Special high-pressure well washing environment-friendly device for oil field water injection well

Abstract

A high-pressure well-washing environment-friendly special device for an oil field water injection well relates to the technical field of oil field sewage recovery and comprises a well mouth, a well mouth water supply system, a well mouth return liquid dosing system, a filtering and precipitating system, a reinjection system and a discharge system. The wellhead incoming water system injects up-to-standard incoming water into a wellhead to perform conventional well flushing or inverse well flushing, reverse-out liquid of the conventional well flushing or inverse well flushing enters the wellhead reverse-out liquid dosing system, the reverse-out liquid is purified through a pressurization procedure, the reverse-out liquid after dosing enters the filtering and precipitating system to be filtered and precipitated, and precipitated waste residues are discharged. The device is further provided with a discharging system, and forced discharging is carried out after the device is started. The skid-mounted device is of a skid-mounted structure, can automatically treat well washing reverse outlet liquid on line, and can reinject treated water reaching the standard, so that the skid-mounted device does not need to be transported by a tank car, and is low in cost. And meanwhile, the situation that dirty oil falls to the ground is avoided, and the environmental protection property is good.

Description

Technical Field

[0001] The utility model belongs to the technical field of oilfield sewage recovery, and particularly relates to a special environmental protection device for high-pressure well washing of oilfield injection wells. Background Technique

[0002] At present, the backflow liquid of oilfield well washing is recovered and centrally treated by tanker trucks. This method has high costs, long time, low recovery rate, and the situation of oil pollution falling to the ground will occur during the process of replacing tanker trucks, and the oil well site does not meet the environmental protection requirements. Therefore, there is an urgent need for an environmental protection treatment device that can recover the backflow liquid on site and perform on-line filtration treatment on the backflow liquid to meet the reinjection standard. Content of the Utility Model

[0003] In order to solve the problem of high cost of transporting and treating the backflow liquid of well washing, the utility model provides a special environmental protection device for high-pressure well washing of oilfield injection wells. The utility model is of a skid-mounted structure, which can automatically treat the backflow liquid of well washing on line, and can reinject the treated qualified water, so there is no need for tanker truck transportation, and the cost is reduced. At the same time, this application avoids the situation of oil pollution falling to the ground and has good environmental protection.

[0004] The technical solution provided by the present utility model is: a special environmental protection device for high-pressure well flushing of oilfield injection wells, which includes a wellhead, a wellhead incoming water system, a wellhead backflow liquid dosing system, a filtration and sedimentation system, a reinjection system, and an external discharge system; the wellhead includes a flushing liquid inlet port and a backflow liquid port; the wellhead incoming water system includes an incoming water pipeline and a retrieved water jet pump, the incoming water pipeline is connected to the flushing liquid inlet port of the wellhead, the retrieved water jet pump is connected in series in the incoming water pipeline, and the retrieved water jet pump pumps the water in the incoming water pipeline towards the flushing liquid inlet port; the wellhead backflow liquid dosing system includes a backflow liquid pipeline, a dosing jet pump, a dosing tank, and a dosing pipeline, one end of the backflow liquid pipeline is connected to the backflow liquid port of the wellhead, the dosing jet pump is connected in series in the backflow liquid pipeline, the dosing pipeline connects the dosing tank and the dosing jet pump, when the dosing jet pump works, the liquid medicine in the dosing tank is sucked into the dosing jet pump, and the liquid medicine reacts chemically with the backflow liquid for treatment; the filtration and sedimentation system includes a buffer tank, a filtration and sedimentation tank, and a sedimentation and recovery tank, the other end of the backflow liquid pipeline is connected to the buffer tank, the liquid outlet of the buffer tank is connected to the inlet of the filtration and sedimentation tank, the filtration and sedimentation tank plays a role in filtration and sedimentation, the outlet of the filtration and sedimentation tank is connected to the sedimentation and recovery tank, and the sedimentation and recovery tank plays a role in sedimentation and storage; the reinjection system includes a reinjection pipeline and a return water valve, one end of the reinjection pipeline is connected to the sedimentation and recovery tank, the other end of the reinjection pipeline is connected to the retrieved water jet pump, the return water valve is connected in series in the reinjection pipeline, and when the retrieved water jet pump works, the reinjection liquid in the reinjection pipeline is sucked into the retrieved water jet pump; the external discharge system includes an external discharge pipeline, an external discharge piston pump, and a piston pump inlet valve, one end of the external discharge pipeline is connected to the sedimentation and recovery tank, the other end of the external discharge pipeline is connected to the reinjection pipeline upstream of the return water valve, and the external discharge piston pump and the piston pump inlet valve are connected in series in the external discharge pipeline.

