A temperature-resistant and salt-resistant slow-expanding microsphere based on double emulsion, and a preparation method and application thereof

Abstract

The application discloses a kind of temperature-resistant salt-tolerant slow swelling microspheres based on double emulsion and preparation method and application, it is related to oilfield chemical technical field, preparation method includes the following steps: emulsifier is weighed and dissolved in deionized water, ultrasonic dispersion is uniformly, then acrylamide, sulfonic monomer, hydrophobic monomer, polyoxyethylene ether functional monomer, di-vinyl benzene and initiator are added into the dispersion solution of emulsifier respectively, and water phase is prepared by stirring, water phase is slowly added into inner oil phase, and oil-in-water primary emulsion is obtained by high-speed stirring, then oil-in-water primary emulsion is added into outer oil phase and stirred to obtain double emulsion.Double emulsion is deoxidized by nitrogen, and the product is collected after aging at room temperature after stirring polymerization, washed, air-dried to constant weight, and temperature-resistant salt-tolerant slow swelling microspheres are obtained;In the application, the temperature-resistant salt-tolerant slow swelling microspheres prepared based on double emulsion template have spatial isolation effect of annular liquid film, the amphiphilic environment of emulsion provides multiphase reaction space for the synthesis of microspheres, and the microspheres have uniform particle size and excellent dispersity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil field chemistry, and particularly relates to a temperature-resistant and salt-resistant slow-swelling microsphere based on double emulsion and a preparation method and application thereof. BACKGROUND

[0002] Under the background of the continuous growth of global energy demand, the efficient development of ultra-high temperature and high salinity reservoirs (temperature > 120℃, salinity > 2×10 5 mg L -1 ) has become a key issue to ensure energy security. Such reservoirs account for more than 40% of the world's proven oil and gas reserves. After long-term water injection development, the reservoir heterogeneity is intensified, and the preferential seepage channels are developed, which leads to the bypass flow of injected water and the remaining oil recovery rate is generally less than 25%, seriously restricting the improvement of oil and gas production.

[0003] Deep profile control technology, which blocks high permeability channels by injecting profile control agents and guides fluid flow to low permeability areas, is a core means to improve the development effect of such reservoirs. However, the existing profile control agent system has significant limitations: in-situ cross-linked gel has low cost, but the gelation time is difficult to control and is easily degraded by shearing, and the plugging stability is poor; preformed particle gels (PPGs) have good salt resistance, but the particle size is mostly millimeter level, which is difficult to enter the deep pore throat of the formation, and the expanded particles are easy to break; traditional polyacrylamide microspheres face the dual dilemma of "rapid swelling leading to near-well plugging" and "molecular chain hydrolysis failure under high temperature and high salinity", and cannot achieve long-term deep plugging.

[0004] To break through the above bottleneck, researchers optimize the performance of microspheres through molecular design, such as constructing a double network and introducing salt-tolerant monomers, but single function optimization is difficult to meet the three core requirements of ultra-high temperature resistance (> 120℃), high salt resistance (> 2×10 5 mg L -1 ) and slow swelling. Menzel proposed a new strategy to synthesize micron-sized core-shell particles, using water-in-oil-in-water (W1 / O / W2) double emulsion as a template, synchronously polymerizing the inner water phase and the intermediate oil phase, and forming a cross-linked poly-porous hydrophobic shell. The "oil phase locking" mechanism of rapid gelation of the oil phase can reduce the mass transfer from the inner water phase to the outer phase, and stabilize the W1-W2 phase. Acrylic acid monomer makes the W1 / O interface lose stability, which promotes the coarsening of the inner water phase, and affects the formation of the particles. The particles can be used as adsorbents to simultaneously remove and encapsulate organic and inorganic cationic substances in the aqueous solution. The O / W / O type double emulsion has the advantages of multi-phase encapsulation and precise structure control, and can construct a stable layered structure to provide a separate microenvironment for active components. However, such a method has not been applied to the preparation of polymer microspheres for oil fields. In summary, there is little research on the synthesis of polymer microspheres for oil fields using double emulsion. Therefore, it is of great practical significance to develop profile control microspheres based on double emulsion technology, which have multiple excellent properties. SUMMARY

[0005] In view of this, the present application provides a kind of based on double emulsion temperature-resistant salt-tolerant swelling microspheres and preparation method and application, by O / W / O type double emulsion polymerization method preparation temperature-resistant salt-tolerant swelling microspheres, can resist ultrahigh temperature and high salt environment, suitable for the development of high temperature high salt reservoir remaining oil.

