A three-dimensional device and process for producing water treatment

Abstract

The present invention proposes a three-dimensional device for produced water treatment, including: a buffer water tank, an air flotation unit, a filter tank, an ultraviolet sterilizer, a purified water tank and a controller; the inlet of the buffer water tank is connected to a produced pipeline; the inlet of the air flotation unit is connected to the outlet of the buffer water tank, and an air flotation device and a chain scraper are arranged in the air flotation unit; the inlet of the filter tank is connected to the outlet of the air flotation unit, and a filter layer is arranged in the filter tank; the inlet of the ultraviolet sterilizer is connected to the outlet of the filter tank; the inlet of the purified water tank is connected to the outlet of the ultraviolet sterilizer, and the outlet of the purified water tank is connected to a reinjection pipeline; the signal input end of the controller is connected to a pressure difference detection device and a plurality of liquid level detection devices through a signal line, and the operation of the air flotation unit and the filter tank can be controlled according to the signals of the pressure difference detection device and the liquid level detection device. The present invention also proposes a produced water treatment process, which is implemented by the above-mentioned three-dimensional device for produced water treatment.

Description

Technical Field

[0001] The invention belongs to the field of surface construction engineering for oil field development, and in particular relates to a three-dimensional device and process for producing water treatment. Background Art

[0002] At present, most water-driven oil reservoirs have entered the middle and late stages of development. The water content of the oil fields is high and the degree of water drive control is low. With the annual transformation of the formation oil reservoirs and the continuous addition of demulsifiers, the properties of the produced water in the late stage of oil reservoir development are quite different from those of the early water drive produced water. The emulsified oil increases, gravity separation is difficult, and the amount of particles in the water is large, but the particle size is small and difficult to settle. At the same time, many oil reservoir development blocks are small, and the amount of produced water generated is also small. The construction cost of conventional produced water treatment systems is high, the cycle is long, the area occupied is large, and the degree of operation automation is low. Therefore, it is necessary to optimize the process of produced water treatment to reduce the area occupied and speed up the construction. Summary of the invention

[0003] In view of this, the present invention provides a three-dimensional produced water treatment device and process for overcoming the above-mentioned problems or at least partially solving or alleviating the above-mentioned problems.

[0004] A three-dimensional produced water treatment device, comprising:

[0005] A buffer water tank, the inlet of which is connected to a produced water pipeline for introducing produced water;

[0006] An air flotation unit, the inlet of which is connected to the outlet of the buffer water tank through a pipeline, and an air flotation device and a chain scraper are arranged in the air flotation unit;

[0007] A filter tank, the inlet of which is connected to the outlet of the air flotation unit through a pipeline, and a filter layer is arranged in the filter tank;

[0008] An ultraviolet sterilizer, the inlet of the ultraviolet sterilizer is connected to the outlet of the filter tank through a pipeline;

[0009] A purified water tank, the inlet of which is connected to the outlet of the ultraviolet sterilizer through a pipeline, and the outlet of the purified water tank is connected to a reinjection pipeline for reinjecting the water into the formation;

[0010] A controller, wherein a signal input end of the controller is connected to a pressure difference detection device and a plurality of liquid level detection devices through a signal line, the pressure difference detection device is arranged in the filter tank 3, and the liquid level detection device is arranged in the buffer water tank, the air flotation unit and the purified water tank, and the controller can control the operation of the air flotation unit and the filter tank according to the signals of the pressure difference detection device and the liquid level detection device.

[0011] The three-dimensional produced water treatment device of the present invention also has the following optional features.

[0012] Optionally, the flotation unit includes a first flotation lift pump and a first flotation tank; the inlet of the first flotation lift pump is connected to the outlet of the buffer water tank, the outlet of the first flotation lift pump is connected to the inlet of the first flotation tank, and the chain scraper is arranged in the upper port of the first flotation tank.

[0013] Optionally, a vortex aerator is further provided in the first air flotation tank of the first air flotation lift pump.

