Oilfield produced water treatment agent and preparation method thereof

Abstract

The present invention belongs to the technical field of oilfield produced water treatment agents, and specifically relates to an oilfield produced water treatment agent and a preparation method thereof. The oilfield produced water treatment agent is composed of the following raw materials in parts by weight: polysilicate ferric sulfate aluminum modified vermiculite, diethyltriamine penta-methylenephosphonic acid, sulfonated succinic acid di-2-ethylhexyl sodium salt, 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether, N,N,N',N'-tetraphenyl-1,4-phenylenediamine, lauric acid imidazoline quaternary ammonium salt, phosphono-succinic acid, polypropylene glycol monostearate, tetrahydroxymethyl sulfate phosphorus. The oilfield produced water treatment agent prepared by the preparation method of the present invention has excellent oil removal rate, suspended solid removal rate, COD removal rate and scale inhibition rate, and has a lower corrosion rate; when it is used for reinjection, it has good compatibility with formation water, and formation blockage does not occur.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield produced water treatment agents, and specifically relates to an oilfield produced water treatment agent and a preparation method thereof. Background Art

[0002] Oilfield produced water refers to the water-containing crude oil extracted from underground, which is called "produced liquid". The water separated by electric dehydration is also called "oilfield wastewater". Due to different oil production methods, crude oil characteristics, geological conditions and other conditions, the water quality of oilfield produced water varies. Oilfield produced water has its own particularities, but also has commonalities. The main characteristics of oilfield produced water are as follows: First, it has high oil content, high suspended solids content, and high mineralization. Oil and suspended solids often interact with each other, and the density difference with water is small. At the same time, a considerable part of it exists in a stable colloidal state; second, the composition is complex, including petroleum substances, formation clay particles, soluble minerals, bacteria, and oilfield oil production additives; third, the water quality is variable: the water quality varies with the geological conditions of the reservoir, the oil production process, the length of the production time, etc., that is, the water quality conditions of the wastewater produced from different oil wells in different periods of the same block may vary greatly; fourth, it is easy to breed bacteria. Since oilfield wastewater contains a large amount of organic matter, for wastewater with a temperature below 50°C, a large number of bacteria (such as SRB, TGB, iron bacteria) often grow. Direct discharge of untreated or unqualified oilfield produced water has a great impact on the natural environment and ecological balance, and also causes serious waste of water resources. Therefore, the treatment of oilfield produced water is urgent and has important significance for maintaining ecological balance, water resource circulation and economic sustainable development.

[0003] At present, there are three main ways to treat oilfield produced water: (1) treat it to meet the discharge standards and then discharge it; (2) treat it to meet certain standards and then use it as reinjection water for water injection or injection into waste formations; (3) use it as water for preparing polymer flooding solutions. From the current domestic oilfield treatment process, the most economical and effective one is still to use it as reinjection water for water injection or injection into waste formations after it meets certain standards. However, no matter which method is used, the problem that needs to be solved urgently is the removal of impurities.

[0004] After oil field produced water is treated by oil removal, heating, sedimentation, adding chemical agents, etc., the produced sewage has poor compatibility with formation sewage, leading to formation pollution and formation blockage. Formation pollution and blockage will lead to a decrease in crude oil production and cause serious scaling. Therefore, it is necessary to explore a new type of oil field produced water treatment agent to enhance the compatibility of the treated produced water with formation sewage. Summary of the invention

[0005] The purpose of the present invention is to provide an oilfield produced water treatment agent, which has excellent oil removal and coagulation effects; in addition, the present invention also provides a preparation method thereof.

