Integrated equipment for in-situ treatment of oilfield produced water and working method of integrated equipment

Abstract

The invention relates to integrated equipment for in-situ treatment of oilfield produced water and a working method of the integrated equipment. A micro-nano bubble technology is used for replacing a traditional multi-stage flocculation air flotation process, so that the removal rate of suspended solids is increased; walnut peel filtration is replaced by silicon carbide ultrafiltration / microfiltration to ensure the removal efficiency of residual oil and tiny suspended matters, and furthermore, accurate addition of ozone is realized by adopting a micro-nano ozone bubble technology, so that the energy consumption is reduced, and effective removal and disinfection of sulfides, bacteria and microorganisms can be ensured. The modular design concept is adopted, and the technologies are integrated into a whole, so that the effect of saving the occupied area is achieved. According to the integrated equipment, it can be guaranteed that in-situ treatment of oilfield reinjection water reaches the standard of in-situ reinjection water, meanwhile, the whole process from produced liquid inflow to reinjection water utilization can be achieved in one piece of equipment, extra water does not need to be introduced into the whole equipment system, and the integrated equipment has the advantages that resources are saved, and energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to integrated equipment for in-situ treatment of oilfield produced water and a working method thereof, belonging to the technical field of novel environmental protection equipment. Background Art

[0002] In-situ reinjection of oilfield produced water is an environmentally friendly and cost-effective measure. It involves treating produced water from oilfields and reinjecting it into underground reservoirs to assist in oil production operations. Using produced water as reinjection water not only helps conserve water resources but also improves overall oil recovery. However, when the quality management of produced water fails to meet reinjection requirements, the precipitation of suspended solids and other particulate matter during the reinjection process can reduce the porosity of the oil layer, thereby reducing the permeability of the reservoir, affecting subsequent production efficiency and even leading to production accidents. Furthermore, residual oil, harmful substances such as sulfides, bacteria, and microorganisms can also seep into the groundwater during the reinjection operation, potentially causing groundwater pollution. To prevent the occurrence of these accidents or incidents, the petrochemical industry has established strict standards for the water quality of reinjection water used as a source of produced water.

[0003] Currently, produced water is typically treated to meet reinjection standards using a combination of gravity settling, multi-stage flocculation flotation, walnut peel filtration, and advanced treatment. However, gravity settling is time-consuming and requires extensive equipment space. Multi-stage flocculation flotation not only uses large amounts of chemicals, resulting in increased costs, but also consumes high amounts of energy, significantly increasing treatment costs. Long-term continuous operation can cause walnut peel filler clogging, severely impacting the removal efficiency of residual oil in the water and making advanced treatment more difficult. Furthermore, these combined processes have poor shock resistance, making it difficult to guarantee water quality standards if the produced fluid experiences significant fluctuations in quality (such as increased oil content or suspended solids). Furthermore, because each stage of these traditional combined processes is independent, the equipment is poorly integrated, occupies a large area, is costly to construct, and is complex and labor-intensive. These factors significantly hinder the cost-effective and efficient implementation of in-situ produced water reinjection in oilfields. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, especially the traditional combined process, each process section of which exists independently, has the defects of low equipment integration, large floor space, high construction cost, complex operation, high labor intensity, etc. The present invention provides an integrated equipment for in-situ regeneration and reinjection of drilling reinjection water. Micro-nano bubble technology replaces the traditional multi-stage flocculation flotation process to improve the removal rate of suspended matter; silicon carbide ultrafiltration / microfiltration is used to replace walnut shell filtration to ensure the removal efficiency of residual oil and tiny suspended matter, and micro-nano ozone bubble technology is further used to achieve precise addition of ozone, which not only reduces high energy consumption, but also ensures the effective removal and disinfection of sulfides, bacteria and microorganisms. The modular design concept is adopted to integrate the above technologies into one, thereby saving floor space. The integrated equipment of the present invention can not only ensure that the on-site treatment of oilfield reinjection water meets the standards of in-situ reinjection water, but also realize the whole process from produced fluid intake to reinjection water utilization in one equipment. The entire equipment system does not need to introduce additional water, which has the advantages of saving resources and reducing energy consumption.

