CN113980169A - Fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent and preparation method thereof - Google Patents

Abstract

A fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent and a preparation method thereof are disclosed, wherein the material is as follows: sodium dodecyl sulfate, TMN-10, n-butanol, deionized water, styrene, ethyl acrylate, ammonium persulfate, glucose and potassium dihydrogen phosphate; synthesizing oil-in-water styrene-acrylic emulsion polymer microspheres by optimizing reaction monomers and selecting a rigid monomer styrene and a soft monomer ethyl acrylate as main raw materials, and adding the strength of the polymer microspheres; the synthesized oil-in-water type styrene-acrylic polymer microspheres take water as a solvent, so that pollution caused by using white oil can be avoided, the problem of high cost caused by using a large amount of white oil can be solved, carbon quantum dot nanoparticles are introduced into the oil-in-water type styrene-acrylic polymer microsphere profile control and flooding agent, and dynamic monitoring and evaluation of the profile control and flooding process of the polymer microspheres are realized through the fluorescent tracing effect of the carbon quantum dots; meanwhile, the defects of poor capability of resisting metal ions in underground water and the like caused by introducing organic fluorescent dye into the existing fluorescent polymer microspheres are overcome.

Description

Fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent and preparation method thereof

Technical Field

The invention relates to the technical field of oil and gas field development, in particular to a fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent and a preparation method thereof.

Background

The profile control agent is a very key chemical additive in the development process of oil and gas fields, particularly in the later stage of water injection development. Aiming at the performance defects of weak strength, difficult monitoring and the like of the existing polymer microspheres for oil field profile control and flooding and the problems of high cost and serious pollution in application, the project uses hard monomer styrene and soft monomer ethyl acrylate as main raw materials, and synthesizes the oil-in-water type styrene-acrylic polymer microsphere nano profile control and flooding agent which takes water as a solvent through an emulsion polymerization method, so that the oil-in-water type polymer microspheres with good elasticity and excellent strength are realized; and on the basis, the carbon quantum dots with fluorescence property are introduced to prepare the polymer microsphere with fluorescence function, so that a novel profile control agent is provided for the development of low-permeability oil fields. From different perspectives, many scholars have developed different profile control and flooding agents. In the existing research, patent CN201811235025.4 discloses a preparation method of a temperature-resistant salt-resistant viscoelastic polymer gel microsphere and a profile control agent, wherein the water-soluble polymer microsphere contains an acrylamide structural unit, has a mobility control effect on a low-permeability reservoir, and can be used for field application of enhanced recovery ratio such as deep profile control and oil displacement for tertiary oil recovery of a high-temperature high-salt reservoir. In 2018, vol 47, No 11, petrochemical, Weijun et al, use acrylamide, 2-acrylamido-2-methylpropanesulfonic acidThe emulsion type hydrophobic modified polyacrylamide is prepared by adopting a redox initiation system through adopting reverse microemulsion polymerization by using polymerizable surface active monomer alkyl dimethyl allyl ammonium chloride as a polymerization monomer, Span80 and Tween60 as composite emulsifiers and white oil as a continuous phase. Most of the polymer microsphere profile control and flooding agents synthesized at present are crosslinked polyacrylamide microspheres, and the poor shear resistance of the polymer microspheres in the formation environment can be caused only by using acrylamide as a main monomer. To increase the strength of the polymer microspheres, 2018, vol 8, No. 18, Colloids and Surfaces A, Tang X et al, incorporated SiO into acrylamide microspheres₂Inorganic component, inorganic/organic polymer microsphere is synthesized by dispersion polymerization. In 2017, volume 134, Journal of Applied Polymer Science, Ji et al, volume 46, prepared poly (acrylamide-co-acrylic acid)/silica (poly (AM-co-AA)/SiO) by reversed phase suspension polymerization₂) And (3) microspheres.

