An efficient fracturing flowback fluid treatment method

Abstract

The application discloses a kind of high-efficiency fracturing flowback fluid processing methods, it is related to oilfield fracturing flowback fluid processing technical field, the specific steps of this processing method are as follows: S100, photoacoustic electricity collaborative pretreatment: the fracturing flowback fluid to be treated is introduced into reaction vessel, the application is by introducing ultraviolet light source, ultrasonic generator and electrochemical device, and the use of light response type multifunctional agent, the rapid, efficient degradation of pollutants in fracturing flowback fluid is realized, this collaborative processing mode not only improves processing efficiency, but also significantly enhances processing effect, compared with traditional single processing method, the application can more effectively remove organic matter, heavy metal pollutants in fracturing flowback fluid, reduce the difficulty and cost of subsequent processing, simultaneously, photoacoustic electricity collaborative pretreatment technology also has the advantages that operation is simple, controllability is strong, provides a kind of new solution for the treatment of fracturing flowback fluid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oilfield fracturing flowback fluid treatment, in particular to a high-efficiency fracturing flowback fluid treatment method. BACKGROUND

[0002] In the process of oil and gas exploitation, fracturing flowback fluid as an important type of wastewater, its treatment has always been a technical problem, fracturing flowback fluid contains a large amount of suspended solids, organic matter, heavy metal pollutants, if directly discharged, not only will cause serious pollution to the environment, but also waste valuable water resources, therefore, developing a kind of efficient, environmentally friendly fracturing flowback fluid treatment method, for the sustainable development of oil and gas exploitation industry has important significance, in recent years, with the enhancement of environmental awareness and the progress of science and technology, various new wastewater treatment technologies have emerged, providing new ideas and solutions for the treatment of fracturing flowback fluid.

[0003] The traditional fracturing flowback fluid treatment method mainly includes physical method, chemical method and biological method, however, these methods have obvious shortcomings in treatment efficiency, treatment effect and environmental protection, physical method such as filtration, sedimentation, although the operation is simple, but the treatment efficiency is low, it is difficult to achieve ideal treatment effect, chemical method although the treatment efficiency is high, but often needs a large amount of chemical reagent, not only increases the treatment cost, but also may introduce new pollutants, biological method although environmental protection is good, but the treatment period is long, and the water quality requirement is high, it is difficult to adapt to the complex fracturing flowback fluid treatment demand, therefore, it is urgent to develop a new fracturing flowback fluid treatment method which can overcome the shortcomings of traditional technology.

[0004] Therefore, developing a kind of efficient fracturing flowback fluid treatment method will provide new technical support for the sustainable development of oil and gas exploitation industry. SUMMARY

[0005] The purpose of the present application is to make up for the shortcomings of the prior art, and provide a high-efficiency fracturing flowback fluid treatment method, which integrates photoacoustic-electric synergistic pretreatment, enzyme-nano composite agent purification, photo-Fenton-biochar enhanced treatment, deep flocculation and sedimentation, and solid-liquid separation and detection multiple innovative steps, by precisely controlling the amount of reagent, light intensity, ultrasonic frequency and electrochemical conditions, the deep removal of suspended solids, organic matter, heavy metals and other pollutants in fracturing flowback fluid is realized, the present application not only significantly improves the treatment efficiency, but also ensures that the effluent water quality meets the discharge standard or is resource utilization.

[0006] The present application provides the following technical solution to solve the above technical problems: a high-efficiency fracturing flowback fluid treatment method, the specific steps of the treatment method are:

[0007] S100, photoacoustic electric synergistic pretreatment: the fracturing flowback fluid to be treated is introduced into a reaction container, the water quality of the fracturing flowback fluid is preliminarily detected, the indexes of chemical oxygen demand COD, heavy metal content and suspended solid content are determined, a light response type multifunctional agent is added at a proportion of 1-5 grams per liter, the light response type multifunctional agent is mainly composed of organic molecules with photoactivity and metal salts, can change structure and release active groups under light, a UV light source is turned on, the irradiation intensity is 5-20 W / m2, the wavelength is 200-400 nm, the UV light of the wavelength can effectively excite the activity of the light response type multifunctional agent, and an ultrasonic generator and an electrochemical device are started at the same time, and the treatment is performed for 15-60 minutes;

