CN114213594A

CN114213594A - Preparation method and application of heterogeneous oil displacement system based on temperature-resistant salt-resistant viscoelastic particle oil displacement agent

Info

Publication number: CN114213594A
Application number: CN202111185991.1A
Authority: CN
Inventors: 齐书磊; 杨姗; 李慎伟; 陈海燕; 姚勇; 杨军; 陈文锋; 杜河新
Original assignee: Shandong Juxing Petroleum Technology Co ltd
Current assignee: Shandong Juxing Petroleum Technology Co ltd
Priority date: 2021-10-12
Filing date: 2021-10-12
Publication date: 2022-03-22
Anticipated expiration: 2041-10-12
Also published as: CN114213594B

Abstract

The invention provides a preparation method and application of a heterogeneous oil displacement system based on a temperature-resistant salt-resistant viscoelastic particle oil displacement agent, and belongs to the technical field of oil exploitation, transportation and chemical engineering. The heterogeneous oil displacement system is prepared by a temperature-resistant and salt-resistant viscoelastic particle oil displacement agent with a certain concentration, a polyacrylamide emulsion and a nano oil washing agent step by step, wherein the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent is prepared by polymerizing acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide serving as monomer molecules step by step. The heterogeneous oil displacement system based on the temperature-resistant salt-resistant viscoelastic particle oil displacement agent can still synergistically exert an excellent deep profile control effect in a high-temperature high-salt oil reservoir, a heterogeneous oil reservoir and a polymer oil displacement reservoir, wherein the temperature of the heterogeneous oil displacement system is less than or equal to 90 ℃, and the total mineralization degree of the heterogeneous oil displacement system is less than or equal to 32848 mg/L.

Description

Preparation method and application of heterogeneous oil displacement system based on temperature-resistant salt-resistant viscoelastic particle oil displacement agent

Technical Field

The invention belongs to the technical field of oil exploitation, transportation and chemical engineering, and relates to a preparation method and application of a heterogeneous oil displacement system based on a temperature-resistant salt-resistant viscoelastic particle oil displacement agent.

Background

The polymer flooding technology is popularized and applied in 1997 in the victory oil field, in recent years, the polymer flooding reservoir is continuously transferred to a subsequent water flooding reservoir for many years, the heterogeneity of an oil layer is more serious, the residual oil is more dispersed, and the yield of a water flooding transfer unit is obviously reduced. How to further develop a large amount of residual oil in the oil reservoir after the polymer flooding is a problem of bitter thinking of three-mining people. The existing heterogeneous oil displacement system based on pre-crosslinked gel particles has the problems of easy particle sedimentation, easy end face blockage, overhigh pressure, poor viscoelastic performance, limited temperature and salt resistance and the like when being applied to an oil reservoir after polymer flooding, so that the research on the heterogeneous oil displacement system based on the temperature and salt resistant viscoelastic particle oil displacement agent, which is suitable for severe oil reservoir conditions such as a high-temperature and high-salt oil reservoir, a heterogeneous oil reservoir, a polymer oil displacement reservoir and the like, has very important significance.

The prior art discloses a heterogeneous system (LiCell, heterogeneous system property evaluation and oil displacement effect research [ J ], China Petroleum university, 2018), wherein the recorded heterogeneous system only consists of a temperature-resistant salt-resistant viscoelastic particle oil displacement agent and a polymer, and a nano oil washing agent is not introduced, so that a large amount of residual oil in a fine crack after being injected into the system is difficult to displace, and the extraction degree after relative water displacement is limited. In addition, the prior art also discloses a heterogeneous combination flooding technology (Zhang, heterogeneous combination flooding technology [ J ] after polymer flooding of medium and high-permeability cemented reservoir, Xinjiang petroleum geology, 2021), wherein the formula of the recorded heterogeneous flooding system is 1200.0mg/L polymer +2000.0mg/L active agent +600.0mg/L PPG, and the temperature resistance and salt resistance of the PPG are relatively poor, so that the deep profile control effect is difficult to exert in a high-temperature and high-salt reservoir. In addition, the particle size of the active agent is large, and the oil washing effect is difficult to exert synergistically in a low-permeability stratum. Therefore, a heterogeneous oil displacement system based on a temperature-resistant salt-resistant viscoelastic particle oil displacement agent and capable of cooperatively playing the functions of strong flow control, strong flow steering, strong spreading and strong oil washing capacity is in urgent need of development.

Disclosure of Invention

The invention provides a preparation method and application of a heterogeneous oil displacement system based on a temperature-resistant salt-tolerant viscoelastic particle oil displacement agent (novel pre-crosslinked gel particles), wherein the heterogeneous oil displacement system can fully and synergistically play the roles of liquid flow diversion and oil washing in a stratum with the temperature of less than or equal to 90 ℃ and the mineralization degree of less than or equal to 32848mg/L so as to obtain the optimal recovery ratio.

In order to achieve the aim, the invention provides a preparation method of a heterogeneous oil displacement system based on a temperature-resistant and salt-tolerant viscoelastic particle oil displacement agent, which comprises the following steps:

preparing a nano oil washing agent solution with the mass concentration of 0.1-0.4 per mill at the stirring speed of 180-220r/min, fully and uniformly stirring, slowly adding a polyacrylamide emulsion into the nano oil washing agent solution, adjusting the stirring speed to 380-420r/min, and continuously stirring for 10-15 min to prepare a polyacrylamide emulsion solution with the concentration of 800-1200 mg/L;

the stirring speed is adjusted to 380-.

The synergistic action mechanism of the heterogeneous oil displacement system based on the temperature-resistant salt-resistant viscoelastic particle oil displacement agent is described as follows:

the temperature is less than or equal to 90 ℃, the mineralization degree is less than or equal to 32848mg/L, the temperature-resistant salt-resistant viscoelastic particle oil-displacing agent absorbs water and expands, has better viscoelasticity, can realize effective plugging of a high-permeability reservoir stratum, improves the formation heterogeneity, and has synergistic effect with polyacrylamide emulsion, so that the sweep coefficient is increased, and the oil-displacing efficiency is improved. In addition, the suspension performance of the temperature-resistant salt-resistant viscoelastic particle oil displacement agent is greatly enhanced, the oil displacement agent can be transported to the deep part of a rock core under the action of pressure, and continuously transported, blocked and deformed in the pore throat of the rock core to pass through, and after the oil displacement agent penetrates into a low-permeability reservoir, part of movable oil can easily enter a large gap by virtue of the strong oil washing capacity of the composite nano oil washing agent, so that the purposes of starting residual oil and driving the residual oil are achieved, and the development effect is improved.