[0005] The technical solutions of the present invention are as follows:

[0006] An integrated equipment for in-situ treatment of oilfield produced water, comprising: a micro-nano bubble separation module, a solid-liquid separation module, and a fine treatment and reinjection module;

[0007] The micro-nano bubble separation module includes a blower, a dissolved air tank, a mixer, a dissolved air releaser, a flotation tank body and a dosing system connected in sequence. The flotation tank body is provided with a scraper, a slag collecting tank and a screw pump connected in sequence. The screw pump is also connected to the inclined plate oil storage tank. The mixer is also connected to a first high-pressure pump. The bottom of the flotation tank body is provided with a first water outlet.

[0008] The solid-liquid separation module includes a reaction tank body, the reaction tank body is provided with a multi-pipe silicon carbide membrane interface, a low-position water outlet trough and a second water outlet, and the first water outlet is connected to the reaction tank body;

[0009] The fine treatment and reinjection module includes an ozone catalytic tank, an ozone generator, a gas-liquid mixer, and a buffer tank. A fourth lift pump and a second high-pressure pump are provided in the ozone catalytic tank. The fourth lift pump is connected to the buffer tank through a third check valve. The buffer tank is connected to the gas-liquid mixer. The ozone catalytic tank is connected to the ozone generator through the second check valve. The ozone generator is connected to the gas-liquid mixer through the first check valve. The gas-liquid mixer is connected to the reaction tank body through a backwash pump. The second water outlet is connected to the ozone catalytic tank.

[0010] According to the present invention, preferably, the dosing system includes a drug storage tank provided with a stirrer, and the drug storage tank is connected to the flotation tank body via a dosing pump.

[0011] According to the present invention, preferably, the flotation tank body is further provided with a micro-oxygen nano bubble generator and a first lifting pump, and the flotation tank body is connected to the mixer via the first lifting pump.

[0012] According to the present invention, preferably, the inclined plate oil storage tank is provided with 2-3 layers of inclined plates from top to bottom, and the dense width of the inclined plates decreases successively from top to bottom; further preferably, the inclined plate oil storage tank is also provided with a liquid level controller and a second lifting pump, and the inclined plate oil storage tank is connected to the mixer through the second lifting pump.

[0013] According to the present invention, preferably, a third lifting pump is further provided at the bottom of the reaction tank body, and the reaction tank body is connected to the mixer via the third lifting pump.

[0014] According to the present invention, preferably, the ozone catalytic tank is further connected to the mixer via a fourth lift pump; further preferably, a mechanical stirrer is further provided in the ozone catalytic tank.

[0015] According to the present invention, preferably, the high-pressure pipeline used by the second high-pressure pump is made of stainless steel or nickel-based alloy.

[0016] According to the present invention, preferably, the aeration device provided in the ozone catalytic tank is further preferably an OHR AERATOR aerator.

[0017] According to the present invention, preferably, the mixer and / or the gas-liquid mixer is an OHR MIXER aeration device.

[0018] According to the present invention, preferably, the pool wall of the ozone catalytic pool is provided with a silicon carbide plate membrane loaded with an MMA-LDH coating.

[0019] According to the present invention, preferably, the pipes and valves for transporting ozone connected to the ozone generator are made of 316 or 316L stainless steel.

[0020] According to the present invention, preferably, the integrated equipment for in-situ treatment of oilfield produced water also includes: an intelligent control system module, the intelligent control system module includes a monitoring instrument group, a control instrument group, a PLC control module and a human-machine interface (HMI); the intelligent control system module is respectively connected to the micro-nano bubble separation module, the solid-liquid separation module, and the fine treatment and reinjection module.

[0021] According to the present invention, the PLC control module can transmit operating data to a host computer (such as a SCADA system) to further implement intelligent control. Specifically, the monitoring instrument group monitors water quality indicators and the equipment operating environment during normal operation. Various monitoring indicators include, but are not limited to, various wastewater indicators (such as COD, pH, SS concentration, H2S, oil content, and bacterial count). Various operating environment monitoring includes, but is not limited to, pressure, temperature, density, and pipeline corrosion. The control instrument group regulates operations during normal operation, including, but not limited to, wastewater flow, ventilation volume, pump operation, dosage, and the start and stop of various valves. The monitoring instrument group collects and aggregates monitoring data into the PLC control module, which then executes the set parameters. When the PLC is integrated with the host computer, it performs optimization based on the collected data, and the PLC control module then sets control parameters to achieve intelligent operation of the equipment.

