Method for improving treatment effect of high-water-content produced liquid and produced water

Abstract

The invention provides a method for improving the treatment effect of high-water-content produced liquid and produced water. The method mainly solves the problems that according to an existing high-water-content produced liquid and produced water treatment method, the number of agent types is large, the number of agent adding points is large, the water quality is poor, and the yield of dirty oil and oily sludge is high. The preparation method is characterized by comprising the following steps: S1, sequentially dissolving a non-cationic reverse demulsifier and a chelating agent in an alcohol / water solution system according to a certain proportion, mixing, and fully stirring to prepare a uniform and stable solution or emulsion; and S2, adding the prepared anti-scale reverse demulsifier into inflow water of a watering heating furnace of a watering system of a produced liquid gathering and transportation process according to a certain dosing concentration. According to the method, chemical treatment methods of the high-water-content produced liquid and the produced water are integrated and upgraded, so that the dosage types of chemicals are reduced, the treatment effects of the produced liquid and the produced water are improved, the quality of the produced water is remarkably improved, solid impurities such as floc are prevented from being generated, and the generation amount of sump oil and oily sludge is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of oil production engineering, and in particular to a method for improving the treatment effect of high-water-content produced fluid and produced water. Background Art

[0002] Domestic old oil fields are generally in the late stage of high water content development. The comprehensive water content of produced fluids from Daqing old oil fields is generally above 90% and is still rising. Due to the high water content of produced fluids from oil fields in the high water content period, the probability of oil droplets colliding with each other in water-in-oil emulsions is reduced, and the difficulty of oil droplet aggregation and separation increases; at the same time, due to the supersaturation of scale-forming ions such as calcium and magnesium in produced water, which are easy to precipitate and form carbonate particles, these new mineral particles gather on the surface of oil droplets to form steric hindrance, further hindering the aggregation of oil droplets, making it more difficult to separate oil and water from produced fluids and produced water. At the same time, new mineral particles are easily deposited at wellheads, ground gathering and transportation pipelines, and oil and water treatment facilities, resulting in serious scaling problems. Unsettled new mineral particles are suspended in produced water, resulting in excessive suspended solids content in produced water.

[0003] At present, the chemical agents used in oilfield produced fluid treatment mainly include crude oil fluidity improvers, first-stage demulsifiers (oil-water separators, water-soluble demulsifiers), second-stage demulsifiers (dehydrating demulsifiers, oil-soluble demulsifiers), dirty oil demulsifiers, scale inhibitors, cationic reverse demulsifiers (oil removers), etc. The chemical agents used in produced water treatment mainly include cationic flocculants, cationic coagulants, filter cleaning agents and bactericides. These chemical agents for oilfield produced fluid and produced water treatment are all chemical treatment agents developed and researched for oilfields in the low and medium water content development period.

[0004] At present, oil fields use the method of dripping anti-scaling agents at the wellhead or adding anti-scaling agents to the water mixed back to the wellhead at the oil transfer and water discharge station to prevent scale at the wellhead and gathering and transportation pipelines, adding demulsifiers to the liquid manifold of the oil transfer station or the joint station, the three-phase separator / free water remover inlet pipeline for oil-water separation, and adding water clarifiers (including flocculants, coagulants, reverse demulsifiers, etc.) to the sedimentation tank inlet pipeline of the sewage treatment process section to remove oil and impurities from the produced water. There are many types of agents, many points for agent addition, and high amounts of dirty oil and oily sludge.

[0005] Since the emulsion type of high-water-content produced fluid is mainly water-in-oil emulsion, which is consistent with the emulsion type of produced water, the prerequisites for advancing the treatment method of produced water, integrating and upgrading the produced fluid and produced water treatment methods, reducing the types of reagents added and improving the treatment efficiency of produced fluid and produced water are already in place. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the problems of the existing high-water-content produced fluid and produced water treatment methods in the background technology, such as the large number of reagent types, large number of reagent addition points, poor water quality, and high production of dirty oil and oily sludge, and to provide a method for improving the treatment effect of high-water-content produced fluid and produced water. The method for improving the treatment effect of high-water-content produced fluid and produced water integrates and upgrades the produced fluid and produced water treatment methods, can reduce the types of reagents added and the reagent addition points, and improve the produced fluid and produced water treatment efficiency.