[0014] Optionally, the air flotation unit further includes a second air flotation lift pump and a second air flotation tank; the inlet of the second air flotation lift pump is connected to the outlet of the first air flotation tank, and the outlet of the second air flotation lift pump is connected to the inlet of the second air flotation tank.

[0015] Optionally, the flotation unit further comprises a nitrogen generator, which is connected to the second flotation tank via a pipeline, and a regulating valve, a nitrogen dissolving pump and a nitrogen dissolving tank are sequentially connected to the pipeline between the nitrogen generator and the second flotation tank.

[0016] Optionally, a backwash water tank is further included, the inlet of the backwash water tank is connected to the outlet of the ultraviolet sterilizer through a pipeline, the outlet of the backwash water tank is connected to the water outlet side of the filter layer in the filter tank through a pipeline, the inlet of the filter tank is also connected to a backwash bypass pipeline, and the backwash bypass pipeline is connected to the inlet pipeline of the flotation unit; the outlet pipeline of the backwash water tank is connected to a filter backwash pump.

[0017] Optionally, two filter pressure pumps are connected in parallel to the inlet pipeline of the filter tank.

[0018] Optionally, the buffer water tank, the purified water tank and the backwash water tank are respectively provided with an overflow port and a drain port, and the overflow port and the drain port are connected to an overflow drain pipeline.

[0019] Optionally, the buffer water tank, the air flotation unit, the filter tank and the purified water tank form a two-layer detachable skid-mounted structure, and the buffer water tank and the purified water tank are located above the air flotation unit and the filter tank.

[0020] The present invention also proposes a produced water treatment process, which is implemented using the above-mentioned three-dimensional produced water treatment device, and includes the following steps:

[0021] S001: Inject produced water into the buffer water tank;

[0022] S002: pumping produced water from the buffer water tank and injecting it into the first flotation tank to perform cavitation flotation and scraping of the produced water;

[0023] S003: pumping the produced water after scraping the slag in the first flotation tank into the second flotation tank for nitrogen injection flotation and scraping the slag;

[0024] S004: pumping the produced water after scraping in the second flotation tank to a filter tank for filtering;

[0025] S005: sterilize the filtered produced water through an ultraviolet sterilizer;

[0026] S006: Pass a portion of the sterilized produced water into a purified water tank for reinjection into the formation;

[0027] S007: Pass a portion of the sterilized produced water into the backwash water tank to backwash the filter tank.

[0028] The three-dimensional produced water treatment device and process of the present invention can flexibly separate, settle and sterilize small-size particles in a small amount of produced water in small-block oil wells, and can also realize automatic control of the main functions and even remote operation; the three-dimensional produced water treatment device of the invention is convenient for relocation, reuse and rapid installation, has a short design cycle and sputtering cycle, occupies a small area, can provide strong technical support for small-block oil reservoir development, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the system structure of the three-dimensional produced water treatment device of the present invention.

[0030] In the above figure, 1 is a buffer water tank; 101 is a production pipeline; 2 is a chain scraper; 3 is a filter tank; 301 is a filter layer; 302 is a backwash bypass pipeline; 4 is an ultraviolet sterilizer; 5 is a purified water tank; 501 is a reinjection pipeline; 6 is a backwash water tank; 7 is a first flotation tank; 8 is a vortex aerator; 9 is a second flotation tank; 10 is a first flotation lift pump; 11 is a second flotation lift pump; 12 is a nitrogen generator; 13 is a regulating valve; 14 is a nitrogen dissolved air pump; 15 is a nitrogen dissolved air tank; 16 is a filter backwash pump; 17 is a filter pressure pump; 18 is an overflow vent pipeline; 19 is a sewage pipeline. DETAILED DESCRIPTION

[0031] The present invention is further described below through a specific embodiment.