[0022] According to the present invention, the working method of the above-mentioned integrated equipment for in-situ regeneration and reinjection of drilling reinjection water includes the following steps:

[0023] Drilling oil sludge wastewater is supplied with air by a fan through a pipeline and pressed into a dissolved air tank. Under the high pressure of the first high-pressure pump, air and wastewater are fully mixed in the mixer. The pressure is then released by the dissolved air releaser, and the wastewater flows into the flotation tank. During this process, the dosing system adds the required chemicals, the agitator evenly stirs the chemicals in the storage tank, and the dosing pump lifts them into the flotation tank. The tiny bubbles generated by the micro-oxygen nano-bubble generator combine with suspended matter and grease in the water to form scum that floats to the water surface. The scum is cleaned by a scraper, stored in a slag trough, and then pumped to the inclined plate oil storage tank by a screw pump.

[0024] The inclined plate oil storage tank is equipped with 2-3 layers of inclined plates to separate the collected scum into three layers: floating oil, water, heavy oil and mud. The inclined plate oil storage tank is equipped with a liquid level controller, and preferably a water outlet is set at the second layer of the inclined plate of the inclined plate oil storage tank and equipped with a second lifting pump to return the treated water to the mixer for recycling. A first water outlet is also provided in the clarification area at the bottom of the flotation tank, from which the treated wastewater flows into the solid-liquid separation module. Part of the treated water is returned to the mixer for recycling through the first lifting pump to enhance the treatment effect.

[0025] After passing through the micro-nano bubble separation module, it enters the solid-liquid separation module, where suspended solids are separated through filtration at the multi-channel silicon carbide membrane interface. The water discharged from the low-level water outlet trough and the outlet in the reaction tank enters the fine treatment and reinjection module for sterilization. During the backwash process, the ozone generator is equipped with a pipeline and a first check valve to control the ozone to be sent into the gas-liquid mixer, and the sewage is sent into the buffer tank through the third check valve and the fourth lift pump, and then enters the gas-liquid mixer. After the ozone is mixed with water, the backwash pump controls the backwashing of the multi-channel silicon carbide membrane interface in the solid-liquid separation module. The backwash water generated during the backwash process contains some oil sludge residue, which is returned to the mixer by the second lift pump after filtration at the multi-pipeline silicon carbide membrane interface.

[0026] After flotation oil removal and silicon carbide membrane to remove suspended particles, it enters the fine treatment and reinjection module mainly for SBR bacteria elimination. The sewage enters the ozone catalytic pool. The ozone generator provides ozone and is controlled by the second check valve to be connected to the ozone catalytic pool through a pipeline. The drilling oilfield water is mostly alkaline, which is conducive to ozone sterilization. The fourth lifting pump returns part of the drilling oilfield water after treatment in the ozone catalytic pool to the mixer for recycling, and part is controlled by the third check valve and lifted by the fourth lifting pump into the gas-liquid mixer for backwashing water. The other part flows to the injection well system under the action of the second high-pressure pump to complete the reinjection.

[0027] This creates an integrated, self-circulating system that is completely self-sufficient and requires no external water supply. This system not only enables internal recycling of water resources, but also ensures that water quality meets recycling standards through multi-level module purification, allowing for long-term stable operation without relying on external water supply.

[0028] According to the present invention, preferably, the amount of sewage entering the system during the entire operation process is preferably 125-150%Q, of which 25-50%Q is preferably returned to the mixer through the first lift pump and the second lift pump for recycling of this module, and further preferably, 130%Q of sewage enters the system, 30%Q is recycled in this module, and Q amount of sewage enters the next treatment module.

[0029] According to the present invention, preferably, during normal operation, the ozone generator is connected to the micro-nano bubble separation module, which is finely controlled by an electric gas flowmeter, and a very small amount of ozone is introduced for micro-aeration to further optimize the water quality; during normal operation, the first check valve provided on the connecting pipe between the ozone generator and the gas-liquid mixer is closed, and opened during backwashing, and the time ratio of normal operation to backwashing process is 8 / 2min; during normal operation, the second check valve connecting the ozone generator and the ozone catalytic tank is normally open, and closed during backwashing, and the time ratio of normal operation to backwashing process is 8 / 2min; during normal operation, the third check valve connecting the ozone catalytic tank and the gas-liquid mixer and the backwash pump are closed, and opened for operation during backwashing, and the time ratio of normal operation to backwashing process is 8 / 2min.

