An offshore heavy oil high-temperature produced water treatment and reinjection system

Abstract

The present invention belongs to the field of water treatment technology, and in particular relates to a high-temperature produced water treatment and reinjection system for offshore heavy oil. The present invention addresses the problem that the effect of removing impurities in the prior art does not meet the requirements of existing reinjection water, and provides an offshore heavy oil high-temperature produced water treatment and reinjection system, comprising an oil removal system and a fine filtration system that are interconnected. The fine filtration system is further connected to a membrane filtration system at one end away from the oil removal system. The membrane filtration system comprises a membrane filtration raw water tank, a safety filter, a high-temperature ultrafiltration device, and a water injection buffer tank that are sequentially connected. The membrane filtration raw water tank is connected to the fine filtration system, and the water injection buffer tank is connected to an injection well. The present invention is provided with a membrane filtration system, and the produced water is finely filtered and then sequentially passes through the membrane filtration raw water tank, the safety filter, and the high-temperature ultrafiltration device to achieve membrane filtration, which significantly improves the water treatment effect and meets the requirements of reinjection or discharge. The filtered produced water can be directly injected into the injection well.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a high-temperature produced water treatment and reinjection system for offshore heavy oil. Background Art

[0002] High-temperature produced water from offshore heavy oil production often contains and carries large amounts of dissolved petroleum substances, inorganic salts, bacteria, and solid particles, resulting in complex water quality and significant treatment challenges. Typically, the oil content in produced water ranges from 100 to 5000 mg / L, of which approximately 90% is suspended and dispersed oil, while approximately 10% is emulsified oil and a small amount of dissolved oil. Suspended matter is composed of various solid particles, such as clay, paraffin, micelles, silt, and insoluble organic matter. The current mainstream treatment process utilizes a flotation-sand filtration-walnut shell filtration process. However, with increasing standards for produced water, this process is no longer able to meet filtration requirements. Furthermore, the oil sludge and sludge generated during traditional treatment processes are hazardous wastes that require external transport, resulting in high storage and transportation costs. Furthermore, existing equipment is inefficiently integrated and requires significant floor space. Therefore, there is an urgent need for a new treatment system suitable for treating high-temperature produced water from offshore heavy oil production.

[0003] However, its effect in removing impurities is limited, and most of the produced water after treatment cannot meet the reinjection standards, and the impurity removal effect needs to be improved.

[0004] For example, a Chinese invention patent discloses a method for treating oilfield produced water [application number: 201910328713.3]. The invention application includes: it uses a gravity sedimentation device, an electric field oil removal device and a filtration device, and includes the following steps: gravity sedimentation, transporting the produced water to the gravity sedimentation device for preliminary separation of oil, water and mud; electric field oil removal, transporting the sewage after gravity sedimentation to the electric field oil removal device to remove emulsified oil and suspended matter; and filtration, transporting the effluent after electric field oil removal to the filtration device to further remove emulsified oil and suspended matter, so that the effluent meets the reinjection requirements.

[0005] This invention has the advantage of being able to achieve rapid, efficient and low-cost treatment of oilfield produced water, and in particular, can improve the removal efficiency of emulsified oil, but it still does not solve the above-mentioned problems. Summary of the Invention

[0006] The purpose of the present invention is to solve the above problems and provide a high-temperature produced water treatment and reinjection system for offshore heavy oil.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A high-temperature produced water treatment and reinjection system for offshore heavy oil includes an oil removal system and a fine filtration system that are interconnected. The oil removal system is also connected to a waste oil treatment system for treating waste oil separated by the oil removal system. The fine filtration system is also connected to a sludge treatment system for treating solid impurities separated by the fine filtration system. The fine filtration system is also connected to a membrane filtration system at one end away from the oil removal system. The membrane filtration system includes a membrane filtration raw water tank, a safety filter, a high-temperature ultrafiltration device and a water injection buffer tank that are connected in sequence. The membrane filtration raw water tank is connected to the fine filtration system, and the water injection buffer tank is connected to a water injection well.

[0009] In the above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system, the oil removal system includes a cyclone separator connected to the high-temperature produced water source, one end of the flotation device is connected to the cyclone separator, and the other end is connected to the fine filtration system;

[0010] The waste oil treatment system includes a waste oil storage tank, a thermal cracking device and an oil-water separation device which are connected in sequence. The flotation device is connected to the waste oil storage tank and the waste oil separated in the flotation device is stored in the waste oil storage tank. The oil-water separation device is connected to the flotation device and the water phase separated in the oil-water separation device is refluxed into the flotation device.

[0011] In the above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system, the fine filtration system includes a fine filtration raw water tank, a self-cleaning filter, a multi-media filter and a walnut shell filter connected in sequence, the fine filtration raw water tank is connected to the oil removal system, and the walnut shell filter is connected to the membrane filtration raw water tank.

[0012] In the above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system, the membrane filtration system also includes an ultrafiltration chemical cleaning device and an ultrafiltration backwash device, both of which are connected to the high-temperature ultrafiltration device. The ultrafiltration backwash device is respectively connected to the self-cleaning filter, the multi-media filter and the walnut shell filter, and the ultrafiltration backwash device can transport backwash water to the self-cleaning filter, the multi-media filter and the walnut shell filter respectively.

[0013] In the above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system, the sludge treatment system includes a backwash wastewater collection tank, a sedimentation tank, a sludge concentration tank, a sludge filter press system and a sludge drying equipment connected in sequence. The self-cleaning filter, the multi-media filter and the walnut shell filter are all connected to the backwash wastewater collection tank, the sedimentation tank is connected to the fine filtration raw water tank, and the water phase separated after sedimentation in the sedimentation tank is transported to the fine filtration raw water tank.

[0014] The above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system also includes a seawater desalination system, which includes a sand filter device, a reverse osmosis device, a water production tank and a dosing system connected in sequence. The reverse osmosis device is connected to the sludge drying equipment, and the concentrated water output by the reverse osmosis device is used to accelerate the removal of steam generated in the sludge drying equipment.