[0007] The present invention solves the problem by the following technical solution: The method for improving the treatment effect of high-water-content produced fluid and produced water comprises the following steps:

[0008] S1: The non-cationic reverse demulsifier and the chelating agent are dissolved in an alcohol / water solution system in a certain proportion and mixed, and then stirred thoroughly to prepare a uniform and stable solution or emulsion;

[0009] S2: Add the prepared anti-scaling reverse demulsifier into the water inlet of the water-adding heating furnace of the produced liquid gathering and transportation process water-adding system at a certain dosage concentration.

[0010] Preferably, the anti-scaling reverse demulsifier is added at the wellhead through the water mixing system of the oilfield produced liquid gathering and transportation process, and enters the ground gathering and transportation system with the produced liquid, and the gathering and transportation pipeline from the wellhead to the joint station is used to extend the action time of the agent's demulsification function. The anti-scaling reverse demulsifier can produce chelation with scale-forming ions at the wellhead and in the produced water, controlling the scaling of the ground gathering and transportation system and the high content of suspended solids in the produced water caused by the precipitation of new mineral particles due to oversaturation at the source.

[0011] Preferably, the dosing point of the anti-scaling reverse demulsifier is the inlet of the water-mixing heating furnace of the oil field produced liquid gathering and transportation process oil transfer station, oil transfer and water discharge station or joint station.

[0012] Preferably, the dosage concentration of the anti-scaling reverse demulsifier is 5-20 mg / L based on the produced liquid.

[0013] Preferably, the anti-scaling reverse demulsifier is composed of the following components and mass percentages: non-cationic reverse demulsifier 15% to 30%; chelating agent, 15% to 30%; alcohol, 0% to 10%; water, 30% to 50%.

[0014] Preferably, the non-cationic reverse demulsifier is a composite of one or more of SP, BP and AE demulsifiers.

[0015] Preferably, the main component of the SP type demulsifier is polyoxyethylene polyoxypropylene octadecyl ether; the BP type demulsifier is a polyoxyethylene polyoxypropylene block polyether with propylene glycol as the initiator; and the AE type demulsifier is a polyoxyethylene polyoxypropylene block polyether with polyethylene polyamine as the initiator.

[0016] Preferably, the BP type demulsifier is BP16921; the AE type demulsifier is AE121, AE0604; and the SP type demulsifier is SP169.

[0017] Preferably, the chelating agent is at least one of 2-phosphonobutane-1,2,4-tricarboxylic acid, hydroxyethylidene diphosphonic acid and 2-hydroxypropane-1,2,3-tricarboxylic acid.

[0018] Preferably, the alcohol is at least one of methanol, ethanol, propanol, butanol and fusel alcohol.

[0019] Compared with the above background technology, the present invention has the following beneficial effects:

[0020] Compared with the surface produced liquid and produced water treatment method of adding anti-scaling agent to the mixed water at the wellhead or oil transfer and water discharge station, adding demulsifier at the liquid manifold of the oil transfer station or the combined station, the liquid inlet pipeline of the three-phase separator / free water remover, and adding flocculant and other water treatment agents at the water inlet of the produced water treatment facility, the patent of the present invention has the following beneficial effects: the patent of the present invention compounds a chelating agent with anti-scaling / scale inhibition effect and a demulsifier with demulsification function to form a new type of anti-scaling reverse demulsifier integrating anti-scaling function, alkaline earth metal carbonate particle precipitation inhibition function and high-efficiency demulsification function. The anti-scaling reverse demulsifier is added at the wellhead through the water injection system and enters the ground gathering and transportation system with the produced fluid, which not only prevents the reduction of furnace efficiency caused by scaling of the water injection heating furnace, local overheating and burning of the fireworks tube, etc.; the anti-scaling function and demulsification function of the agent are advanced to the wellhead of the produced well, and the agent is combined with scale-forming ions such as calcium and magnesium at the wellhead to reduce the generation of scale-forming particles such as alkaline earth carbonate particles. At the same time, the gathering and transportation pipeline from the wellhead to the joint station is used to extend the action time of the agent's demulsification function, so that the oil droplets in the gathering and transportation pipeline are fully aggregated and the demulsification effect is improved. Through the addition and application of the patented agent of the present invention, the water quality of the first stage of the oilfield produced fluid treatment process is improved, and the oil content and suspended solid content of the water in the produced water treatment process section are reduced. The addition of water treatment agents such as flocculants and water purifiers can be stopped in the produced water treatment process section, reducing the amount of solid impurities generated, greatly reducing the amount of dirty oil and sludge generated in the water treatment process, while ensuring the water quality of the injected water and reducing the amount of added drugs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart showing the optimization of the types and dosing points of chemical treatment agents for oilfield produced fluid and produced water before and after the application of the process of the present invention;

[0022] Figure 2 This is a picture of the water quality improvement before and after the application of the present invention in the poly-312 oil-to-water wastewater station in Example 6 of the present invention;

[0023] Figure 3 Example 6 of the present invention: the oil content curve and average oil content curve of the water discharged from each process point before and after the application of the present invention in the poly-312 oil-to-oil wastewater station;

[0024] Figure 4 Example 6 of the present invention shows the suspended solid content curve and the average suspended solid content curve of the water discharged from each process point before and after the application of the present invention in the Juzhong 312 oil-to-water wastewater station.