[0008] S200, enzyme-nano composite agent purification: a biological enzyme and nano material composite agent are added at a proportion of 0.5-3 grams per liter, the ultrasonic wave and the electrochemical device are kept running, and the treatment is continuously performed for 2-8 hours;

[0009] S300, photo-Fenton-biochar reinforced treatment: Fenton reagent and biochar are added to the reaction container, the UV irradiation, ultrasonic wave and electrochemical device are kept running, the light energy excites the reaction of ferrous ions in the Fenton reagent and hydrogen peroxide to produce more hydroxyl radicals, enhances the oxidation capacity of organic matter, and cooperates with the free radicals generated by the light response type multifunctional agent to further deeply oxidize organic matter, and the treatment is performed for 3-12 hours;

[0010] S400, deep flocculation and precipitation: after the step S300 ends, the UV light source, ultrasonic wave and electrochemical device are turned off, a flocculation aid is added to the reaction container, stirring is performed at 50-150 r / min for 5-15 minutes, the flocculation aid is uniformly dispersed in the reaction liquid, after uniform stirring, standing is performed for 1-3 hours, the fine particles and flocs generated in the reaction process are further coagulated and precipitated, the flocculation ions generated by the light response type multifunctional agent in the early stage and some precipitates generated in the reaction process are further aggregated in this stage to form larger precipitation particles, and subsequent separation is facilitated;

[0011] S500, solid-liquid separation and detection: the supernatant and the precipitate in the reaction container are separated through filtration and centrifugation, the indexes of COD, heavy metal content and suspended solid content of the supernatant after separation are detected, the supernatant is discharged or reused if the indexes meet the standards, the precipitate is harmlessly treated if the indexes do not meet the standards, and the precipitate is reprocessed.

[0012] Further, the S100, the light-responding multifunctional agent in the photoacoustic-electric synergistic pretreatment is composed of photoactive organic molecules and metal salts. Under ultraviolet irradiation, the molecular structure of the light-responding multifunctional agent changes, the photoactive groups in the light-responding multifunctional agent absorb light energy and undergo electron transition, and strong oxidizing free radicals are released. These free radicals have extremely high oxidation potential and can rapidly attack organic molecules, oxidizing and decomposing them into small molecular substances. At the same time, the metal salts in the agent undergo hydrolysis under the action of light and electric field, generating ions with flocculation effect, such as aluminum ions and iron ions, which make part of the pollutants coagulate and precipitate.

[0013] The photoactive organic molecules are organic molecules containing azobenzene and diaryl ethylene groups.

[0014] The metal salts are:

[0015] Iron salts: ferrous sulfate or ferric chloride;

[0016] Aluminum salts: aluminum sulfate or polyaluminum chloride.

[0017] Further, in the S100, the frequency of the ultrasonic generator in the photoacoustic-electric synergistic pretreatment is set to 20-100 kHz, and the current density of the electrochemical device is set to 10-50 A / m².

[0018] Further, in the S200, the biological enzyme and nanomaterial in the enzyme-nanocomposite agent purification are combined together by physical adsorption or chemical bonding to form a biological enzyme and nanomaterial. The biological enzyme is selected from lipase, protease or amylase, and the nanomaterial is nanometer titanium dioxide or nanometer activated carbon.

[0019] Further, in the S300, the Fenton reagent in the photo-Fenton-biochar enhanced treatment is prepared from ferrous sulfate and hydrogen peroxide. The addition amount of ferrous sulfate is 0.1-1 gram per liter of fracturing flowback fluid, and the addition amount of hydrogen peroxide is 0.5-5 grams per liter of fracturing flowback fluid.

[0020] Further, in the S300, the addition amount of biochar in the photo-Fenton-biochar enhanced treatment is 1-5 grams per liter of fracturing flowback fluid. The abundant pore structure and surface functional groups of biochar can adsorb intermediate products and unreacted pollutants generated during the reaction.

[0021] Further, in the S400, the flocculation aid in the deep flocculation and precipitation is polyacrylamide, and the addition amount is 0.01-0.1 gram per liter of fracturing flowback fluid. Polyacrylamide has a high molecular chain structure and can further coagulate small particles and flocs through bridging.

[0022] Further, the S500, solid-liquid separation and detection in the selection of plate and frame filter press filtration, plate and frame filter press filtration pressure is 0.1-0.5MPa.