[0015] In the above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system, the high-temperature ultrafiltration device includes an outer shell having a filter cavity inside, a mounting part is fixedly provided inside the outer shell, a water outlet cavity is provided above the mounting part, one end of the filter membrane thread is fixedly connected to the mounting part, and the other end is a free end, the filter cavity is connected to the water outlet cavity through the filter membrane thread, the upper end of the outer shell is also provided with a water production port and an upper discharge port, the water production port is connected to the water outlet cavity, the upper discharge port is connected to the filter cavity, the lower end of the outer shell is also provided with a water inlet and a lower discharge port, the water inlet and the lower discharge port are both connected to the filter cavity, an aeration structure is also provided in the filter cavity, the aeration structure is slidably connected to the outer shell, and one end of the aeration structure extends to the outside of the outer shell and is connected to an external air source.

[0016] In the above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system, the aeration structure includes a cylindrical aeration body, on which a gas hose is provided. One end of the gas hose, remote from the aeration body, is connected to an air inlet provided on an outer shell. The air inlet is connected to an external air source. A plurality of gas transmission channels are defined within the aeration body. One end of each gas transmission channel is connected to the gas hose, and the other end of each gas transmission channel penetrates the top and side surfaces of the aeration body to form axial and radial gas outlets.

[0017] In the above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system, the bottom of the aeration body is further connected to a lifting structure, and the side of the aeration body is provided with a guide groove recessed toward the interior of the aeration body, and the guide groove is slidably connected to a guide block protruding from the inner surface of the outer shell;

[0018] The aeration structure also includes a convergence disk fixedly connected to the inner surface of the aeration body. The convergence disks are provided in plurality and are arranged in sequence along the axial direction of the aeration body. A clearance hole penetrating the convergence disk is provided at the center of the convergence disk. The convergence disk is also provided with a plurality of membrane wire limiting holes evenly distributed circumferentially along the axial direction of the convergence disk. The sliding aeration body can allow the free end of the filter membrane wire to pass through the membrane wire limiting hole.

[0019] In the above-mentioned offshore heavy oil high-temperature produced water treatment and reinjection system, the filter membrane is made of a hydrophilic PVDF material, and the hydrophilic PVDF material is prepared by the following method:

[0020] Step 1: Pre-irradiate the PVDF powder under an electron accelerator, adjust the irradiation equipment parameters so that the irradiation dose is 20-200 kGy and the irradiation dose rate is 50-15000 Gy / s, preferably, the irradiation dose is 30-120 kGy and the irradiation dose rate is 2000-10000 Gy / s; obtain the pretreated PVDF material;

[0021] Step 2: dissolving the pretreated PVDF material obtained in step 1 in a strong polar organic solvent, N-methyl-2-pyrrolidone can be selected as the strong polar organic solvent, stirring under nitrogen protection until completely dissolved, and then adding a vinyl hydrophilic monomer and an initiator, wherein the vinyl hydrophilic monomer is one or more of acrylamide, acrylic acid and hydroxyethyl acrylate, and the amount of the hydrophilic monomer is 0.1%-10% of the amount of the pretreated PVDF material. The initiator is an organic peroxide initiator and / or an azo initiator, for example, azobisisobutyronitrile, and the amount of the initiator is 0.1%-5% of the mass of the solution system. The temperature is raised to 50-80°C, stirred for reaction for 3-6 hours, and the reaction solution is filtered to obtain a hydrophilic PVDF material.

[0022] Hydrophilic PVDF material can be made into filter membrane by the following methods:

[0023] The hydrophilic PVDF material, porogen, and additives are dissolved in a solvent. The porogen can be polyethylene glycol, added in an amount of 0.5%-3% of the hydrophilic PVDF material. The additive can include polysiloxane, added in an amount of 0.1-0.5% of the hydrophilic PVDF material. The solution is stirred and dissolved at 50-70°C, then allowed to stand for degassing to produce a casting solution. The casting solution is extruded from a spinneret, then passed through an external coagulation bath and rinsed to produce a hydrophilic PVDF hollow filter membrane.

[0024] Compared with the existing technology, the advantages of the present invention are:

[0025] 1. The present invention realizes resource utilization for produced water from offshore platforms. In terms of water resources, water is reused as reinjection water; in terms of oil components, thermal cracking products are sold as fuel oil; in terms of energy, high-temperature produced water is reused as high-temperature reinjection water, reducing energy consumption.

[0026] 2. There is a membrane filtration system. The produced water is finely filtered and then passes through the membrane filtration raw water tank, safety filter and high-temperature ultrafiltration device in sequence to achieve membrane filtration, which significantly improves the water treatment effect and meets the requirements of reinjection or discharge. The filtered produced water can be directly injected into the injection well.

[0027] 3. The present invention uses part of the produced water as backwash water for the high-temperature ultrafiltration device, realizing internal backwash water supply without the need for external input. The backwash water of the high-temperature ultrafiltration device is used as backwash water for the fine filtration system, further ensuring the reuse of the backwash water inside the system, which can greatly save water. At the same time, the setting of the sludge treatment system realizes the efficient treatment of the backwash water and improves the environmental performance of the system.

[0028] 4. The present invention provides an aeration structure that can move up and down in the high-temperature ultrafiltration device to improve the aeration efficiency. The aeration structure is also provided with a radial air outlet that can discharge air in a direction perpendicular to the axis of the filter membrane wire, so that more surface contact can occur between the filter membrane wires during the aeration process, which promotes the removal of impurities attached to the surface of the filter membrane wire due to filtration. At the same time, a plurality of membrane wire limiting holes arranged along the axis direction are used to relatively limit the position of the filter membrane wire, which can avoid the problem of entanglement and knotting between the filter membrane wires during the aeration process to a certain extent.

[0029] 5. The present invention uses modified hydrophilic PVDF material to make filter membrane filaments, so that the filter membrane filaments can withstand higher temperatures while ensuring hydrophilicity, so that the membrane filtration system can directly perform filtering operations at higher temperatures without cooling the produced water to be filtered, simplifying the operating steps and equipment structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the present invention;

[0031] Figure 2 It is a structural schematic diagram of a high-temperature ultrafiltration device;

[0032] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0033] Figure 4 is a structural diagram of the aeration structure;