[0025] In the figure: 1-incoming liquid manifold; 2-water-blending heating furnace inlet pipeline; 3-water-blending pipeline; 4-three-phase separator oil outlet pipeline; 5-free water oil outlet pipeline; 6-free water outlet pipeline; 7-oil post external water pipeline-water station water pipeline-first sink water inlet pipeline; 8-second sink water outlet pipeline; 9-external water pipeline; 10-oil and water collection pipeline; 11-oil collection pipeline. Specific implementation method:

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, the content of the present invention is not limited to the following embodiments.

[0027] As attached Figure 1 As shown, the present invention discloses a method for improving the treatment effect of high-water-content produced fluid and produced water, comprising the following steps:

[0028] The chemical treatment process of oilfield produced fluid and produced water is:

[0029] The produced liquid from the oil well (including admixture water) enters the three-phase separator through the liquid manifold 1 for preliminary separation of oil, gas and water. The separated produced water enters the heating furnace through the water admixture heating furnace inlet pipeline 2 for heating, and the heated admixture water is mixed back to the wellhead of the oil well through the water admixture pipeline 3; the water-containing oil separated by the three-phase separator enters the free water remover through the three-phase separator oil outlet pipeline 4 for further oil-water separation, and the water-containing oil separated by the free water remover is sent to the dehydration process for dehydration through the free water oil outlet pipeline 5, and the separated produced water is discharged through the free water oil outlet pipeline 5. The water outlet pipeline 6 of the water remover enters the oil-gang sedimentation tank for buffering and sedimentation; the water from the oil-gang sedimentation tank enters the primary sedimentation tank for sedimentation through the oil-gang external water pipeline-water station water pipeline-first sink water inlet pipeline 7, the water from the first sink enters the secondary sedimentation tank for sedimentation, the water from the second sink enters the primary filter tank and the secondary filter tank in turn through the second sink water outlet pipeline 8, the water from the second filter is buffered by the purified water tank and then transmitted to the outside through the external water pipeline 9; the backwash water recovered from the first and second filters first enters the recovery pool, and then the dirty oil and wastewater are recovered to the first sink inlet through the oil collection and water collection pipeline 10. The oil collected from the top of the first sink, the second sink and the purified water tank is recovered to the inlet of the free water remover through the oil collection tank and the oil collection pipeline 11.

[0030] The water discharged from the three-phase separator enters the water-injection heating furnace through the water-injection heating furnace inlet pipeline 2 for heating, and the heated produced water is transported to the oil well through the water-injection pipeline 3 as injection water. The injection water is mixed with the produced liquid at the wellhead, and the oil well produced liquid containing the injection water enters the three-phase separator through the incoming liquid manifold, forming an oilfield produced liquid gathering and transportation process injection water system.

[0031] The original dosing method of the high-water produced liquid and produced water treatment process is to add a scale inhibitor to the water mixing heater inlet pipeline 2, add a section of demulsifier to the three-phase separator oil outlet pipeline 4, and add a water purifier or flocculant or coagulant at the oil station water pipeline-water station water pipeline-first sink water inlet pipeline 7. Among them, the three-phase separator oil outlet pipeline 4 is short, and the demulsifier agent has a short action time and does not work fully.

[0032] The dosing method of the patent of the present invention: it is only necessary to add anti-scaling reverse demulsifier to the inlet pipeline 2 of the water-mixing heating furnace, control the generation of new particles at the front end, and use the flow field in the incoming liquid manifold 1 to make the agent fully act, promote the aggregation of emulsified oil droplets in the produced liquid, and enhance the oil-water separation effect.

