pressure relief pipe.

[0010] The inlet valve is a one-way valve, and the liquid in the upper four-way valve cannot flow out through the inlet valve.

[0011] The drain valve is a one-way valve, allowing liquid inside the upper four-way valve to flow out, while external liquid cannot flow into the upper four-way valve through the drain valve.

[0012] A seal is provided between the hanger and the upper opening of the lower four-way valve.

[0013] A seal is provided between the optical rod and the sealer.

[0014] A seal is provided between the booster plunger and the booster pump barrel.

[0015] The diameter of the balance plunger is smaller than that of the booster plunger, so that when the intake pressure acts on the upper part of the booster plunger and the discharge pressure acts on the lower part of the balance plunger, a downward thrust is generated, ensuring that the booster plunger can move smoothly downward.

[0016] The diameter of the optical rod is smaller than the diameter of the inner plunger, creating an annular space between the optical rod and the outer wall of the inner plunger.

[0017] A seal is provided between the inner plunger and the inner pump cylinder. The connecting joint is used to block the interior of the booster plunger from the balance plunger (not communicating), and the connecting hole is used to connect the lower outer side of the booster plunger, the upper outer side of the balance plunger, and the interior of the booster plunger.

[0018] When the above-mentioned device is working, the polished rod is connected to the pumping unit, which drives the polished rod to rotate. The polished rod drives the inner plunger, the booster plunger, the connecting joint, and the balance plunger to move up and down reciprocally. During the downstroke, the space above the booster plunger increases, the drain valve closes, and the inlet valve opens. Water is injected into the upper cavity of the booster plunger through the inlet valve. During the upstroke, the space above the booster plunger decreases, the drain valve opens, and the inlet valve closes. The pressurized water is injected into the formation through the drain valve and the casing.

[0019] During the downstroke, the inner plunger, booster plunger, and balance plunger descend synchronously. The upper part of the booster plunger carries the pressure from the water injection network, while the lower part of the balance plunger carries the boosted pressure. The pressure difference and the area difference between the booster and balance plungers generate a downward thrust, allowing the booster plunger to descend smoothly. During the upstroke, the inner plunger, booster plunger, and balance plunger ascend synchronously. The upper part of the booster plunger carries the boosted pressure, and the lower part of the balance plunger carries the boosted pressure. The area difference between the booster and balance plungers generates an upward thrust, reducing the load on the pumping unit.

[0020] Liquid from the lower outer side of the booster plunger and the upper outer side of the balance plunger is discharged through the connecting hole, the inner bore of the inner plunger, the discharge hole, and the inner pump cylinder via the pressure relief pipe. The connecting hole on the connector between the booster plunger and the balance plunger allows leaks from the gaps between the booster plunger and the booster pump cylinder, and between the balance plunger and the balance pump cylinder, to drain into the inner bore of the booster plunger and the inner plunger. The leaked liquid then exits through the discharge hole on the inner plunger and is discharged through the pressure relief pipe, maintaining a low pressure at the connection between the booster plunger and the balance plunger, thus ensuring the normal operation of the entire device.

[0021] The beneficial effects of this invention are:

[0022] A balancing plunger and a balancing pump cylinder are installed at the bottom to form a balancing mechanism. When descending, the upper part of the pressurizing plunger is pressurized by the water injection network, and the lower part of the balancing plunger is pressurized. Under the action of the pressure difference and the area difference between the pressurizing plunger and the balancing plunger, a downward thrust is generated, allowing the invention to be installed in water injection wells that require pressurized water injection. The pressurizing plunger can descend smoothly without the need for a separate underground well. After the incoming water is pressurized, it is directly injected into the water injection well, eliminating the need to lay high-pressure water injection pipelines and reducing manpower and material resources. When the device ascends, the balancing mechanism generates an upward thrust, which can reduce the upward load of the pumping unit, reduce the load difference between the upward and downward movement of the pumping unit, reduce the torque of the pumping unit gearbox, and improve the operating conditions of the pumping unit. On the one hand, it may save energy and reduce consumption, and on the other hand, it improves the operating safety of the pumping unit.

