An oil-preventing device for a water return system of an injection-production station

Abstract

The utility model discloses an injection station backwater system anti -oil device relates to injection station backwater system technical field, specifically is an injection station backwater system anti -oil device, including pipeline body and deoiling part, the inflow end portion of pipeline body is installed with import control valve, and the outflow end portion of pipeline body is installed with export control valve, the utility model discloses a one -level oil collection pipe and secondary oil collection pipe are set up, and install control valve on the oil collection pipe, can periodically discharge the separated crude oil, avoid its into backwater system. Meanwhile, by setting up the auxiliary pipe, the quick -open blind plate and the coalescence filler on the pipeline body, further enhance the separation effect of crude oil. This design not only reduces the probability of crude oil into backwater system, but also effectively reduces the risk of crude oil leakage when backwater system sweeps the line, reduces the environmental pollution.

Description

Technical Field

[0001] This utility model relates to the technical field of water return systems in injection and production stations, specifically to an oil ingress prevention device for water return systems in injection and production stations. Background Technology

[0002] Oil extraction follows the principle of injection-production balance. After initial oil extraction, due to the reduction of formation energy, water injection is used to replenish the formation's energy. Before maintenance operations on injection wells, the bottom-hole pressure needs to be released. During the water well release process, in the early and late stages of release, due to the replenishment of formation energy, a small amount of crude oil will enter the single-well return water pipeline with the released water flow. From there, it enters the injection-production station's return water manifold and flows into the injection-production station's return water system. When the wastewater tanks at each pumping station are shut down, oil can easily be carried into the return water system. The wastewater tanks at each pumping station mainly handle pump shutdowns for pressure release, single-well return water maintenance pressure release, and return water manifold and injection-production station return water system maintenance pressure release. Therefore, wastewater pumps and wastewater pump inlet / outlet processes are used in conjunction with the wastewater tanks. The wastewater pumps periodically transfer the wastewater from the wastewater tanks into the return water system. However, the wastewater tanks contain crude oil due to the pressure release of the single-well pipelines.

[0003] Currently, none of the injection and production stations have oil ingress prevention devices in their return water systems. Therefore, during water cut-off, some crude oil is also cut into the return water pipeline. The return water system of the injection and production station is the only output of the water pipeline and is a frequently used type of pipeline. Due to the low pressure and corrosive nature of the water in the return water pipeline, fiberglass pipelines are generally used to extend the service life of the pipeline. If the return water system is not cleaned in a timely manner, it will cause oil blockage in the return water system, increasing the cleaning cost and difficulty. In addition, fiberglass pipelines have low pressure resistance and are prone to pipeline rupture during cleaning, resulting in crude oil and sewage leaks and environmental pollution.

[0004] Existing patent technologies, such as the one disclosed in patent number CN203971484U, include a dedicated return water filtration device for metering stations. This device includes a filter housing and a filter element housed within the filter housing. A wastewater inlet is located on the filter housing below the filter element, and a liquid outlet is located on the filter housing above the filter element. A drain port is located at the bottom of the filter housing below the filter element, connected to a safety valve for discharge from a controller. This device is installed before the metering assembly and, after three steps—filtration, sedimentation, and draining—removes large particulate impurities from the wastewater, ensuring that the wastewater passing through the water meter meets the requirements for passing through, thus achieving stable and accurate metering. However, while the primary purpose of this device is to filter impurities from wastewater, because it contains a filter element and has a vertical structure, and water is denser than crude oil, any crude oil entering the device will float to the top and clog the filter. Therefore, this device cannot effectively filter crude oil in the return water system pipeline. Utility Model Content

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this utility model provides an oil ingress prevention device for the water return system of an injection and production station, which solves the problems mentioned in the background art.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, this utility model provides the following technical solution: an oil-prevention device for a water return system in an injection-production station, comprising a pipeline body and an oil removal component. An inlet control valve is installed at the inflow end of the pipeline body, and an outlet control valve is installed at the outflow end of the pipeline body. The oil removal component includes a primary filter plate and a secondary filter plate. The primary filter plate is detachably installed on the inner top wall of the pipeline body, and is located near the inflow port of the pipeline body. The secondary filter plate is detachably installed on the inner top wall of the pipeline body, and is located near the outflow port of the pipeline body.