[0033] Example 1

[0034] The invention is applied to the treatment of produced liquid of La 381 joint station of the sixth oil production plant of Daqing Oilfield, and the added agent is anti-scaling reverse demulsifier FSP-2106 (its ratio is BP type demulsifier BP-1692125%, 2-phosphonic acid butane-1,2,4 tricarboxylic acid 20%, butanol 5%, water 50%), the polymer content of produced liquid of La 381 station is 126mg / L, and the carbonate supersaturation of produced water is 37mg / L. Take the anti-scaling reverse demulsifier for infusion outside La 381 station under the conditions of keeping warm at 40℃ and settling for 30min, add the agent concentration of 15mg / L, the oil content of water phase is reduced from 8153mg / L to 170mg / L, add the agent concentration of 20mg / L, the suspended solid content is reduced from 120mg / L to 20mg / L, and the effective separation of oil and water and the removal of suspended solids are achieved.

[0035] Example 2

[0036] The invention is applied to the treatment of produced liquid from the No. 208 oil transfer station of the first oil production plant of Daqing Oilfield, and the added agent is the anti-scaling reverse demulsifier FSP-2111 (its ratio is 20% of AE type demulsifier AE0604, 10% of 2-hydroxypropane-1,2,3-tricarboxylic acid, 10% of hydroxyethylidene diphosphonic acid, 10% of ethanol, and 50% of water), the polymer content of the produced liquid from the No. 208 station is 634 mg / L, and the carbonate supersaturation of the produced water is 15 mg / L. The anti-scaling reverse demulsifier is applied to the external infusion of the No. 208 station, and under the conditions of keeping warm at 40°C and settling for 30 minutes, the agent concentration is 5 mg / L, the oil content of the water phase is reduced from 891 mg / L to 270 mg / L, and the suspended solid content is reduced from 30 mg / L to 14 mg / L, thereby achieving effective separation of oil and water and removal of suspended solids.

[0037] Example 3

[0038] The invention is applied to the treatment of produced liquid of the Xingnan No. 2 oil station of the Fifth Oil Production Plant of Daqing Oilfield, and the added agent is the anti-scaling reverse demulsifier FSP-2105 (its proportion is 15% of SP type demulsifier SP169, 10% of 2-phosphonic acid butane-1,2,4-tricarboxylic acid, 10% of hydroxyethylidene diphosphonic acid, 10% of 2-hydroxypropane-1,2,3-tricarboxylic acid, 5% of propanol, and 50% of water), the polymer content of the produced liquid of the Xingnan No. 2 oil station is 196 mg / L, and the carbonate supersaturation of the produced water is 62 mg / L. The anti-scaling reverse demulsifier is used for the infusion outside the Xingnan No. 2 oil station, and under the conditions of keeping temperature at 40°C and settling for 30 minutes, the agent concentration is 10 mg / L, the oil content of the water phase is reduced from 134 mg / L to 38 mg / L, and the suspended solid content is reduced from 7 mg / L to 2 mg / L, thereby achieving effective separation of oil and water and removal of suspended solids.

[0039] Example 4

[0040] The invention is applied to the treatment of produced liquid of Xingbei 1601 oil transfer station of the fourth oil production plant of Daqing Oilfield, the added agent is anti-scaling reverse demulsifier FSP-2101 (its ratio is 15% of AE type demulsifier AE121, 30% of hydroxyethylidene diphosphonic acid, 5% of methanol, and 50% of water), the polymer content of produced liquid of Xingbei 1601 oil transfer station is 145mg / L, and the carbonate supersaturation of produced water is 51mg / L. The anti-scaling reverse demulsifier is applied to the infusion outside the Xingbei 1601 oil transfer station, and under the conditions of keeping warm at 40℃ and settling for 30min, the added agent concentration is 15mg / L, the oil content of the water phase is reduced from 608mg / L to 22mg / L, and the added agent concentration is 5mg / L, the suspended solid content is reduced from 6mg / L to 5mg / L, and the effective separation of oil and water and the removal of suspended solids are achieved.

[0041] Example 5

[0042] The present invention is applied to the oil-water treatment system of Xingsi Joint Station of the Fifth Oil Production Plant of Daqing Oilfield. The dosing agent is the anti-scaling reverse demulsifier FSP-2101 (its ratio is AE type demulsifier AE12115%, hydroxyethylidene diphosphonic acid 30%, methanol 5%, water 50%). Xingsi Joint Station has 5 water-driven oil transfer stations (Xingnan No. 1 Oil Transfer Station, Xingnan No. 3 Oil Transfer Station, Xingnan No. 4 Oil Transfer Station, Xingnan No. 5 Oil Transfer Station, Xingnan No. 20 Oil Transfer Station). The produced liquids of each oil transfer station are gathered and enter the Xingsi Joint Station for oil-water separation and sewage treatment. The produced liquid treatment process is a two-stage free water remover + electric dehydrator. The separated produced water passes through the sewage treatment post of this station for 2000m 3 The wastewater is treated by sedimentation tank + cross flow + three-stage filtration system and then exported. The treated wastewater is polymer-containing wastewater with an average polymer content of 40 mg / L.