Preferably, the mass of the polyacrylamide emulsion added is m_aWherein m is_a0.24g to 0.36 g; the mass of the added temperature-resistant salt-resistant viscoelastic particle oil displacement agent is m_bWherein m is_b0.15g to 0.3 g; the mass of the added nano oil washing agent solution is 300-m_a-m_b g。

Preferably, the median diameter of the nanometer oil washing agent is in the range of 20-50 nm.

Preferably, the temperature-resistant salt-tolerant viscoelastic particle oil displacement agent is prepared by the following steps:

adding deionized water and acrylic acid into a reaction kettle, adding 2-acrylamide-2-methylpropanesulfonic acid into a reaction system after the deionized water and the acrylic acid are completely dissolved, keeping the reaction system at 10-15 ℃, and stirring the mixture until the mixture is fully and uniformly mixed;

adding a cross-linking agent N, N-dimethylacrylamide into the reaction system, fully and uniformly mixing, adjusting the pH value in the reaction kettle under the protection of nitrogen, slowly adding a molybdenum polyoxometallate-polyol initiation system into the reaction system, sealing the reaction kettle, and reacting for 3-4 hours to initiate the prepolymerization of the aqueous solution;

after the prepolymerization reaction is finished, adding the prepolymerization product into acrylamide, and continuing to react for 2-3 h at the final reaction temperature of 40 +/-1 ℃;

and (3) introducing steam into a steam heater of the reaction kettle to raise the temperature, raising the temperature of the colloid in the kettle to 75-80 ℃ to perform hydrolysis reaction for 4-6 hours, taking out the polymerization sample after the reaction is finished, grinding and granulating, drying and screening to obtain the temperature-resistant salt-resistant viscoelastic particle oil displacement agent.

Preferably, the mass ratio of the added acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and deionized water is (0.1-0.3): (0.01-0.05): (0.15-0.5): 1. it is understood that the mass ratio of the added acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and deionized water may be adjusted within the above range according to the actual circumstances, and may be, for example, 0.1:0.01:0.15:1, 0.1:0.05:0.5:1, 0.2:0.03:0.325:1, 0.3:0.01:0.15:1, 0.3:0.05:0.5:1, 0.3:0.05:0.15:1, 0.2:0.02:0.3:1, 0.2:0.03:0.2:1, 0.2:0.04:0.4:1, 0.1:0.02:0.2:1, 0.3:0.04:0.2: 1.

Preferably, the mass of the added crosslinking agent N, N-dimethylacrylamide accounts for 1-3% of the total mass of the reaction system.

Preferably, the pH value in the reaction kettle is adjusted to 8-10. It can be understood that the proper pH value of the solution can effectively adjust the crosslinking degree and the branching degree of the viscoelastic particle oil-displacing agent, if the pH value is too high, the reaction rate is higher, which means that the concentration of active free radicals in the solution is increased, the temperature-resistant salt-resistant viscoelastic particle oil-displacing agent monomer molecules are rapidly crosslinked, and the branching effect is poor; if the pH value is too low, the initiation rate of monomer molecules is reduced, and the chain length of the molecular main chain of the temperature-resistant salt-resistant viscoelastic particle oil displacement agent is shortened.

Preferably, the ratio of the multimetal heteropolyacid salt of molybdenum in the initiating system: the mass ratio of the polyhydric alcohol is (0.05-0.1): 1, and the initiating system accounts for 0.1 to 0.3 percent of the total mass of the reaction system. It is understood that the mass ratio of the polyoxometalate of molybdenum and the polyol can be adjusted within the above range according to practical circumstances, and for example, can also be 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1 or any ratio within the above range. In addition, the initiation system may also be present in an amount of 0.1, 0.15, 0.2, 0.25, 0.3% or any value within the above range, based on the total mass of the reaction system.

Preferably, the multimetal heteropolyacid salt of molybdenum in the initiating system is selected from, but not limited to, [ Bmim ]]₄[SiMo₁₂O₄₀]、[Hmim]₄[SiMo₁₂O₄₀]、[Hmim]₃[PMo₁₂O₄₀]、[Dhmim]₃[AsMo₁₂O₄₀]、[Hpy]₄[SiGe₁₂O₄₀]One or more of them.

Preferably, the polyol in the initiation system is at least one selected from the group consisting of ethylene glycol, glycerol, and pentaerythritol.

Preferably, the added nano oil washing agent has a median particle size in the range of 20-50 nm. It can be understood that the nano oil washing agent added in the scheme can be obtained commercially, for example, the nano oil washing agent can be selected from Dongyang Compase oil science and technology Limited company, the nano oil washing agent used in the invention takes alkanol carboxylate as a main component, the content of active substances is 30%, the dispersed phases are water phases, and the nano oil washing agent is respectively numbered as KPS-1, KPS-2, KPS-3 and KPS-4 according to different median values of particle diameters, wherein the median value of the particle diameter of KPS-1 is 20 nm; the median particle size of KPS-2 is 30 nm; the median particle size of KPS-3 is 40 nm; the median particle size of KPS-4 was 50 nm.

Preferably, the added polyacrylamide emulsion is commercially available, for example, from victory oil field victory chemical company, the content of the effective substance is 35%, and the effective substance can be respectively numbered as 20C and 30C according to different copolymerization temperature-resistant and salt-resistant monomers, wherein 20C is a copolymer of acrylamide and a small amount of AMPS, and 30C is a copolymer of acrylamide, a small amount of AA and AMPS. Compared with the conventional powdery polymer, the polyacrylamide emulsion added in the scheme has good temperature resistance and salt resistance and high dissolution speed, is far shorter than the dissolution time of the conventional powdery polyacrylamide, is completely dissolved without generating fish eyes, and is beneficial to on-site injection, thereby ensuring the construction continuity and supporting on-line injection. In addition, the polyacrylamide emulsion is liquid and has fluidity, and can be pumped by an injection pump.

Compared with the prior art, the invention has the advantages and positive effects that:

1. the temperature-resistant salt-resistant viscoelastic particle oil displacement agent in the heterogeneous oil displacement system is prepared by polymerizing acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide serving as monomer molecules step by step, can effectively control the polymerization reaction speed, and enables a terminal branched chain of a polymer network to be more stretched, so that the polymer has higher viscosity and better temperature-resistant salt-resistant performance, and the chain length shortening and viscosity reduction of linear polymers caused by implosion are avoided.