[0006] The oilfield produced water treatment agent of the present invention is composed of the following raw materials in parts by weight: 10-12 parts of polysilicate ferric sulfate aluminum modified vermiculite, 4.2-4.5 parts of diethyltriamine penta-methylenephosphonic acid, 6-8 parts of sulfonated succinic acid di-2-ethylhexyl sodium salt, 2-2.5 parts of 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether, 0.5-0.8 parts of N,N,N',N'-tetraphenyl-1,4-phenylenediamine, 3.2-3.5 parts of lauric acid imidazoline quaternary ammonium salt, 1.4-1.6 parts of phosphonosuccinic acid, 2.0-2.3 parts of polypropylene glycol monostearate, and 1.2-1.5 parts of tetrakis hydroxymethyl phosphonium sulfate; wherein the preparation method of polysilicate ferric sulfate aluminum modified vermiculite is composed of the following steps:

[0007] ① The vermiculite was washed with deionized water, then dried at 55-58°C for 46-47h, and finally calcined at 750°C for 1.5min. After cooling, the vermiculite was ground through a 200-mesh sieve to prepare calcined vermiculite;

[0008] ② Add the calcined vermiculite to the polysilicate aluminum iron sulfate solution, stir the mixture with magnetic force for reaction for 5.2-5.5 hours, filter, dry and grind to prepare the polysilicate aluminum iron modified vermiculite.

[0009] in:

[0010] In step ②, the mass ratio of calcined vermiculite to polysilicate aluminum ferric sulfate solution is 1:10.

[0011] The mass concentration of the polysilicate aluminum ferric sulfate solution in step ② is 10%.

[0012] In step ②, the magnetic stirring speed is 250-300 r / min.

[0013] In step ②, the drying temperature is 105-108° C. and the drying time is 4-4.5 h; the mixture is ground through a 200-mesh sieve.

[0014] The structural formula of lauric acid imidazoline quaternary ammonium salt is: .

[0015] The oilfield produced water treatment agent of the present invention has raw materials that interact and cooperate with each other, and while removing impurities from the oilfield produced water, ensures that the treated produced water has good compatibility with formation water when used for reinjection, without formation blockage and scaling. In order to reduce the production cost of the prepared oilfield produced water treatment agent, the vermiculite is modified and added as an adsorption coagulation impurity remover. When vermiculite is used alone, the removal effect of suspended solids and organic matter is poor. Therefore, polysilicate ferric sulfate aluminum is selected to modify the vermiculite. After high-temperature calcination, the water molecules of vermiculite are vaporized due to heating, which increases the interlayer spacing of the vermiculite, making it have a strong ion exchange capacity and a large specific surface area. The polysilicate ferric sulfate aluminum is compounded. The relative molecular mass of polysilicate ferric sulfate aluminum is large, the particle size is large, and it has adsorption-bridging ability. The precipitation particles formed are large and the precipitation time is short; therefore, after the vermiculite is modified by polysilicate ferric sulfate aluminum, flocs with a high density of inorganic mineral particles as the skeleton are formed, which effectively promotes the sedimentation of the flocs, thereby removing the dissolved minerals, suspended matter and demulsified oil-containing substances in the oilfield produced water. Diethyltriamine penta (methylene phosphonic acid) is added to inhibit the formation of carbonate and sulfate scale, and its temperature resistance is good.

[0016] The oilfield produced water treatment agent of the present invention uses a compound of sulfonated succinic acid di-2-ethylhexyl sodium salt and 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether to remove dispersed oil, emulsified oil and heavy oil such as colloid asphalt in the oilfield produced water to achieve demulsification. Among them, the molecular structure of sulfonated succinic acid di-2-ethylhexyl sodium salt contains both hydrophilic groups and lipophilic groups, which are used to reduce the oil-water interfacial tension, enhance the penetration ability, dispersion ability and adsorption ability of the water treatment agent, play a certain degreasing and oil removal effect, and can also destroy the stability of the oily colloid. 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether is a nonionic surfactant, which reduces the elasticity and viscosity of the interface film by replacing the oilfield oil production auxiliary agents such as emulsifiers adsorbed on the oil-water interface, thereby reducing the strength of the interface film, accelerating the coalescence of droplets and achieving demulsification and oil removal. The quaternary ammonium salt of lauric acid imidazoline, phosphonobutanedioic acid and N,N,N',N'-tetraphenyl-1,4-phenylenediamine are compounded and used to act as a corrosion inhibitor. Among them, the quaternary ammonium salt of lauric acid imidazoline has excellent corrosion inhibition performance in high salt systems. The structure contains two nitrogen-containing five-membered rings, which enhances the adsorption effect on the metal surface, so that it still has a high corrosion inhibition efficiency at higher temperatures. After addition, the metal corrosion reaction needs to overcome a higher energy barrier, thereby effectively inhibiting the corrosion reaction. Phosphonobutanedioic acid can form a protective film composed of chemical adsorption and complex precipitation film on the metal surface, and can chelate with divalent metal ions to have a certain scale inhibition effect. In addition, due to its stable chemical structure, it can be used in media with higher temperatures. Considering that dissolved oxygen has a great impact on the use of oilfield produced water during reinjection, it not only directly affects the corrosion of oilfield produced water to metals, but also the dissolved oxygen in the water will cause soluble iron to form insoluble iron oxide precipitation, thus causing blockage. Therefore, N,N,N',N'-tetraphenyl-1,4-phenylenediamine is added to deoxygenate and used in combination with corrosion inhibitors to fundamentally prevent the occurrence of metal corrosion reactions. In addition, polypropylene glycol monostearate is added to the oilfield produced water treatment agent as a defoamer, and tetrakis hydroxymethyl phosphonium sulfate is used as a bactericide to inhibit the growth of sulfate-reducing bacteria and iron bacteria.