[0030] The integrated equipment for in-situ regeneration and reinjection of drilling reinjection water of the present invention has the characteristics of integrated self-circulation and regeneration and reinjection. Its integrated self-circulation characteristics are reflected in the self-circulation of water resources and the absence of external water supply; the regeneration and reinjection is reflected in the treatment of drilling oilfield water through three modules respectively to meet the national standards for reinjection.

[0031] Specifically, the integrated self-circulation feature is reflected in the following aspects: First, the sludge in the inclined plate oil storage tank in the water-oil separation module is separated from water and oil again, and the water layer is returned to the mixer to continue to participate in the system operation to achieve self-circulation. The mechanism is that there is a density difference between the sludge and the liquid and stratification will occur. The inclined plates with decreasing width density are used to separate them into three layers, namely the floating oil layer, the water layer, the heavy oil and the mud layer. Therefore, the water layer can flow back to achieve the recycling of internal water resources. Second, the sewage in the sterilization module mainly for SBR bacteria removal is sent to the gas-liquid mixer through the backwash pump to backwash the multi-pipe silicon carbide membrane interface in the suspended solids separation module, further reducing the dependence on external water supply, thereby achieving integrated self-circulation without external water supply.

[0032] Specifically, the regeneration and reinjection characteristics are reflected in the oil removal process of flotation and the recovery of floating oil, the removal of suspended solid particles through the multi-channel silicon carbide membrane interface, and the sterilization treatment in the contact reaction tank through the ozone generator, so as to achieve the three-removal treatment of oil, slag and bacteria for the drilling oilfield water, so that it is sufficient to meet the national standards for in-situ reinjection.

[0033] The entire system integrates multiple levels of functions such as advanced sewage treatment modules, ozone disinfection and oxidation units, sludge treatment and resource recovery, microfiltration and ultrafiltration systems, reverse osmosis and nanofiltration technologies, intelligent monitoring and automatic control, to build an integrated equipment self-circulating system that does not require external water supply and is completely self-sufficient, realizing an efficient, stable and sustainable water treatment solution.

[0034] Beneficial effects of the present invention:

[0035] The integrated in-situ regeneration and reinjection equipment of the present invention has a high efficiency and energy-saving effect on removing pollutants from drilling sludge water and recovering floating oil. It has the characteristics of simple structure, small footprint, resource recycling and utilization, and easy control. Its unique integrated setting can greatly improve the utilization rate of water resources and reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the main structure of the integrated equipment for in-situ treatment of oilfield produced water according to the present invention;

[0037] Among them: 1. Fan; 2. Dissolved air tank; 3. Mixer; 4. First high-pressure pump; 5. Dissolved air releaser; 6. Dosing system; 7. Flotation tank; 8. Micro-oxygen nano bubble generator; 9. First lifting pump; 10. Slag scraper; 11. Slag collecting tank; 12. Screw pump; 13. Inclined plate oil storage tank; 14. Second lifting pump; 15. Liquid level controller; 16. First water outlet; 17. Dosing pump; 18. Agitator; 19. Drug storage Tank; 20. Reaction tank body; 21. Multi-channel silicon carbide membrane interface; 22. Low-level water outlet trough; 23. Second water outlet; 24. First check valve; 25. Gas-liquid mixer; 26. Third lift pump; 27. Ozone catalytic tank; 28. Ozone generator; 29. Mechanical agitator; 30. Second check valve; 31. Fourth lift pump; 32. Buffer tank; 33. Backwash pump; 34. Third check valve; 35. Second high-pressure pump. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to specific embodiments and accompanying drawings, but is not limited to these descriptions.