[0005] A further technical solution is: the special environmental protection device for high-pressure well flushing of oilfield injection wells further includes a PLC controller with a human-machine interface;

[0006] The wellhead incoming water system further includes an incoming water pressure sensor, an incoming water quality inspection and alarm instrument, and an incoming water rotameter, and the incoming water pressure sensor, the incoming water quality inspection and alarm instrument, and the incoming water rotameter are respectively electrically connected to the PLC controller;

[0007] The wellhead backflow liquid dosing system further includes a backflow liquid temperature sensor, a backflow liquid pressure sensor, a backflow liquid rotameter, a backflow liquid quality inspection and alarm instrument, and an electric valve for the outlet of the dosing tank, and the backflow liquid temperature sensor, the backflow liquid pressure sensor, the backflow liquid rotameter, the backflow liquid quality inspection and alarm instrument, and the electric valve for the outlet of the dosing tank are respectively electrically connected to the PLC controller;

[0008] The described buffer tank is provided with a buffer tank pressure gauge; the described filtration and sedimentation tank is provided with a sedimentation tank pressure gauge; the buffer tank pressure gauge and the sedimentation tank pressure gauge are respectively electrically connected to the PLC controller;

[0009] The described reinjection system further includes a return water rotameter and a return water quality inspection and alarm instrument. The described return water valve is an electric valve. The return water rotameter, the return water quality inspection and alarm instrument, and the return water valve are respectively electrically connected to the PLC controller;

[0010] The described plunger pump inlet valve is an electric valve and is electrically connected to the PLC controller.

[0011] A further technical solution is that the described special environmental protection device for high-pressure well washing of oilfield injection wells further includes an anti-flushing system. The anti-flushing system includes an anti-flushing pipeline and an anti-flushing inlet electric valve. The described filtration and sedimentation tank is provided with an anti-flushing inlet and an anti-flushing outlet. One end of the anti-flushing pipeline is connected to the water inlet pipeline, and the other end of the anti-flushing pipeline is connected to the anti-flushing inlet of the filtration and sedimentation tank. The anti-flushing outlet of the filtration and sedimentation tank is connected to the sedimentation and recovery tank.

[0012] A further technical solution is that the described well washing fluid inlet port includes a normal well washing inlet pipeline and a reverse well washing inlet pipeline. The normal well washing inlet pipeline and the reverse well washing inlet pipeline are in parallel. Among them, an oil pipe water inlet electric valve is connected in series on the normal well washing inlet pipeline, and a casing water inlet electric valve is connected in series on the reverse well washing inlet pipeline; the described reverse liquid outlet port includes a normal well washing outlet pipeline and a reverse well washing outlet pipeline. The normal well washing outlet pipeline and the reverse well washing outlet pipeline are in parallel. Among them, a casing water outlet electric valve is connected in series on the normal well washing outlet pipeline, and an oil pipe water outlet electric valve is connected in series on the reverse well washing outlet pipeline; the oil pipe water inlet electric valve, the casing water inlet electric valve, the casing water outlet electric valve, and the oil pipe water outlet electric valve are respectively electrically connected to the PLC controller.

[0013] A further technical solution is that the described special environmental protection device for high-pressure well washing of oilfield injection wells further includes a turbo generator system. The turbo generator system includes a bypass pipeline, a turbo generator, a generator water inlet valve, and a generator water outlet valve. Both ends of the bypass pipeline are connected to the water inlet pipeline. The turbo generator is connected in series in the bypass pipeline. The generator water inlet valve is connected in series in the bypass pipeline upstream of the turbo generator, and the generator water outlet valve is connected in series in the bypass pipeline downstream of the turbo generator. A turbo generator bypass valve is installed on the water inlet pipeline between both ends of the bypass pipeline. A further technical solution is that the current generated by the turbo generator is connected to the external discharge plunger pump and the PLC controller through a wire.