[0009] Optionally, the oil removal component further includes a primary oil collection pipe and a secondary oil collection pipe. The lower end of the primary oil collection pipe is fixedly connected to the upper wall of the pipe body and the two are in communication. The primary oil collection pipe is close to the primary filter plate. The lower end of the secondary oil collection pipe is fixedly connected to the upper wall of the pipe body and the two are in communication. The secondary oil collection pipe is close to the secondary filter plate.

[0010] Optionally, both the primary and secondary filter plates are crescent-shaped, and both are perpendicular to the axis of the pipe body. The lower edge of each primary or secondary filter plate is lower than the lowest liquid level of the fluid medium inside the pipe body.

[0011] Optionally, a first control valve is installed on the primary oil return pipe, and a second control valve is installed on the secondary oil return pipe.

[0012] Optionally, a first connector is welded to the inflow port of the pipe body, the inlet control valve is detachably installed with the first connector, and an inlet pipe is detachably installed at the end of the inlet control valve away from the pipe body, the pipe body being connected to the inlet pipe through the inlet control valve; a second connector is welded to the outflow port of the pipe body, the outlet control valve is detachably installed with the second connector, and a drain pipe is detachably installed at the end of the outlet control valve away from the second connector, the pipe body being connected to the drain pipe through the outlet control valve.

[0013] Optionally, the pipe body consists of a straight pipe and two constricted pipes, with the two ends of the straight pipe welded to the two constricted pipes respectively; the first joint and the second joint are welded to the two constricted pipes respectively.

[0014] Optionally, the oil removal component further includes an auxiliary pipe, a quick-opening blind flange, and coalescing packing. The lower end of the auxiliary pipe is fixedly connected to the upper wall of the pipe body and the two are in communication. The quick-opening blind flange is fixedly installed at the upper end of the auxiliary pipe. The coalescing packing is detachably installed on the inner wall of the auxiliary pipe. The lower part of the coalescing packing is located in the internal flow channel of the pipe body, and the lower edge of the coalescing packing is lower than the lowest liquid level line of the fluid medium inside the pipe body.

[0015] (III) Beneficial Effects

[0016] This utility model provides a device for preventing oil ingress into the return water system of an injection and production station, which has the following beneficial effects:

[0017] 1. This invention relates to an oil ingress prevention device for a water return system in an injection and production station. It utilizes a primary and secondary filter plate within the pipeline body, taking advantage of the lower density of crude oil compared to water, to separate crude oil from water. The primary and secondary filter plates are crescent-shaped and perpendicular to the pipeline axis. Their lower edges are below the lowest liquid level of the fluid medium inside the pipeline, effectively intercepting crude oil, causing it to accumulate at the filter plates and flow upwards, ultimately being discharged through the primary and secondary oil return pipes. This design not only effectively reduces the probability of crude oil entering the water return system but also prevents crude oil accumulation within the pipeline, thereby reducing the risk of oil blockage in the water return system. Compared to existing technologies, this invention significantly reduces the oil ingress rate, greatly improving the operating efficiency and stability of the water return system.

[0018] 2. This utility model, by setting up a primary and secondary oil collection pipe and installing a control valve on the oil collection pipe, can periodically discharge the separated crude oil, preventing it from entering the return water system. Simultaneously, by incorporating auxiliary pipes, quick-opening blind flanges, and coalescing packing into the pipeline body, the crude oil separation effect is further enhanced. This design not only reduces the probability of crude oil entering the return water system but also effectively reduces the risk of crude oil leakage during pipeline cleaning, thus reducing environmental pollution. Furthermore, by reducing the frequency of oil blockage in the return water system, it lowers cleaning costs and difficulty, extends the service life of the fiberglass pipeline, and significantly reduces maintenance costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a front view structural diagram of Embodiment 1 of the present utility model;

[0021] Figure 2 This is a schematic diagram of the principle structure of Embodiment 1 of this utility model;

[0022] Figure 3 This is a three-dimensional structural diagram of Embodiment 2 of the present invention;

[0023] Figure 4 This is a three-dimensional structural diagram of the auxiliary tube in Embodiment 2 of this utility model;

[0024] Figure 5 This is a cross-sectional structural diagram of Embodiment 2 of the present invention.