[0039] Example 1

[0040] like Figure 1 As shown, an integrated equipment for in-situ treatment of oilfield produced water includes: a micro-nano bubble separation module, a solid-liquid separation module, and a fine treatment and reinjection module;

[0041] The micro-nano bubble separation module includes a blower 1, a dissolved air tank 2, a mixer 3, a dissolved air releaser 5, a flotation tank 7 and a dosing system 6 connected in sequence. The flotation tank 7 is provided with a scraper 10, a slag collecting tank 11 and a screw pump 12 connected in sequence. The screw pump 12 is also connected to a sloping plate oil storage tank 13. The mixer 3 is also connected to a first high-pressure pump 4. The bottom of the flotation tank 7 is provided with a first water outlet 16;

[0042] The solid-liquid separation module includes a reaction tank body 20, which is provided with a multi-channel silicon carbide membrane interface 21, a low-position water outlet 22 and a second water outlet 23, and the first water outlet 16 is connected to the reaction tank body 20;

[0043] The fine treatment and reinjection module includes an ozone catalytic pool 27, an ozone generator 28, a gas-liquid mixer 25, and a buffer tank 32. A fourth lift pump 31 and a second high-pressure pump 35 are provided in the ozone catalytic pool 27. The fourth lift pump 31 is connected to the buffer tank 32 through a third check valve 34. The buffer tank 32 is connected to the gas-liquid mixer 25. The ozone catalytic pool 27 is connected to the ozone generator 28 through a second check valve 30. The ozone generator 28 is connected to the gas-liquid mixer 25 through a first check valve 24. The gas-liquid mixer 25 is connected to the reaction pool body 20 through a backwash pump 33. The second water outlet 23 is connected to the ozone catalytic pool 27.

[0044] In this embodiment, the dosing system 6 includes a drug storage tank 19 equipped with an agitator 18. The drug storage tank 19 is connected to the flotation tank 7 via a dosing pump 17. The high-pressure piping used by the second high-pressure pump 35 is made of stainless steel. The walls of the ozone catalytic tank 27 are equipped with a silicon carbide membrane coated with MMA-LDH. The ozone transport pipes and valves connected to the ozone generator 28 are made of 316L stainless steel.

[0045] The flotation tank 7 of this embodiment is provided with two layers of partitions. The inclined plate oil storage tank 13 is a truncated cone-cylinder combination structure made of stainless steel, and has three layers of densely packed inclined plates of the same width evenly distributed along the tank length.

[0046] Example 2

[0047] As shown in Example 1, the difference is:

[0048] The flotation tank body 7 is further provided with a micro-oxygen nano bubble generator 8 and a first lifting pump 9 , and the flotation tank body 7 is connected to the mixer 3 via the first lifting pump 9 .

[0049] The inclined plate oil storage tank 13 is a frustum structure, in which three layers of inclined plates are provided, which should be of different density widths, and the density from top to bottom is from small to large.

[0050] Example 3

[0051] As shown in Example 2, the difference is:

[0052] The inclined plate oil storage tank 13 is further provided with a liquid level controller 15 and a second lifting pump 14 , and the inclined plate oil storage tank 13 is connected to the mixer 3 via the second lifting pump 14 .

[0053] Example 4

[0054] As shown in Example 3, the difference is:

[0055] A third lifting pump 26 is further provided at the bottom of the reaction tank body 20 , and the reaction tank body 20 is connected to the mixer 3 via the third lifting pump 26 .

[0056] Example 5

[0057] As shown in Example 4, the difference is:

[0058] The ozone catalytic tank 27 is also connected to the mixer 3 via a fourth lift pump 31 , and a mechanical stirrer 29 is also provided in the ozone catalytic tank 27 .

[0059] Example 6

[0060] As shown in Example 5, the difference is:

[0061] The aeration device provided in the ozone catalytic tank 27 is an OHR AERATOR aerator.

[0062] The mixer 3 and the gas-liquid mixer 25 are OHR MIXER aeration devices.

[0063] Example 7

[0064] As shown in Example 6, the difference is:

[0065] The integrated equipment for in-situ treatment of oilfield produced water also includes: an intelligent control system module, which includes a monitoring instrument group, a control instrument group, a PLC control module and a human-machine interface (HMI); the intelligent control system module is respectively connected to the micro-nano bubble separation module, the solid-liquid separation module, and the fine treatment and reinjection module.