[0034] In the figure: oil removal system 1, fine filtration system 2, membrane filtration system 3, waste oil treatment system 4, sludge treatment system 5, seawater desalination system 6, aeration structure 7, cyclone separator 11, flotation device 12, fine filtration raw water tank 21, self-cleaning filter 22, multi-media filter 23, walnut shell filter 24, membrane filtration raw water tank 31, security filter 32, high-temperature ultrafiltration device 33, water injection buffer tank 34, water injection well 35, ultrafiltration chemical cleaning device 36, ultrafiltration backwash device 37, waste oil storage tank 41, thermal cracking device 42, oil-water separator 43, backwash wastewater collection tank 51, sedimentation tank 5 2. Sludge thickening tank 53, sludge filter press system 54, sludge drying equipment 55, sand filter device 61, reverse osmosis device 62, water production tank 63, dosing system 64, aeration body 71, air hose 72, air inlet 73, air transmission channel 74, axial air outlet 75, radial air outlet 76, lifting structure 77, guide groove 78, guide block 79, convergence disk 7a, membrane wire limiting hole 7b, clearance hole 7c, filter cavity 331, outer shell 332, mounting part 333, water outlet cavity 334, filter membrane filament 335, water production port 336, upper discharge port 337, lower discharge port 338, water inlet 339. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0036] Example 1

[0037] This embodiment provides a system for processing and reinjecting high-temperature produced water from offshore heavy oil. Figure 1 As shown, it includes an oil removal system 1 and a fine filtration system 2 that are interconnected. The oil removal system 1 is also connected to a waste oil treatment system 4 for treating the waste oil separated by the oil removal system 1. The fine filtration system 2 is also connected to a sludge treatment system 5 for treating solid impurities separated by the fine filtration system 2. The fine filtration system 2 is also connected to a membrane filtration system 3 at one end away from the oil removal system 1.

[0038] Oil removal system 1 removes oil from high-temperature produced water, reducing its oil content. Fine filtration system 2 further filters fine impurities from produced water, improving water quality. Membrane filtration system 3 performs high-efficiency filtration, further purifying the water and providing high-quality water for injection. Sludge treatment system 5 processes sludge generated at various stages to prevent environmental pollution.

[0039] Specifically, the oil removal system 1 includes a cyclone separator 11 connected to a high-temperature produced water source, and an air flotation device 12 is connected to the cyclone separator 11 at one end and to the fine filtration system 2 at the other end.

[0040] Pollutants in high-temperature produced water primarily include suspended solids and oil accumulated during the reinjection water recycling process. The influent water quality has a suspended solids content of ≥100 mg / L, an oil content of ≥100 mg / L, a pH of 5-9, and a temperature of 60-100°C. The high-temperature produced water passes sequentially through a cyclone separator 11 and an air flotation device 12. The cyclone separator 11 uses centrifugal force to initially separate the oil from the high-temperature produced water. The air flotation device 12 further removes the oil and some solid impurities from the produced water, resulting in a preliminary filtrate with an oil content of ≤20 mg / L.

[0041] Specifically, the fine filtration system 2 includes a fine filtration raw water tank 21, a self-cleaning filter 22, a multi-media filter 23 and a walnut shell filter 24 connected in sequence. The fine filtration raw water tank 21 is connected to the oil removal system 1, and the walnut shell filter 24 is connected to the membrane filtration raw water tank 31.

[0042] The preliminary filtrate is transported from the flotation device 12 to the fine filtration system 2, which performs fine filtration on the produced water after oil removal to remove fine impurities and obtain a fine filtration filtrate, in which the oil content is ≤5mg / L and the suspended matter is ≤5mg / L.

[0043] The liquid inlet of the self-cleaning filter 22 is connected to the liquid outlet of the fine filtration raw water tank 21, automatically filtering out larger particles of impurities in the inlet liquid and being able to clean the filter screen by itself, thus ensuring the continuity and stability of filtration and reducing manual maintenance costs;

[0044] The liquid inlet of the multi-media filter 23 is connected to the liquid outlet of the self-cleaning filter 22. The filtration speed of the multi-media filter 23 is between 6-20m / h. It uses different media to further remove impurities such as suspended particles and organic matter in the inlet liquid, thereby further improving the water quality.

[0045] The liquid inlet end of the walnut shell filter 24 is connected to the liquid outlet end of the multi-media filter 23. It uses walnut shell as the filter medium, and the filtration speed is between 15-20m / h. It deeply filters the oil, tiny particles, etc. in the water, especially the treatment effect of oil-containing produced water is better, and can effectively reduce the oil content and impurity content in the produced water. After triple fine filtration, fine filtered liquid is obtained; the liquid outlet end of the walnut shell filter 24 is connected to the liquid inlet end of the membrane filtration raw water tank 31, and the fine filtered liquid is further transported to the membrane filtration system 3 for subsequent treatment.

[0046] The backwash water inlet of the self-cleaning filter 22, the backwash water inlet of the multi-media filter 23, and the backwash water inlet of the walnut shell filter 24 are respectively connected to the backwash water output end of the high-temperature ultrafiltration device 33; since the self-cleaning filter 22, the multi-media filter 23, and the walnut shell filter 24 must have residual pollution inside after the inlet liquid is filtered, the backwash water of the high-temperature ultrafiltration device 33 can be respectively transported to the self-cleaning filter 22, the multi-media filter 23, and the walnut shell filter 24 as backwash water for cleaning, which can greatly save the external water required for cleaning.

[0047] Specifically, the membrane filtration system 3 includes a membrane filtration raw water tank 31, a security filter 32, a high-temperature ultrafiltration device 33 and a water injection buffer tank 34 which are connected in sequence. The membrane filtration raw water tank 31 is connected to the fine filtration system 2, and the water injection buffer tank 34 is connected to the water injection well 35.

[0048] The liquid inlet of the membrane filtration system 3 is connected to the liquid outlet of the fine filtration system 2, and the water outlet of the high-temperature ultrafiltration device 33 is connected to the water injection well 35. The precision filtration filtrate is transported from the walnut shell filter 24 to the membrane filtration raw water tank 31, and is filtered again by the high-temperature ultrafiltration device 33 to obtain the final water production. The suspended solids in the water production are ≤1mg / L, and the oil content is ≤3mg / L, ensuring that the water quality of the high-temperature produced water reaches high standards after treatment and meets the requirements for reinjection or discharge.

[0049] Specifically, the waste oil treatment system 4 includes a waste oil storage tank 41, a thermal cracking device 42, and an oil-water separator 43 that are connected in sequence. The flotation device 12 is connected to the waste oil storage tank 41, and the waste oil separated in the flotation device 12 is stored in the waste oil storage tank 41. The oil-water separator 43 is connected to the flotation device 12, and the water phase separated in the oil-water separator 43 is returned to the flotation device 12.