In order to endow a polymer microsphere profile control agent with a fluorescent function, in 2015, 31, 10, polymer materials are scientific and engineering, and in allusion to the problem that polyacrylamide microspheres and an acrylamide polymer solution cannot be distinguished from a produced liquid containing an acrylamide polymer after being injected into a stratum together, thunderbolt et al propose that acryloyloxy fluorescein and acrylamide are copolymerized to synthesize the polyacrylamide fluorescent microspheres containing fluorescein. In 2018, at 558, colloidal and Surfaces A, Yang H and the like use allylrhodamine as a fluorescent dye to prepare a fluorescent polymer microsphere, and the stability influencing factors and the stability mechanism of a fluorescent polymer microsphere profile control and drive system are researched by using the proposed fluorescence stability index.

There are major problems: (1) the research and application of the polymer microsphere profile control agent are single, and the research and application mainly focus on the water-in-oil acrylamide polymer microspheres. The water-in-oil type acrylamide polymer microspheres have the problems of weak strength and the like in the using process, at present, inorganic components are mainly introduced into the acrylamide polymer microspheres, and the strength of the polymer microspheres is increased by the inorganic components, but the introduction of the inorganic components causes the problems of complex structure, complex synthesis process, increased cost and the like of the polymer microspheres. (2) The synthesis of the water-in-oil acrylamide polymer microspheres mainly takes white oil as a reaction solvent; the use of a large amount of white oil causes the production cost to be increased and the environmental protection property to be poor. (3) After the polymer microspheres are injected into a stratum, the positions of the microspheres entering a reservoir layer cannot be judged, the output concentration of the microspheres is difficult to detect, and in order to effectively perform dynamic monitoring and evaluation on the polymer microspheres for profile control and flooding, researchers mainly use fluorescent polymer microspheres synthesized by organic fluorescent dyes at present, but the organic dyes have many problems including poor thermal stability, poor pH resistance, poor metal ion interference resistance in underground water and the like. Therefore, there is a need to develop new fluorescent functional polymeric microsphere profile control and flooding agents.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent and the preparation method thereof, wherein water is used as a solvent in the synthesis process of the oil-in-water type polymer microsphere, so that the preparation method is safe, environment-friendly and low in production cost; the main raw material for synthesizing the polymer microspheres selects rigid monomer styrene to increase the strength of the polymer microspheres; the introduction of the carbon quantum dot nano-particles realizes dynamic monitoring and evaluation of the polymer microsphere profile control and flooding process; meanwhile, the defects of poor capability of resisting metal ions in underground water and the like caused by introducing organic fluorescent dye into the existing fluorescent polymer microspheres are overcome.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent comprises the following raw materials in parts by weight: 4-5 parts of sodium dodecyl sulfate, 102-3 parts of TMN, 5-7 parts of n-butanol, 2990 parts of deionized water 2855-.

A preparation method of a fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent comprises the following steps:

step one, weighing 4-5 parts of sodium dodecyl sulfate, 5-7 parts of TMN-102-3 parts of n-butanol and 5-5 parts of sodium dodecyl sulfate in parts by mass respectively in a beaker, and adding 750 parts of deionized water 700-plus in the beaker containing the substances to fully dissolve the substances to obtain a mixed solution I;

step two, weighing 325 parts of 315-styrene and 750 parts of 700-ethyl acrylate in another beaker to obtain a mixed solution II;

step three, adding the mixed solution II into the mixed solution I, and performing ultrasonic emulsification for 10-15min by adopting an ultrasonic cell crusher to prepare a pre-emulsion;

weighing 32-35 parts of ammonium persulfate in the beaker, adding 1980 and 2050 parts of deionized water into the beaker, uniformly stirring the mixture, and marking the mixture as an initiator aqueous solution;

transferring the initiator aqueous solution into a three-neck flask, placing the three-neck flask in a water bath at the temperature of 60-80 ℃, and stirring for 5-10min under mechanical stirring at 300r/min to uniformly mix the initiator;

after stirring, dropwise adding the pre-emulsion into the three-neck flask by using a constant-pressure dropping funnel, after dropwise adding, continuing to perform heat preservation reaction in a water bath until the uniformly dispersed milky emulsion is obtained, and then cooling to room temperature;

seventhly, filtering and discharging to prepare oil-in-water type styrene-acrylic polymer emulsion;