[0066] Example 8

[0067] The working method of the integrated equipment for in-situ regeneration and reinjection of drilling reinjection water described in Example 7 includes the following steps:

[0068] Drilling oil sludge wastewater is supplied with air by a fan 1 through a pipeline and pressed into a dissolved air tank 2. Under the high pressure of a first high-pressure pump 4, the air and wastewater are fully mixed in a mixer 3. The pressure is then released by a dissolved air releaser 5, and the wastewater flows into a flotation tank 7. During this process, a dosing system 6 adds the required chemicals, an agitator 18 evenly stirs the chemicals in a storage tank 19, and then a dosing pump 17 delivers them to the flotation tank 7. Furthermore, tiny bubbles generated by a micro-oxygen nano-bubble generator 8 combine with suspended matter and grease in the water to form scum that floats to the water surface. The scum is then cleaned by a scraper 10, stored in a slag trough 11, and delivered to a swash plate oil storage tank 13 by a screw pump 12.

[0069] The inclined plate oil storage tank 13 is provided with three layers of inclined plates to separate the collected scum into floating oil, water, heavy oil and mud. A liquid level controller 15 is provided in the inclined plate oil storage tank 13, and a second lift pump 14 is preferably provided at the second layer of the inclined plate of the inclined plate oil storage tank 13 to return the treated water to the mixer 3 for recycling. A first water outlet 16 is also provided in the clarification area at the bottom of the flotation tank 7, through which the treated wastewater flows into the solid-liquid separation module. Part of the treated water is returned to the mixer 3 for recycling via the first lift pump 9 to enhance the treatment effect.

[0070] After passing through the micro-nano bubble separation module, it enters the solid-liquid separation module, where it is filtered through the multi-channel silicon carbide membrane interface 21 to separate the suspended solids. The water discharged from the low-level water outlet 22 and the water outlet 23 in the reaction tank body 20 enters the fine treatment and reinjection module for sterilization. During the backwash process, the ozone generator 28 is controlled by the first check valve 24 to send ozone into the gas-liquid mixer 25, and the sewage is sent to the buffer tank 32 through the third check valve 34 and the fourth lift pump 31, and then enters the gas-liquid mixer 25. After the ozone is mixed with water, it is controlled by the backwash pump 33 to backwash the multi-channel silicon carbide membrane interface 21 in the solid-liquid separation module. The backwash water generated during the backwash process contains some oil sludge and residue, which is filtered through the multi-channel silicon carbide membrane interface 21 and returned to the mixer 3 by the second lift pump 26.

[0071] After flotation oil removal and silicon carbide membrane removal of suspended particles, the wastewater enters the fine treatment and reinjection module mainly for SBR bacteria elimination, and enters the ozone catalytic tank 27. The ozone generator 28 provides ozone, which is controlled by the second check valve 30 and sent into the ozone catalytic tank 27. This drilling oilfield water is mostly alkaline, which is conducive to ozone sterilization; the fourth lifting pump 31 returns part of the drilling oilfield water after treatment in the ozone catalytic tank 27 to the mixer 3 for recycling, and part is controlled by the third check valve 34 and lifted by the fourth lifting pump 31 into the buffer tank 32, and then enters the gas-liquid mixer 25 for backwashing water. The other part flows to the injection well system under the action of the second high-pressure pump 35 to complete the reinjection.

[0072] In this embodiment, the amount of sewage entering the system is 150%Q, of which 50%Q is returned to the mixer 3 through the first lift pump 9 and the second lift pump 14 for recycling of this module. The ratio of incoming water: recycled water: water entering the solid-liquid separation module is 3:1:2.

[0073] The first check valve 24 provided on the connecting pipe between the ozone generator 28 and the gas-liquid mixer 25 is closed during normal operation and opened during backwashing, and the time ratio of normal operation to backwashing process is 14 / 2min; the second check valve 30 connecting the ozone generator 28 and the ozone catalytic tank 27 is normally open during normal operation and closed during backwashing, and the time ratio of normal operation to backwashing process is 14 / 2min; the third check valve 34 connecting the ozone catalytic tank 27 and the gas-liquid mixer 25 and the backwashing pump 33 are closed during normal operation and opened during backwashing, and the time ratio of normal operation to backwashing process is 14 / 2min.