[0050] The floating oil input of the waste oil storage tank 41 is connected to the floating oil output of the flotation device 12, receiving the floating oil separated by the flotation device 12 during produced water treatment. This connection allows the floating oil dispersed in the produced water to be collected and centralized, providing raw material for subsequent treatment steps. This design allows subsequent treatment to proceed according to a consistent rhythm and process, rather than dealing with a continuous flow of floating oil in real time, facilitating unified management and control of the waste oil treatment process.

[0051] Thermal cracking unit 42 performs cryogenic distillation on the floating oil collected in waste oil storage tank 41, separating its components by utilizing the differences in boiling points. This process evaporates water and low-boiling-point impurities, retaining the oil for purification and improving its quality for subsequent recycling. This distillation process isolates recyclable components, such as pure oil, providing pure raw material for subsequent oil-water separation, achieving initial recovery of some waste oil resources and reducing waste.

[0052] The oil-water separator 43 receives the mixed liquid after the thermal cracking unit is processed to achieve fine oil-water separation, such as using physical or chemical methods such as gravity, centrifugation, and coalescence to finely separate the residual oil and water, ensuring that the oil is pure and the water meets the standards, which is convenient for subsequent processing and recycling.

[0053] The water outlet of the oil-water separator 43 is connected to the liquid inlet of the flotation device 12, enabling water recycling. Water containing a small amount of oil and some impurities is returned to the flotation device 12 for further flotation treatment, achieving water recycling, improving utilization efficiency, and reducing dependence on external fresh water. The flotation device 12 is used to provide a source of waste oil and recycle treated water. During produced water treatment, the flotation device 12 uses its own oil removal mechanism, such as injecting tiny bubbles to cause oil droplets to adhere and float, separating the floating oil and outputting it to the waste oil storage tank 41 to feed the waste oil treatment. At the same time, it receives water treated by the oil-water separator 43 and returns it to the liquid inlet of the flotation device 12 to participate in the produced water oil removal treatment again, achieving water recycling, reducing the demand for fresh water, maintaining the water balance of the device, and maintaining a stable treatment effect.

[0054] like Figure 1 As shown, the membrane filtration system 3 also includes an ultrafiltration chemical cleaning device 36 and an ultrafiltration backwash device 37, both of which are connected to the high-temperature ultrafiltration device 33. The ultrafiltration backwash device 37 is connected to the self-cleaning filter 22, the multi-media filter 23 and the walnut shell filter 24 respectively, and the ultrafiltration backwash device 37 can transport backwash water to the self-cleaning filter 22, the multi-media filter 23 and the walnut shell filter 24 respectively.

[0055] The ultrafiltration chemical cleaning device 36 is connected to the high-temperature ultrafiltration device 33. Its produced water is primarily reused as oilfield reinjection water, with a portion used as backwash water for the high-temperature ultrafiltration device 33. Backwash water accounts for approximately 5%-10% of the total produced water. The ultrafiltration chemical cleaning device 36 uses the remaining produced water within the high-temperature ultrafiltration device 33 to backwash the high-temperature ultrafiltration device 33, removing membrane contamination and restoring its filtration performance. Using a portion of the produced water as backwash water for the high-temperature ultrafiltration device 33 achieves internal backwash water supply, eliminating the need for external water supply and significantly saving water. The ultrafiltration chemical cleaning device 36 can also chemically clean the high-temperature ultrafiltration device 33 in the membrane filtration system 3, using a deep cleaning agent to remove membrane contamination and restore filtration performance.

[0056] The backwash water output of the high-temperature ultrafiltration device 33 is connected to the backwash water inlet of the fine filtration system 2. An ultrafiltration backwash device 37 is disposed between the high-temperature ultrafiltration device 33 and the fine filtration system 2. Its liquid inlet is connected to the backwash water output of the high-temperature ultrafiltration device 33, and its liquid outlet is connected to the backwash water inlet of the fine filtration system 2. The ultrafiltration backwash device 37 primarily collects backwash water discharged from the high-temperature ultrafiltration device 33 during the backwash operation, temporarily storing the backwash water and preventing the indiscriminate discharge of backwash water, which could cause environmental pollution or waste of water resources.

[0057] like Figure 1 As shown, the sludge treatment system 5 includes a backwash wastewater collection tank 51, a sedimentation tank 52, a sludge concentration tank 53, a sludge filter press system 54 and a sludge drying equipment 55 which are connected in sequence. The self-cleaning filter 22, the multi-media filter 23 and the walnut shell filter 24 are all connected to the backwash wastewater collection tank 51, and the sedimentation tank 52 is connected to the fine filtration raw water tank 21, and the water phase separated after precipitation in the sedimentation tank 52 is transported to the fine filtration raw water tank 21.

[0058] The liquid inlet end of the backwash wastewater collection box 51 is connected to the backwash water output end of the self-cleaning filter 22, the backwash water output end of the multi-media filter 23, and the backwash water output end of the walnut shell filter 24, respectively, and is used to collect the backwash wastewater generated by the backwash of the fine filtration system 2.

[0059] The sedimentation tank 52 receives the total backwash water delivered by the backwash wastewater collection box 51. It can be any one of the horizontal flow sedimentation tanks, high-density tanks, and micro-sand sedimentation tanks, or any combination of several of them. The suspended sludge particles in the wastewater are naturally settled to the bottom of the tank by gravity, thereby achieving the initial separation of sludge and water. After treatment in the sedimentation tank, the concentration of the settled sludge can be between 95% and 99%.

[0060] After sedimentation in the sedimentation tank 52, the sludge enters the sludge thickening tank 53. The sludge thickening tank 53 further concentrates the sludge sent from the sedimentation tank 52. Through natural sedimentation or other auxiliary means, such as the addition of flocculants, the water in the sludge is further discharged, the solid content of the sludge is increased, and the volume of the sludge is reduced to facilitate subsequent sludge treatment operations, such as filter pressing and drying.

[0061] After being compressed in the sludge thickening tank 53, the sludge enters the sludge filter press system 54, which can be a filter press or a screw press. The sludge filter press system 54 performs a filter press operation on the concentrated sludge sent from the sludge thickening tank 53. By applying a certain pressure, the water in the sludge is forced out through filter media such as filter cloth, achieving a more thorough separation of the sludge and water. The screw press utilizes the principle of screw extrusion. The changes in screw diameter and pitch, as well as the strong squeezing force generated by the tiny gap between the floating ring and the fixed ring, squeeze and dehydrate the sludge, producing a filter cake-like sludge with a low moisture content. This improves the dehydration efficiency of the sludge and facilitates subsequent sludge disposal or utilization.