step eight, respectively weighing 0.9-1.2 parts of glucose and 23-26 parts of monopotassium phosphate in a beaker, and then adding 175-190 parts of deionized water to fully dissolve the glucose and the monopotassium phosphate;

transferring the solution into a high-pressure reaction kettle lined with PTFE, introducing nitrogen for 2-2.5h, and covering the bottle mouth with a preservative film to remove dissolved oxygen;

step ten, placing the mixture into an oven for reaction at the temperature of 180 ℃ and 200 ℃ for 10-12 h;

step eleven, after the reaction is finished, centrifuging the product in the chamber at a high speed, collecting light yellow supernatant, adding absolute ethyl alcohol for purification treatment, observing generation of white precipitate, and standing for separation;

step twelve, filtering the ethanol solution by using a PTFE injection filter, and evaporating excessive ethanol by using a rotary evaporator to obtain purified carbon quantum dot particles;

thirteen, weighing 1-1.2 parts of the carbon quantum dot particles in the step twelve into a three-neck flask, and adding 330-350 parts of the styrene-acrylic polymer emulsion in the step seven and performing ultrasonic treatment to ensure uniform dispersion;

fourteen, stirring for 0.5-1h at 200-300r/min under mechanical stirring to fully blend the carbon quantum dot particles and the styrene-acrylic polymer emulsion into uniform emulsion, and obtaining the composite microsphere profile control and flooding agent.

Compared with the prior art, the invention has the following advantages:

(1) according to the invention, the reaction monomer is optimized, the rigid monomer styrene and the soft monomer ethyl acrylate are selected as main raw materials to synthesize the oil-in-water styrene-acrylic emulsion polymer microsphere, and the strength of the polymer microsphere can be increased on the basis of not increasing reaction steps and not complicating the structure of the polymer microsphere.

(2) The oil-in-water type styrene-acrylic polymer microspheres synthesized by the method take water as a solvent, can avoid pollution caused by using white oil, can solve the problem of high cost caused by using a large amount of white oil, and is safe, environment-friendly and low in production cost.

(3) The styrene-acrylic polymer/fluorescent carbon quantum dot composite microspheres are realized by copolymerizing oil-in-water type styrene-acrylic polymers and fluorescent carbon quantum dots, and the defects that the fluorescent polymer microspheres synthesized by introducing fluorescent dye at present are poor in salt tolerance and the like can be overcome by introducing the fluorescent carbon quantum.

(4) Introducing carbon quantum dot nano particles into the oil-in-water type styrene-acrylic polymer microsphere profile control and flooding agent, and realizing dynamic monitoring and evaluation on the polymer microsphere profile control and flooding process through the fluorescent tracing effect of the carbon quantum dots; meanwhile, the defects of poor capability of resisting metal ions in underground water and the like caused by introducing organic fluorescent dye into the existing fluorescent polymer microspheres are overcome.

Drawings

FIG. 1 is a TEM photograph of a styrene-acrylic polymer emulsion, in which: FIG. 1a is a TEM photograph of the first embodiment; FIG. 1b is a TEM photograph of example two.

FIG. 2 is a diagram of the UV-VIS absorption spectrum of carbon quantum dots, with the inset being a fluorescent photograph of the carbon quantum dots in sunlight (left) and under 365nm UV lamp illumination (right), respectively.

FIG. 3 shows fluorescence intensity of carbon quantum dots.

FIG. 4 is a schematic diagram of the synthesis of styrene-acrylic polymer/carbon quantum dot composite polymer microspheres.

Fig. 5(a) is a TEM photograph of the carbon quantum dots, and fig. 5(b) is an HRTEM photograph.

FIG. 6 is a pressure (P) versus injected fluid volume (PV); wherein: a. water flooding; b. polymer flooding c; and (5) performing subsequent water flooding.

FIG. 7 is a photograph of the composite profile control agent after treatment of mineralized water with different degrees of mineralization under irradiation of an ultraviolet lamp.

Detailed Description

The invention will be described in detail below by selecting a certain oilfield core sample and combining the drawings.