[0017] The method for preparing the oilfield produced water treatment agent of the present invention comprises the following steps:

[0018] (1) adding polysilicate ferric aluminum sulfate modified vermiculite and 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether to sulfonated di-2-ethylhexyl sodium succinate and mixing them evenly to prepare a first reaction system;

[0019] (2) adding N,N,N',N'-tetraphenyl-1,4-phenylenediamine, lauric acid imidazoline quaternary ammonium salt and phosphonosuccinic acid to polypropylene glycol monostearate and mixing evenly, and then cooling to room temperature to prepare a second reaction system;

[0020] (3) mixing diethyltriamine penta(methylenephosphonic acid) and tetrakis(hydroxymethyl)phosphonium sulfate evenly to prepare a third reaction system;

[0021] (4) The first reaction system and the second reaction system are added to the third reaction system and mixed evenly to prepare an oilfield produced water treatment agent.

[0022] in:

[0023] In step (1), the mixing temperature is 50-55° C. and the mixing time is 8-12 min.

[0024] In step (2), the mixing temperature is 210-215° C. and the mixing time is 5-10 min.

[0025] In step (3), the mixing temperature is 40-45° C. and the mixing time is 15-17 min.

[0026] In step (4), the mixing temperature is 30-35° C. and the mixing time is 20-25 min.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The raw materials of the oilfield produced water treatment agent described in the present invention cooperate with each other and work synergistically. Polysilicate ferric sulfate aluminum modified vermiculite is added as an adsorption coagulation impurity remover, diethyltriamine penta (methylene phosphonic acid) is added as a scale inhibitor, sulfonated succinic acid di-2-ethylhexyl sodium salt and 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether work synergistically to play a role in demulsification and oil removal, N,N,N',N'-tetraphenyl-1,4-phenylenediamine, lauric acid imidazoline quaternary ammonium salt and phosphonobutyl succinic acid interact with each other to play a role in deoxidation and corrosion inhibition, polypropylene glycol monostearate is added as a defoamer, and tetrakis (hydroxymethyl) phosphonium sulfate is added as a sterilizing agent. Thus, the removal of organic and inorganic impurities in oilfield produced water is achieved.

[0029] (2) The oilfield produced water treatment agent prepared by the preparation method of the present invention has excellent oil removal rate, suspended solids removal rate, COD removal rate and scale inhibition rate, and has a low corrosion rate; when it is used for reinjection, it has good compatibility with formation water and does not cause formation blockage.

[0030] (3) The method for preparing the oilfield produced water treatment agent of the present invention has a simple process and easy-to-control parameters. The prepared produced water treatment agent has stable performance and a wide range of applications. DETAILED DESCRIPTION

[0031] The present invention is further described below with reference to the embodiments.