[0062] After being processed by the sludge filter press system 54, the sludge enters the sludge drying equipment 55. This equipment can utilize a vacuum rake dryer. The resulting water can be directly discharged into the sea, while the resulting oily sludge is sent for external processing. The sludge drying equipment 55 dries the filter cake sludge delivered from the sludge filter press system 54. Through heating, ventilation, and other drying methods, the sludge is further dehydrated, further reducing its moisture content to a lower level and transforming it into a dry, solid substance. This facilitates storage, transportation, or final disposal, such as landfill or incineration. This also reduces the volume and weight of the sludge, lowering subsequent processing costs.

[0063] The liquid outlet of the sludge thickening tank 53 and the liquid outlet of the sludge filter press system 54 are respectively connected to the liquid inlet of the sedimentation tank 52, and the liquid outlet of the sedimentation tank 52 is connected to the liquid inlet of the fine filtration raw water tank 21. In this way, the liquid treated by the sludge thickening tank and the sludge filter press device returns to the sedimentation tank again, and the produced water obtained after sedimentation in the sedimentation tank can be returned to the fine filtration raw water tank for storage and reserved for later use.

[0064] like Figure 1 As shown, it also includes a seawater desalination system 6, which includes a sand filter device 61, a reverse osmosis device 62, a water production tank 63 and a dosing system 64 connected in sequence. The reverse osmosis device 62 is connected to the sludge drying equipment 55, and the concentrated water output by the reverse osmosis device 62 is accelerated to remove the steam generated in the sludge drying equipment 55 through the Venturi effect and the vacuum pump.

[0065] The primary function of the sand filter 61 is to perform preliminary filtration of seawater entering the desalination system. The sand filter media intercepts larger particles of impurities, such as silt and suspended solids, in the seawater, reducing the turbidity of the seawater. This provides relatively clean feed water for the subsequent reverse osmosis unit 62, prevents large particles from clogging the reverse osmosis membrane, and extends the service life of the reverse osmosis unit 62.

[0066] The reverse osmosis unit 62 is the core component of the seawater desalination system. Utilizing the principle of a semipermeable membrane, under pressure, water molecules in seawater are forced through the membrane while impurities such as salt are retained, thereby desalinating the seawater and producing fresh water and concentrated water. The fresh water is transported to the production water tank 63 for storage and further use as a high-quality water resource, while the concentrated water contains a higher concentration of salt and other impurities.

[0067] The liquid inlet of the dosing system 64 is connected to the liquid outlet of the water production tank 63. The water production tank 63 is used to store the fresh water obtained by desalination of the reverse osmosis device 62, and plays a role of buffering and temporary storage. Ensure a stable supply of fresh water to the subsequent dosing system 64, etc., to meet the demand for fresh water in subsequent treatment or use processes, and ensure the continuity and stability of the entire produced water treatment system. After the dosing system 64 receives the desalinated water sent by the water production tank 63, it further adjusts and treats the desalinated water by adding specific agents, such as disinfectants, pH regulators, etc., so that it meets specific usage requirements or complies with relevant water quality standards, so that it can be used safely and effectively in subsequent application scenarios, such as industrial water, domestic water, etc.

[0068] Combine Figure 2-4 As shown, the high-temperature ultrafiltration device 33 includes an outer shell 332 with a filter cavity 331 inside. A mounting member 333 is fixedly provided in the outer shell 332. A water outlet cavity 334 is provided above the mounting member 333. One end of the filter membrane filament 335 is fixedly connected to the mounting member 333 and the other end is a free end. The filter cavity 331 is connected to the water outlet cavity 334 through the filter membrane filament 335. A water outlet 336 and an upper discharge port 337 are also provided at the upper end of the outer shell 332. The water production port 336 is connected to the water outlet cavity 334, the upper discharge port 337 is connected to the filter cavity 331, and the lower end of the outer shell 332 is further provided with a water inlet 339 and a lower discharge port 338, both of which are connected to the filter cavity 331. An aeration structure 7 is also provided in the filter cavity 331, and the aeration structure 7 is slidably connected to the outer shell 332. One end of the aeration structure 7 extends to the outside of the outer shell 332 and is connected to an external air source.

[0069] Raw water to be filtered enters the filter cavity 331 through the water inlet 339. After being filtered by the filter membrane filaments 335, the produced water passes through the hollow cavity inside the filter membrane filaments 335 and enters the water outlet cavity 334, and is discharged through the water outlet 336. After filtration, the concentrated water remaining in the water outlet cavity 334 can be discharged through the lower discharge port 338.

[0070] The water temperature required for filtration at the high-temperature ultrafiltration device 33 is about 80°C, but most of the materials used to prepare the filter membrane filaments 335 in the prior art cannot withstand such high temperatures, so the water to be filtered must first be cooled by a heat exchange device. This requires additional heat exchange devices and heat exchange steps, which leads to complex operating steps and equipment structures. Moreover, heat loss cannot be avoided during the heat exchange process. PVDF material is a high-temperature resistant material, but its own nature is hydrophobic (in the technical field involved in the present invention, hydrophilic material refers to a material that is water-permeable but not air-permeable, and hydrophobic material refers to a material that is impermeable but air-permeable), and cannot be used in the preparation of the filter membrane filaments 335.

[0071] Therefore, the present invention modifies the PVDF material to obtain a modified hydrophilic PVDF material suitable for preparing the filter membrane filament 335. The specific steps are as follows:

[0072] Step 1: Pre-irradiate the PVDF powder under an electron accelerator, adjust the irradiation equipment parameters so that the irradiation dose is 200 kGy and the irradiation dose rate is 50 Gy / s, and obtain the pre-treated PVDF material;

[0073] Step 2: Dissolve the pretreated PVDF material obtained in step 1 in N-methyl-2-pyrrolidone, stir under nitrogen protection until completely dissolved, then add acrylic acid monomer and azobisisobutyronitrile, the amount of acrylic acid monomer added is 0.1% of the pretreated PVDF material, and the amount of azobisisobutyronitrile added is 5% of the mass of the solution system, heat to 80°C, stir and react for 6 hours, and filter the reaction solution to obtain a hydrophilic PVDF material.