[0023] Therefore, this invention has significant economic and social benefits. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the water injection well pressurization and water injection device of the present invention.

[0025] Figure 2 This is a schematic diagram of the upper part of the present invention.

[0026] Figure 3 This is a schematic diagram of the lower part of the structure in this invention.

[0027] In the diagram: 1. Inlet valve, 2. Smooth rod, 3. Pressure relief pipe, 4. Seal, 5. Drain valve, 6. Upper four-way valve, 7. Upper flange, 8. Hanger, 9. Lower four-way valve, 10. Lower flange, 11. Inner pump barrel, 12. Sleeve, 13. Booster pump barrel, 14. Inner plunger, 15. Booster plunger, 16. Connecting joint, 17. Balance pump barrel, 18. Balance plunger, 19. Discharge port, 20. Connecting port. Detailed Implementation

[0028] like Figure 1 , Figure 2 and Figure 3As shown, the water injection device for boosting water injection wells of the present invention includes an inlet valve 1, a polished rod 2, a pressure relief pipe 3, a sealer 4, a drain valve 5, an upper four-way valve 6, an upper flange 7, a hanger 8, a lower four-way valve 9, a lower flange 10, an inner pump cylinder 11, a casing 12, a booster pump cylinder 13, an inner plunger 14, a booster plunger 15, a connecting joint 16, a balance pump cylinder 17, and a balance plunger 18.

[0029] Sealer 4, upper four-way 6, upper flange 7, lower four-way 9, and lower flange 10 are connected sequentially from top to bottom. Lower flange 10 is connected to the upper part of sleeve 12, and the lower end of sleeve 12 is open. Hanger 8 is installed inside lower four-way 9 and a seal is provided between it and lower four-way 9. Inlet valve 1 is installed at the left port of upper four-way 6. Liquid enters upper four-way 6 through inlet valve 1. Inlet valve 1 is a one-way valve, and liquid inside upper four-way 6 cannot flow out through inlet valve 1. Drain valve 5 is installed at the right port of upper four-way 6. Drain valve 5 is a one-way valve, and liquid inside upper four-way 6 can flow out through drain valve 5. Liquid outside drain valve 5 cannot flow into upper four-way 6 through drain valve 5. Pressure relief pipe 3 is installed at the lower part of sealer 4. Pressure relief pipe 3 communicates with the inside of sealer 4, and liquid inside sealer 4 can be discharged through pressure relief pipe 3. The upper part of the booster pump barrel 13 is connected to the hanger 8, thus suspending the booster pump barrel 13 on the lower four-way 9. The upper part of the inner pump barrel 11 is connected to the lower part of the seal 4, and the lower part passes through the upper four-way 6, upper flange 7, hanger 8, lower four-way 9, and lower flange 10 in sequence into the sleeve 12. The polished rod 2 passes through the seal 4 and the inner pump barrel 11, and the polished rod 2 cooperates with the seal 4 to seal. The booster plunger 15 is located inside the booster pump barrel 13, and the upper part of the booster plunger 15 is connected to the lower part of the inner plunger 14. The booster pump barrel 13 and the booster plunger 15 cooperate to seal (the working method is the same as that of the plunger pump barrel on the existing oil pump). The lower part of the polished rod 2 is connected to the upper part of the inner plunger 14, and the upper part of the polished rod 2 is connected to the oil pumping unit. The inner plunger 14 and the inner pump barrel 11 cooperate to seal (the working method is the same as that of the plunger pump barrel on the existing oil pump). The drain valve 5 is connected to the lower four-way valve 9. The lower part of the booster plunger 15 is connected to the upper part of the connecting joint 16. The upper part of the balance plunger 18 is connected to the lower part of the connecting joint 16. The lower part of the booster pump barrel 13 is connected to the upper part of the balance pump barrel 17. The balance plunger 18 is located inside the balance pump barrel 17, and the balance plunger 18 and the balance pump barrel 17 are sealed together (the working method is the same as that of the plunger pump barrel on the existing oil pump). The inner plunger 14 has a discharge hole 19 at its upper part. The connecting joint 16 prevents the interior of the booster plunger 15 from communicating with the balance plunger 18. The connecting joint 16 is provided with a connecting hole 20. The connecting hole 20 allows the lower outer part of the booster plunger 15 and the upper outer part of the balance plunger 18 to communicate with the interior of the booster plunger 15. Liquid from the lower outer part of the booster plunger 15 and the upper outer part of the balance plunger 18 is discharged from the pressure relief pipe 3 through the connecting hole 20, the inner hole of the inner plunger 14, the discharge hole 19, and the inner pump cylinder 11.