[0014] Compared with the prior art, the beneficial effects of the present utility model are as follows: This application has a skid-mounted structure and can process the backflow liquid from well flushing online. After adding medicine to it and undergoing buffering, filtration, and sedimentation, it becomes qualified water quality, and the qualified water can be re-injected into the well for flushing. Therefore, this application no longer requires tanker transportation, saving costs. At the same time, since this application no longer requires switching tankers, the situation of dirty oil falling to the ground is avoided, and the environmental protection of this application is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the connection relationship of the present utility model.

[0016] The dotted lines in the figure are the connection lines for electrically connecting each electrical component to the PLC controller.

[0017] The dash-dotted line in the figure is a schematic diagram of the wire connection between the turbo generator, the chemical dosing jet pump, and the PLC controller.

[0018] In the figure: 01, incoming water gate; 02, incoming water pressure sensor; 03, incoming water check valve; 04, bypass valve of the turbo generator; 05, generator inlet valve; 06, turbo generator; 07, generator outlet valve; 08, incoming water quality inspection alarm instrument; 09, incoming water rotameter; 10, water retrieval jet pump; 11, return water valve; 12, return water quality inspection alarm instrument; 13, return water rotameter; 14, backwashing inlet electric valve; 15, buffer tank emptying valve; 16, casing inlet electric valve; 17, tubing inlet electric valve; 18, normal well flushing liquid outlet pipeline; 19, reverse well flushing liquid outlet pipeline; 20, tubing outlet electric valve; 21, casing outlet electric valve; 22, backflow liquid temperature sensor; 23, backflow liquid pressure sensor; 24, backflow liquid rotameter; 25, well outlet water quality inspection alarm instrument; 26, external drainage circulation check valve; 27, external drainage piston pump; 28, external drainage piston pump inlet valve; 29, chemical dosing tank venting electric valve; 30, chemical dosing tank; 31, chemical dosing tank outlet electric valve; 32, chemical dosing jet pump; 33, buffer tank A; 34, buffer tank B; 35, buffer tank pressure gauge; 36, slag discharge valve; 37, slag discharge check valve; 38, sedimentation recovery tank; 39, sedimentation recovery tank emptying valve; 40, sedimentation tank pressure gauge; 41, filtration sedimentation tank connection electric valve; 42, first-stage high-pressure filtration sedimentation tank; 43, second-stage high-pressure filtration sedimentation tank; 44, third-stage high-pressure filtration sedimentation tank; 45, sedimentation recovery tank check valve; 46, PLC controller; 47, incoming water pipeline; 48, reverse well flushing liquid inlet pipeline; 49, normal well flushing liquid inlet pipeline; 50, bypass pipeline; 51, external drainage pipeline; 52, backflow liquid pipeline; 53, backwashing pipeline; 54, reinjection pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To enable those skilled in the art to better understand the solution of the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0020] This embodiment is a special environmental protection device for high-pressure well washing of oilfield injection wells, which specifically includes a wellhead, a wellhead incoming water system, a wellhead backflow liquid dosing system, a filtration and sedimentation system, a reinjection system, an external discharge system, a PLC controller with a human-machine interface, a backwashing system, and a turbo generator system, which will be detailed one by one below.