[0032] Example 1

[0033] refer to Figure 1The present invention proposes a three-dimensional device for producing water treatment, comprising: a buffer water tank 1, an air flotation unit, a filter tank 3, an ultraviolet sterilizer 4, a purified water tank 5 and a controller; the inlet of the buffer water tank 1 is connected with a produced pipeline 101 for introducing produced water; the inlet of the air flotation unit is connected with the outlet of the buffer water tank 1 through a pipeline, and the air flotation unit is provided with an air flotation device and a chain scraper 2; the inlet of the filter tank 3 is connected with the outlet of the air flotation unit through a pipeline, and the filter tank 3 is provided with a filter layer 301; the inlet of the ultraviolet sterilizer 4 is connected with the outlet of the filter tank 3 The outlet is connected by a pipeline; the inlet of the purified water tank 5 is connected to the outlet of the ultraviolet sterilizer 4 through a pipeline, and the outlet of the purified water tank 5 is connected to a reinjection pipeline 501 for reinjecting into the formation; the signal input end of the controller is connected to a pressure difference detection device and a plurality of liquid level detection devices through a signal line, the pressure difference detection device is arranged in the filter tank 3, and the liquid level detection device is arranged in the buffer water tank 1, the flotation unit and the purified water tank 5, and the controller can control the operation of the flotation unit and the filter tank 3 according to the signals of the pressure difference detection device and the liquid level detection device.

[0034] The produced water from the gathering and transportation system enters the buffer water tank 1, and after buffering adjustment and gravity sedimentation, enters the flotation unit to remove the scum and oil in the produced water, and then enters the filter tank 3 to filter out 3 / 4 of the suspended matter through the filter layer 301. The filter layer uses different levels of filter media to achieve the best filtering effect, and then passes through the ultraviolet sterilizer 5, which can effectively kill iron bacteria, sulfate-reducing bacteria, and saprophytic bacteria, and effectively prevent the generation of toxic and harmful gases such as hydrogen sulfide and the corrosion of downstream pipelines and facilities. After treatment, it enters the purified water tank 5 for storage and can be used for reinjection into the formation. The controller can be connected to the remote control system signal through the network signal, and the automatic control of the main function can be realized through the flow, pressure, liquid level monitoring, machine pump status display, and electric valve design of the key nodes in the process. At the same time, the real-time data status can be uploaded, and remote monitoring operation can be realized, and the device processing conditions can be mastered in detail.

[0035] Example 2

[0036] refer to Figure 1 On the basis of Example 1, the flotation unit includes a first flotation lift pump 10 and a first flotation tank 7; the inlet of the first flotation lift pump 10 is connected to the outlet of the buffer water tank 1, the outlet of the first flotation lift pump 10 is connected to the inlet of the first flotation tank 7, and the chain scraper 2 is arranged in the upper port of the first flotation tank 7.

[0037] The produced water in the buffer water tank 1 is pumped into the first flotation tank 7 by the first flotation lift pump 10. The scum and oil in the first flotation tank 7 are brought to the water surface along with the bubbles. The chain scraper 2 can scrape the scum and oil on the surface of the first flotation tank 7, and the scum and oil are finally passed into the sewage pipe. The bottom of the first flotation tank 7 is also connected to the sewage pipe, so that the sediment can be discharged. Among them, a high and low liquid level detection device is provided in the buffer water tank 1. The first flotation lift pump 10 is interlocked with the high and low liquid level detection device. When the high and low liquid level detection device detects that the liquid level in the buffer water tank 1 is high, the first flotation lift pump 10 starts to send the produced water in the buffer water tank 1 into the first flotation tank 7.

[0038] Example 3

[0039] refer to Figure 1 On the basis of Embodiment 2, a vortex aerator 8 is further provided in the first air flotation tank 7 of the first air flotation lift pump.

[0040] The vortex aerator 8 generates and cuts bubbles, and the steam drum rises to the water surface in the produced water in the first air flotation tank 7, bringing the scum and oil to the water surface, and the scum and oil are scraped out by the chain scraper 2 and discharged centrally.

[0041] Example 4

[0042] refer to Figure 1 On the basis of Example 2, the flotation unit further includes a second flotation lift pump 11 and a second flotation tank 9; the inlet of the second flotation lift pump 11 is connected to the outlet of the first flotation tank 7, and the outlet of the second flotation lift pump 11 is connected to the inlet of the second flotation tank 9.