[0030] A further measure of the present invention is that the diameter of the balance plunger 18 is smaller than the diameter of the booster plunger 15, so that when the suction pressure acts on the upper part of the booster plunger 1 and the discharge pressure acts on the lower part of the balance plunger 18, a downward thrust can be generated to ensure that the booster plunger 15 can descend smoothly.

[0031] A further measure of the present invention is that the diameter of the smooth rod 2 is smaller than the diameter of the inner plunger 14, creating an annular space between the smooth rod 2 and the outer wall of the inner plunger 14. This space is used to discharge liquid from the lower outer part of the booster plunger 15 and the upper outer part of the balance plunger 18. If the booster pump cylinder 13 and the booster plunger 15, and the balance pump cylinder 17 and the balance plunger 18 are sealed with a metal fit, there will be a certain amount of leakage, which needs to be discharged to the low-pressure end to ensure the normal operation of the entire device.

[0032] During operation, the polished rod 2 is connected to the pumping unit. The pumping unit drives the polished rod 2 to rotate, which in turn drives the inner plunger 14, the booster plunger 15, the connecting joint 16, and the balance plunger 18 to reciprocate up and down. During the downstroke (moving downwards) of the inner plunger 14 and the booster plunger 15, the upper space of the booster plunger 15 increases, the drain valve 5 closes, and the inlet valve 1 opens, allowing water from the injection pipeline to enter the upper cavity of the booster plunger 15 through the inlet valve 1. During the upstroke (moving upwards) of the inner plunger 14 and the booster plunger 15, the upper space of the booster plunger 15 decreases, the drain valve 5 opens, and the inlet valve 1 closes, allowing the pressurized water to be injected into the formation through the drain valve 5 and the casing 12. The stroke of an oil pumping unit is generally 3-6m, and the number of strokes is generally 3-9. Therefore, it has a long stroke and a slow stroke, resulting in low pulse and large fluctuation of pressurized water. It is suitable for water injection wells with blocked formations, which helps to unblock and clear the formation, improve the permeability of the water injection well, and increase the water injection volume.

[0033] During the downstroke of the inner plunger 14 and the booster plunger 15, the balance plunger 18 moves downwards synchronously. The upper part of the booster plunger 15 carries the pressure of the water injection network, while the lower part of the balance plunger 18 carries the boosted pressure. The pressure difference and the area difference between the booster plunger 15 and the balance plunger 18 generate a downward thrust, allowing the booster plunger 15 to move smoothly downwards. During the upstroke of the pumping unit, which drives the polished rod 2, inner plunger 14, booster plunger 15, and balance plunger 18, the upper part of the booster plunger 15 carries the boosted pressure, and the lower part of the balance plunger 18 carries the boosted pressure. The area difference between the booster plunger 15 and the balance plunger 18 generates an upward thrust, reducing the load on the pumping unit. Therefore, the smaller load difference between the upstroke and downstroke of the pumping unit reduces the torque of the pumping unit gearbox, improving the operating condition of the pumping unit.