[0025] In the diagram: 1. Inlet pipe; 2. First control valve; 3. First-stage oil return pipe; 4. Second control valve; 5. Second-stage oil return pipe; 6. First-stage filter plate; 7. Second-stage filter plate; 8. Downstream flow channel; 9. Drain pipe; 10. Inlet control valve; 11. First connector; 12. Outlet control valve; 13. Second connector; 14. Pipe body; 1401. Straight pipe; 1402. Necked pipe; 15. Auxiliary pipe; 16. Quick-opening blind flange; 17. Coalescing packing. Detailed Implementation

[0026] The technical solution of this utility model will now be clearly and completely described in conjunction with the accompanying drawings. In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying anything.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0028] Example 1, please refer to Figures 1 to 2This utility model provides a technical solution: an oil ingress prevention device for a water return system in an injection-production station, comprising a pipeline body 14 and an oil removal component. An inlet control valve 10 is installed at the inflow end of the pipeline body 14, and an outlet control valve 12 is installed at the outflow end of the pipeline body 14. The oil removal component includes a primary filter plate 6 and a secondary filter plate 7. The primary filter plate 6 is detachably installed on the inner top wall of the pipeline body 14, and is located near the inflow port of the pipeline body 14. The secondary filter plate 7 is detachably installed on the inner top wall of the pipeline body 14, and is located near the outflow port of the pipeline body 14.

[0029] The pipeline body 14, as the main structure of the entire device, is used to contain the fluid medium (oil-water mixture) and guide its flow, effectively cooperating with the oil removal components to separate crude oil from water. The primary filter plate 6's main function is to initially intercept crude oil, utilizing the principle that crude oil's density is less than water, causing crude oil to accumulate at the primary filter plate 6. The lower edge of the primary filter plate 6 is below the lowest liquid level line of the fluid medium inside the pipeline body 14, effectively intercepting larger crude oil particles and reducing their chance of entering downstream equipment. Simultaneously, the design of the primary filter plate 6 also considers ease of disassembly and cleaning, allowing maintenance personnel to regularly clean the accumulated oil on the filter plate, ensuring the long-term stable operation of the device. The secondary filter plate 7's main function is to further filter the fluid medium after treatment by the primary filter plate 6, intercepting remaining crude oil particles. The lower edge of the secondary filter plate 7 is below the lowest liquid level line of the fluid medium inside the pipeline body 14. Through two-stage filtration, the crude oil separation effect can be effectively improved, ensuring that the crude oil content in the treated fluid medium is extremely low, thereby preventing crude oil from entering the return water system.

[0030] Specifically, the oil removal component also includes a primary oil collection pipe 3 and a secondary oil collection pipe 5. The lower end of the primary oil collection pipe 3 is fixedly connected to the upper wall of the pipe body 14 and the two are in communication. The primary oil collection pipe 3 is close to the primary filter plate 6. The lower end of the secondary oil collection pipe 5 is fixedly connected to the upper wall of the pipe body 14 and the two are in communication. The secondary oil collection pipe 5 is close to the secondary filter plate 7.

[0031] The primary oil collection pipe 3 serves to collect and discharge the crude oil intercepted by the primary filter plate 6. A first control valve 2 is installed on the primary oil collection pipe 3 to control the timing and flow rate of oil collection, ensuring timely discharge of crude oil and preventing excessive accumulation within the device that could affect the oil removal efficiency. The secondary oil collection pipe 5 collects the crude oil intercepted by the secondary filter plate 7 and discharges it from the device. A second control valve 4 is installed on the secondary oil collection pipe 5 to control the timing and flow rate of oil collection, ensuring timely discharge of crude oil and further improving the crude oil separation effect.

[0032] Specifically, both the primary filter plate 6 and the secondary filter plate 7 are crescent-shaped, and both the primary filter plate 6 and the secondary filter plate 7 are perpendicular to the axis of the pipe body 14. The lower edge of the primary filter plate 6 or the secondary filter plate 7 is lower than the lowest liquid level line of the fluid medium inside the pipe body 14.