[0006] The application discloses a preparation method of temperature-resistant salt-tolerant swelling microspheres based on double emulsion, comprising the following steps:

[0007] Step S1: weigh the emulsifier, dissolve in deionized water, ultrasonic dispersion until uniform, then add acrylamide, sulfonic monomer, hydrophobic monomer, polyoxyethylene ether functional monomer, divinylbenzene and initiator into the dispersion solution of the emulsifier respectively, and stir to obtain an aqueous phase;

[0008] Step S2: slowly drop the aqueous phase into the inner oil phase, and obtain an oil-in-water primary emulsion by high-speed stirring (or ultrasonic dispersion), then add the oil-in-water primary emulsion into the outer oil phase and stir to obtain a double emulsion;

[0009] Step S3: remove oxygen from the double emulsion by nitrogen blowing, stir to polymerize, and then place at room temperature for aging; collect the product, wash, air dry until constant weight, and obtain the temperature-resistant salt-tolerant swelling microspheres.

[0010] In an embodiment of the present application, the amount of the emulsifier is 0.35-0.45 parts by weight, the amount of deionized water is 14-16 parts by weight, the amount of acrylamide is 2.8-3.2 parts by weight, the amount of sulfonic monomer is 0.55-0.65 parts by weight, the amount of hydrophobic monomer is 0.15-0.19 parts by weight, the amount of polyoxyethylene ether functional monomer is 0.15-0.19 parts by weight, the amount of divinylbenzene is 0.17-0.19 parts by weight, and the amount of initiator is 0.07-0.09 parts by weight.

[0011] In an embodiment of the present application, the preparation conditions of the aqueous phase are as follows: the raw materials are stirred at a speed of 450-550 r / min at room temperature for 8-12 min.

[0012] In an embodiment of the present application, in step S2, the ratio of the inner oil phase to the aqueous phase is 1:2 by volume ratio, and the oil-in-water primary emulsion is prepared by high-speed stirring at a speed of not less than 1500 r / min at room temperature for 8-12 min.

[0013] The ratio of the oil-in-water primary emulsion to the outer oil phase is 1:2 by volume ratio, and the double emulsion is prepared by stirring at a speed of 450-550 r / min at room temperature for 8-12 min.

[0014] One embodiment of the present application is that the specific conditions of the double emulsion stirring polymerization and standing aging are that the stirring polymerization is carried out at 58-62 DEG C under the stirring speed of 280-520 r / min for 0.8-1.2 h, and then standing aging for 10-14 h.

[0015] One embodiment of the present application is that the inner oil phase is white oil.

[0016] The outer oil phase is a solution of Span 80, MOA-3 and cyclohexane, wherein, in terms of weight parts, Span 80 is 0.8-1.2 parts, MOA-3 is 1.8-2.2 parts, and cyclohexane is 53-55 parts.

[0017] One embodiment of the present application is that the sulfonic acid group monomer in step S1 is one of sodium styrene sulfonate, 2-acrylamido-2-methylpropane sulfonic acid, sodium vinyl sulfonate and sodium allyl sulfonate.

[0018] The hydrophobic monomer is one of octadecyl methacrylate, cetyl methacrylate, stearyl acrylate and N-octadecyl acrylamide.

[0019] The polyoxyethylene ether functional monomer is one of methallyl polyoxyethylene ether, allyl polyoxyethylene ether, polyoxyethylene fatty alcohol ether and vinyl polyoxyethylene ether.