[0021] The wellhead includes a washing fluid inlet port and a backflow liquid outlet port. The washing fluid inlet port includes a normal well washing inlet pipeline 49 and a reverse well washing inlet pipeline 48. The normal well washing inlet pipeline 49 and the reverse well washing inlet pipeline 48 are in parallel. Among them, an oil pipe water inlet electric valve 17 is connected in series on the normal well washing inlet pipeline 49, and a casing water inlet electric valve 16 is connected in series on the reverse well washing inlet pipeline 48. The backflow liquid outlet port includes a normal well washing outlet pipeline 18 and a reverse well washing outlet pipeline 19. The normal well washing outlet pipeline 18 and the reverse well washing outlet pipeline 19 are in parallel. Among them, a casing water outlet electric valve 21 is connected in series on the normal well washing outlet pipeline 18, and an oil pipe water outlet electric valve 20 is connected in series on the reverse well washing outlet pipeline 19. The oil pipe water inlet electric valve 17, the casing water inlet electric valve 16, the casing water outlet electric valve 21, and the oil pipe water outlet electric valve 20 are respectively electrically connected to the PLC controller 46. During normal well washing, the oil pipe water inlet electric valve 17 and the casing water outlet electric valve 21 are opened through the PLC controller 46, and the casing water inlet electric valve 16 and the oil pipe water outlet electric valve 20 are closed. During reverse well washing, the oil pipe water inlet electric valve 17 and the casing water outlet electric valve 21 are closed through the PLC controller 46, and the casing water inlet electric valve 16 and the oil pipe water outlet electric valve 20 are opened.

[0022] The described wellhead incoming water system includes an incoming water pipeline 47, which is respectively connected to the normal flushing well liquid inlet pipeline 49 and the reverse flushing well liquid inlet pipeline 48, so as to supply water to the normal flushing well liquid inlet pipeline 49 and the reverse flushing well liquid inlet pipeline 48. An incoming water pressure sensor 02, an incoming water check valve 03, an incoming water water quality inspection alarm instrument 08, an incoming water rotameter 09 and a retrieved water jet pump 10 are sequentially connected in series on the incoming water pipeline 47 according to the water flow direction. The retrieved water jet pump 10 pumps the water in the incoming water pipeline 47 towards the inlet of the flushing well liquid. The incoming water pressure sensor 02 is used to monitor the incoming water pressure; the incoming water check valve 03 is used to prevent the incoming water from flowing back; the incoming water water quality inspection alarm instrument 08 is used for water quality inspection and sending out an alarm; the incoming water rotameter 09 is used to monitor the flow rate of the incoming water. The incoming water pressure sensor 02, the incoming water water quality inspection alarm instrument 08 and the incoming water rotameter 09 are respectively electrically connected to the PLC controller 46, and transmit the monitored information to the PLC controller 46.

[0023] The wellhead reverse effluent dosing system includes a reverse effluent pipeline 52 and a dosing pipeline. One end of the reverse effluent pipeline 52 is respectively connected to the normal flushing well effluent pipeline 18 and the reverse flushing well effluent pipeline 19, so as to discharge the reverse effluent of the normal flushing well / reverse flushing well through the reverse effluent pipeline 52. A reverse effluent rotameter 24, a reverse effluent temperature sensor 22, a reverse effluent pressure sensor 23, a reverse effluent water quality inspection alarm instrument 25 and a dosing jet pump 32 are sequentially arranged on the reverse effluent pipeline 52. The dosing pipeline 52 connects the dosing tank 30 and the dosing jet pump 32. A dosing tank water outlet electric valve 31 is connected in series in the dosing pipeline. A dosing tank venting electric valve 29 is also connected above the dosing tank 30. The reverse effluent rotameter 24 is used to measure the flow rate of the reverse effluent; the reverse effluent temperature sensor 22 is used to monitor the temperature of the reverse effluent; the reverse effluent pressure sensor 23 is used to monitor the pressure of the reverse effluent; the reverse effluent water quality inspection alarm instrument 25 is used to detect the water quality of the reverse effluent. When the water quality does not meet the standard, the dosing tank water outlet electric valve 31 is opened, and the liquid medicine enters the dosing jet pump 32 from the dosing tank 30. The liquid medicine is mixed with the reverse effluent to treat the reverse effluent. The reverse effluent rotameter 24, the reverse effluent temperature sensor 22, the reverse effluent pressure sensor 23 and the reverse effluent water quality inspection alarm instrument 25 are respectively electrically connected to the PLC controller 46, and transmit the monitored information to the PLC controller 46.