[0033] Below both the primary filter plate 6 and the secondary filter plate 7 is a downward flow channel 8. Within the internal cross-section of the pipe body 14, the ratio of the cross-sectional area of ​​the primary filter plate 6 to the cross-sectional area of ​​the downward flow channel 8 below it is 1:1. The ratio of the cross-sectional area of ​​the secondary filter plate 7 to the cross-sectional area of ​​the downward flow channel 8 below it is 2:1.

[0034] Both the primary filter plate 6 and the secondary filter plate 7 are crescent-shaped, a design that effectively filters and intercepts crude oil, improving filtration efficiency. Simultaneously, the downward flow channel 8 beneath the primary filter plate 6 or the secondary filter plate 7 allows water flow, preventing significant impact on water circulation. The lower edges of both the primary filter plate 6 and the secondary filter plate 7 are below the lowest liquid level of the fluid medium inside the pipe body 14. This design ensures that the filter plates effectively intercept crude oil, preventing it from directly entering downstream equipment from below the filter plates.

[0035] More specifically, a first control valve 2 is installed on the primary oil return pipe 3, and a second control valve 4 is installed on the secondary oil return pipe 5.

[0036] The first control valve 2 controls the opening and closing of the primary oil receiving pipe 3, thereby controlling the timing of the discharge of crude oil intercepted by the primary filter plate 6. This ensures that crude oil can be discharged in a timely manner, preventing excessive accumulation within the device and affecting the oil removal effect. The second control valve 4 controls the opening and closing of the secondary oil receiving pipe 5, thereby controlling the timing of the discharge of crude oil intercepted by the secondary filter plate 7. This ensures that crude oil can be discharged in a timely manner, further improving the crude oil separation effect.

[0037] Specifically, a first connector 11 is welded to the inflow port of the pipe body 14. The inlet control valve 10 is detachably installed with the first connector 11. An inlet pipe 1 is detachably installed at the end of the inlet control valve 10 away from the pipe body 14, and the pipe body 14 is connected to the inlet pipe 1 through the inlet control valve 10. A second connector 13 is welded to the outflow port of the pipe body 14. The outlet control valve 12 is detachably installed with the second connector 13. A drain pipe 9 is detachably installed at the end of the outlet control valve 12 away from the second connector 13, and the pipe body 14 is connected to the drain pipe 9 through the outlet control valve 12.

[0038] The inlet control valve 10 controls the flow rate and pressure of the fluid medium entering the device, ensuring safe and stable operation. Adjusting the opening of the inlet control valve 10 precisely controls the flow rate of the oil-water mixture entering the device, preventing excessive internal pressure due to excessive flow and ensuring effective oil removal. The outlet control valve 12 controls the flow rate and pressure of the degreased fluid medium (mainly water) exiting the device. Adjusting the opening of the outlet control valve 12 ensures smooth discharge of the degreased fluid medium, while preventing damage to the internal structure of the device due to excessive pressure.

[0039] The first connector 11 connects the inlet control valve 10 and the inlet pipe 1. The first connector 11 facilitates the installation and maintenance of the inlet control valve 10, ensures the seal between the inlet control valve 10 and the pipe body 14, and allows for easy replacement of the inlet control valve 10 or the inlet pipe 1 when needed. The inlet pipe 1 introduces the oil-water mixture into the device. The material and structure of the inlet pipe 1 can withstand certain pressure and corrosion, ensuring its long-term stable operation. The second connector 13 connects the outlet control valve 12 and the drain pipe 9. The second connector 13 facilitates the installation and maintenance of the outlet control valve 12, ensures the seal between the outlet control valve 12 and the pipe body 14, and allows for easy replacement of the outlet control valve 12 or the drain pipe 9 when needed. The drain pipe 9 discharges the degreased fluid medium from the device, ensuring its smooth discharge. The material and structure of the drain pipe 9 can withstand certain pressure and corrosion, ensuring its long-term stable operation.

[0040] Specifically, the pipe body 14 consists of a straight pipe 1401 and two constricted pipes 1402, with the two ends of the straight pipe 1401 welded to the two constricted pipes 1402 respectively. The first joint 11 and the second joint 13 are welded to the two constricted pipes 1402 respectively.

[0041] The straight pipe 1401, as the main part of the pipe body 14, is used to contain the fluid medium and guide its flow. The straight pipe 1401 can effectively cooperate with the oil removal component to achieve the separation of crude oil and water. The length and diameter of the straight pipe 1401 are designed according to the actual working conditions to ensure that the fluid medium can flow fully in the pipe, while providing sufficient space for the oil removal component.