[0043] The dosing point of the anti-scaling reverse demulsifier is the liquid manifold of the Xingnan Sanhe and Xingnan Ershi oil stations under Xing Silian. The dosage of the agent is 15mg / L to 25mg / L (based on the total liquid volume). During the dosing period, the original anti-scaling agent and the first-stage demulsifier are stopped at the same time. The process flow diagram before and after the change of the agent is shown in Figure 1 .

[0044] Before and after changing the dressing, drain the free water of Xingsilian and drain the water of Yougang sedimentation tank (2000m 3 The water quality of discharge water), pre-filtration water, general sewage external transmission water (one filtration), and deep external transmission water (three filtrations) is shown in Table 1.

[0045] Table 1 Water quality monitoring results at each process point

[0046]

[0047] As can be seen from Table 1, the oil content of the free water remover discharge water was reduced from 1014 mg / L before the dressing change to below 300 mg / L and as low as 242 mg / L, the oil content of the sewage treatment system sedimentation tank effluent was reduced from 370 mg / L before the dressing change to below 150 mg / L and as low as 14 mg / L, the suspended solid content was reduced from 33 mg / L before the dressing change to below 20 mg / L and as low as 10 mg / L, the oil content of the general sewage external water was reduced from 85 mg / L before the dressing change to below 20 mg / L and as low as 2 mg / L, the suspended solid content was reduced from 13 mg / L before the dressing change to below 8 mg / L and as low as 2 mg / L, the oil content of the deep sewage external water was reduced from 30 mg / L before the dressing change to below 5 mg / L and as low as 1 mg / L, the suspended solid content was reduced from 10 mg / L before the dressing change to below 5 mg / L and as low as 1 mg / L. Without adding any additional water treatment agents such as water purifiers and flocculants to the sewage treatment system, the station's general sewage water delivery has achieved the high permeability reservoir reinjection water index of double "20" (i.e. the oil content of water before filtration reaches 20mg / l, and the suspended solids are below the control index of 20mg / l). The station's deep sewage water delivery has achieved the low permeability reservoir reinjection water index of double "5" (i.e. the oil content and suspended solids are both 5mg / l).

[0048] Example 6

[0049] The invention is applied to the polymer flooding oil and water treatment system of the Poly-Zhong 312 oil conversion wastewater station of the first oil production plant of Daqing Oilfield. The dosing agent is the anti-scaling reverse demulsifier FSP-2101 (its ratio is 15% of AE type demulsifier AE121, 30% of hydroxyethylidene diphosphonic acid, 5% of methanol, and 50% of water). The liquid (including water) in the metering room of the polymer flooding system of the Poly-Zhong 312 oil conversion wastewater station is about 10300m 3 / d, water mixing is the water release of the water drive system of this station, about 1700m 3 / d, the discharged water enters the sewage station of this station for treatment after passing through the oil station sedimentation tank. To ensure the water quality, 5.5kg / d of dry powder flocculant is added into the water. The treated low-water oil and the low-water oil of the water drive system are transported together to the Zhong 16 Joint Station for further dehydration treatment. Some treatment parameters are shown in Table 2.

[0050] Table 2 Some treatment parameters of Juzhong 312 oil-to-water wastewater station

[0051] Polymer content, mg / L 347 Oil treatment load rate, % 88 Water treatment load rate, % 59 <![CDATA[Backwashing water volume, m 3 / d]]> 766 <![CDATA[External water output, m 3 / d]]> 10960

[0052] During the field trial:

[0053] 1. Stop adding demulsifier and flocculant in use;

[0054] 2. Add the newly developed anti-scaling reverse demulsifier at a dosage of 11-16 mg / L (the original demulsifier dosage is about 20 mg / L), and use the water mixing system to move the dosing point forward to the wellhead. The agent can be used before the output fluids of each well are mixed to prevent the generation of new solid particles after the water phase is oversaturated. At the same time, pipeline demulsification is used to exert the oil-water separation effect of the anti-scaling reverse demulsifier to ensure that the treatment meets the standards.