[0024] The filtration and sedimentation system includes a buffer tank, a filtration and sedimentation tank, and a sedimentation and recovery tank 38. In this embodiment, there are two buffer tanks, namely buffer tank A 33 and buffer tank B 34. The outlet of buffer tank A 33 is connected to the inlet of buffer tank B 34. The two buffer tanks play a sequential buffering role. The other end of the reverse effluent pipeline 52 is connected to buffer tank A 33, and a buffer tank vent valve 15 is connected above buffer tank A 33. In this embodiment, there are three filtration and sedimentation tanks, namely a primary filtration and sedimentation tank 42, a secondary filtration and sedimentation tank 43, and a tertiary filtration and sedimentation tank 44. The tertiary filtration and sedimentation tanks are connected in sequence to play a sequential sedimentation role. Filtration and sedimentation tank connecting motorized valves 41 are arranged between them. The buffer tank B 34 is connected to the inlet of the primary filtration and sedimentation tank 42, and the buffered reverse effluent is discharged into the primary filtration and sedimentation tank 42 for filtration and sedimentation. The outlet of the tertiary filtration and sedimentation tank 44 is connected to the sedimentation and recovery tank 38, and the sedimentation and recovery tank 38 plays a role of sedimentation and storage. A sedimentation and recovery tank vent valve 39 is connected above the sedimentation and recovery tank 38. Buffer tank pressure gauges 35 are respectively arranged on the buffer tank A 33 and the buffer tank B 34; Sedimentation tank pressure gauges 40 are respectively arranged on the primary filtration and sedimentation tank 42, the secondary filtration and sedimentation tank 43, and the tertiary filtration and sedimentation tank 44. The buffer tank pressure gauges 35 and the sedimentation tank pressure gauges 40 are respectively electrically connected to the PLC controller 46, and the monitored information is transmitted to the PLC controller 46. The filtration and sedimentation tank connecting motorized valves 41 are electrically connected to the PLC controller 46 and receive instructions sent by the PLC controller 46.

[0025] The reinjection system includes a reinjection pipeline 51. One end of the reinjection pipeline 51 is connected to the sedimentation and recovery tank 38, and the other end is connected to the retrieved water jet pump 10. A sedimentation and recovery tank check valve 45, a return water rotameter 13, and a return water valve 11 are sequentially arranged on the reinjection pipeline 51. When the retrieved water jet pump 10 operates, the reinjection liquid in the reinjection pipeline 51 is sucked into the incoming water pipeline 47. A reinjection water quality inspection alarm instrument 12 is arranged on the sedimentation and recovery tank 38, and the return water rotameter 13 is used to monitor the flow rate of the reinjected water; The return water rotameter 13, the return water valve 11, and the reinjection water quality inspection alarm instrument 12 are respectively electrically connected to the PLC controller 46. When the reinjection water quality inspection alarm instrument 12 monitors that the quality of the reinjected water on the upper layer of the sedimentation and recovery tank 38 meets the standard, the PLC controller 46 sends an instruction to open the return water valve 11, and the reinjection system is started.

[0026] The external drainage system includes an external drainage pipeline 54. One end of the external drainage pipeline 54 is connected to the sedimentation recovery tank 38, and the other end of the external drainage pipeline 54 is connected to the reinjection pipeline 51 upstream of the return water valve 11. A plunger pump inlet valve 28, an external drainage plunger pump 27, and an external drainage water circulation check valve 26 are sequentially arranged on the external drainage pipeline 54. When the reinjection water volume inhaled by the retrieved water jet pump 10 is very small, the plunger pump inlet valve 28 is opened, and the external drainage plunger pump 27 is used to forcibly suck the water in the sedimentation recovery tank 38. The plunger pump inlet valve 28 is an electric valve, and the plunger pump inlet valve 28 is electrically connected to the PLC controller 46 and accepts the instructions of the PLC controller 46 for start / stop.

[0027] The backwashing system includes a backwashing pipeline 53 and a backwashing inlet electric valve 14. One end of the backwashing pipeline 53 is connected to the water inlet pipeline 47. When the oil pipe inlet electric valve 17 and the casing inlet electric valve 16 are all closed, the clear water in the water inlet pipeline 47 enters the backwashing pipeline 53. The backwashing pipeline 53 is respectively connected to the first-stage filtration sedimentation tank 42, the second-stage filtration sedimentation tank 43, and the third-stage filtration sedimentation tank 44 to backwash the three filtration sedimentation tanks. The backwashing water enters the sedimentation recovery tank 38. A slag discharge valve 36 is provided for each stage of the filtration sedimentation tank, and a slag discharge one-way valve 37 is provided between each stage of the filtration sedimentation tank and the sedimentation recovery tank 38.