[0043] After the produced water passes through the first flotation tank 7 and the chain scraper 2 therein to remove the scum and oil, it is then sent to the second flotation tank 9 by the second flotation lift pump 11 to further remove the scum and oil, and the scum and oil are finally passed into the sewage pipe 19. The bottom of the second flotation tank 9 is also connected to the sewage pipe 19, so that the sediment can be discharged. Among them, a high and low liquid level detection device is provided in the first flotation tank 7, and the high and low liquid level detection device is interlocked with the second flotation lift pump 11. When the high and low liquid level detection device detects that the liquid level in the first flotation tank 7 is high, the second flotation lift pump 11 passes the produced water into the second flotation tank 9.

[0044] Example 5

[0045] refer to Figure 1 On the basis of Example 3, the flotation unit further includes a nitrogen generator 12, which is connected to the second flotation tank 9 through a pipeline, and a regulating valve 13, a nitrogen dissolving pump 14 and a nitrogen dissolving tank 15 are sequentially connected to the pipeline between the nitrogen generator 12 and the second flotation tank 9.

[0046] The nitrogen produced by the nitrogen generator 12 is pressure-regulated by the regulating valve 13, and then mixed with the produced water through the nitrogen dissolving pump 14 and the nitrogen dissolving tank 15, and then enters the secondary flotation tank 9, bringing the scum and oil in the secondary flotation tank 9 to the surface of the water, and then is removed by the chain scraper 2. Since the scraping and bottom sewage discharge of the second flotation tank 9 are gravity sewage discharge, there may be blockage, and the compressed gas generated by the nitrogen generator 12 and the pressure regulating valve 13 can be used to purge the lower section of the sewage pipeline to reduce the blockage.

[0047] Example 6

[0048] refer to Figure 1 On the basis of Example 1, it further includes a backwash water tank 6, the inlet of the backwash water tank 6 is connected to the outlet of the ultraviolet sterilizer 4 through a pipeline, the outlet of the backwash water tank 6 is connected to the water outlet side of the filter layer 301 in the filter tank 3 through a pipeline, the inlet of the filter tank 3 is also connected to a backwash bypass pipeline 302, and the backwash bypass pipeline 302 is connected to the inlet pipeline of the flotation unit; the outlet pipeline of the backwash water tank 6 is connected to a filter backwash pump 16.

[0049] A portion of the produced water after filtration and disinfection by the filter tank 3 and the ultraviolet sterilizer 4 is passed into the backwash water tank 6. When it is necessary to backwash the filter layer 301 in the filter tank 3, the produced liquid can be extracted from the backwash water tank 6 and pressurized by the filter backwash pump 16, so that the pressurized produced liquid flows back into the filter tank 3 from the outlet pipe of the backwash water tank 6 to backwash the filter layer 301 in the filter tank 3. The produced water after flushing flows into the inlet pipe of the flotation unit through the backwash bypass pipe 302 for flotation treatment. Among them, a pressure difference detection device is provided in the filter tank 3, and a liquid level detection device is provided in the backwash water tank 6. When the pressure difference between the front and rear sides of the filter layer 301 of the filter tank 3 is greater than the set value, and the liquid level of the backwash water tank 6 reaches the limit value, the filter backwash pump 16 automatically starts to backwash the filter layer 301 in the filter tank 3. The filter backwash pump 16 can also be set to start at a time to achieve timed backwashing.

[0050] Example 7

[0051] refer to Figure 1 On the basis of Example 1, two filter pressure pumps 17 are connected in parallel to the inlet pipeline of the filter tank 3.

[0052] The filter pressure pump 17 pressurizes the produced liquid so that the produced liquid can pass through the filter layer 301 in the filter tank 3. The purified water tank 5 is provided with a liquid level detection device. When the liquid level detection device detects that the liquid level in the purified water tank 5 rises to a preset height, a high liquid level alarm is issued and the filter pressure pump 17 is shut down.

[0053] Example 8

[0054] refer to Figure 1 On the basis of Example 1, the buffer water tank 6, the purified water tank 5 and the backwash water tank 6 are respectively provided with overflow ports and drain ports, and the overflow ports and drain ports are connected with overflow drain pipelines 18.