[0032] Example 1

[0033] The oilfield produced water treatment agent described in Example 1 is composed of the following raw materials in parts by weight: 11 parts of polysilicate ferric sulfate aluminum modified vermiculite, 4.3 parts of diethyltriamine penta-methylenephosphonic acid, 7 parts of sulfonated succinic acid di-2-ethylhexyl sodium salt, 2.3 parts of 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether, 0.6 parts of N,N,N',N'-tetraphenyl-1,4-phenylenediamine, 3.3 parts of lauric acid imidazoline quaternary ammonium salt, 1.5 parts of phosphonosuccinic acid, 2.1 parts of polypropylene glycol monostearate, and 1.3 parts of tetrakis hydroxymethyl sulfate; wherein the preparation method of polysilicate ferric sulfate aluminum modified vermiculite is composed of the following steps:

[0034] ① The vermiculite was washed with deionized water, then dried at 56°C for 46.5h, and finally calcined at 750°C for 1.5min. After cooling, the vermiculite was ground through a 200-mesh sieve to prepare calcined vermiculite;

[0035] ② The calcined vermiculite was added to the polysilicate aluminum iron sulfate solution, and the mixture was mixed and reacted with magnetic stirring for 5.3 hours. The polysilicate aluminum iron modified vermiculite was prepared by suction filtration, drying and grinding.

[0036] in:

[0037] In step ②, the mass ratio of calcined vermiculite to polysilicate aluminum ferric sulfate solution is 1:10.

[0038] The mass concentration of the polysilicate aluminum ferric sulfate solution in step ② is 10%.

[0039] In step ②, the magnetic stirring speed is 280 r / min.

[0040] In step ②, the drying temperature is 106° C. and the drying time is 4.3 h; the mixture is ground through a 200-mesh sieve.

[0041] The structural formula of lauric acid imidazoline quaternary ammonium salt is: .

[0042] The preparation method of the oilfield produced water treatment agent described in this embodiment 1 is composed of the following steps:

[0043] (1) adding polysilicate ferric aluminum sulfate modified vermiculite and 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether to sulfonated di-2-ethylhexyl sodium succinate and mixing them evenly to prepare a first reaction system;

[0044] (2) adding N,N,N',N'-tetraphenyl-1,4-phenylenediamine, lauric acid imidazoline quaternary ammonium salt and phosphonosuccinic acid to polypropylene glycol monostearate and mixing evenly, and then cooling to room temperature to prepare a second reaction system;

[0045] (3) mixing diethyltriamine penta(methylenephosphonic acid) and tetrakis(hydroxymethyl)phosphonium sulfate evenly to prepare a third reaction system;

[0046] (4) The first reaction system and the second reaction system are added to the third reaction system and mixed evenly to prepare an oilfield produced water treatment agent.

[0047] in:

[0048] In step (1), the mixing temperature is 53° C. and the mixing time is 10 min.

[0049] In step (2), the mixing temperature is 213° C. and the mixing time is 8 min.

[0050] In step (3), the mixing temperature is 43° C. and the mixing time is 16 min.

[0051] In step (4), the mixing temperature is 33° C. and the mixing time is 23 min.

[0052] Example 2

[0053] The oilfield produced water treatment agent described in Example 2 is composed of the following raw materials in parts by weight: 12 parts of polysilicate ferric sulfate aluminum modified vermiculite, 4.2 parts of diethyltriamine penta (methylene phosphonic acid), 6 parts of sulfonated succinic acid di-2-ethylhexyl sodium salt, 2.5 parts of 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether, 0.5 parts of N,N,N',N'-tetraphenyl-1,4-phenylenediamine, 3.5 parts of lauric acid imidazoline quaternary ammonium salt, 1.4 parts of phosphonosuccinic acid, 2.3 parts of polypropylene glycol monostearate, and 1.2 parts of tetrakis (hydroxymethyl) phosphite; wherein the preparation method of polysilicate ferric sulfate aluminum modified vermiculite is composed of the following steps:

[0054] ① The vermiculite was washed with deionized water, then dried at 58°C for 46 hours, and finally calcined at 750°C for 1.5 minutes. After cooling, the vermiculite was ground through a 200-mesh sieve to prepare calcined vermiculite;

[0055] ② The calcined vermiculite was added to the polysilicate aluminum iron sulfate solution, and the mixture was stirred with magnetic force for reaction for 5.2 hours. The polysilicate aluminum iron modified vermiculite was prepared by filtration, drying and grinding.