[0074] Combine Figure 2-4 As shown, the aeration structure 7 includes a cylindrical aeration body 71, on which a gas hose 72 is provided. One end of the gas hose 72 away from the aeration body 71 is connected to an air inlet 73 provided on the outer shell 332, and the air inlet 73 is connected to an external air source. A plurality of gas delivery channels 74 are opened in the aeration body 71, one end of the gas delivery channel 74 is connected to the gas hose 72, and the other end passes through the top surface and side surface of the aeration body 71 to form an axial gas outlet 75 and a radial gas outlet 76.

[0075] Although the ultrafiltration chemical cleaning device 36 can chemically clean the filter membrane filaments 335 to remove membrane contamination, long-term and frequent chemical cleaning will damage the filter membrane filaments 335 and shorten their service life. Therefore, an aeration structure 7 is provided to perform air washing on the surface of the filter membrane filaments 335 while performing aeration, thereby cleaning the surface of the filter membrane filaments 335 and restoring the filtering performance. The aeration structure 7 is also provided with a radial air outlet 76 that can discharge air in a direction perpendicular to the axis of the filter membrane filaments 335, so that more surface contact can occur between the filter membrane filaments 335 during the aeration process, promoting the shedding of impurities attached to the surface of the filter membrane filaments 335 due to filtration, and improving the air washing effect.

[0076] like Figure 3 As shown, a lifting structure 77 is connected to the bottom of the aeration body 71. A guide groove 78 is provided on the side of the aeration body 71, which is recessed into the aeration body 71. The guide groove 78 is slidably connected to a guide block 79 protruding from the inner surface of the outer shell 332. The lifting structure 77 can drive the aeration body 71 to move along the axis, thereby improving aeration efficiency.

[0077] like Figure 4 As shown, the aeration structure 7 also includes a convergence disk 7a fixedly connected to the inner surface of the aeration body 71. The convergence disk 7a is provided with a plurality of convergence disks 7a and arranged in sequence along the axial direction of the aeration body 71. A clearance hole 7c penetrating the convergence disk 7a is provided at the center position of the convergence disk 7a. The convergence disk 7a is also provided with a plurality of membrane wire limiting holes 7b uniformly distributed along the axial direction of the convergence disk 7a. The membrane wire limiting holes 7b are tiny holes and are uniformly distributed on the surface of the convergence disk 7a. The sliding aeration body 71 can allow the free end of the filter membrane wire 335 to pass through the membrane wire limiting hole 7b. After the aeration body 71 moves in the direction close to the filter membrane wire 335, several filter membrane wires 335 with similar distances pass through the membrane wire limiting holes 7b in a bundle. Therefore, the present invention uses multiple membrane wire limiting holes 7b arranged along the axial direction to relatively limit the position of the filter membrane wire 335, which can avoid the problem of entanglement and knotting between the filter membrane wires 335 during the aeration process to a certain extent.

[0078] Example 2

[0079] This embodiment provides a system for processing and reinjecting high-temperature produced water from offshore heavy oil. Figure 1-4 As shown, its specific structure is substantially the same as that described in Example 1, and the only difference is the preparation method of the hydrophilic PVDF material for preparing the filter membrane filament 335. The specific preparation method is as follows:

[0080] Step 1: Pre-irradiate the PVDF powder under an electron accelerator, adjust the irradiation equipment parameters so that the irradiation dose is 20 kGy and the irradiation dose rate is 15000 Gy / s, and obtain the pre-treated PVDF material;

[0081] Step 2: Dissolve the pretreated PVDF material obtained in step 1 in N-methyl-2-pyrrolidone, stir under nitrogen protection until completely dissolved, then add acrylic acid monomer and azobisisobutyronitrile, the amount of acrylic acid monomer added is 10% of the pretreated PVDF material, and the amount of azobisisobutyronitrile added is 0.1% of the mass of the solution system, heat to 50°C, stir and react for 3 hours, and filter the reaction solution to obtain a hydrophilic PVDF material.

[0082] Example 3

[0083] This embodiment provides a system for processing and reinjecting high-temperature produced water from offshore heavy oil. Figure 1-4 As shown, its specific structure is substantially the same as that described in Example 1, and the only difference is the preparation method of the hydrophilic PVDF material for preparing the filter membrane filament 335. The specific preparation method is as follows:

[0084] Step 1: Pre-irradiate the PVDF powder under an electron accelerator, adjust the irradiation equipment parameters so that the irradiation dose is 75 kGy and the irradiation dose rate is 6000 Gy / s, and obtain the pre-treated PVDF material;

[0085] Step 2: Dissolve the pretreated PVDF material obtained in step 1 in N-methyl-2-pyrrolidone, stir under nitrogen protection until completely dissolved, then add acrylic acid monomer and azobisisobutyronitrile, the amount of acrylic acid monomer added is 5% of the pretreated PVDF material, and the amount of azobisisobutyronitrile added is 2% of the mass of the solution system, heat to 65°C, stir and react for 4.5h, filter the reaction solution to obtain a hydrophilic PVDF material.

[0086] Comparative Example 1

[0087] This comparative example provides a high-temperature produced water treatment and reinjection system for offshore heavy oil, combined with Figure 1-4 As shown, its specific structure is substantially the same as that described in Example 1, and the only difference is the preparation method of the hydrophilic PVDF material for preparing the filter membrane filament 335. The specific preparation method is as follows:

[0088] Step 1: Dissolve PVDF powder in N-methyl-2-pyrrolidone and stir under nitrogen protection until completely dissolved, then add acrylic acid monomer and azobisisobutyronitrile, the amount of acrylic acid monomer added is 5% of the pretreated PVDF material, and the amount of azobisisobutyronitrile added is 2% of the mass of the solution system. Heat to 65°C, stir and react for 4.5 hours, and filter the reaction solution to obtain a hydrophilic PVDF material.