2. The temperature-resistant salt-tolerant viscoelastic particle oil displacement agent in the heterogeneous oil displacement system provided by the invention has good elastic modulus of a water dispersion system, a median particle size after swelling, network structure content and viscosity of the water dispersion system at the temperature of 90 ℃ and the mineralization degree of 32868mg/L, can realize excellent viscoelastic performance and migration performance, can be deeply inserted into an oil reservoir after polymer flooding, a high-temperature high-salt oil reservoir and a severe heterogeneous oil reservoir to play a role in plugging, profile control and flooding, expands the swept range and improves the recovery ratio.

3. The temperature-resistant salt-tolerant viscoelastic particle oil displacement agent and the polyacrylamide emulsion in the heterogeneous oil displacement system can realize on-line blending, completely meet the requirements of improving the water displacement development effect of complex fault blocks, offshore oil fields and the like, play a synergistic role, improve the suspension performance of the heterogeneous system, increase the viscosity and the viscoelasticity, greatly improve the interface viscoelasticity modulus, further expand the swept volume and improve the oil displacement effect. In addition, the temperature-resistant salt-tolerant viscoelastic particle oil displacement agent can perform a deep profile control effect after being deformed and moved to a low-permeability reservoir, the nano oil washing agent can penetrate into small cracks and narrow channels to perform a strong oil washing effect, and the nano oil washing agent perform a synergistic effect to further improve the recovery ratio.

Detailed Description

In order to more clearly and specifically describe the preparation method and the application of the heterogeneous oil displacement system based on the temperature-resistant and salt-tolerant viscoelastic particle oil displacement agent provided by the embodiment of the invention, the technical scheme in the embodiment of the invention will be clearly and completely described below, and it is obvious that the described embodiment is only a part of the embodiment of the invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Preparation of victory brine III: placing a 5L narrow-necked flask on a 10kg balance, adding 4831.8g of distilled water to the narrow-necked flask, placing it on a magnetic stirrer after adding the magnetic stirrer, starting the stirrer to swirl the solution, and adding the following substances in the order listed: 9.716g of anhydrous calcium chloride, 7.344g of magnesium chloride hexahydrate and 151.19g of sodium chloride. Each reagent is added until it is completely dissolved before the other reagent is added. Stirring with magnetic stirrer for 15 min. The total mineralization of the obtained solution is 32868mg/L, wherein the total amount of calcium ions and magnesium ions is 874 mg/L.

The method for measuring the product performance comprises the following steps:

1 solid content

1.1 weigh clean and dried to constant weight bottle mass to an accuracy of 0.0001g, recorded as m₁。

1.2 adding about 2g of temperature-resistant and salt-resistant viscoelastic particle oil displacement agent sample into a weighing bottle with constant weight, uniformly spreading the sample in the weighing bottle until the sample is accurate to 0.0001g, and recording the sample as m₂。

1.3 placing the weighing bottle with the sample in the 1.2 into a constant temperature drying box, and drying for 2 hours at the constant temperature of (105 +/-2) DEG C.

1.4 taking out the weighing bottle, putting the weighing bottle into a dryer, cooling for 30min, weighing until the weight is accurate to 0.0001g, and recording as m₃。

1.5 three replicates of one sample were taken and the arithmetic mean was used as the measurement. When the individual values deviate from the arithmetic mean by more than 0.5%, a resampling measurement is required.

1.6 the solids S is calculated as follows:

s-solid content,%;

m₁-weighing the vial mass, g;

m₂-sample mass before oven drying, g;

m₃-sample mass after oven drying, g.

2 content of network structure

2.1 accurately weighing 1 g-1.5 g of temperature-resistant and salt-resistant viscoelastic particle oil displacement agent sample, and accurately weighing the sample to 0.0001g, and recording the sample as m₁。

2.2 weighing a certain amount of simulated saline (degree of mineralization 32868mg/L) into a 150mL beaker, starting a constant speed stirrer, slowly adding a sample along the vortex wall for 30s at the speed of (400 +/-20) r/min, and then stirring for 15-30 min at the speed of (500 +/-20) r/min until the particles are uniformly dispersed.

2.3 transferring the prepared solution into a 1000mL measuring cylinder, washing the beaker with a small amount of water for several times, and adding standard prepared saline into the measuring cylinder to ensure that the liquid level is maintained at a distance of about 5-10 cm from the upper opening end.

2.4 to prevent the particles from being entrained by the dissolved air bubbles in the water, the mixture was gently stirred with a glass rod every 10min and repeated three times.

2.5 precipitation for about 5-6 h. In the process of pouring the solution, attention is paid to an interface between the network structure of the temperature-resistant salt-resistant viscoelastic particle oil displacement agent and the aqueous solution at any time, and the interface reaches a distance of 5cm from the outlet end and stops.

2.6 repeat steps 2.4, 2.5 three times.

2.7 taking the precipitate below the interface, washing with absolute ethyl alcohol to obtain a white insoluble substance, repeatedly washing with absolute ethyl alcohol for 2 times, standing for a little, transferring the insoluble substance to a surface dish, placing in a constant-temperature drying oven, and drying at 90 ℃ for 2 h.

2.8 taking out the insoluble substances, putting into a dryer, cooling for 30min, weighing to the accuracy of 0.0001g, recording as m₂。

2.9 network structure N is calculated as:

in the formula:

n-network structure content,%;

m₁-initial sample mass, g;

m₂-sample mass after washing the pellet, g.

3 median particle diameter after swelling

3.1 accurately weighing (5/S) g of temperature-resistant and salt-tolerant viscoelastic particle oil displacement agent sample (S is solid content) to be accurate to 0.0001 g. Weighing (1000-5/S) g of simulated saline in a 1000mL wide-mouth bottle, starting a constant speed stirrer to slowly add a sample along the vortex wall for 30S at (400 +/-20) r/min, and then stirring for 2h at the stirring speed of (500 +/-20) r/min to obtain a solution with the concentration of 5000 mg/L.

3.2 taking a proper amount of the test solution prepared in the step 3.1, and measuring the median particle size (D50) on a laser particle distribution measuring instrument according to the operation steps.

4 modulus of elasticity of aqueous dispersion

4.1 taking a proper amount of victory brine III for testing the temperature-resistant salt-resistant viscoelastic particle oil displacement agent.

4.2 starting up and setting conditions according to the rheometer operating instruction, setting the measuring temperature to be 35 ℃, selecting a flat plate mode and a rotor model PP60Ti, taking a proper amount of test solution on the flat plate, setting the gap to be 200 mu m, descending the machine head to the set gap, and wiping off redundant test solution. And (3) determining the elastic modulus of the water dispersion system of the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent with the concentration of 5000mg/L according to the operation instruction of a rheometer.