Example one

The embodiment of the invention relates to a fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent which comprises the following raw materials in parts by weight: 0.176g of sodium dodecyl sulfate, 0.220g of TMN-100.088 g of n-butanol, 126.75g of deionized water, 13.829g of styrene, 30.730g of ethyl acrylate, 1.405g of ammonium persulfate, 0.040g of glucose and 1.010g of monopotassium phosphate.

The preparation method of the embodiment comprises the following steps:

step one, 0.176g of sodium dodecyl sulfate, 0.220g of n-butanol and 0.088g of TMN-10 are respectively weighed in a beaker, and 31g of deionized water is added to fully dissolve the sodium dodecyl sulfate, so as to obtain a mixed solution I.

Step two, 13.829g of styrene and 30.730g of ethyl acrylate are weighed in another beaker to obtain a mixed solution II.

And step three, adding the mixed solution II into the mixed solution I, and ultrasonically emulsifying for 10min by using an ultrasonic cell crusher to prepare the pre-emulsion.

Weighing 1.405g of ammonium persulfate in a beaker, adding 88g of deionized water, and uniformly stirring to mark as an initiator aqueous solution.

And step five, transferring the initiator aqueous solution into a three-neck flask, placing the three-neck flask in a water bath at the temperature of 80 ℃, and stirring for 5min under the mechanical stirring of 300r/min to uniformly mix the initiator.

And step six, after stirring is finished, simultaneously dripping the pre-emulsion and the initiator aqueous solution into the three-neck flask by using a constant-pressure dropping funnel, keeping the temperature in a water bath to react until the uniformly dispersed milky emulsion is obtained, and then cooling to room temperature.

And seventhly, filtering and discharging to prepare the O/W type styrene-acrylic polymer emulsion with the TEM characterization result shown in figure 1(a) for later use. From fig. 1(a), it can be seen from the TEM image that the synthesized nano styrene-acrylic polymer microspheres have uniform particle size distribution.

And step eight, respectively weighing 0.040g of glucose and 1.010g of potassium dihydrogen phosphate in a beaker, and then adding 7.75g of deionized water to fully dissolve the glucose and the potassium dihydrogen phosphate.

And step nine, transferring the solution into a high-pressure reaction kettle lined with PTFE, blowing nitrogen into the high-pressure reaction kettle for 2 hours, and covering the bottle mouth with a preservative film to remove dissolved oxygen.

Step ten, putting the mixture into an oven at 200 ℃ for reaction for 10 hours.

And step eleven, after the reaction is finished, centrifuging the product in the chamber at a high speed, collecting light yellow supernatant, adding absolute ethyl alcohol for purification treatment, observing that white precipitate is generated, and standing for separation.

Step twelve, filtering the yellow ethanol solution by using a PTFE injection filter, and evaporating excessive ethanol by using a rotary evaporator to obtain purified carbon quantum dots. The ultraviolet-visible absorption spectrum of the carbon quantum dot is shown in fig. 2, and the fluorescence intensity is shown in fig. 3. As can be seen from FIG. 2, the carbon quantum dots have an ultraviolet absorption peak at about 280 nm. The inset is a photograph of the carbon quantum dots in sunlight and under excitation of a 365nm ultraviolet lamp. The carbon quantum dots are light yellow in sunlight and have clear and transparent appearance; after the ultraviolet irradiation, the carbon quantum dots show blue fluorescence, which indicates that the carbon quantum dots show good fluorescence performance. From fig. 3, it can be seen that the carbon quantum dots exhibit a certain fluorescence intensity.

Step thirteen, 0.044g of carbon quantum dot particles are weighed in a three-neck flask, 14.487g of styrene-acrylic polymer emulsion is added for ultrasonic treatment, and uniform dispersion is ensured.

And step fourteen, stirring for 0.5h under mechanical stirring of 300r/min, so that the carbon quantum dot particles and the styrene-acrylic polymer emulsion are fully blended to form the composite polymer microspheres with fluorescent property. The synthetic scheme is shown in figure 4.

Example two

The embodiment of the invention relates to a fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent which comprises the following raw materials in parts by weight: 0.220g of sodium dodecyl sulfate, 0.307g of TMN-100.132 g of n-butanol, 131.56g of deionized water, 14.268g of styrene, 32.925g of ethyl acrylate, 1.537g of ammonium persulfate, 0.053g of glucose and 1.141g of monopotassium phosphate.