[0020] One embodiment of the present application is that the emulsifier in step S1 is YH-R15.

[0021] The initiator is azobisdimethylamid hydrochloride.

[0022] In addition, the present application also discloses the double emulsion-based temperature-resistant and salt-resistant slow-swelling microspheres prepared according to the above method.

[0023] And the application method of the above-mentioned double emulsion-based temperature-resistant and salt-resistant slow-swelling microspheres, wherein the double emulsion-based temperature-resistant and salt-resistant slow-swelling microspheres can be applied to the super-high-temperature and high-salt reservoirs with the temperature higher than 120 DEG C and the salinity higher than 2*10 5 mg·L -1 .

[0024] The technical effect of the present application is that:

[0025] (1) The double emulsion-based temperature-resistant and salt-resistant slow-swelling microspheres prepared according to the present application have the spatial isolation effect of the annular liquid film, the double emulsifier provides a multi-phase reaction space for the synthesis of the microspheres, the microspheres have uniform particle size and excellent dispersibility.

[0026] (2) The three-dimensional covalent cross-linking network constructed by divinylbenzene in the raw materials of the slow-swelling microspheres and the hydrophobic monomer have synergistic effect, and can tolerate the super-high-temperature reservoir environment.

[0027] (3) The sulfonic acid groups provided by the sulfonic acid group monomer in the slow swelling microspheres of the application can maintain high negative potential on the surface of the microspheres, and can effectively inhibit the agglomeration under high salinity, and have strong anti-salt ion shielding capacity;

[0028] (4) The hydrophobic microzone of the slow swelling microspheres of the application initially resists water penetration, and the 24h swelling rate is less than 20%, avoiding near-well plugging; and the slow dissociation in the later period realizes long-acting swelling, and the final swelling multiple can reach about 14, which is suitable for deep migration requirements;

[0029] (5) The slow swelling microspheres in the application can improve the recovery efficiency by more than 25% in core displacement experiments, and the plugging efficiency reaches about 90%, which is significantly better than similar materials, and can effectively improve the development effect of super-high-temperature high-salt reservoirs;

[0030] (6) The application can be applied to deep profile control of super-high-temperature high-salt reservoirs, and solves the core problems of traditional profile control agents, such as "not being able to be injected, not being able to go far, and not being able to be plugged", and has significant economic benefits and application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a micro-morphology diagram of the primary emulsion and double emulsion in Example 1 in the application;

[0032] Figure 2 is a double emulsion stability test result diagram of the primary emulsion in Example 1 in the application compared with different external oil phases;

[0033] Figure 3 is a Fourier transform infrared spectroscopy test result diagram of the PTS microspheres of each example in the application;

[0034] Figure 4 is a constant temperature aging experiment result diagram of the PTS microspheres of each example in the application;

[0035] Figure 5 is a core displacement experiment result diagram of the PTS microspheres of Example 1 in the application;

[0036] Figure 6 is a core displacement experiment result diagram of the PTS microspheres of Example 2 in the application;

[0037] Figure 7 is a core displacement experiment result diagram of the PTS microspheres of Example 3 in the application. DETAILED DESCRIPTION

[0038] The application will be further described in detail below in combination with examples, but the implementation manner of the application is not limited thereto, wherein, the experimental methods used in the following examples are conventional methods unless otherwise specified; and the materials, reagents and the like used therein are commercially available unless otherwise specified.

[0039] Example 1

[0040] (1) 0.35 g of YH-R15 was weighed into 14.0 g of deionized water, and ultrasonic dispersion was performed for 3 min to obtain a water phase matrix, 2.8 g of acrylamide (AM), 0.55 g of sodium styrene sulfonate (NaSS), 0.15 g of stearyl methacrylate (SMA-18), 0.15 g of methallyl polyoxyethylene ether (HPEG), 0.17 g of divinylbenzene (DVB), and 0.07 g of azobisdimethylvaleronitrile hydrochloride (V50) were added thereto, and mechanical stirring was performed at a speed of 450 r / min for 12 min to obtain a water phase;