[0023] Further, the S500, solid-liquid separation and detection in the selection of centrifuge separation, centrifuge speed is set to 2000-5000r / min, centrifugal time is 5-15 minutes.

[0024] Compared with the prior art, the efficient fracturing flowback fluid treatment method has the following beneficial effects:

[0025] First, the present application introduces ultraviolet light source, ultrasonic generator and electrochemical device, and combines the use of light-responsive multifunctional agent, realizes the rapid and efficient degradation of pollutants in fracturing flowback fluid, this synergistic treatment method not only improves the treatment efficiency, but also significantly enhances the treatment effect, compared with the traditional single treatment method, the present application can more effectively remove organic matter and heavy metal pollutants in fracturing flowback fluid, reduces the difficulty and cost of subsequent treatment, at the same time, the photoacoustic electric synergistic pretreatment technology also has the advantages of simple operation and strong controllability, which provides a new solution for the treatment of fracturing flowback fluid.

[0026] Second, the present application introduces biological enzyme and nanomaterial composite agent, which can further remove refractory pollutants in fracturing flowback fluid by using the catalytic action of biological enzyme and the adsorption performance of nanomaterial, and the light-fenton-biochar enhanced treatment further improves the treatment efficiency and treatment effect by the combined action of ultraviolet irradiation, fenton reagent and biochar, this combined use method not only enhances the specificity and effectiveness of treatment, but also makes the present application show more outstanding advantages in treating high-concentration and refractory fracturing flowback fluid, in addition, the present application also has the steps of deep flocculation and sedimentation, solid-liquid separation and detection, which ensures that the water quality after treatment meets the discharge standard or reuse requirement, realizes the dual goals of resource utilization and environmental protection of fracturing flowback fluid.

[0027] Other advantages, objects, and features of the present application will be apparent to those skilled in the art in view of the following detailed description and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0029] Figure 1 A flow chart of a high-efficiency fracturing flowback fluid treatment method. DETAILED DESCRIPTION

[0030] To further illustrate the technical means and effects taken by the present application to achieve the predetermined inventive purposes, the specific embodiments, structures, features and effects according to the present application are described in detail below in combination with the drawings and preferred embodiments.

[0031] Example 1:

[0032] Fracturing flowback fluid treatment for small oil extraction enterprises

[0033] A small oil extraction enterprise produces about 10 cubic meters of fracturing flowback fluid per day, which is introduced into a reaction container with a volume of 15 cubic meters.

[0034] First, photoacoustic-electric synergistic pretreatment (S100) is performed: water quality detection is performed on the fracturing flowback fluid, and the COD is measured to be 800 mg / L, the heavy metal content (calculated as lead) is 10 mg / L, and the suspended solids content is 300 mg / L. A light-responsive multifunctional agent is added at a ratio of 3 grams per liter, in which the light-active organic molecules are selected from organic molecules containing azobenzene groups, and the metal salt is selected from ferrous sulfate. An ultraviolet light source is turned on, the irradiation intensity is set to 10 W / m², the wavelength is 300 nm, an ultrasonic generator is started at the same time, the frequency is set to 50 kHz, and the current density of the electrochemical device is set to 30 A / m². The treatment is performed for 30 minutes. In this process, the light-responsive multifunctional agent releases strong oxidizing free radicals under ultraviolet irradiation, attacks organic molecules, and part of the organic matter is oxidized and decomposed into small molecular substances. At the same time, ferrous sulfate undergoes hydrolysis under the action of light and electric field to generate ions with flocculation effect, causing part of the pollutants to coagulate and precipitate.

[0035] Then, enzyme-nano composite agent purification (S200) is performed: a composite agent composed of lipase and nano-titanium dioxide combined by physical adsorption is added at a ratio of 2 grams per liter, and the ultrasonic wave and electrochemical device are kept running for 5 hours. The lipase specifically decomposes the remaining complex organic matter in the fracturing flowback fluid, and the nano-titanium dioxide adsorbs the biocatalyst decomposition products and other impurities by virtue of its high specific surface area.

[0036] Then the photo-Fenton-biochar enhanced treatment (S300) is carried out: fenton reagent prepared by adding ferrous sulfate (0.5 g per liter of fracturing flowback fluid) and hydrogen peroxide (3 g per liter of fracturing flowback fluid) into the reaction container, and 3 g of biochar per liter of fracturing flowback fluid are added, and the ultraviolet irradiation, ultrasonic wave and electrochemical device are maintained to operate, and the treatment is carried out for 8 hours, the iron ions in the fenton reagent are excited by light energy to react with hydrogen peroxide to produce more hydroxyl radicals, which synergistically act with the free radicals produced by the light-responsive multifunctional agent to further deeply oxidize organic matter, and the biochar adsorbs the intermediate products produced in the reaction process and the unreacted pollutants.