[0055] Before and after the application of the present invention, the processing conditions of each process point are shown in Figure 2 , Figure 3 , Figure 4 . Figure 2 This is a picture of the water quality improvement before and after the application of the present invention in the Poly-Zhong 312 oil-to-water wastewater station; Figure 3 The oil content curve and average oil content curve of the discharged water at each process point before and after the application of the present invention in the Poly-Zhong 312 oil-to-water wastewater station; Figure 4 The suspended solid content curves and average suspended solid content curves of the water discharged from each process point of the Juzhong 312 oil-to-water wastewater station before and after the application of the present invention.

[0056] from Figure 2 , Figure 3 and Figure 4 It can be seen that the addition of FSP-2101 of the present invention significantly reduced the oil content of the water discharged from the three-phase separator of the 312 oil-to-water transfer station in Poly-Zhong and the water discharged from the oil-gang sedimentation tank, and the oil content of the water before filtration was 10 mg / L on average; the average supersaturation of water was reduced to 4 mg / L, and the suspended solid index of the water discharged from the oil-gang sedimentation tank was significantly improved, and the average suspended solid index of the water before filtration was 10 mg / L. The water quality of each process point was significantly improved, and the water before filtration reached the control index of 20 mg / l oil content and 20 mg / l suspended solids.

Claims

1. A method for improving the treatment effect of high-water-content produced fluid and produced water, characterized in that: The following steps are involved: S1: The non-cationic reverse demulsifier and the chelating agent are dissolved in an alcohol / water solution system in a certain proportion and mixed, and then stirred thoroughly to prepare a uniform and stable solution or emulsion; S2: Add the prepared anti-scaling reverse demulsifier into the water inlet of the water-adding heating furnace of the produced liquid gathering and transportation process water-adding system at a certain dosage concentration.

2. The method for improving the treatment effect of high-water-content produced fluid and produced water according to claim 1, characterized in that: The dosing point of the anti-scaling reverse demulsifier is the inlet of the water-mixing heating furnace of the oil field produced liquid gathering and transportation process oil transfer station, oil transfer and water discharge station or combined station.

3. The method for improving the treatment effect of high-water-content produced fluid and produced water according to claim 2, characterized in that: The anti-scaling reverse demulsifier is added at the wellhead through the water mixing system of the oilfield produced liquid gathering and transportation process, and enters the ground gathering and transportation system with the produced liquid. The gathering and transportation pipeline from the wellhead to the joint station is used to extend the action time of the demulsification function of the agent; The anti-scaling reverse demulsifier can chelate the scale ions in the wellhead and produced water, controlling the new mineral particles precipitated due to oversaturation at the source.

4. The method for improving the treatment effect of high-water produced fluid and produced water according to claim 1 or 2, characterized in that: The dosage concentration of anti-scaling reverse demulsifier is 5-20 mg / L based on the produced liquid.

5. The method for improving the treatment effect of high-water-content produced fluid and produced water according to claim 1, characterized in that: The anti-scaling reverse demulsifier is composed of the following components and mass percentages: 15% to 30% of non-cationic reverse demulsifier; 15% to 30% of chelating agent; 0% to 10% of alcohol; and 30% to 50% of water.

6. The method for improving the treatment effect of high-water-content produced fluid and produced water according to claim 5, characterized in that: The non-cationic reverse demulsifier is a composite of one or more of SP type, BP type and AE type demulsifiers.

7. The method for improving the treatment effect of high-water-content produced fluid and produced water according to claim 6, characterized in that: The main component of SP type demulsifier is polyoxyethylene polyoxypropylene octadecyl ether; BP type demulsifier is a polyoxyethylene polyoxypropylene block polyether with propylene glycol as the initiator; AE type demulsifier is a polyoxyethylene polyoxypropylene block polyether with polyethylene polyamine as the initiator.

8. The method for improving the treatment effect of high-water-content produced fluid and produced water according to claim 7, characterized in that: The BP type demulsifier is BP16921; the AE type demulsifier is any one of AE121 and AE0604; the SP type demulsifier is SP169.

9. The method for improving the treatment effect of high-water-content produced fluid and produced water according to claim 5, characterized in that: The chelating agent is at least one of 2-phosphonobutane-1,2,4-tricarboxylic acid, hydroxyethylidene diphosphonic acid and 2-hydroxypropane-1,2,3-tricarboxylic acid.

10. The method for improving the treatment effect of high-water-content produced fluid and produced water according to claim 5, characterized in that: The alcohol is at least one of methanol, ethanol, propanol, butanol and fusel alcohol.

Images