The preparation method of the embodiment comprises the following steps:

step one, 0.220g of sodium dodecyl sulfate, 0.307g of n-butanol and 0.132g of TMN-10 are respectively weighed in a beaker, and 33g of deionized water is added to make the solution fully dissolved, so as to obtain a mixed solution I.

Step two, 14.268g of styrene and 32.925g of ethyl acrylate are weighed in another beaker to obtain a mixed solution II.

And step three, adding the mixed solution II into the mixed solution I, and ultrasonically emulsifying for 15min by using an ultrasonic cell crusher to prepare the pre-emulsion.

Step four, weighing 1.537g of ammonium persulfate in a beaker, adding 90.2g of deionized water, stirring uniformly, and marking as an initiator aqueous solution.

And step five, transferring the initiator aqueous solution into a three-neck flask, placing the three-neck flask in a water bath at 60 ℃, and stirring for 10min under the mechanical stirring of 300r/min to uniformly mix the initiator.

And step six, after stirring is finished, simultaneously dripping the pre-emulsion and the initiator aqueous solution into the three-neck flask by using a constant-pressure dropping funnel, keeping the temperature in a water bath to react until the uniformly dispersed milky emulsion is obtained, and then cooling to room temperature.

And seventhly, filtering and discharging to prepare the O/W type styrene-acrylic polymer emulsion with the TEM characterization result shown in figure 1(b) for later use. The TEM image shows that the particle size distribution of the synthesized nano styrene-acrylic polymer microspheres is about 300-400 nm.

And step eight, respectively weighing 0.053g of glucose and 1.141g of potassium dihydrogen phosphate in a beaker, and then adding 8.36g of deionized water to fully dissolve the glucose and the potassium dihydrogen phosphate.

And step nine, transferring the solution into a high-pressure reaction kettle lined with PTFE, blowing nitrogen into the high-pressure reaction kettle for 2.5 hours, and covering the bottle mouth with a preservative film to remove dissolved oxygen.

Step ten, putting the mixture into an oven at 180 ℃ for reaction for 12 hours.

And step eleven, after the reaction is finished, centrifuging the product in the chamber at a high speed, collecting light yellow supernatant, adding absolute ethyl alcohol for purification treatment, observing that white precipitate is generated, and standing for separation.

Step twelve, filtering the yellow ethanol solution by using a PTFE injection filter, and evaporating excessive ethanol by using a rotary evaporator to obtain purified carbon quantum dots. The fluorescence intensity is shown in fig. 3, and it can be seen that the carbon quantum dots show a certain fluorescence intensity similar to the carbon quantum dots synthesized in example one. TEM and HRTEM characterization results of the carbon quantum dots are shown in fig. 5(a), and the carbon quantum dots are uniformly dispersed. In FIG. 5(b), in order to show the lattice fringes of the prepared carbon quantum dots, the fringes of the carbon quantum dot crystals at 10nm were clearly visible. The successful synthesis of the carbon quantum dots and the fluorescence property of the carbon quantum dots are proved.

And step thirteen, weighing 0.053g of carbon quantum dot particles into a three-neck flask, and adding 15.356g of styrene-acrylic polymer emulsion for ultrasonic treatment to ensure uniform dispersion.

Fourteen steps, stirring for 1h under the mechanical stirring of 200r/min, and fully blending the carbon quantum dot particles and the styrene-acrylic polymer emulsion to obtain the composite polymer microsphere with the fluorescent property.

Effects of the embodiment

Combining an oil field core sample, respectively saturating the core with water and saturated oil, and performing water flooding, composite microsphere flooding and subsequent water flooding by injecting water, the synthesized composite microsphere profile control agent and water into the core; the profile control performance of the injection liquid is analyzed, and the relationship between the injection pressure and the pore volume of the injection liquid is shown in figure 6. As can be seen, in the water flooding stage (fig. 6a), the pressure is lower and more stable; in the composite microsphere flooding stage (fig. 6b), it can be seen that after the synthesized composite microsphere flooding agent is injected, the injection pressure is obviously increased and continuously increased, which can indicate that the microspheres block the core pores until the fluid flow is diverted; in the subsequent water flooding phase (fig. 6c) it can be seen that the pressure is increased compared to the first phase (water flooding phase), but shows a gentle trend. The pressure ratios in the three stages according to fig. 6 can show that the microspheres have a plugging effect on the core and have oil displacement performance.