[0037] Then the deep flocculation and precipitation (S400) is carried out: the ultraviolet light source, ultrasonic wave and electrochemical device are turned off, polyacrylamide is added as a flocculation aid into the reaction container, the addition amount is 0.05 g per liter of fracturing flowback fluid, and stirring is carried out at 100 r / min for 10 minutes to make the flocculation aid uniformly dispersed in the reaction liquid, and after uniform stirring, standing is carried out for 2 hours to make the fine particles and flocs produced in the reaction process further coagulate and precipitate.

[0038] Finally, solid-liquid separation and detection (S500) are carried out: a plate and frame filter press is selected for filtration, the filtration pressure is 0.3 MPa, the supernatant and the precipitate in the reaction container are separated, after separation, the COD of the supernatant is 50 mg / L, the heavy metal content (calculated by lead) is 0.5 mg / L, and the suspended solid content is 10 mg / L, which reaches the discharge standard, the supernatant is discharged, and the precipitate is subjected to harmless treatment.

[0039] In summary, in the fracturing flowback fluid treatment of a small oil exploitation enterprise, 10 cubic meters of fracturing flowback fluid are introduced into a 15 cubic meter reaction container, and the process of photoacoustic electric synergistic pretreatment, enzyme-nano composite agent purification, photo-Fenton-biochar enhanced treatment, deep flocculation and precipitation and solid-liquid separation and detection is carried out, and reasonable selection of light active molecules such as azobenzene groups, lipase agents and parameters is carried out, so that the original fracturing flowback fluid with a COD of 800 mg / L which does not meet the standard is successfully treated to a COD of 50 mg / L which meets the discharge standard, effective purification is realized, it is proved that the present application is feasible for the fracturing flowback fluid treatment of a small enterprise, can meet the environmental protection requirements, and helps the enterprise to realize green production.

[0040] Example two:

[0041] Fracturing flowback fluid treatment of a medium-sized shale gas exploitation site

[0042] A medium-sized shale gas exploitation site produces about 50 cubic meters of fracturing flowback fluid per day, and an 80 cubic meter reaction container is used for treatment.

[0043] Photoacoustic-electric synergistic pretreatment (S100): water quality detection shows that the COD of the fracturing flowback fluid is 1200 mg / L, the heavy metal content (calculated by cadmium) is 15 mg / L, and the suspended matter content is 400 mg / L. A light response type multifunctional agent is added at a ratio of 4 grams per liter. The light active organic molecule is an organic molecule containing a diaryl ethylene group, and the metal salt is ferric chloride. A UV light source is turned on, the irradiation intensity is 15 W / m2, the wavelength is 350 nm, the ultrasonic generator frequency is set to 70 kHz, and the electrochemical device current density is set to 40 A / m2. The treatment time is 45 minutes. At this time, the light response type multifunctional agent changes its structure under light to release free radicals to oxidize organic matter, and ferric chloride is hydrolyzed to generate flocculating ions to precipitate pollutants.

[0044] Enzyme-nano composite agent purification (S200): 2.5 grams of a composite agent formed by chemical bonding of protease and nano activated carbon is added per liter, and the ultrasonic wave and electrochemical device are kept running for 6 hours. The protease decomposes specific organic matter, and the nano activated carbon adsorbs the decomposition products and impurities.

[0045] Photo-Fenton-biochar enhanced treatment (S300): Fenton reagent prepared by adding ferrous sulfate (0.8 grams per liter of fracturing flowback fluid) and hydrogen peroxide (4 grams per liter of fracturing flowback fluid) and 4 grams of biochar per liter of fracturing flowback fluid are added, and the related equipment is kept running for 10 hours. The photoexcitation Fenton reaction generates hydroxyl radicals to synergistically oxidize, and the biochar adsorbs intermediate products and pollutants.

[0046] Deep flocculation and sedimentation (S400): After the equipment is turned off, 0.08 grams of polyacrylamide flocculation aid per liter of fracturing flowback fluid is added, stirred at 120 r / min for 12 minutes, and then left to stand for 2.5 hours to promote the coagulation and sedimentation of particles and flocs.