[0055] The overflow hole is located near the upper end of the buffer water tank 6, the purified water tank 7 and the backwash water tank 6, and the drain port is located near the bottom plate. The overflow hole and the drain port are respectively connected to the overflow drain pipeline 18. When necessary, the excess produced liquid can be discharged in a centralized manner. When maintaining the system, the accumulated produced liquid can also be discharged in a centralized manner.

[0056] Example 9

[0057] refer to Figure 1 On the basis of Example 1, the buffer water tank 1, the air flotation unit, the filter tank 3 and the purified water tank 5 form a two-layer detachable skid-mounted structure, and the buffer water tank 1 and the purified water tank 5 are located above the air flotation unit, the filter tank 3 and the controller.

[0058] The buffer water tank 1 and the purified water tank 5 are vibration-free water storage units and are arranged on the second layer. The flotation unit, the filter tank 3, the flotation unit, etc. are vibrating and are arranged on the first layer, which can reduce the vibration amplitude of the overall structure. Moreover, the upper and lower steel structures are detachable, which is convenient for lifting, relocation and transportation.

[0059] Example 10

[0060] The present invention proposes a produced water treatment process, which is implemented by adopting the three-dimensional produced water treatment device, and includes the following steps: S001: injecting produced water into a buffer water tank; S002: pumping produced water from the buffer water tank and injecting it into a first flotation tank to perform vortex flotation and scraping of the produced water; S003: pumping the produced water after scraping in the first flotation tank into a second flotation tank to perform nitrogen injection flotation and scraping of the produced water; S004: pumping the produced water after scraping in the second flotation tank into a filter tank for filtering; S005: sterilizing the filtered produced water through an ultraviolet sterilizer; S006: passing a part of the sterilized produced water into a purification water tank for reinjection into the formation; S007: passing a part of the sterilized produced water into a backwash water tank to backwash the filter tank.

[0061] During the normal operation of this process, the produced water from the gathering and transportation system enters the buffer water tank 1, where the produced water is buffered, regulated and gravity-precipitated; the produced water enters the first air flotation tank 7, where it is cut by the vortex air flotation aerator 8 to generate bubbles, which drive the floating oil and finely dispersed oil to rise to the water surface and are scraped off by the chain scraper 2; the produced water then enters the secondary air flotation tank 9, where the nitrogen generator 12 passes nitrogen into the secondary air flotation tank 9 through the regulating valve 13, the nitrogen dissolving pump 12 and the nitrogen dissolving tank 15, where the nitrogen bubbles bring the floating scum and floating oil therein to the water surface, and then the floating scum and floating oil are scraped off by the chain scraper 2; the secondary The produced water in the flotation tank 9 enters the filter tank 3 and passes through the two-stage multi-media filter layer 301 to remove suspended matter. The various filter media inside are combined with different gradations to achieve the optimal filtering effect; the filtered produced water enters the pipeline ultraviolet sterilizer 4 to kill iron bacteria, sulfate-reducing bacteria, and saprophytic bacteria, prevent the generation of toxic and harmful gases such as hydrogen sulfide and the corrosion of downstream pipelines and facilities; a part of the produced water after sterilization enters the purified water tank 5 and is finally injected back into the bottom layer; the other part of the produced water after sterilization enters the backwash water tank 6, and the filter layer 301 in the filter tank 3 can be backwashed when necessary.