[0089] Comparative Example 2

[0090] This comparative example provides a high-temperature produced water treatment and reinjection system for offshore heavy oil, combined with Figure 1-4 As shown, its specific structure is substantially the same as that described in Example 1, and the only difference is the preparation method of the hydrophilic PVDF material for preparing the filter membrane filament 335. The specific preparation method is as follows:

[0091] Step 1: Pre-irradiate the PVDF powder under an electron accelerator, adjust the irradiation equipment parameters so that the irradiation dose is 10 kGy and the irradiation dose rate is 6000 Gy / s, and obtain the pre-treated PVDF material;

[0092] Step 2: Dissolve the pretreated PVDF material obtained in step 1 in N-methyl-2-pyrrolidone, stir under nitrogen protection until completely dissolved, then add acrylic acid monomer and azobisisobutyronitrile, the amount of acrylic acid monomer added is 5% of the pretreated PVDF material, and the amount of azobisisobutyronitrile added is 2% of the mass of the solution system, heat to 65°C, stir and react for 4.5h, filter the reaction solution to obtain a hydrophilic PVDF material.

[0093] Comparative Example 3

[0094] This embodiment provides a system for processing and reinjecting high-temperature produced water from offshore heavy oil. Figure 1-4 As shown, its specific structure is substantially the same as that described in Example 1, and the only difference is the preparation method of the hydrophilic PVDF material for preparing the filter membrane filament 335. The specific preparation method is as follows:

[0095] Step 1: Pre-irradiate the PVDF powder under an electron accelerator, adjust the irradiation equipment parameters so that the irradiation dose is 300 kGy and the irradiation dose rate is 6000 Gy / s, and obtain the pre-treated PVDF material;

[0096] Step 2: Dissolve the pretreated PVDF material obtained in step 1 in N-methyl-2-pyrrolidone, stir under nitrogen protection until completely dissolved, then add acrylic acid monomer and azobisisobutyronitrile, the amount of acrylic acid monomer added is 5% of the pretreated PVDF material, and the amount of azobisisobutyronitrile added is 2% of the mass of the solution system, heat to 65°C, stir and react for 4.5h, filter the reaction solution to obtain a hydrophilic PVDF material.

[0097] Comparative Example 4

[0098] This embodiment provides a system for processing and reinjecting high-temperature produced water from offshore heavy oil. Figure 1-4 As shown, its specific structure is substantially the same as that described in Example 1, and the only difference is the preparation method of the hydrophilic PVDF material for preparing the filter membrane filament 335. The specific preparation method is as follows:

[0099] Step 1: Pre-irradiate the PVDF powder under an electron accelerator, adjust the irradiation equipment parameters so that the irradiation dose is 75 kGy and the irradiation dose rate is 20 Gy / s, and obtain the pre-treated PVDF material;

[0100] Step 2: Dissolve the pretreated PVDF material obtained in step 1 in N-methyl-2-pyrrolidone, stir under nitrogen protection until completely dissolved, then add acrylic acid monomer and azobisisobutyronitrile, the amount of acrylic acid monomer added is 5% of the pretreated PVDF material, and the amount of azobisisobutyronitrile added is 2% of the mass of the solution system, heat to 65°C, stir and react for 4.5h, filter the reaction solution to obtain a hydrophilic PVDF material.

[0101] Comparative Example 5

[0102] This embodiment provides a system for processing and reinjecting high-temperature produced water from offshore heavy oil. Figure 1-4 As shown, its specific structure is substantially the same as that described in Example 1, and the only difference is the preparation method of the hydrophilic PVDF material for preparing the filter membrane filament 335. The specific preparation method is as follows:

[0103] Step 1: Pre-irradiate the PVDF powder under an electron accelerator, adjust the irradiation equipment parameters so that the irradiation dose is 75 kGy and the irradiation dose rate is 30,000 Gy / s, and obtain the pre-treated PVDF material;

[0104] Step 2: Dissolve the pretreated PVDF material obtained in step 1 in N-methyl-2-pyrrolidone, stir under nitrogen protection until completely dissolved, then add acrylic acid monomer and azobisisobutyronitrile, the amount of acrylic acid monomer added is 5% of the pretreated PVDF material, and the amount of azobisisobutyronitrile added is 2% of the mass of the solution system, heat to 65°C, stir and react for 4.5h, filter the reaction solution to obtain a hydrophilic PVDF material.

[0105] Application Example 1

[0106] The same batch of offshore heavy oil high-temperature produced water was divided into six parts and treated by the offshore heavy oil high-temperature produced water treatment and reinjection system provided in Example 3 and Comparative Examples 1-5, respectively. The suspended matter content and oil content of the reinjection water obtained by treatment were measured using the method described in "Q / SY DQ0605-2006 Daqing Oilfield Reservoir Waterflooding Water Quality Indicators and Analysis Methods". The results are shown in the following table:

[0107]

[0108]

[0109] Result analysis: By comparing the above experimental results, it can be seen that the filtration membrane made of the hydrophilic PVDF material provided by the present invention has a good filtration effect, achieving the intended purpose of the present invention.

[0110] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

[0111] Although this article uses more oil removal system 1, fine filtration system 2, membrane filtration system 3, waste oil treatment system 4, sludge treatment system 5, seawater desalination system 6, aeration structure 7, cyclone separator 11, flotation device 12, fine filtration raw water tank 21, self-cleaning filter 22, multi-media filter 23, walnut shell filter 24, membrane filtration raw water tank 31, security filter 32, high-temperature ultrafiltration device 33, water injection buffer tank 34, water injection well 35, ultrafiltration chemical cleaning device 36, ultrafiltration backwash device 37, waste oil storage tank 41, thermal cracking device 42, oil-water separation device 43, backwash wastewater collection box 51, sedimentation tank 52, sludge concentration The terms tank 53, sludge filter press system 54, sludge drying equipment 55, sand filter device 61, reverse osmosis device 62, water production tank 63, dosing system 64, aeration body 71, air hose 72, air inlet 73, air channel 74, axial air outlet 75, radial air outlet 76, lifting structure 77, guide groove 78, guide block 79, convergence plate 7a, membrane thread limiting hole 7b, clearance hole 7c, filtration cavity 331, outer shell 332, mounting member 333, water outlet cavity 334, filtration membrane thread 335, water production port 336, upper outlet 337, lower outlet 338, and water inlet 339 are used, but the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention.