4.3 Each sample should be processed into 3 parallel samples according to 4.1-4.2, the relative error of each measured value and the arithmetic mean value is not more than 10%, and the arithmetic mean value is taken as the measured result.

5 viscosity of aqueous Dispersion

5.1 taking a proper amount of the victory brine III for the experiment of the temperature-resistant salt-resistant viscoelastic particle oil displacement agent.

5.2 starting up and setting conditions according to the rheometer operation instruction, setting the measurement temperature to be 90 ℃, moving the solution to be measured into a measuring cylinder, keeping the temperature for 3min, selecting a coaxial cylinder mode, setting the rotor model number CC27 and the shear rate to be 7.34s^-1And measuring the viscosity of the dispersion system with the concentration of 5000mg/L within 1min according to the operation instruction of the rheometer, and taking the average value of the viscosity to obtain the viscosity of the dispersion system.

5.3 each sample should be processed into 3 parallel samples according to 5.1-5.2, the relative error of each measured value and the arithmetic mean value is not more than 10%, and the arithmetic mean value is taken as the measured result.

6 oil washing rate

6.1 cleaning quartz sand (or stratum core debris) with the thickness of 0.8mm-1.2mm, drying, uniformly mixing with crude oil (density rho) of a target layer according to the ratio of 6:1, and standing for more than 2 hours. (oil sands cannot be too dilute, otherwise the oil sand proportions are readjusted);

6.2 adding 500mL of heterogeneous oil displacement system solution into a ground scale imbibition bottle (Amott cell), and keeping the temperature at 50 ℃ for 60 min;

6.3 addition of m₁g (about 10 g) oil sand, and reacting for 3 hours at 50 ℃;

6.4 observing and recording the amount V of the oil eluted;

6.5 oil sands are removed and washed with solvent, air-dried and weighed, and recorded as m₂；

6.6 oil wash calculation

P＝(Vρ/m₁-m₂)ⅹ100％

In the formula:

p-oil wash rate,%;

v-volume of oil discharged, mL;

m₁oil sand quality, g

m₂-mass of quartz sand, g

rho-Experimental crude oil Density, g/cm³。

Examples of the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent

A series of temperature-resistant and salt-resistant viscoelastic particle oil displacement agents for a heterogeneous oil displacement system are synthesized in a laboratory, and specifically can be JX-1, JX-2, JX-3, JX-4, JX-5, JX-6, JX-7, JX-8 and JX-9.

Example 1

Adding 100Kg of deionized water into a reaction kettle, adding 10Kg of Acrylic Acid (AA), adding 1Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 10 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. Adding 1.26Kg of N, N-Dimethylacrylamide (DMAM) into the reaction system, and after the N, N-Dimethylacrylamide (DMAM) is dissolved and uniformly mixed, introducing nitrogen into the reaction liquid for 30min at a nitrogen port at the bottom of the reaction kettle so as to be convenient for fully removing oxygen in the reaction system. Adjusting the pH value in the reaction kettle, and slowly adding 0.006Kg of [ Bmim ] into the reaction system under the protection of nitrogen]₄[SiMo₁₂O₄₀]And 0.12Kg of an aqueous ethylene glycol-initiated system was prepolymerized. The reaction kettle is sealed, and the reaction time is 3 hours.

After the prepolymerization was completed, the prepolymerization product was added to 15Kg AM, and the reaction was continued for 2 hours at a final reaction temperature of about 40 ℃ and the temperature change during the reaction was recorded. And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, so that the temperature of colloid in the kettle is raised to 75 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 4h, taking out a polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard screen to obtain the viscoelastic particle oil displacement agent JX-1.

Example 2

Adding 100Kg of deionized water into a reaction kettle, adding 10Kg of Acrylic Acid (AA), adding 5Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 15 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. 4.95Kg of N, N-Dimethylacrylamide (DMAM) is added into the reaction system, and after the N, N-dimethylacrylamide is dissolved and uniformly mixed, nitrogen is introduced into the reaction liquid for 30min from a nitrogen port at the bottom of the reaction kettle, so that oxygen in the reaction system can be removed sufficiently. Adjusting the pH value in the reaction kettle, and slowly adding 0.045Kg [ Hmim ] into the reaction system under the protection of nitrogen]₄[SiMo₁₂O₄₀]And 0.45Kg of an aqueous pentaerythritol initiating system. The reaction kettle is sealed, and the reaction time is 4 hours.

After the prepolymerization was completed, the prepolymerization product was added to 50Kg AM, and the reaction was continued for 3 hours at a final reaction temperature of about 40 ℃ and the temperature change during the reaction was recorded. And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, raising the temperature of the gel in the kettle to 80 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 6 hours, taking out the polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard sieve to obtain the viscoelastic particle oil-displacing agent JX-2.

Example 3

Adding 100Kg of deionized water into a reaction kettle, adding 20Kg of Acrylic Acid (AA), adding 3Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 12 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. Adding 3.11Kg of N, N-Dimethylacrylamide (DMAM) into the reaction system, and after the N, N-Dimethylacrylamide (DMAM) is dissolved and uniformly mixed, introducing nitrogen into the reaction liquid for 30min at a nitrogen port at the bottom of the reaction kettle, so as to be convenient for fully removing oxygen in the reaction system. Adjusting the pH value in the reaction kettle, and slowly adding 0.0217Kg of [ Hpy ] into the reaction system under the protection of nitrogen]₄[GeMo₁₂O₄₀]And 0.2893Kg of glycerol as an aqueous initiation system. Sealing of reaction kettleThe reaction time is 3.5 h.

After the prepolymerization was completed, the prepolymerization product was added to 32.5Kg AM and the reaction was continued for 2.5 hours at a final reaction temperature of about 40 ℃ and the temperature change during the course was recorded. And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, raising the temperature of the gel in the kettle to 78 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 5 hours, taking out the polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard sieve to obtain the viscoelastic particle oil-displacing agent JX-3.

Example 4

Adding 100Kg of deionized water into a reaction kettle, adding 30Kg of Acrylic Acid (AA), adding 1Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 10 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. Adding 1.45Kg of N, N-Dimethylacrylamide (DMAM) into the reaction system, and after the N, N-Dimethylacrylamide (DMAM) is dissolved and uniformly mixed, introducing nitrogen into the reaction liquid for 30min at a nitrogen port at the bottom of the reaction kettle so as to be convenient for fully removing oxygen in the reaction system. Adjusting the pH value in the reaction kettle, and slowly adding 0.0069Kg of Dhmim into the reaction system under the protection of nitrogen]₃[AsMo₁₂O₄₀]And 0.1381Kg of glycerol as an aqueous initiation system. The reaction kettle is sealed, and the reaction time is 3 hours.