[0056] in:

[0057] In step ②, the mass ratio of calcined vermiculite to polysilicate aluminum ferric sulfate solution is 1:10.

[0058] The mass concentration of the polysilicate aluminum ferric sulfate solution in step ② is 10%.

[0059] In step ②, the magnetic stirring speed is 300 r / min.

[0060] In step ②, the drying temperature is 108° C. and the drying time is 4 h; the mixture is ground through a 200-mesh sieve.

[0061] The structural formula of lauric acid imidazoline quaternary ammonium salt is: .

[0062] The preparation method of the oilfield produced water treatment agent described in this embodiment 2 is composed of the following steps:

[0063] (1) adding polysilicate ferric aluminum sulfate modified vermiculite and 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether to sulfonated di-2-ethylhexyl sodium succinate and mixing them evenly to prepare a first reaction system;

[0064] (2) adding N,N,N',N'-tetraphenyl-1,4-phenylenediamine, lauric acid imidazoline quaternary ammonium salt and phosphonosuccinic acid to polypropylene glycol monostearate and mixing evenly, and then cooling to room temperature to prepare a second reaction system;

[0065] (3) mixing diethyltriamine penta(methylenephosphonic acid) and tetrakis(hydroxymethyl)phosphonium sulfate evenly to prepare a third reaction system;

[0066] (4) The first reaction system and the second reaction system are added to the third reaction system and mixed evenly to prepare an oilfield produced water treatment agent.

[0067] in:

[0068] In step (1), the mixing temperature is 50° C. and the mixing time is 12 min.

[0069] In step (2), the mixing temperature is 215° C. and the mixing time is 5 min.

[0070] In step (3), the mixing temperature is 45° C. and the mixing time is 15 min.

[0071] In step (4), the mixing temperature is 35° C. and the mixing time is 20 min.

[0072] Example 3

[0073] The oilfield produced water treatment agent described in Example 3 is composed of the following raw materials in parts by weight: 10 parts of polysilicate ferric sulfate aluminum modified vermiculite, 4.5 parts of diethyltriamine penta (methylene phosphonic acid), 8 parts of sulfonated succinic acid di-2-ethylhexyl sodium salt, 2 parts of 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether, 0.8 parts of N,N,N',N'-tetraphenyl-1,4-phenylenediamine, 3.2 parts of lauric acid imidazoline quaternary ammonium salt, 1.6 parts of phosphonobutyl succinic acid, 2.0 parts of polypropylene glycol monostearate, and 1.5 parts of tetrakis (hydroxymethyl) phosphite sulfate; wherein the preparation method of polysilicate ferric sulfate aluminum modified vermiculite is composed of the following steps:

[0074] ① The vermiculite was washed with deionized water, then dried at 55°C for 47h, and finally calcined at 750°C for 1.5min. After cooling, the vermiculite was ground through a 200-mesh sieve to prepare calcined vermiculite;

[0075] ② The calcined vermiculite was added to the polysilicate aluminum iron sulfate solution, and the mixture was mixed and reacted with magnetic stirring for 5.5 hours. The polysilicate aluminum iron modified vermiculite was prepared by filtration, drying and grinding.

[0076] in:

[0077] In step ②, the mass ratio of calcined vermiculite to polysilicate aluminum ferric sulfate solution is 1:10.

[0078] The mass concentration of the polysilicate aluminum ferric sulfate solution in step ② is 10%.

[0079] In step ②, the magnetic stirring speed is 250 r / min.

[0080] In step ②, the drying temperature is 105° C. and the drying time is 4.5 h; the mixture is ground through a 200-mesh sieve.

[0081] The structural formula of lauric acid imidazoline quaternary ammonium salt is: .