Claims

1. A system for treating and reinjecting high-temperature produced water from offshore heavy oil, comprising an oil removal system (1) and a fine filtration system (2) connected to each other, wherein the oil removal system (1) is further connected to a waste oil treatment system (4) for treating waste oil separated by the oil removal system (1), and the fine filtration system (2) is further connected to a sludge treatment system (5) for treating solid impurities separated by the fine filtration system (2), characterized in that: The fine filtration system (2) is further connected to a membrane filtration system (3) at one end away from the oil removal system (1). The membrane filtration system (3) comprises a membrane filtration raw water tank (31), a security filter (32), a high-temperature ultrafiltration device (33), and a water injection buffer tank (34) which are connected in sequence. The membrane filtration raw water tank (31) is connected to the fine filtration system (2), and the water injection buffer tank (34) is connected to a water injection well (35). The high-temperature ultrafiltration device (33) includes an outer shell (332) having a filter cavity (331) therein, a mounting member (333) is fixedly provided in the outer shell (332), a water outlet cavity (334) is provided above the mounting member (333), one end of the filter membrane thread (335) is fixedly connected to the mounting member (333), and the other end is a free end, the filter cavity (331) is connected to the water outlet cavity (334) through the filter membrane thread (335), and a water outlet (336) and an upper discharge port (337) are further provided at the upper end of the outer shell (332). The water production port (336) is connected to the water outlet cavity (334), the upper discharge port (337) is connected to the filter cavity (331), and the lower end of the outer shell (332) is further provided with a water inlet (339) and a lower discharge port (338), both of which are connected to the filter cavity (331). An aeration structure (7) is further provided in the filter cavity (331), and the aeration structure (7) is slidably connected to the outer shell (332). One end of the aeration structure (7) extends to the outside of the outer shell (332) and is connected to an external air source. The aeration structure (7) includes a cylindrical aeration body (71), an air delivery hose (72) is provided on the aeration body (71), one end of the air delivery hose (72) away from the aeration body (71) is connected to an air inlet (73) provided on the outer shell (332), and the air inlet (73) is connected to an external air source. A plurality of air delivery channels (74) are provided in the aeration body (71), one end of the air delivery channel (74) is connected to the air delivery hose (72), and the other end passes through the top surface and side surface of the aeration body (71) to form an axial air outlet (75) and a radial air outlet (76); The bottom of the aeration body (71) is also connected to a lifting structure (77), and the side of the aeration body (71) is provided with a guide groove (78) recessed toward the inside of the aeration body (71), and the guide groove (78) is slidably connected to a guide block (79) protruding from the inner surface of the outer shell (332); The aeration structure (7) further comprises a convergence disk (7a) fixedly connected to the inner surface of the aeration body (71), wherein the convergence disk (7a) is provided with a plurality of convergence disks (7a) arranged in sequence along the axis of the aeration body (71), a clearance hole (7c) penetrating the convergence disk (7a) is provided at the center of the convergence disk (7a), and the convergence disk (7a) is further provided with a plurality of membrane wire limiting holes (7b) uniformly distributed along the axis of the convergence disk (7a) in the circumferential direction, and the sliding aeration body (71) can allow the free end of the filter membrane wire (335) to pass through the membrane wire limiting hole (7b).

2. The offshore heavy oil high-temperature produced water treatment and reinjection system according to claim 1, characterized in that: The oil removal system (1) includes a cyclone separator (11) connected to a high-temperature produced water source, an air flotation device (12) having one end connected to the cyclone separator (11) and the other end connected to the fine filtration system (2); The waste oil treatment system (4) comprises a waste oil storage tank (41), a thermal cracking device (42) and an oil-water separation device (43) which are connected in sequence. The flotation device (12) is connected to the waste oil storage tank (41) and the waste oil separated in the flotation device (12) is stored in the waste oil storage tank (41). The oil-water separation device (43) is connected to the flotation device (12) and the water phase separated in the oil-water separation device (43) is returned to the flotation device (12).

3. The offshore heavy oil high-temperature produced water treatment and reinjection system according to claim 1, characterized in that: The fine filtration system (2) comprises a fine filtration raw water tank (21), a self-cleaning filter (22), a multi-media filter (23), and a walnut shell filter (24) which are connected in sequence. The fine filtration raw water tank (21) is connected to the oil removal system (1), and the walnut shell filter (24) is connected to the membrane filtration raw water tank (31).

4. The offshore heavy oil high-temperature produced water treatment and reinjection system according to claim 3, characterized in that: The membrane filtration system (3) further comprises an ultrafiltration chemical cleaning device (36) and an ultrafiltration backwashing device (37) both of which are connected to the high-temperature ultrafiltration device (33); the ultrafiltration backwashing device (37) is respectively connected to the self-cleaning filter (22), the multi-media filter (23) and the walnut shell filter (24); and the ultrafiltration backwashing device (37) can transport backwash water to the self-cleaning filter (22), the multi-media filter (23) and the walnut shell filter (24).

5. The offshore heavy oil high-temperature produced water treatment and reinjection system according to claim 3, characterized in that: The sludge treatment system (5) includes a backwash wastewater collection tank (51), a sedimentation tank (52), a sludge concentration tank (53), a sludge filter press system (54) and a sludge drying device (55) which are connected in sequence. The self-cleaning filter (22), the multi-media filter (23) and the walnut shell filter (24) are all connected to the backwash wastewater collection tank (51). The sedimentation tank (52) is connected to the fine filtration raw water tank (21), and the water phase separated after sedimentation in the sedimentation tank (52) is transported to the fine filtration raw water tank (21).

6. The offshore heavy oil high-temperature produced water treatment and reinjection system according to claim 5, characterized in that: The system further includes a seawater desalination system (6), wherein the seawater desalination system (6) includes a sand filter device (61), a reverse osmosis device (62), a water production tank (63), and a dosing system (64) that are sequentially connected. The reverse osmosis device (62) is connected to the sludge drying equipment (55), and the concentrated water output by the reverse osmosis device (62) is used to accelerate the removal of steam generated in the sludge drying equipment (55).

7. The offshore heavy oil high-temperature produced water treatment and reinjection system according to claim 1, characterized in that: The filter membrane (335) is made of a hydrophilic PVDF material, and the hydrophilic PVDF material is prepared by the following method: Step 1: Place the PVDF powder under an electron accelerator for pre-irradiation, adjust the irradiation equipment parameters so that the irradiation dose is 20-200 kGy and the irradiation dose rate is 50-15000 Gy / s, and obtain the pretreated PVDF material; Step 2: Dissolve the pretreated PVDF material obtained in step 1 in a strong polar organic solvent, stir under nitrogen protection until completely dissolved, then add vinyl hydrophilic monomer and initiator, heat to 50-80°C, stir and react for 3-6 hours, filter the reaction solution to obtain hydrophilic PVDF material.

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