After the prepolymerization was completed, the prepolymerization product was added to 15Kg AM, and the reaction was continued for 2 hours at a final reaction temperature of about 40 ℃ and the temperature change during the reaction was recorded. And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, so that the temperature of colloid in the kettle is raised to 75 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 4h, taking out a polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard screen to obtain the viscoelastic particle oil displacement agent JX-4.

Example 5

Adding 100Kg of deionized water into a reaction kettle, adding 30Kg of Acrylic Acid (AA), adding 5Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 15 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. Adding 5.55Kg of N, N-Dimethylacrylamide (DMAM) into the reaction system, and dissolving and mixing uniformlyAnd introducing nitrogen into the reaction liquid for 30min at a nitrogen port at the bottom of the reaction kettle, so as to be convenient for fully removing oxygen in the reaction system. Adjusting the pH value in the reaction kettle, and slowly adding 0.0505Kg of Hmim into the reaction system under the protection of nitrogen]₃[PMo₁₂O₄₀]And 0.5045Kg of ethylene glycol as an aqueous initiating system. The reaction kettle is sealed, and the reaction time is 4 hours.

After the prepolymerization was completed, the prepolymerization product was added to 50Kg AM, and the reaction was continued for 3 hours at a final reaction temperature of about 40 ℃ and the temperature change during the reaction was recorded. And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, raising the temperature of the gel in the kettle to 80 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 6 hours, taking out the polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard sieve to obtain the viscoelastic particle oil-displacing agent JX-5.

Comparative example 1

Adding 100Kg of deionized water into a reaction kettle, adding 10Kg of acrylic Acid (AM), adding 1Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 10 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. Adding 1.26Kg of N, N-Dimethylacrylamide (DMAM) into the reaction system, and after the N, N-Dimethylacrylamide (DMAM) is dissolved and uniformly mixed, introducing nitrogen into the reaction liquid for 30min at a nitrogen port at the bottom of the reaction kettle so as to be convenient for fully removing oxygen in the reaction system. Adjusting the pH value in the reaction kettle, and slowly adding 0.006Kg of [ Bmim ] into the reaction system under the protection of nitrogen]₄[SiMo₁₂O₄₀]And 0.12Kg of an aqueous ethylene glycol-initiated system was prepolymerized. The reaction kettle is sealed, and the reaction time is 3 hours.

After the prepolymerization was completed, the prepolymerization product was added to 15Kg of AA and the reaction was continued for 2 hours at a final reaction temperature of about 35 ℃ and the temperature change during the reaction was recorded. And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, so that the temperature of colloid in the kettle is raised to 75 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 4h, taking out a polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard screen to obtain the viscoelastic particle oil displacement agent JX-6.

Comparative example 2

Adding 100Kg of deionized water into a reaction kettle, adding 20Kg of Acrylic Acid (AA), adding 3Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 12 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. Adding 3.11Kg of N, N-Dimethylacrylamide (DMAM) into the reaction system, and after the N, N-Dimethylacrylamide (DMAM) is dissolved and uniformly mixed, introducing nitrogen into the reaction liquid for 30min at a nitrogen port at the bottom of the reaction kettle, so as to be convenient for fully removing oxygen in the reaction system. Adjusting the pH value in the reaction kettle, and slowly adding 0.0217Kg of [ Hpy ] into the reaction system under the protection of nitrogen]₃[GeMo₁₂O₄₀]And 0.2893Kg of glycerol as an aqueous initiation system. The reaction kettle is sealed, the reaction time is 3.5h, the final reaction temperature is about 30 ℃, and the temperature change in the process is recorded.

And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, raising the temperature of the gel in the kettle to 78 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 5 hours, taking out the polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard sieve to obtain the viscoelastic particle oil-displacing agent JX-7.

Comparative example 3

Adding 100Kg of deionized water into a reaction kettle, adding 30Kg of Acrylic Acid (AA), adding 1Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 10 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. Adding 1.45Kg of N, N-Dimethylacrylamide (DMAM) into the reaction system, and after the N, N-Dimethylacrylamide (DMAM) is dissolved and uniformly mixed, introducing nitrogen into the reaction liquid for 30min at a nitrogen port at the bottom of the reaction kettle so as to be convenient for fully removing oxygen in the reaction system. Adjusting the pH value in the reaction kettle, and slowly adding 0.0069Kg of Dhmim into the reaction system under the protection of nitrogen]ReO₄And 0.1381Kg of glycerol as an aqueous initiation system. The reaction kettle is sealed, and the reaction time is 3 hours.

After the prepolymerization was completed, the prepolymerization product was added to 15Kg AM, and the reaction was continued for 2 hours at a final reaction temperature of about 40 ℃ and the temperature change during the reaction was recorded. And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, so that the temperature of colloid in the kettle is raised to 75 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 4h, taking out a polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard screen to obtain the viscoelastic particle oil displacement agent JX-8.

Comparative example 4

Adding 100Kg of deionized water into a reaction kettle, adding 30Kg of Acrylic Acid (AA), adding 5Kg of AMPS into the reaction system after completely dissolving, simultaneously keeping the temperature of the reaction system at 15 ℃, stirring for 1h, and finally fully stirring and uniformly mixing. Adding 5.55Kg of N, N-Dimethylacrylamide (DMAM) into the reaction system, and after the N, N-Dimethylacrylamide (DMAM) is dissolved and uniformly mixed, introducing nitrogen into the reaction liquid for 30min at a nitrogen port at the bottom of the reaction kettle so as to be convenient for fully removing oxygen in the reaction system. Adjusting the pH value in the reaction kettle, and slowly adding 0.0505Kg of Hmim into the reaction system under the protection of nitrogen]₄[Mo₈O₂₆]And 0.5045Kg of ethylene glycol as an aqueous initiating system. The reaction kettle is sealed, and the reaction time is 4 hours.