[0028] The turbine generator system includes a bypass pipeline 50, a turbine generator 06, a generator inlet valve 05, and a generator outlet valve 07. Both ends of the bypass pipeline 50 are connected to the water inlet pipeline 47. The turbine generator 06 is connected in series in the bypass pipeline 50. The generator inlet valve 05 is connected in series in the bypass pipeline 50 upstream of the turbine generator 06. The generator outlet valve 07 is connected in series in the bypass pipeline 50 downstream of the turbine generator 06. A turbine generator bypass valve 04 is installed on the water inlet pipeline 47 between both ends of the bypass pipeline 50. The current generated by the turbine generator 06 is connected to the external drainage plunger pump 27 and the PLC controller 46 through a wire. The main function of the turbine power generation system is to supply power to the external drainage plunger pump 27 and the PLC controller 46 to ensure stable current.

[0029] It should be noted that the PLC program applied in the present utility model is the simplest, most basic, and most commonly used program, which belongs to the prior art and will not be elaborated here.

[0030] This application has a skid-mounted structure, and all the above-mentioned systems are installed on the skid, which is more convenient for transportation. This application can process the well flushing return fluid online, add medicine to the unqualified return fluid, and make it into a qualified fluid through buffering, filtering, and sedimentation. The qualified fluid can be reinjected into the well for flushing again. Therefore, this application no longer requires tank trucks to transport the well flushing return fluid, saving transportation costs. At the same time, since this application no longer requires switching tank trucks, the risk of oil pollution on the ground is well avoided, and the environmental protection of this application is better.

Claims

1. An environmentally friendly special device for high-pressure well washing of oilfield injection wells, characterized in that: It includes a wellhead, a wellhead incoming water system, a chemical addition system for the wellhead backflow liquid, a filtration and sedimentation system, a reinjection system, and an external discharge system; The wellhead mentioned above includes a washing well liquid inlet port and a backflow liquid port; The wellhead incoming water system includes an incoming water pipeline (47) and a retrieved water jet pump (10). The incoming water pipeline (47) is connected to the washing well liquid inlet port of the wellhead, and the retrieved water jet pump (10) is connected in series in the incoming water pipeline (47); The chemical addition system for the wellhead backflow liquid includes a backflow liquid pipeline (52), a chemical addition jet pump (32), a chemical addition tank (30), and a chemical addition pipeline. One end of the backflow liquid pipeline (52) is connected to the backflow liquid port of the wellhead, the chemical addition jet pump (32) is connected in series in the backflow liquid pipeline (52), and the chemical addition pipeline connects the chemical addition tank (30) and the chemical addition jet pump (32); The filtration and sedimentation system includes a buffer tank, a filtration and sedimentation tank, and a sedimentation and recovery tank (38). The other end of the backflow liquid pipeline (52) is connected to the buffer tank, the liquid outlet of the buffer tank is connected to the inlet of the filtration and sedimentation tank, and the outlet of the filtration and sedimentation tank is connected to the sedimentation and recovery tank (38); The reinjection system includes a reinjection pipeline (51) and a return water valve (11). One end of the reinjection pipeline (51) is connected to the sedimentation and recovery tank (38), the other end of the reinjection pipeline (51) is connected to the retrieved water jet pump (10), and the return water valve (11) is connected in series in the reinjection pipeline (51); The external discharge system includes an external discharge pipeline (54), an external discharge piston pump (27), and a piston pump inlet valve (28). One end of the external discharge pipeline (54) is connected to the sedimentation and recovery tank (38), and the other end of the external discharge pipeline (54) is connected to the reinjection pipeline (51) upstream of the return water valve (11); 2. The special environmental protection device for high-pressure well washing of oilfield injection wells according to claim 1, wherein: The special environmental protection device for high-pressure washing of oilfield injection wells mentioned above also includes a PLC controller (46) with a human-machine interface; The wellhead incoming water system also includes an incoming water pressure sensor (02), an incoming water quality detection and alarm instrument (08), and an incoming water rotameter (09). The incoming water pressure sensor (02), the incoming water quality detection and alarm instrument (08), and the incoming water rotameter (09) are respectively electrically connected to the PLC controller (46); The chemical addition system for the wellhead backflow liquid also includes a backflow liquid temperature sensor (22), a backflow liquid pressure sensor (23), a backflow liquid rotameter (24), a backflow liquid quality detection and alarm instrument (25), and an electric valve for the outlet of the chemical addition tank (31). The backflow liquid temperature sensor (22), the backflow liquid pressure sensor (23), the backflow liquid rotameter (24), the backflow liquid quality detection and alarm instrument (25), and the electric valve for the outlet of the chemical addition tank (31) are respectively electrically connected to the PLC controller (46); The buffer tank is provided with a buffer tank pressure gauge (35); the filtration and sedimentation tank is provided with a sedimentation tank pressure gauge (40); the buffer tank pressure gauge (35) and the sedimentation tank pressure gauge (40) are respectively electrically connected to the PLC controller (46); The described reinjection system further includes a return water rotameter (13) and a return water quality verification alarm instrument (12). The return water valve (11) is an electric valve. The return water rotameter (13), the return water quality verification alarm instrument (12), and the return water valve (11) are respectively electrically connected to the PLC controller (46). The inlet valve (28) of the plunger pump is an electric valve, and the inlet valve (28) of the plunger pump is electrically connected to the PLC controller (46).