[0041] (2) 9.0 g of white oil was added to a 250 mL three-necked flask as an inner oil phase, and ultrasonic treatment was performed for 8 min to ensure uniform dispersion. The water phase was slowly added to the inner oil phase under magnetic stirring at a volume ratio of 1:2, and high-speed stirring was performed for 12 min after the addition was completed to form a stable oil-in-water (O / W) primary emulsion. 0.9 g of Span80 and 1.9 g of MOA-3 were added to another three-necked flask, and 53.0 g of cyclohexane was added, and stirring was performed at room temperature for 15 min until complete dissolution to obtain an outer oil phase. The above-mentioned primary emulsion was slowly added to the outer oil phase at a volume ratio of (1 / 2):2, and stirring was performed at a speed of 450 r / min for 12 min to obtain a stable oil-in-water-in-oil (O / W / O) double emulsion;

[0042] (3) The double emulsion was transferred to a three-necked flask, and high-purity nitrogen was introduced to remove oxygen for 25 min. The flask was placed in a 58°C water bath and polymerized at a speed of 280 r / min for 1.2 h, and then the reaction was completed after being left to stand at room temperature for 10 h. The product was washed by centrifugation 4 times with a mixture of anhydrous ethanol and distilled water at a volume ratio of 1:3, and the washed product was placed in a 38°C ventilated cabinet and air-dried for 26 h until the weight was constant to obtain a temperature-resistant and salt-resistant slow-swelling microsphere (PTS-1).

[0043] Example 2

[0044] (1) 0.40 g of YH-R15 was weighed into 15.0 g of deionized water, and ultrasonic dispersion was performed for 3 min to obtain a water phase matrix, 3.0 g of acrylamide (AM), 0.60 g of sodium styrene sulfonate (NaSS), 0.17 g of stearyl methacrylate (SMA-18), 0.16 g of methallyl polyoxyethylene ether (HPEG), 0.18 g of divinylbenzene (DVB), and 0.08 g of azobisdimethylvaleronitrile hydrochloride (V50) were added thereto, and mechanical stirring was performed at a speed of 500 r / min for 10 min to obtain a water phase;

[0045] (2) Into a 250 mL three-necked flask, 10.0 g of white oil was added as the inner oil phase, and ultrasonic treatment was performed for 8 min to ensure uniform dispersion. Under magnetic stirring, the water phase was slowly added to the inner oil phase at an oil-water volume ratio of 1:2, and after the addition was completed, high-speed stirring was performed for 10 min to form a stable oil-in-water (O / W) primary emulsion. Into another three-necked flask, 1.0 g of Span80 and 2.0 g of MOA-3 were added, and 54.0 g of cyclohexane was then added. Stirring was performed at room temperature for 15 min until complete dissolution to prepare the outer oil phase. The above-mentioned primary emulsion was slowly added to the outer oil phase at a volume ratio of (1 / 2):2, and stirring was performed at a speed of 500 r / min for 10 min to obtain a structurally stable oil-in-water-in-oil (O / W / O) double emulsion;

[0046] (3) The double emulsion was transferred to a three-necked flask, and high-purity nitrogen was introduced to remove oxygen for 30 min. The flask was placed in a 60°C water bath and polymerized at a stirring speed of 300 r / min for 1.0 h, and then the reaction was completed after the flask was left to stand at room temperature for 12 h. The product was washed by centrifugation three times with a mixture of anhydrous ethanol and distilled water at a volume ratio of 1:3. The washed product was placed in a 40°C fume hood and air-dried for 24 h until the weight was constant to obtain a temperature-resistant and salt-tolerant slow-swelling microsphere (PTS-2).