[0042] The necked tube 1402 is connected to either the first connector 11 or the second connector 13. The design of the necked tube 1402 effectively reduces the diameter of the pipe body 14, thereby increasing the flow rate of the fluid medium and improving the oil removal effect. At the same time, the necked tube 1402 also enhances the structural strength of the pipe body 14, ensuring that the device will not be damaged due to excessive pressure during operation.

[0043] The first control valve 2, the second control valve 4, the inlet control valve 10, and the outlet control valve 12 in this technical solution all include, but are not limited to, clamp valves, thereby making the device easy to disassemble and maintain.

[0044] In this technical solution, the first connector 11 and the second connector 13 both include, but are not limited to, using clamp heads to facilitate installation and connection via clamps. They are implemented in conjunction with clamp valves to facilitate disassembly and maintenance.

[0045] In this technical solution, the primary filter plate 6 and the secondary filter plate 7 are, but are not limited to, one of the following: metal coalescing filter plate, ceramic coalescing filter plate, polymer composite coalescing filter plate, metal-fiber composite filter plate, etc., to meet the needs of implementing crude oil and water filtration and separation.

[0046] The pipe body 14 in this technical solution includes, but is not limited to, materials made of stainless steel.

[0047] This technical solution does not impose restrictive definitions on the parameters and dimensions of each component. For example, the wall thickness of the pipe body 14 and the cross-sectional diameter of the internal flow channel can be adjusted and modified according to actual implementation needs.

[0048] During operation, before releasing pressure in the injection well (first open the single-well inlet and return water manifold valves, then open the return water manifold main valve), the oil-water mixture flows in from the inlet end of the pipeline body 14. After entering the pipeline body 14, the oil-water mixture first undergoes preliminary filtration through the primary filter plate 6, intercepting larger crude oil particles. The fluid medium after passing through the primary filter plate 6 continues to flow forward and enters the secondary filter plate 7 for further filtration, intercepting the remaining crude oil particles. The fluid medium after two stages of filtration enters the downstream equipment of the pipeline body 14 through the downstream flow channel 8, and is finally discharged from the device through the drain pipe 9.

[0049] During the filtration process, crude oil intercepted by the primary filter plate 6 and the secondary filter plate 7 is discharged from the device through the primary oil return pipe 3 and the secondary oil return pipe 5, respectively. It is recommended that during the water well depressurization period, oil be collected at the primary oil return pipe 3 every week and at the secondary oil return pipe 5 every two weeks. If the oil output is high, the number of collection cycles can be increased within the same time period. Simultaneously, an oil collection tank can be used at the wellhead to further reduce the probability of crude oil entering the return water system, ultimately ensuring that the return water system pipelines are not blocked by oil and guaranteeing the stable operation of the return water system.

[0050] Example 2, please refer to Figures 3 to 5The main difference between this embodiment and Embodiment 1 is that the oil removal component also includes an auxiliary pipe 15, a quick-opening blind flange 16, and coalescing packing 17. The lower end of the auxiliary pipe 15 is fixedly connected to the upper wall of the pipe body 14, and the two are in communication. The quick-opening blind flange 16 is fixedly installed at the upper end of the auxiliary pipe 15. The coalescing packing 17 is detachably installed on the inner wall of the auxiliary pipe 15. The lower part of the coalescing packing 17 is located in the internal flow channel of the pipe body 14, and the lower edge of the coalescing packing 17 is lower than the lowest liquid level line of the fluid medium inside the pipe body 14.

[0051] The auxiliary pipe 15 primarily provides installation space for the coalescing packing 17 and enables rapid disassembly and maintenance via the quick-opening blind flange 16. The design of the auxiliary pipe 15 further enhances the crude oil separation effect, ensuring efficient operation of the unit. The quick-opening blind flange 16 is used for rapid disassembly and maintenance of the coalescing packing 17. Its design considers operational convenience and safety, ensuring quick and easy operation when the coalescing packing 17 needs replacement or cleaning, reducing maintenance time and improving unit operating efficiency. The main function of the coalescing packing 17 is to further enhance the crude oil separation effect. Its design allows crude oil, after initial separation by the primary filter plate 6 and secondary filter plate 7, to further coalesce into larger oil droplets, making it easier to be discharged from the unit via the oil collection pipe. The lower edge of the coalescing packing 17 is lower than the lowest liquid level line of the fluid medium inside the pipe body 14, ensuring it remains in contact with the fluid medium during operation for optimal separation. The coalescing packing 17 is preferably selected from polypropylene (PP) corrugated plate packing, modified polypropylene fiber bundle packing, or glass fiber composite packing.