After the prepolymerization was completed, the prepolymerization product was added to 50Kg AM, and the reaction was continued for 3 hours at a final reaction temperature of about 40 ℃ and the temperature change during the reaction was recorded. And (3) introducing steam into a steam heater in the reaction kettle to raise the temperature, raising the temperature of the gel in the kettle to 80 ℃, starting hydrolysis reaction, wherein the hydrolysis reaction period is 6 hours, taking out the polymerization sample after the hydrolysis reaction is finished, grinding and granulating, drying in a vacuum drying oven at 105 ℃, and screening by a standard screen to obtain the viscoelastic particle oil-displacing agent JX-9.

Performance testing

In order to further verify that the obtained product has good temperature resistance and salt resistance effects, when the viscoelastic particle oil-displacing agent aqueous solution is measured according to a product performance test method, the experiment is carried out based on the existing technical requirement Q/SH 102023742020 of the viscoelastic particle oil-displacing agent, and on the premise that other conditions are not changed, the specified test mineralization degree is increased from 19334mg/L to 32868mg/L by the particle size median value and the network structure content after swelling; the elastic modulus test temperature of the aqueous dispersion is increased from (25 +/-0.5) DEG C to (35 +/-0.5) DEG C, and the test mineralization is increased from 19334mg/L to 32868 mg/L; the viscosity test temperature of the aqueous dispersion is increased from (75 +/-0.5) DEG C to (90 +/-0.5) DEG C, and the test mineralization degree is increased from 19334mg/L to 32868 mg/L. Specific results are shown in table 1.

TABLE 1 Performance test results for various examples/comparative examples

Note: [1] the measurement results of the particle size median value after swelling in 6.6 of the technical requirement Q/SH 102023742020 on viscoelastic particle oil displacement agent under room temperature and mineralization degree of 19334 mg/L;

[2] in the product performance measuring method, the median value of the particle size after 3 swelling is measured under the conditions of room temperature and the mineralization degree of 32868 mg/L;

[3] the determination result of the elastic modulus test condition of 6.7.2 water dispersion system in the technical requirement Q/SH 102023742020 of viscoelastic particle oil displacement agent at 25 ℃ and the mineralization degree of 19334 mg/L;

[4] in the product performance measuring method, the 4-water dispersion system elastic modulus test condition is 35 ℃, and the measurement result is under the mineralization degree of 32868 mg/L;

[5] 6.8.2 in the technical requirement Q/SH 102023742020 on viscocity test condition of a water dispersion system of 6.8.2, and a measurement result under the condition of the mineralization degree of 19334 mg/L;

[6] in the product performance measuring method, the viscosity test condition of a 5 water dispersion system is 90 ℃, and the measurement result is under the mineralization degree of 32868 mg/L;

[7] the test condition of 6.5 network structure content in the technical requirement Q/SH 102023742020 on the viscoelastic particle oil displacement agent is 90 ℃, and the result is measured under the mineralization degree of 19334 mg/L;

[8] in the product performance measuring method, the 2-network structure content is measured under the conditions of 90 ℃ and the mineralization degree of 32868 mg/L;

as can be seen from the above table, when tested according to the technical requirements specified by the product performance measuring method, the technical indexes of JX-1, JX-2, JX-3, JX-4 and JX-5 are obviously higher than those of the existing standard gaugeThe technical requirements are determined, and the method is also measured under the condition of increasing the test temperature and testing the mineralization degree. Different from example 1, the reaction raw materials AM and AA in comparative example 1 are added in the same order, and the reaction raw material AM in the first step in the comparative example reacts with AMPS to generate free radical with large steric hindrance and limited movement capacity, so that the AA is difficult to sufficiently initiate further reaction, the reaction conversion rate is low, the length of a branched chain at the tail end of a polymer network is limited, and the viscosity of the JX-6 aqueous dispersion system is low. In comparative example 2, the two-step reaction in example 3 is changed into one-step reaction to directly generate a polymer, the reaction speed is difficult to control, and implosion is easy to occur. In addition, AM does not take part in the polymerization reaction as a raw material, so that the terminal branch of a network structure is short and few, and the two factors act together to cause the low viscosity of the JX-7 aqueous dispersion system. Initiation System of comparative example 4 from [ Hmim ] in example 5]₃[PMo₁₂O₄₀]Becomes [ Hmim ]]₄[Mo₈O₂₆]On one hand, the active points of free radicals are relatively less, and the adjacent carbon of each hydroxyl group of the polyhydric alcohol is difficult to be fully excited to initiate free radical polymerization to form a branched chain and a cross-link; on the other hand, the structure of the catalyst is relatively weak in controllability, and it is difficult to sufficiently change the central atom and the coordinating atom by such a control action to achieve the purpose of various oxidativeness and reducibility. The two factors act together to greatly reduce the median of the particle size after the JX-9 is swelled, the elastic modulus of the water dispersion system, the viscosity of the water dispersion system and the content of the network structure. The initiation system of comparative example 3 consisted of [ Dhmim ] in example 4]₃[AsMo₁₂O₄₀]Becomes [ Dhmim ]]ReO₄The free radical active sites are fewer, and the self structure has no adjustability, so that the particle size median value after JX-8 swelling, the elastic modulus of the water dispersion system, the viscosity of the water dispersion system and the content of network structures are lower. Therefore, the final performance of the product provided by the invention can be fully exerted only under the formula and the component proportion set by the invention.

Embodiment of heterogeneous oil displacement system based on temperature-resistant and salt-resistant viscoelastic particle oil displacement agent

In addition, a series of heterogeneous oil displacement systems are prepared in a laboratory, and specifically can be TX-1, TX-2, TX-3, TX-4, TX-5, TX-6, TX-7, TX-8 and TX-9.

The victory brine iii used in the following examples was prepared by the following method:

a clean 5L jar was placed on a balance, 4831.75g of deionized water was added, the solution was stirred in a magnetic stirrer to vortex, and the following reagents were added in order: 9.7144g of anhydrous calcium chloride, 7.3442g of magnesium chloride hexahydrate and 151.1887g of sodium chloride. Each reagent is added until it is completely dissolved before the other reagent is added. Stirring was continued until complete dissolution. The prepared saline water is homogeneous and transparent, has no precipitation phenomenon, and has the validity period of 7 days.