[0082] The preparation method of the oilfield produced water treatment agent described in this embodiment 3 is composed of the following steps:

[0083] (1) adding polysilicate ferric aluminum sulfate modified vermiculite and 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether to sulfonated di-2-ethylhexyl sodium succinate and mixing them evenly to prepare a first reaction system;

[0084] (2) adding N,N,N',N'-tetraphenyl-1,4-phenylenediamine, lauric acid imidazoline quaternary ammonium salt and phosphonosuccinic acid to polypropylene glycol monostearate and mixing evenly, and then cooling to room temperature to prepare a second reaction system;

[0085] (3) mixing diethyltriamine penta(methylenephosphonic acid) and tetrakis(hydroxymethyl)phosphonium sulfate evenly to prepare a third reaction system;

[0086] (4) The first reaction system and the second reaction system are added to the third reaction system and mixed evenly to prepare an oilfield produced water treatment agent.

[0087] in:

[0088] In step (1), the mixing temperature is 55° C. and the mixing time is 8 min.

[0089] In step (2), the mixing temperature is 210° C. and the mixing time is 10 min.

[0090] In step (3), the mixing temperature is 40° C. and the mixing time is 17 min.

[0091] In step (4), the mixing temperature is 30° C. and the mixing time is 25 min.

[0092] Comparative Example 1

[0093] The preparation method of the produced water treatment agent of the present comparative example 1 is the same as that of the embodiment 1, and the only difference is that the raw material composition is different. The produced water treatment agent of the present comparative example 1 is composed of the following raw materials in parts by weight: 4.3 parts of diethyltriamine penta (methylene phosphonic acid), 7 parts of sodium salt of di-2-ethylhexyl sulfonated succinate, 2.3 parts of 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether, 0.6 parts of N,N,N',N'-tetraphenyl-1,4-phenylenediamine, 3.3 parts of lauric acid imidazoline quaternary ammonium salt, 1.5 parts of phosphono succinic acid, 2.1 parts of polypropylene glycol monostearate, and 1.3 parts of tetrakis hydroxymethyl phosphonium sulfate.

[0094] Comparative Example 2

[0095] The preparation method of the oilfield produced water treatment agent described in this comparative example 2 is the same as that in Example 1, and the only difference is that the raw material composition is different. The oilfield produced water treatment agent described in this comparative example 2 is composed of the following raw materials in parts by weight: 11 parts of polysilicate ferric sulfate aluminum modified vermiculite, 4.3 parts of diethyltriamine penta (methylene phosphonic acid), 0.6 parts of N,N,N',N'-tetraphenyl-1,4-phenylenediamine, 3.3 parts of lauric acid imidazoline quaternary ammonium salt, 1.5 parts of phosphono succinic acid, 2.1 parts of polypropylene glycol monostearate, and 1.3 parts of tetrakis hydroxymethyl phosphonium sulfate; wherein, the preparation method of polysilicate ferric sulfate aluminum modified vermiculite is the same as that in Example 1.

[0096] Comparative Example 3

[0097] The preparation method of the oilfield produced water treatment agent described in this comparative example 3 is the same as that in Example 1, and the only difference is that the raw material composition is different. The oilfield produced water treatment agent described in this comparative example 3 is composed of the following raw materials in parts by weight: 11 parts of polysilicate ferric sulfate aluminum modified vermiculite, 4.3 parts of diethyltriamine penta-methylenephosphonic acid, 7 parts of sulfonated succinic acid di-2-ethylhexyl sodium salt, 2.3 parts of 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether, 2.1 parts of polypropylene glycol monostearate, and 1.3 parts of tetrakis hydroxymethyl phosphonic acid; wherein, the preparation method of polysilicate ferric sulfate aluminum modified vermiculite is the same as that in Example 1.

[0098] The performance test of the oilfield produced water treatment agent prepared in Examples 1-3 and Comparative Examples 1-3 was carried out. The water quality of the oilfield produced water was: total mineralization of 32927 mg / L, suspended solid content of 30 mg / L, and oil content of 400 mg / L. The agent was added to the oilfield produced water sample to be treated, with a dosage of 15 mg / L, and the oil removal rate, suspended solid removal rate and COD removal rate were tested after stirring for 3 hours to fully react. The corrosion inhibition performance refers to SY / T5273-2014 "Performance Indicators and Evaluation Methods of Corrosion Inhibitors for Oilfield Produced Water Treatment", and the experimental conditions are: temperature 60°C, time 120h, test piece: Q235 steel, rotation rate 100r / min. The scale inhibition performance of calcium carbonate was tested with reference to SY / T 5673-93 "Performance Evaluation Method of Oilfield Antiscalant", the test temperature was 70±2°C, and the time was 25h. The test results are shown in Table 1.