50000mg/L, 60000mg/L and 70000mg/L of mineralized water are respectively prepared, the profile control agent emulsion is diluted into 0.5 wt% aqueous dispersion by using mineralized water with different degrees of mineralization, and whether the profile control agent emulsion breaks emulsion and flocculates is observed, and the result is shown in figure 7. At normal temperature, after the treatment of 50000mg/L, 60000mg/L and 70000mg/L mineralized water, the phenomenon of demulsification and flocculation does not occur, and the profile control and flooding agent microspheres are uniformly dispersed in the mineralized water to form uniform water dispersion. Meanwhile, the modifying and flooding agent emulsion can still keep good fluorescence performance after being treated by different mineralized water.

Therefore, the novel composite microsphere synthesized by introducing the fluorescent carbon quantum dots into the oil-in-water type styrene-acrylic polymer microsphere has profile control and flooding properties and good fluorescence properties, replaces a polymer microsphere profile control and flooding agent with a fluorescence function synthesized by introducing a fluorescent dye in a traditional mode, and overcomes the defects of poor salt resistance and the like of the traditional fluorescent dye.

The price of the water-in-oil type acrylamide polymer microspheres is about 12500 yuan/ton, the price of the white oil is about 6000 yuan/ton, the solid content of the currently synthesized acrylamide polymer microspheres is 25-40%, and if the oil-in-water type polymer microspheres are designed and synthesized, the cost is saved by about 40%. Therefore, the synthesized oil-in-water type polymer microsphere profile control and flooding agent can greatly save the cost and overcome the defect of high cost of acrylamide polymer microspheres taking white oil as a solvent. Meanwhile, the novel composite microspheres in the invention take water as a solvent, so that the pollution of white oil to the environment is avoided.

Description of the principles of the Experimental method

The polymer microsphere profile control and flooding technology is an important work in the tertiary oil recovery process, and plays an important role in improving the water drive development effect and increasing the recovery ratio of a high-water-content oil field. In the process of tertiary oil recovery, the polymer microspheres can block a high-permeability stratum to cause water flow to flow into a low-permeability stratum in a diversion manner, so that effective water drive is performed, and more residual oil is displaced. The traditional polymer microsphere profile control and flooding agent has single variety and is mainly concentrated on water-in-oil acrylamide polymer microspheres. The synthesis of the water-in-oil acrylamide polymer microspheres mainly takes white oil as a reaction solvent, and the problems of weak strength, high production cost, poor environmental protection and the like can occur in part in the using process. Although the acrylamide polymer microspheres have good deformability, the strength of the acrylamide polymer microspheres is weak, and related researches increase the strength of the acrylamide polymer microspheres by introducing inorganic components, but the introduction of the inorganic components increases reaction steps and makes the structure of the polymer microspheres more complex. Meanwhile, after the polymer microspheres are injected into the stratum, the positions of the microspheres entering a reservoir layer cannot be judged, the output concentration of the microspheres is difficult to detect, and the effective method cannot be adopted to dynamically monitor and evaluate the polymer microspheres for profile control and flooding, so that the effectiveness of profile control and flooding of the polymer microspheres is weakened. The fluorescent polymer microsphere profile control and flooding agent proposed at present is prepared by polymerizing organic fluorescent dye and acrylamide, but the organic dye is difficult to adapt to high-temperature and high-salt stratum environments. Therefore, the novel polymer microspheres need to overcome the defects of acrylamide microsphere profile control and flooding agents and fluorescent microsphere profile control and flooding agents, have stable fluorescence performance, high strength, environmental friendliness and low cost, improve the profile control and flooding effect of the polymer microspheres through dynamic monitoring and analysis, and are effectively applied to the real-time operation process of tertiary oil recovery. The invention synthesizes styrene-acrylic polymer microspheres with styrene and ethyl acrylate as main monomers based on an emulsion polymerization method, synthesizes carbon quantum dot nanoparticles based on a hydrothermal method, and synthesizes styrene-acrylic polymer/carbon quantum dot composite microspheres with a fluorescent function based on a blending method. The method fully considers the performance requirements of the polymer microspheres in the profile control and flooding process, continuously optimizes the polymer microspheres by representing and testing the performances of the polymer microspheres such as particle size, morphology, fluorescence, stability and the like, improves the reliability of the synthetic method and parameters, realizes dynamic monitoring of the composite microspheres based on the fluorescence tracer of the composite microspheres, ensures effective exertion of the profile control and flooding effect of the composite microspheres, and is used for field application for improving the recovery ratio.