[0047] Example 3

[0048] (1) 0.45 g of YH-R15 was weighed into 16.0 g of deionized water, and ultrasonic dispersion was performed for 3 min until uniform to obtain a water phase matrix. Then, 3.2 g of acrylamide (AM), 0.65 g of sodium styrene sulfonate (NaSS), 0.19 g of stearyl methacrylate (SMA-18), 0.19 g of methallyl polyoxyethylene ether (HPEG), 0.19 g of divinylbenzene (DVB), and 0.09 g of azobisdimethylamino formamide hydrochloride (V50) were added, and mechanical stirring was performed at a speed of 550 r / min for 8 min until the mixture was uniform to prepare a water phase.

[0049] (2) Into a 250 mL three-necked flask, 11.0 g of white oil was added as the inner oil phase, and ultrasonic treatment was performed for 8 min to ensure uniform dispersion. Under magnetic stirring, the water phase was slowly added to the inner oil phase at an oil-water volume ratio of 1:2, and after the addition was completed, high-speed stirring was performed for 8 min to form a stable oil-in-water (O / W) primary emulsion. Into another three-necked flask, 1.1 g of Span80 and 2.1 g of MOA-3 were added, and 55.0 g of cyclohexane was then added. Stirring was performed at room temperature for 15 min until complete dissolution to prepare the outer oil phase. The above-mentioned primary emulsion was slowly added to the outer oil phase at a volume ratio of (1 / 2):2, and stirring was performed at a speed of 550 r / min for 8 min to obtain a structurally stable oil-in-water-in-oil (O / W / O) double emulsion;

[0050] (3) The double emulsion was transferred to a three-necked flask, and high-purity nitrogen was introduced to remove oxygen for 35 min. The mixture was then placed in a 62℃ water bath and polymerized at 520 r / min for 0.8 h. After that, the mixture was allowed to stand at room temperature for 14 h to complete the reaction. The product was washed twice by centrifugation with a mixture of anhydrous ethanol and distilled water in a volume ratio of 1:3. The washed product was then placed in a fume hood at 42℃ and air-dried for 22 h until constant weight was obtained to obtain temperature- and salt-resistant slow-swelling microspheres (PTS-3).

[0051] To further illustrate the technical effects of the present invention, the present invention also provides relevant performance evaluations of the above embodiments in practical applications.

[0052] I. Evaluation of the microstructure and stability of the emulsion

[0053] The microstructure of the primary emulsion and the double emulsion prepared in step (2) of Example 1 was observed using an optical microscope, and their stability was evaluated by monitoring the emulsification index. The results are as follows: Figure 1 As shown, it can be seen that Figure 1 The microscopic observation results shown clearly show a structure where large droplets enclose small droplets, which is a typical double emulsion structure. The emulsion droplets are relatively uniform, and the small droplets inside are obvious, proving that the emulsion has good stability.

[0054] Meanwhile, the pre-emulsion prepared in step (2) of Example 1 was mixed with different proportions of the external oil phase to form a double emulsion. The ratio of the pre-emulsion to the external oil phase was 1:1, 1:2, 1:3, and 1:4. The sedimentation was observed after standing for 14 days, and the specific results are as follows: Figure 2 As shown. Based on Figure 2 The test results show that the ratio of primary emulsion to external oil phase is the key factor affecting the stability of double emulsion: no sedimentation occurred at an oil-water ratio of 1:2, which is the optimal oil-water ratio, and the emulsion index of the emulsion changed very little within 1 day and 14 days, indicating good stability.

[0055] II. Infrared characterization of temperature- and salt-resistant slow-swelling microspheres (PTS)

[0056] The PTS microspheres prepared in Examples 1-3 were mixed with KBr at a mass ratio of 1:100, ground, and pressed into transparent sheets. The microspheres were then analyzed in a scanning range of 4000-4000 cm⁻¹. -1 4cm resolution -1 Fourier transform infrared spectroscopy was performed under the condition of 32 scans. The results are as follows: Figure 3 As shown, by Figure 3 As you can see, 3432.15cm -1 The peak value is the stretching vibration peak of NH in AM, at 1590.58 cm⁻¹. -1 The peak value is the bending vibration peak of NH in AM, at 1455.25 cm⁻¹. -1 and 2929.10cm -1corresponding to the C=C stretching vibration and the aromatic ring C-H stretching vibration of the benzene ring in NaSS and DVB, respectively, 1122.83 cm -1 is the characteristic stretching vibration peak of -SO3H in NaSS, 1628.8 cm -1 is the absorption peak of C=O in SMA-18, 643.31 cm -1 corresponding to the C-H bending vibration of the vinyl group in DVB, which together confirm that the raw materials in Examples 1-3 have successfully achieved copolymerization, and the synthesis of PTS microspheres is complete.