[0034] Outside the inner pump barrel 11 is high-pressure liquid. After the inner plunger 14 and the inner pump barrel 11 are sealed with a metal fit, the liquid leaking from the gap between the inner plunger 14 and the inner pump barrel 11 flows to the upper part of the inner pump barrel 11 and is discharged through the pressure relief pipe 3. The upper part of the inner pump barrel 11 becomes low pressure, so the sealer 4 and the polished rod 2 can seal. The sealer 4 is an existing sealer on the oil well. The pressure relief pipe 3 is generally connected to the oil pipeline at the well site. The pressure of the oil pipeline is low pressure, which is suitable for the operation of the sealer 4. The connecting hole 20 on the connecting joint 16 connecting the booster plunger 15 and the balance plunger 18 allows the liquid leaking from the gap between the booster plunger 15 and the balance plunger 18 and their mating pump barrel to be discharged through the connecting hole 20 into the booster plunger 15. The liquid then flows out through the discharge hole 19 at the upper part of the inner plunger 14 and is discharged through the pressure relief pipe 3, making the connection between the booster plunger 15 and the balance plunger 18 low pressure, so that the entire device can operate normally.

[0035] Since the inner pump cylinder 14 is a long pump cylinder, in order to facilitate the lowering of the booster pump cylinder into the sleeve 12, a connecting pipe (such as...) needs to be installed on the booster pump cylinder 13. Figure 1 (As shown).

Claims

1. A water injection device for boosting water pressure in a water injection well, characterized in that: It includes a smooth rod, an upper four-way connector, a lower four-way connector, a booster pump barrel, an inner pump barrel, and a balance pump barrel. The upper four-way connector's upper opening is connected to a seal, its lower opening is connected to the upper opening of the lower four-way connector, its left opening is connected to an inlet valve, and its right opening is connected to the right opening of the lower four-way connector via a drain valve. A hanger is installed inside the upper opening of the lower four-way connector, and a sleeve is connected to its lower opening. The hanger extends into the sleeve, and the booster pump barrel is housed within the sleeve and connected to the hanger. A booster plunger is installed inside the booster pump barrel. The lower part is connected to the balance pump cylinder, and a balance plunger is installed inside the balance pump cylinder; the lower part of the seal is connected to the inner pump cylinder, and a pressure relief pipe is installed on the lower outer side of the seal; the inner pump cylinder passes through the upper four-way connector, the hanger, and the lower four-way connector in sequence to enter the booster pump cylinder; the smooth rod passes through the seal and the inner pump cylinder, and the lower end of the smooth rod is connected to the inner plunger, which is placed inside the inner pump cylinder. The inner plunger has an inner hole and a discharge hole; the inner plunger, the booster plunger, the connecting joint, and the balance plunger are connected in sequence from top to bottom, and the connecting joint has a connecting hole; The diameter of the balance plunger is smaller than the diameter of the booster plunger; The diameter of the optical rod is smaller than the diameter of the inner plunger; A seal is provided between the inner plunger and the inner pump cylinder; The connecting joint prevents the interior of the booster plunger from communicating with the balance plunger, while the connecting hole allows the lower outer part of the booster plunger and the upper outer part of the balance plunger to communicate with the interior of the booster plunger. The liquid in the lower outer part of the booster plunger and the upper outer part of the balance plunger is discharged from the pressure relief pipe through the connecting hole, the inner hole of the inner plunger, the discharge hole, and the inner pump cylinder.

2. The water injection device for boosting water pressure in an injection well according to claim 1, characterized in that: The pressure relief pipe is connected to the interior of the seal.

3. The water injection device for boosting water pressure in an injection well according to claim 1, characterized in that: The inlet valve is a one-way valve.

4. The water injection device for boosting water pressure in an injection well according to claim 1, characterized in that: The drain valve is a one-way valve, through which the liquid in the upper four-way valve flows out.

5. The water injection device for boosting water pressure in an injection well according to claim 1, characterized in that: A seal is provided between the hanger and the upper opening of the lower four-way valve.

6. The water injection device for boosting water pressure in an injection well according to claim 1, characterized in that: A seal is provided between the optical rod and the sealer.

7. The water injection device for boosting water pressure in an injection well according to claim 1, characterized in that: A seal is provided between the booster plunger and the booster pump barrel.

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