While the invention has been described in further detail with reference to specific preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (2)

1. The fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent is characterized by comprising the following raw materials in parts by weight: 4-5 parts of sodium dodecyl sulfate, 102-3 parts of TMN, 5-7 parts of n-butanol, 2990 parts of deionized water 2855-.

2. A preparation method of a fluorescent styrene-acrylic polymer composite microsphere profile control and flooding agent is characterized by comprising the following steps:

step one, weighing 4-5 parts of sodium dodecyl sulfate, 5-7 parts of TMN-102-3 parts of n-butanol and 5-5 parts of sodium dodecyl sulfate in parts by mass in a beaker, and adding 750 parts of deionized water 700 and 750 parts of n-butanol in the beaker containing the substances to fully dissolve the substances to obtain a mixed solution I;

step two, weighing 325 parts of 315-styrene and 750 parts of 700-ethyl acrylate in another beaker to obtain a mixed solution II;

step three, adding the mixed solution II into the mixed solution I, and performing ultrasonic emulsification for 10-15min by adopting an ultrasonic cell crusher to prepare a pre-emulsion;

weighing 32-35 parts of ammonium persulfate in the beaker, adding 1980 and 2050 parts of deionized water into the beaker, uniformly stirring the mixture, and marking the mixture as an initiator aqueous solution;

transferring the initiator aqueous solution into a three-neck flask, placing the three-neck flask in a water bath at the temperature of 60-80 ℃, and stirring for 5-10min under mechanical stirring at 300r/min to uniformly mix the initiator;

step six, after stirring, dropwise adding the pre-emulsion into a three-neck flask by using a constant-pressure dropping funnel, after dropwise adding, continuing to perform heat preservation reaction in a water bath until the uniformly dispersed milky emulsion is obtained, and then cooling to room temperature;

seventhly, filtering and discharging to prepare oil-in-water type styrene-acrylic polymer emulsion;

step eight, respectively weighing 0.9-1.2 parts of glucose and 23-26 parts of monopotassium phosphate in a beaker, and then adding 175-190 parts of deionized water to fully dissolve the glucose and the monopotassium phosphate;

transferring the solution into a high-pressure reaction kettle lined with PTFE, introducing nitrogen for 2-2.5h, and covering the bottle mouth with a preservative film to remove dissolved oxygen;

step ten, placing the mixture into an oven for reaction at the temperature of 180 ℃ and 200 ℃ for 10-12 h;

step eleven, after the reaction is finished, centrifuging the product in the chamber at a high speed, collecting light yellow supernatant, adding absolute ethyl alcohol for purification treatment, observing generation of white precipitate, and standing for separation;

step twelve, filtering the ethanol solution by using a PTFE injection filter, and evaporating excessive ethanol by using a rotary evaporator to obtain purified carbon quantum dot particles;

thirteen, weighing 1-1.2 parts of the carbon quantum dot particles in the step twelve into a three-neck flask, and adding 330-350 parts of the styrene-acrylic polymer emulsion in the step seven and performing ultrasonic treatment to ensure uniform dispersion;

fourteen, stirring for 0.5-1h at 200-300r/min under mechanical stirring to fully blend the carbon quantum dot particles and the styrene-acrylic polymer emulsion into uniform emulsion, and obtaining the composite microsphere profile control and flooding agent.

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