3. The special environmental protection device for high-pressure washing of oilfield injection wells according to claim 1, wherein: The described special device for high-pressure well washing and environmental protection of oilfield injection wells further includes a backwashing system. The backwashing system includes a backwashing pipeline (53) and a backwashing inlet electric valve (14). The filter sedimentation tank is provided with a backwashing inlet and a backwashing outlet. One end of the backwashing pipeline (53) is connected to the incoming water pipeline (47), the other end of the backwashing pipeline (53) is connected to the backwashing inlet of the filter sedimentation tank, and the backwashing outlet of the filter sedimentation tank is connected to the sedimentation recovery tank (38).

4. The special device for high-pressure well washing and environmental protection of an oilfield injection well according to claim 1, characterized in that: The inlet port of the wellhead for washing fluid includes a normal well washing inlet pipeline (49) and a reverse well washing inlet pipeline (48). The normal well washing inlet pipeline (49) and the reverse well washing inlet pipeline (48) are in parallel. Among them, an oil pipe water inlet electric valve (17) is connected in series on the normal well washing inlet pipeline (49), and a casing water inlet electric valve (16) is connected in series on the reverse well washing inlet pipeline (48). The outlet port of the wellhead for reverse fluid includes a normal well washing outlet pipeline (18) and a reverse well washing outlet pipeline (19). The normal well washing outlet pipeline (18) and the reverse well washing outlet pipeline (19) are in parallel. Among them, a casing water outlet electric valve (21) is connected in series on the normal well washing outlet pipeline (18), and an oil pipe water outlet electric valve (20) is connected in series on the reverse well washing outlet pipeline (19). The oil pipe water inlet electric valve (17), the casing water inlet electric valve (16), the casing water outlet electric valve (21), and the oil pipe water outlet electric valve (20) are respectively electrically connected to the PLC controller (46).

5. The environmental protection special device for high-pressure washing of oilfield injection wells according to claim 1, wherein: The special device for high-pressure well washing and environmental protection of an oilfield injection well further includes a turbo generator system. The turbo generator system includes a bypass pipeline (50), a turbo generator (06), a generator water inlet valve (05), and a generator water outlet valve (07). Both ends of the bypass pipeline (50) are connected to the incoming water pipeline (47). The turbo generator (06) is connected in series in the bypass pipeline (50). The generator water inlet valve (05) is connected in series in the bypass pipeline (50) upstream of the turbo generator (06). The generator water outlet valve (07) is connected in series in the bypass pipeline (50) downstream of the turbo generator (06). A turbo generator bypass valve (04) is installed on the incoming water pipeline (47) between both ends of the bypass pipeline (50). The current generated by the turbo generator (06) is connected to the external discharge plunger pump (27) and the PLC controller (46) through a wire.

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