Example 6

Adding 299.58g of victory brine III into a 500mL beaker, adjusting the stirring speed to 180r/min, adding 0.03g of nano oil washing agent KPS-1 into the beaker, fully and uniformly stirring, slowly adding 0.24g of polyacrylamide emulsion 20C into the nano oil washing agent solution along the vortex wall within 30s, adjusting the stirring speed to 380r/min, and continuously stirring for 10 min;

and (3) continuously stirring at the speed of 380r/min, slowly adding 0.15g of temperature-resistant salt-resistant viscoelastic particle oil displacement agent JX-1 into the mixed system of the nano oil washing agent and the polyacrylamide emulsion along the vortex wall within 30s, adjusting the stirring speed to 480r/min, and fully stirring for 2h to obtain the heterogeneous oil displacement system TX-1 based on the temperature-resistant salt-resistant viscoelastic particle oil displacement agent JX-1. In the TX-1 system, the mass concentration of the nano oil-washing agent KPS-1 is 0.1 per mill, the concentration of the polyacrylamide emulsion 20C is 800mg/L, and the concentration of the temperature-resistant salt-resistant viscoelastic particle oil-displacing agent JX-1 is 500 mg/L.

Example 7

Adding 299.37g of victory brine III into a 500mL beaker, adjusting the stirring speed to 200r/min, adding 0.09g of nano oil washing agent KPS-2 into the beaker, fully and uniformly stirring, slowly adding 0.3g of polyacrylamide emulsion 30C into the nano oil washing agent solution along the vortex wall within 30s, adjusting the stirring speed to 400r/min, and continuously stirring for 12 min;

and (3) continuously stirring at the speed of 400r/min, slowly adding 0.24g of temperature-resistant and salt-resistant viscoelastic particle oil displacement agent JX-2 into the mixed system of the nano oil washing agent and the polyacrylamide emulsion along the vortex wall within 30s, adjusting the stirring speed to 500r/min, and fully stirring for 2h to obtain the heterogeneous oil displacement system TX-2 based on the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent. In the TX-2 system, the mass concentration of the nano oil-washing agent KPS-2 is 0.3 per mill, the concentration of the polyacrylamide emulsion 30C is 1000mg/L, and the concentration of the temperature-resistant salt-resistant viscoelastic particle oil-displacing agent JX-2 is 800 mg/L.

Example 8

Adding 299.22g of victory brine III into a 500mL beaker, adjusting the stirring speed to be 220r/min, adding 0.12g of nano oil washing agent KPS-3 into the beaker, fully and uniformly stirring, slowly adding 0.36g of polyacrylamide emulsion 30C into the nano oil washing agent solution along the vortex wall within 30s, adjusting the stirring speed to be 420r/min, and continuously stirring for 15 min;

and (3) continuously stirring at the speed of 420r/min, slowly adding 0.3g of temperature-resistant and salt-resistant viscoelastic particle oil displacement agent JX-3 into the mixed system of the nano oil washing agent and the polyacrylamide emulsion along the vortex wall within 30s, adjusting the stirring speed to 520r/min, and fully stirring for 2h to obtain the heterogeneous oil displacement system TX-3 based on the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent. The mass concentration of the nanometer oil-washing agent KPS-3 in the TX-3 system is 0.4 per mill, the concentration of the polyacrylamide emulsion 30C is 1200mg/L, and the concentration of the temperature-resistant salt-resistant viscoelastic particle oil-displacing agent JX-3 is 1000 mg/L.

Example 9

Adding 299.46g of victory brine III into a 500mL beaker, adjusting the stirring speed to 190r/min, adding 0.06g of nano-oil-washing agent KPS-4 into the beaker, fully and uniformly stirring, slowly adding 0.27g of polyacrylamide emulsion 20C into the nano-oil-washing agent solution along the vortex wall within 30s, adjusting the stirring speed to 390r/min, and continuously stirring for 11 min;

and (3) continuously stirring at 390r/min, slowly adding 0.21g of temperature-resistant and salt-resistant viscoelastic particle oil displacement agent JX-4 into the mixed system of the nano oil washing agent and the polyacrylamide emulsion along the vortex wall within 30s, adjusting the stirring speed to 490r/min, and fully stirring for 2h to obtain the heterogeneous oil displacement system TX-4 based on the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent. The mass concentration of the nanometer oil-washing agent KPS-4 in the TX-4 system is 0.2 per mill, the concentration of the polyacrylamide emulsion 20C is 900mg/L, and the concentration of the temperature-resistant salt-resistant viscoelastic particle oil-displacing agent JX-4 is 700 mg/L.

Example 10

Adding 299.31g of victory brine III into a 500mL beaker, adjusting the stirring speed to 210r/min, adding 0.09g of nano oil washing agent KPS-2 into the beaker, fully and uniformly stirring, slowly adding 0.33g of polyacrylamide emulsion 30C into the nano oil washing agent solution along the vortex wall within 30s, adjusting the stirring speed to 410r/min, and continuously stirring for 13 min;

and (3) continuing stirring at the speed of 410r/min, slowly adding 0.27g of temperature-resistant salt-resistant viscoelastic particle oil displacement agent JX-5 into the mixed system of the nano oil washing agent and the polyacrylamide emulsion along the vortex wall within 30s, adjusting the stirring speed to 510r/min, and fully stirring for 2h to obtain the heterogeneous oil displacement system TX-5 based on the temperature-resistant salt-resistant viscoelastic particle oil displacement agent. In the TX-5 system, the mass concentration of the nano oil-washing agent KPS-2 is 0.3 per mill, the concentration of the polyacrylamide emulsion 30C is 1100mg/L, and the concentration of the temperature-resistant salt-resistant viscoelastic particle oil-displacing agent JX-5 is 900 mg/L.

Comparative example 5

and continuously stirring at 380r/min, slowly adding 0.15g of pre-crosslinked gel particles (PPG) into the mixed system of the nano oil washing agent and the polyacrylamide emulsion along the vortex wall within 30s, adjusting the stirring speed to 480r/min, and fully stirring for 2h to obtain the heterogeneous oil displacement system TX-6 based on PPG. In a TX-6 system, the mass concentration of the nano oil-washing agent KPS-1 is 0.1 per mill, the concentration of the polyacrylamide emulsion 20C is 800mg/L, and the concentration of PPG is 500 mg/L.

Comparative example 6

Adding 299.22g of victory brine III into a 500mL beaker, adjusting the stirring speed to be 220r/min, adding 0.12g of nano oil washing agent KPS-3 into the beaker, fully and uniformly stirring, slowly adding 0.36g of type III polyacrylamide dry powder for oil displacement into the nano oil washing agent solution along the vortex wall within 30s, adjusting the stirring speed to be 420r/min, and continuously stirring for 15 min;

and (3) continuously stirring at the speed of 420r/min, slowly adding 0.3g of temperature-resistant salt-resistant viscoelastic particle oil displacement agent JX-3 into the mixed system of the nanometer oil washing agent and the type III polyacrylamide for oil displacement along the vortex wall within 30s, adjusting the stirring speed to 520r/min, and fully stirring for 2h to obtain the heterogeneous oil displacement system TX-7 based on the temperature-resistant salt-resistant viscoelastic particle oil displacement agent. The mass concentration of the nanometer oil-washing agent KPS-3 in a TX-7 system is 0.4 per mill, the concentration of polyacrylamide for III type oil displacement is 1200mg/L, and the concentration of the temperature-resistant salt-resistant viscoelastic particle oil-displacing agent JX-3 is 1000 mg/L.