[0074] Example 9

[0075] As shown in Example 8, the difference is:

[0076] In this embodiment, the amount of sewage entering the system is 130%Q, of which 30%Q is returned to the mixer 3 through the first lift pump 9 and the second lift pump 14 for recycling of this module. The ratio of incoming water: recycled water: water entering the solid-liquid separation module is 13:3:10.

[0077] The first check valve 24 provided on the connecting pipe between the ozone generator 28 and the gas-liquid mixer 25 is closed during normal operation and opened during backwashing, and the time ratio of normal operation to backwashing process is 8 / 2min; the second check valve 30 connecting the ozone generator 28 and the ozone catalytic tank 27 of the third module is normally open during normal operation and closed during backwashing, and the time ratio of normal operation to backwashing process is 8 / 2min; the third check valve 34 connecting the ozone catalytic tank 27 and the gas-liquid mixer 25 and the backwashing pump 33 are closed during normal operation and opened during backwashing, and the time ratio of normal operation to backwashing process is 8 / 2min.

Claims

1. An integrated equipment for in-situ treatment of oilfield produced water, characterized in that: The integrated equipment includes: micro-nano bubble separation module, solid-liquid separation module, fine treatment and reinjection module; The micro-nano bubble separation module comprises a blower (1), a dissolved air tank (2), a mixer (3), a dissolved air releaser (5), a flotation tank (7) and a dosing system (6) connected in sequence. The flotation tank (7) is provided with a scraper (10), a slag collecting tank (11) and a screw pump (12) connected in sequence. The screw pump (12) is also connected to a sloping plate oil storage tank (13). The mixer (3) is also connected to a first high-pressure pump (4). The bottom of the flotation tank (7) is provided with a first water outlet (16). The solid-liquid separation module comprises a reaction tank body (20), the reaction tank body (20) is provided with a multi-channel silicon carbide membrane interface (21), a low-position water outlet trough (22) and a second water outlet (23), and the first water outlet (16) is connected to the reaction tank body (20); The fine treatment and reinjection module comprises an ozone catalytic pool (27), an ozone generator (28), a gas-liquid mixer (25), and a buffer tank (32). A fourth lift pump (31) and a second high-pressure pump (35) are provided in the ozone catalytic pool (27). The fourth lift pump (31) is connected to the buffer tank (32) through a third check valve (34). The buffer tank (32) is connected to the gas-liquid mixer (25). The ozone catalytic pool (27) is connected to the ozone generator (28) through a second check valve (30). The ozone generator (28) is connected to the gas-liquid mixer (25) through a first check valve (24). The gas-liquid mixer (25) is connected to the reaction pool body (20) through a backwash pump (33). The second water outlet (23) is connected to the ozone catalytic pool (27).

2. The integrated equipment for in-situ treatment of oilfield produced water according to claim 1, characterized in that: The dosing system (6) includes a drug storage tank (19) provided with a stirrer (18), and the drug storage tank (19) is connected to the flotation tank (7) via a drug dosing pump (17).

3. The integrated equipment for in-situ treatment of oilfield produced water according to claim 1, characterized in that: The air flotation tank body (7) is further provided with a micro-oxygen nano bubble generator (8) and a first lifting pump (9), and the air flotation tank body (7) is connected to the mixer (3) via the first lifting pump (9).

4. The integrated equipment for in-situ treatment of oilfield produced water according to claim 1, characterized in that: The inclined plate oil storage tank (13) is provided with 2-3 layers of inclined plates from top to bottom, and the dense width of the inclined plates decreases from top to bottom; preferably, the inclined plate oil storage tank (13) is also provided with a liquid level controller (15) and a second lifting pump (14), and the inclined plate oil storage tank (13) is connected to the mixer (3) via the second lifting pump (14).

5. The integrated equipment for in-situ treatment of oilfield produced water according to claim 1, characterized in that: A third lifting pump (26) is also provided at the bottom of the reaction tank body (20), and the reaction tank body (20) is connected to the mixer (3) via the third lifting pump (26).

6. The integrated equipment for in-situ treatment of oilfield produced water according to claim 1, characterized in that: The ozone catalytic tank (27) is also connected to the mixer (3) via a fourth lift pump (31); preferably, a mechanical stirrer (29) is also provided in the ozone catalytic tank (27).