[0047] Solid-liquid separation and detection (S500): A centrifuge is used for separation, the centrifuge speed is set to 3500 r / min, and the centrifugation time is 10 minutes. After separation, the supernatant has a COD of 60 mg / L, a heavy metal content (calculated by cadmium) of 0.8 mg / L, and a suspended matter content of 8 mg / L. After reaching the standard, it is reused, and the sediment is treated harmlessly.

[0048] In summary, 50 cubic meters of fracturing flowback fluid from a medium-sized shale gas exploitation site is treated in an 80 cubic meter reaction container, and each treatment step is sequentially performed. The molecules containing a diaryl ethylene group and the protease agent are selected, and the equipment parameters are adapted. The COD before treatment is 1200 mg / L, which exceeds the standard, and the COD of the supernatant after treatment is 60 mg / L, which meets the reuse standard. This process shows that the present application can efficiently treat fracturing flowback fluid in medium-sized exploitation sites, reduce pollutant content, and achieve water resource reuse, which has important practical significance and application value for environmental protection treatment in the shale gas industry.

[0049] Example Three:

[0050] Large oil field fracturing flowback fluid centralized treatment station treatment

[0051] A large oil field fracturing flowback fluid centralized treatment station needs to treat about 20 cubic meters of fracturing flowback fluid per day, and a large reaction container with a volume of 30 cubic meters is selected.

[0052] Photoacoustic electric synergistic pretreatment (S100): After detection, the COD of the fracturing flowback fluid is 1500 mg / L, the heavy metal content (calculated as mercury) is 20 mg / L, and the suspended solids content is 500 mg / L. Add 5 grams of light-responsive multifunctional agent per liter, in which the light-active organic molecules are selected from organic molecules containing azobenzene groups, and the metal salt is selected from polyaluminum chloride. Turn on the ultraviolet light source, the irradiation intensity is 20W / m², the wavelength is 400nm, start the ultrasonic generator at the same time, set the frequency to 100kHz, and set the current density of the electrochemical device to 50A / m². Process for 60 minutes. In this step, the light-responsive multifunctional agent releases free radicals to oxidize organic matter, and polyaluminum chloride hydrolysis produces flocculation ions to precipitate part of the pollutants.

[0053] Enzyme-nano composite agent purification (S200): Add 3 grams of composite agent composed of amylase and nano titanium dioxide combined by physical adsorption per liter, and keep the ultrasonic and electrochemical device running for 8 hours. Amylase decomposes specific organic matter, and nano titanium dioxide adsorbs decomposition products and other impurities.

[0054] Photo-Fenton-biochar enhanced treatment (S300): Add Fenton reagent prepared from ferrous sulfate (1 gram per liter of fracturing flowback fluid) and hydrogen peroxide (5 grams per liter of fracturing flowback fluid) and 5 grams of biochar per liter of fracturing flowback fluid to the reaction container. Maintain ultraviolet irradiation, ultrasonic and electrochemical device operation, and process for 12 hours. Light energy excites Fenton reagent reaction to produce hydroxyl radicals to cooperate with oxidation, and biochar adsorbs intermediate products and unreacted pollutants.

[0055] Deep flocculation and sedimentation (S400): Turn off the ultraviolet light source, ultrasonic and electrochemical device, add polyacrylamide flocculation aid to the reaction container, the addition amount is 0.1 gram per liter of fracturing flowback fluid, stir at 150 r / min for 15 minutes, and then stand for 3 hours. Make fine particles and flocs further coagulate and precipitate.

[0056] Solid-liquid separation and detection (S500): first, a plate and frame filter press is used for filtering, the filtering pressure is 0.5 MPa, then a centrifuge is used for secondary separation, the centrifuge speed is set to 5000 r / min, the centrifugation time is 15 minutes, finally, the COD of the supernatant is 40 mg / L, the heavy metal content (calculated by mercury) is 0.3 mg / L, and the suspended solids content is 5 mg / L, which reaches the reuse standard, the supernatant is reused, and the precipitate is harmless treated.