[0057] III. Evaluation of the temperature resistance and salt resistance of temperature-resistant and salt-resistant slow-swelling microspheres PTS

[0058] Take the temperature-resistant and salt-resistant slow-swelling microspheres (PTS-1, PTS-2, PTS-3) prepared in Examples 1-3, respectively, to prepare a microsphere solution with a mass concentration of 0.5%, seal the solution in a high-temperature resistant bottle, set the reaction kettle temperature to 120°C, and conduct a constant temperature aging experiment, with an aging period of 90 days. After the aging is completed, take out the high-temperature resistant bottle, and after the solution cools to room temperature, observe the morphological changes of the microspheres, and the specific results are shown in Figure 4 .

[0059] As can be seen from Figure 4 , the microspheres are initially spherical, uniformly dispersed, and have good stability at 120°C. After 90 days of aging, the microsphere emulsions in each example can still maintain the initial state without creaming or precipitation, demonstrating excellent thermal stability. This is because the three-dimensional crosslinked network structure of the microspheres effectively suppresses the thermal motion of the polymer chains, the benzene ring rigid monomer significantly improves the thermal deformation temperature of the microspheres, and the stable multiple emulsion interface design forms a dense microsphere shell. The hydrophobic interaction and covalent bond crosslinking between molecules together maintain the structural integrity and dispersion stability of the PTS microspheres in a high temperature environment.

[0060] Weigh the PTS microspheres into a solution with a salinity of 25 x 10 4 mg·L -1 , prepare a 0.5% PTS dispersion, and place it in a 120°C constant temperature oven. Periodically take out the sample and use a laser particle size analyzer to detect its particle size distribution, and an optical microscope to test whether the spherical shape of the microspheres is intact. The experimental results prove that the microspheres of the three examples all perform excellently in terms of temperature resistance and salt resistance, and the specific data are shown in Table 1.

[0061] Table 1 Comparison of the temperature resistance and salt resistance of PTS microspheres (120°C, salinity 25 x 10 4 mg·L -1 )

[0062]

[0063] IV. Evaluation of plugging and oil displacement performance of temperature and salt resistant and slow swelling microspheres PTS

[0064] The plugging and oil displacement performance of the microspheres with a concentration of 0.3% prepared according to examples 1-3 at 120°C was studied by core displacement experiment. The injection rate during displacement was 0.4 mL / min.

[0065] The experimental results of examples 1-3 are shown in FIGS. 1-3, respectively. In example 2, the injection pressure showed a trend of first decreasing and then increasing after the injection of the PTS microsphere solution, and increased significantly from the initial 0.056 MPa to 0.195 MPa after the injection of 0.6 PV. The experimental results of examples 1 and 3 were similar to that of example 2. The specific data of the enhanced oil recovery and plugging efficiency of the three examples are shown in Table 2. Figures 5-7

[0066] Table 2. Plugging and oil displacement performance of PTS microspheres (120°C)

[0067]

[0068] The above data show that the temperature and salt resistant and slow swelling microspheres prepared in the present application can form effective plugging in the deep part of the core, and the plugging efficiency is more than 90%. At the same time, the microspheres can significantly improve the oil recovery by improving the mobility ratio and expanding the sweep efficiency.