[0052] It should be noted that, for those skilled in the art, it is obvious that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this utility model is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this utility model, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0053] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An oil-preventing device for a water return system of an injection-production station, characterized in that: It includes a pipe body (14) and an oil removal component. An inlet control valve (10) is installed at the inflow end of the pipe body (14), and an outlet control valve (12) is installed at the outflow end of the pipe body (14). The oil removal component includes a primary filter plate (6) and a secondary filter plate (7). The primary filter plate (6) is detachably installed on the inner top wall of the pipe body (14), and the primary filter plate (6) is close to the inflow port of the pipe body (14). The secondary filter plate (7) is detachably installed on the inner top wall of the pipe body (14), and the secondary filter plate (7) is close to the outlet port of the pipe body (14).

2. The oil ingress prevention device for a water return system of an injection production station according to claim 1, characterized in that: The oil removal component also includes a primary oil collection pipe (3) and a secondary oil collection pipe (5). The lower end of the primary oil collection pipe (3) is fixedly connected to the upper wall of the pipe body (14) and the two are in communication. The primary oil collection pipe (3) is close to the primary filter plate (6). The lower end of the secondary oil collection pipe (5) is fixedly connected to the upper wall of the pipe body (14) and the two are in communication. The secondary oil collection pipe (5) is close to the secondary filter plate (7).

3. The oil ingress prevention device for a water back system of an injection production station of claim 1, wherein: The primary filter plate (6) and the secondary filter plate (7) are both crescent-shaped. The primary filter plate (6) or the secondary filter plate (7) is perpendicular to the axis of the pipe body (14). The lower edge of the primary filter plate (6) or the secondary filter plate (7) is lower than the lowest liquid level line of the fluid medium inside the pipe body (14).

4. The oil ingress prevention device for a water back system of an injection production station of claim 2, wherein: The first control valve (2) is installed on the first-stage oil return pipe (3), and the second control valve (4) is installed on the second-stage oil return pipe (5).

5. The oil ingress prevention device for a water back system of an injection production station of claim 1, wherein: A first connector (11) is welded to the inflow port of the pipe body (14). The inlet control valve (10) and the first connector (11) are detachably installed. An inlet pipe (1) is detachably installed at the end of the inlet control valve (10) away from the pipe body (14). The pipe body (14) is connected to the inlet pipe (1) through the inlet control valve (10). A second connector (13) is welded to the outflow port of the pipe body (14). The outlet control valve (12) and the second connector (13) are detachably installed. A drain pipe (9) is detachably installed at the end of the outlet control valve (12) away from the second connector (13). The pipe body (14) is connected to the drain pipe (9) through the outlet control valve (12).

6. The oil ingress prevention device for a water return system of an injection production station according to claim 5, characterized in that: The pipe body (14) is composed of a straight pipe (1401) and two constricted pipes (1402). The two ends of the straight pipe (1401) are welded to the two constricted pipes (1402) respectively. The first joint (11) and the second joint (13) are welded to the two constricted pipes (1402) respectively.

7. The oil ingress prevention device for the return water system of an injection-production station according to claim 1, characterized in that: The oil removal component also includes an auxiliary pipe (15), a quick-opening blind flange (16), and coalescing packing (17). The lower end of the auxiliary pipe (15) is fixedly connected to the upper wall of the pipe body (14) and the two are in communication. The quick-opening blind flange (16) is fixedly installed at the upper end of the auxiliary pipe (15). The coalescing packing (17) is detachably installed on the inner wall of the auxiliary pipe (15). The lower part of the coalescing packing (17) is located in the internal flow channel of the pipe body (14). The lower edge of the coalescing packing (17) is lower than the lowest liquid level line of the fluid medium inside the pipe body (14).

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