[0057] In summary, the 200 cubic meter fracturing flowback fluid in a large oilfield is treated in a 300 cubic meter reaction container, by virtue of the complete process of the application, specific photoactive molecules and amylases are selected, and parameters of each link are accurately set, the original COD of the fracturing flowback fluid of 1500 mg / L is reduced to 40 mg / L after treatment, reaching the reuse standard, the application has remarkable effects in the centralized treatment station of the large oilfield, guarantees the environmental protection of oilfield production, provides a reliable example for large-scale fracturing flowback fluid treatment, and effectively promotes the sustainable development of the industry.

[0058] The above is only a preferred embodiment of the application, and does not limit the application in any form, although the application has been disclosed as above with a preferred embodiment, however, it is not intended to limit the application, any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the application, and equivalent embodiments with equivalent changes are obtained, as long as they do not depart from the technical solution of the application, any brief modification, equivalent change and modification of the above embodiments according to the technical essence of the application are still within the scope of the technical solution of the application.

Claims

1. A high-efficiency fracturing flowback fluid treatment method, characterized in that, The specific steps of the treatment method are: S100, photoacoustic-electric synergistic pretreatment: introducing the fracturing flowback fluid to be treated into a reaction container, adding a light-responsive multifunctional agent in a proportion of 1-5 grams per liter after detecting the water quality, the light-responsive multifunctional agent being composed of photoactive organic molecules and metal salts; the photoactive organic molecules being organic molecules containing azobenzene and diaryl ethylene groups; the metal salts being iron salts: ferrous sulfate or ferric chloride; aluminum salts: aluminum sulfate or polyaluminum chloride; at the same time, turning on an ultraviolet light source, the irradiation intensity being 5-20 W / m² and the wavelength being 200-400 nm, and starting an ultrasonic generator and an electrochemical device, the frequency of the ultrasonic generator being set to 20-100 kHz and the current density of the electrochemical device being set to 10-50 A / m², and the treatment being performed for 15-60 minutes; S200, enzyme-nano composite agent purification: adding a biological enzyme and nano material composite agent in a proportion of 0.5-3 grams per liter, and maintaining the operation of the ultrasonic generator and the electrochemical device, and continuously treating for 2-8 hours; S300, photo-Fenton-biochar enhanced treatment: adding Fenton reagent and biochar to the reaction container, the addition amount of the biochar being 1-5 grams per liter of the fracturing flowback fluid, and maintaining the operation of the ultraviolet irradiation, the ultrasonic generator and the electrochemical device, and treating for 3-12 hours; S400, deep flocculation and sedimentation: after the step S300 is completed, turning off the ultraviolet light source, the ultrasonic generator and the electrochemical device, adding a flocculation aid to the reaction container, stirring at 50-150 r / min for 5-15 minutes, and standing for 1-3 hours after uniform stirring; S500, solid-liquid separation and detection: separating the supernatant and the precipitate in the reaction container by filtration and centrifugation, detecting the COD, heavy metal content and suspended solid content of the supernatant after separation, discharging or recycling if the indicators meet the standards, and performing harmless treatment on the precipitate if the indicators do not meet the standards.

2. The method of claim 1, wherein, In the S200, enzyme-nano composite agent purification, the biological enzyme and the nano material are combined together by physical adsorption or chemical bonding to form a biological enzyme-nano material combination, the biological enzyme being selected from lipase, protease and amylase, and the nano material being nano titanium dioxide or nano activated carbon.

3. The method of claim 1, wherein the method further comprises, In the S300, photo-Fenton-biochar enhanced treatment, the Fenton reagent is prepared from ferrous sulfate and hydrogen peroxide, the addition amount of the ferrous sulfate being 0.1-1 gram per liter of the fracturing flowback fluid, and the addition amount of the hydrogen peroxide being 0.5-5 grams per liter of the fracturing flowback fluid.

4. The method of claim 1, wherein the method further comprises, In the S400, deep flocculation and sedimentation, the flocculation aid is polyacrylamide, and the addition amount of the polyacrylamide is 0.01-0.1 gram per liter of the fracturing flowback fluid.

5. The method of claim 1, wherein the method further comprises, In the S500, solid-liquid separation and detection, a plate-and-frame filter press is selected for filtration, and the filtration pressure of the plate-and-frame filter press is 0.1-0.5 MPa.

6. The method of claim 1, wherein the method is characterized by, In the S500, solid-liquid separation and detection, a centrifuge is selected for separation, the rotation speed of the centrifuge being set to 2000-5000 r / min, and the centrifugation time being 5-15 minutes.

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