[0062] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A three-dimensional device for producing water treatment, characterized in that: include: A buffer water tank (1), the inlet of the buffer water tank (1) being connected to a production pipeline (101) for introducing produced water; an air flotation unit, the inlet of the air flotation unit being connected to the outlet of the buffer water tank (1) via a pipeline, the air flotation unit being provided with an air flotation device and a chain scraper (2); a filter tank (3), the inlet of the filter tank (3) being connected to the outlet of the air flotation unit via a pipeline, the filter tank (3) being provided with a filter layer (301); an ultraviolet sterilizer (4), the inlet of the ultraviolet sterilizer (4) being connected to the outlet of the filter tank (3); a purified water tank (5), the inlet of the purified water tank (5) being connected to the outlet of the ultraviolet sterilizer (4) through a pipeline, the outlet of the purified water tank (5) being connected to a reinjection pipeline (501) for reinjecting into the formation; a controller, the signal input end of the controller being connected to a pressure difference detection device and a plurality of liquid level detection devices through a signal line, the pressure difference detection device being arranged in the filter tank (3), the liquid level detection device being arranged in the buffer water tank (1), the air flotation unit and the purified water tank (5), the controller being able to detect the pressure difference according to the pressure difference detection device and the plurality of liquid level detection devices The signal of the liquid level detection device controls the operation of the flotation unit and the filter tank (3); the flotation unit comprises a first flotation lift pump (10) and a first flotation tank (7); the inlet of the first flotation lift pump (10) is connected to the outlet of the buffer water tank (1), the outlet of the first flotation lift pump (10) is connected to the inlet of the first flotation tank (7), and the chain scraper (2) is arranged in the upper port of the first flotation tank (7); the flotation unit also comprises a second flotation lift pump (11) and a second flotation tank (9); the second flotation lift pump ( The inlet of the second air flotation tank (11) is connected to the outlet of the first air flotation tank (7), the outlet of the second air flotation lift pump (11) is connected to the inlet of the second air flotation tank (9), and the chain scraper (2) is arranged in the upper port of the second air flotation tank (9); the air flotation unit also includes a nitrogen generator (12), the nitrogen generator (12) is connected to the second air flotation tank (9) through a pipeline, and the pipeline between the nitrogen generator (12) and the second air flotation tank (9) is connected in sequence with a regulating valve (13), a nitrogen dissolving pump (14) and a nitrogen dissolving tank (15).

2. The three-dimensional produced water treatment device according to claim 1, characterized in that: A vortex aerator (8) is also provided in the first air flotation tank (7).

3. The three-dimensional produced water treatment device according to claim 1, characterized in that: It also comprises a backwash water tank (6), the inlet of the backwash water tank (6) being connected to the outlet of the ultraviolet sterilizer (4) via a pipeline, the outlet of the backwash water tank (6) being connected to the water outlet side of the filter layer (301) in the filter tank (3) via a pipeline, the inlet of the filter tank (3) being further connected to a backwash bypass pipeline (302), the backwash bypass pipeline (302) being connected to the inlet pipeline of the air flotation unit; and a filter backwash pump (16) being connected to the pipeline at the outlet of the backwash water tank (6).

4. The three-dimensional produced water treatment device according to claim 1, characterized in that: Two filter pressure pumps (17) are connected in parallel to the inlet pipeline of the filter tank (3).

5. The three-dimensional produced water treatment device according to claim 3, characterized in that: The buffer water tank (1), the purified water tank (5) and the backwash water tank (6) are respectively provided with an overflow port and a drain port, and the overflow port and the drain port are connected to an overflow drain pipeline (18).

6. The three-dimensional produced water treatment device according to any one of claims 1 to 5, characterized in that: The buffer water tank (1), the air flotation unit, the filter tank (3) and the purified water tank (5) form a two-layer detachable skid-mounted structure, and the buffer water tank (1) and the purified water tank (5) are located above the air flotation unit and the filter tank (3).

7. A produced water treatment process, implemented using the produced water treatment three-dimensional device according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: S001: injecting produced water into a buffer water tank; S002: pumping produced water from the buffer water tank and injecting it into a first flotation tank to perform vortex flotation and scraping of the produced water; S003: pumping the scraped produced water in the first flotation tank into a second flotation tank to perform nitrogen injection flotation and scraping of the produced water; S004: pumping the scraped produced water in the second flotation tank into a filter tank for filtering; S005: sterilizing the filtered produced water through an ultraviolet sterilizer; S006: passing a portion of the sterilized produced water into a purification water tank for reinjection into the formation; S007: passing a portion of the sterilized produced water into a backwash water tank to backwash the filter tank at regular intervals.

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