7. The integrated equipment for in-situ treatment of oilfield produced water according to claim 1, characterized in that: The aeration device provided in the ozone catalytic tank (27) is preferably an OHR AERATOR aerator; Preferably, the mixer (3) and / or the gas-liquid mixer (25) is an OHR MIXER aeration device.

8. The integrated equipment for in-situ treatment of oilfield produced water according to claim 1, characterized in that: The pool wall of the ozone catalytic pool (27) is provided with a silicon carbide plate membrane loaded with an MMA-LDH coating.

9. The integrated equipment for in-situ treatment of oilfield produced water according to claim 1, characterized in that: The integrated equipment for in-situ treatment of oilfield produced water also includes: an intelligent control system module, which includes a monitoring instrument group, a control instrument group, a PLC control module and a human-machine interface; the intelligent control system module is respectively connected to the micro-nano bubble separation module, the solid-liquid separation module, and the fine treatment and reinjection module.

10. A method for operating the integrated equipment for in-situ regeneration and reinjection of drilling reinjection water according to any one of claims 1 to 9, comprising the following steps: The drilling oil sludge sewage is supplied with air by the fan (1) through the pipeline and is pressed into the dissolved air tank (2). Under the high pressure condition of the first high-pressure pump (4), the air and sewage are fully mixed in the mixer (3); the pressure is then released by the dissolved air releaser (5), and the sewage flows into the flotation tank (7); during this process, the dosing system (6) adds the required drugs, the stirrer (18) evenly stirs the drugs in the drug storage tank (19) and then is lifted into the flotation tank (7) by the dosing pump (17), and the tiny bubbles generated by the micro-oxygen nano bubble generator (8) combine with the suspended matter and grease in the water to form scum and float to the water surface. The scum is cleaned by the scraper (10), stored in the slag collecting tank (11), and sent to the inclined plate oil storage tank (13) by the screw pump (12); The inclined plate oil storage tank (13) is provided with 2-3 layers of inclined plates to separate the collected scum into three layers: floating oil, water, heavy oil and mud. The inclined plate oil storage tank (13) is provided with a liquid level controller (15), and preferably a water outlet is provided at the second layer of the inclined plate of the inclined plate oil storage tank (13) and equipped with a second lifting pump (14) to return the treated water to the mixer (3) for recycling; a first water outlet (16) is also provided in the clarification area at the bottom of the flotation tank (7), from which the treated sewage flows into the solid-liquid separation module; part of the treated water is returned to the mixer (3) for recycling through the first lifting pump (9) to enhance the treatment effect; After passing through the micro-nano bubble separation module, the wastewater enters the solid-liquid separation module, and is filtered through the multi-channel silicon carbide membrane interface (21) to separate the suspended solids. The wastewater is discharged from the low-level water outlet trough (22) and the water outlet (23) in the reaction tank body (20) and enters the fine treatment and reinjection module for sterilization. During the backwashing process, the ozone generator (28) is equipped with a pipeline and a first check valve (24) to control the ozone to be sent to the gas-liquid mixer (25), and the wastewater is sent to the buffer tank (32) through the third check valve (34) and the fourth lift pump (31), and then enters the gas-liquid mixer (25). After the ozone is mixed with water, the multi-channel silicon carbide membrane interface (21) in the solid-liquid separation module is backwashed by the backwashing pump (33). The backwashing water generated during the backwashing process contains some oil sludge residue, which is filtered through the multi-channel silicon carbide membrane interface (21) and returned to the mixer (3) by the second lift pump (26). After being subjected to flotation deoiling and silicon carbide membrane to remove suspended particles, the wastewater enters the fine treatment and reinjection module mainly for SBR sterilization. The wastewater enters the ozone catalytic pool (27). The ozone generator (28) provides ozone, which is controlled by the second check valve (30) and connected to the ozone catalytic pool (27) through a pipeline. In this regard, the drilling oil field water is mostly alkaline, which is conducive to ozone sterilization. The fourth lifting pump (31) returns a part of the drilling oil field water after being treated in the ozone catalytic pool (27) to the mixer (3) for recycling, and a part is controlled by the third check valve (34) and the fourth lifting pump (31) to enter the gas-liquid mixer (25) for backwashing water. The other part flows to the injection well system under the action of the second high-pressure pump (35) to complete the reinjection.

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