[0069] The above description is only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed in the embodiments of the present application can be easily thought by those skilled in the art, and should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be the protection scope of the claims.​

Claims

1. A method for preparing temperature- and salt-resistant slow-swelling microspheres based on a dual emulsion, characterized in that, Includes the following steps: Step S1: Weigh the emulsifier and dissolve it in deionized water and ultrasonically disperse it until uniform. Then, add acrylamide, sulfonic acid monomer, hydrophobic monomer, polyoxyethylene ether functional monomer, divinylbenzene and initiator to the dispersion solution of the emulsifier, and stir to obtain an aqueous phase. Step S2: Slowly add the aqueous phase to the inner oil phase and stir at high speed to obtain an oil-in-water pre-emulsion. Then add the oil-in-water pre-emulsion to the outer oil phase and stir to obtain a double emulsion. Step S3: Nitrogen is passed through the double emulsion to remove oxygen. After stirring and polymerization, the mixture is allowed to stand at room temperature for aging. The product is collected, washed, and air-dried to constant weight to obtain temperature- and salt-resistant slow-swelling microspheres. The sulfonic acid monomer is one of sodium styrene sulfonate, 2-acrylamido-2-methylpropanesulfonic acid, sodium vinyl sulfonate, and sodium allyl sulfonate. The hydrophobic monomer is one of octadecyl methacrylate, hexadecyl methacrylate, octadecyl acrylate, and N-octadecylacrylamide; The polyoxyethylene ether functional monomers are one of methyl allyl polyoxyethylene ether, allyl polyoxyethylene ether, polyoxyethylene fatty alcohol ether, and vinyl polyoxyethylene ether; The emulsifier is added in the following amounts by weight: 0.35-0.45 parts, deionized water 14-16 parts, acrylamide 2.8-3.2 parts, sulfonic acid monomer 0.55-0.65 parts, hydrophobic monomer 0.15-0.19 parts, polyoxyethylene ether functional monomer 0.15-0.19 parts, divinylbenzene 0.17-0.19 parts, and initiator 0.07-0.09 parts.

2. The method for preparing temperature- and salt-resistant slow-swelling microspheres based on a dual emulsion according to claim 1, characterized in that: The aqueous phase was prepared by stirring each raw material at 450-550 r / min for 8-12 min at room temperature.

3. The method for preparing temperature- and salt-resistant slow-swelling microspheres based on a dual emulsion according to claim 1, characterized in that: In step S2, the ratio of the inner oil phase to the water phase is 1:2 by volume. The two phases are stirred at a speed of not less than 1500 r / min at room temperature for 8 to 12 minutes to obtain an oil-in-water primary emulsion. The ratio of the water-in-oil primary emulsion to the external oil phase is 1:2 by volume. The two phases are stirred at 450-550 r / min for 8-12 min at room temperature to obtain a double emulsion.

4. The method for preparing temperature- and salt-resistant slow-swelling microspheres based on a dual emulsion according to claim 1, characterized in that: The specific conditions for the static aging after the double emulsion stirring polymerization are as follows: stirring polymerization at 280~520 r / min for 0.8h~1.2h at 58℃~62℃, followed by static aging for 10h~14h.

5. The method for preparing temperature- and salt-resistant slow-swelling microspheres based on a dual emulsion according to claim 1, characterized in that: The internal oil phase is white oil; The outer oil phase is a solution of Span80 and MOA-3 dissolved in cyclohexane, wherein, by weight, Span80 is 0.8~1.2 parts, MOA-3 is 1.8~2.2 parts, and cyclohexane is 53~55 parts.

6. The method for preparing temperature- and salt-resistant slow-swelling microspheres based on a dual emulsion according to claim 1, characterized in that: The emulsifier mentioned in step S1 is YH-R15; The initiator is azobisisobutyramidine hydrochloride.

7. Temperature- and salt-resistant slow-swelling microspheres based on a dual emulsion prepared according to any one of claims 1 to 6.

8. The application method of the temperature- and salt-resistant slow-swelling microspheres based on dual emulsions according to claim 7, characterized in that, The temperature- and salt-resistant, slow-swelling microspheres based on dual emulsions can be used at temperatures above 120℃ and mineralization levels above 2×10⁻⁶. 5 mg·L - ¹ Ultra-high temperature and high salinity oil reservoirs.

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