[0099] Table 1 Test results of oilfield produced water treatment agents

[0100]

Claims

1. An oilfield produced water treatment agent, characterized in that: The invention is composed of the following raw materials in parts by weight: 10-12 parts of polysilicate ferric sulfate aluminum modified vermiculite, 4.2-4.5 parts of diethylenetriamine penta-methylenephosphonic acid, 6-8 parts of sodium salt of di-2-ethylhexyl sulfonated succinate, 2-2.5 parts of 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether, 0.5-0.8 parts of N,N,N',N'-tetraphenyl-1,4-phenylenediamine, 3.2-3.5 parts of lauric acid imidazoline quaternary ammonium salt, 1.4-1.6 parts of phosphonosuccinic acid, 2.0-2.3 parts of polypropylene glycol monostearate, and 1.2-1.5 parts of tetrakis hydroxymethyl phosphonium sulfate; wherein the preparation method of polysilicate ferric sulfate aluminum modified vermiculite is composed of the following steps: ① The vermiculite was washed with deionized water, then dried at 55-58°C for 46-47h, and finally calcined at 750°C for 1.5min. After cooling, the vermiculite was ground through a 200-mesh sieve to prepare calcined vermiculite; ② Add the calcined vermiculite to the polysilicate aluminum ferric sulfate solution, stir the mixture with magnetic force for reaction for 5.2-5.5 hours, and obtain the polysilicate aluminum ferric sulfate modified vermiculite by suction filtration, drying and grinding.

2. The oilfield produced water treatment agent according to claim 1, characterized in that: In step ②, the mass ratio of calcined vermiculite to polysilicate aluminum ferric sulfate solution is 1:

10.

3. The oilfield produced water treatment agent according to claim 1, characterized in that: The mass concentration of the polysilicate aluminum ferric sulfate solution in step ② is 10%.

4. The oilfield produced water treatment agent according to claim 1, characterized in that: In step ②, the magnetic stirring speed is 250-300 r / min; In step ②, the drying temperature is 105-108° C. and the drying time is 4-4.5 h; the mixture is ground through a 200-mesh sieve.

5. The oilfield produced water treatment agent according to claim 1, characterized in that: The structural formula of lauric acid imidazoline quaternary ammonium salt is: .

6. A method for preparing the oilfield produced water treatment agent according to claim 1, characterized in that: It consists of the following steps: (1) adding polysilicate ferric aluminum sulfate modified vermiculite and 1,1,1-trimethylolpropane polyoxyethylene polyoxypropylene ether to sodium salt of di-2-ethylhexyl sulfonate succinate and mixing them evenly to prepare a first reaction system; (2) adding N,N,N',N'-tetraphenyl-1,4-phenylenediamine, lauric acid imidazoline quaternary ammonium salt and phosphonosuccinic acid to polypropylene glycol monostearate and mixing evenly, and then cooling to room temperature to prepare a second reaction system; (3) mixing diethylenetriaminepenta(methylenephosphonic acid) and tetrakis(hydroxymethyl)phosphonium sulfate evenly to prepare a third reaction system; (4) The first reaction system and the second reaction system are added to the third reaction system and mixed evenly to prepare an oilfield produced water treatment agent.

7. The method for preparing the oilfield produced water treatment agent according to claim 6, characterized in that: In step (1), the mixing temperature is 50-55° C. and the mixing time is 8-12 min.

8. The method for preparing the oilfield produced water treatment agent according to claim 6, characterized in that: In step (2), the mixing temperature is 210-215° C. and the mixing time is 5-10 min.

9. The method for preparing the oilfield produced water treatment agent according to claim 6, characterized in that: In step (3), the mixing temperature is 40-45° C. and the mixing time is 15-17 min.

10. The method for preparing the oilfield produced water treatment agent according to claim 6, characterized in that: In step (4), the mixing temperature is 30-35° C. and the mixing time is 20-25 min.

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