Comparative example 7

299.46g of victory brine III is added into a 500mL beaker, the stirring speed is adjusted to be 190r/min, and 0.06g of oil washing agent AE is added into the beaker₁(Shanghai Yincong New Material science & technology Co., Ltd., alkanol carboxylate as the main ingredient, 60% of the active ingredient, code AE₁) Fully and uniformly stirring, slowly adding 0.27g of polyacrylamide emulsion 20C into the nano oil washing agent solution along the vortex wall within 30s, adjusting the stirring speed to 390r/min, and continuously stirring for 11 min;

and (3) continuously stirring at 390r/min, slowly adding 0.21g of temperature-resistant and salt-resistant viscoelastic particle oil displacement agent JX-4 into the mixed system of the oil washing agent and the polyacrylamide emulsion along the vortex wall within 30s, adjusting the stirring speed to 490r/min, and fully stirring for 2h to obtain the heterogeneous oil displacement system TX-8 based on the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent. Oil washing agent AE in TX-8 system₁The mass concentration of the polyacrylamide emulsion is 0.2 per mill, the concentration of 20C of the polyacrylamide emulsion is 900mg/L, and the concentration of the temperature-resistant salt-resistant viscoelastic particle oil displacement agent JX-4 is 700 mg/L.

Comparative example 8

299.58g of victory brine III is added into a 500mL beaker, the stirring speed is adjusted to 210r/min, 0.09g of nano oil washing agent KPS-2 is added into the beaker, the mixture is stirred uniformly, 0.33g of polyacrylamide emulsion 30C is slowly added into the nano oil washing agent solution along the vortex wall within 30s, the stirring speed is adjusted to 410r/min, and the stirring is continued for 13min, so that the heterogeneous oil displacement system TX-9 is obtained. The mass concentration of the nano oil-washing agent KPS-2 in the TX-9 system is 0.3 per mill, and the concentration of the polyacrylamide emulsion 30C is 1100 mg/L.

Heterogeneous oil displacement systems TX-1, TX-2, TX-3, TX-4, TX-5, TX-6, TX-7, TX-8 and TX-9 prepared in a laboratory have the following performance comparison conditions:

name (R)	Viscosity of aqueous dispersion, mPa.s	Elastic modulus, Pa, of aqueous dispersion	Oil washing rate%
				TX-1	12.5^[1]/21.6^[2]/65.5^[3]	17.3^[4]/8.7^[5]/31.6^[6]	38.17^[7]
TX-2	16.6^[1]/24.3^[2]/79.4^[3]	19.4^[4]/10.4^[5]/38.7[6]	37.22^[7]
				TX-3	18.9^[1]/27.1^[2]/91.5^[3]	23.1^[4]/13.2^[5]/54.4^[6]	39.06^[7]
TX-4	14.2^[1]/23.6^[2]/73.3^[3]	18.7^[4]/9.5^[5]/33.8^[6]	38.43^[7]
				TX-5	17.1^[1]/25.9^[2]/84.3^[3]	20.9^[4]/11.6^[5]/45.5^[6]	37.35^[7]
TX-6	12.7^[1]/16.2^[2]/35.2^[3]	16.9^[4]/5.9^[5]/23.9^[6]	25.58^[7]
				TX-7	9.0^[1]/26.8^[2]/38.7^[3]	10.4^[4]/9.8^[5]/21.8^[6]	20.70^[7]
TX-8	14.3^[1]/23.7^[2]/45.1^[3]	18.5^[4]/11.3^[5]/30.3^[6]	13.91^[7]
				TX-9	17.5^[1]	21.2^[4]	23.34^[7]

[1] In the product performance measuring method, the result of measuring the polymer under the condition that the viscosity of a 5 water dispersion system is tested at 90 ℃ and the mineralization degree is 32868 mg/L;

[2] in the product performance measuring method, the result of measuring the temperature-resistant salt-resistant viscoelastic particle oil displacement agent under the condition that the viscosity of a 5 water dispersion system is tested at 90 ℃ and the mineralization degree of 32868mg/L is obtained;

[3] in the product performance measuring method, the result of a heterogeneous oil displacement system is measured under the condition that the viscosity of a 5 water dispersion system is tested at 90 ℃ and the mineralization degree is 32868 mg/L;

[4] in the product performance measuring method, the result of measuring the polymer under the condition that the elastic modulus of a 4-water dispersion system is tested at 35 ℃ and the mineralization degree is 32868mg/L is obtained;

[5] in the product performance measuring method, the result of measuring the temperature-resistant salt-resistant viscoelastic particle oil displacement agent under the 4-water dispersion system elastic modulus test condition of 35 ℃ and the mineralization degree of 32868mg/L is obtained;

[6] in the product performance measuring method, the result of a heterogeneous oil displacement system is measured under the condition that the elastic modulus of a 4-water dispersion system is tested at 35 ℃ and the mineralization degree is 32868 mg/L;

[7] in the product performance measuring method, the result of a heterogeneous oil displacement system is measured under the condition that the oil washing rate is 50 ℃ and the mineralization degree is 32868 mg/L;

the existing enterprise standard of the company Q/JX 01-2021 provides that the heterogeneous oil displacement system based on the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent has the temperature and salinity of 90 ℃ and the mineralization degree of 32848mg/L, and the viscosity of the aqueous dispersion system of the solution is more than or equal to 50.0mPa & s; the elastic modulus of the aqueous dispersion system of the solution is more than or equal to 25.0Pa at the temperature of 35 ℃ and the mineralization degree of 32848 mg/L; the oil washing rate of the solution is more than or equal to 30.0 percent at 50 ℃ and the mineralization degree of 32848 mg/L.

As can be seen from the above table, under the temperature and mineralization required by the standard, the viscosity of the water dispersion systems of TX-1, TX-2, TX-3, TX-4 and TX-5 in the examples is more than or equal to 65.5mPa.s, the elastic modulus of the water dispersion systems is more than or equal to 31.6Pa, and the oil washing rate is more than or equal to 37.22%, which are obviously higher than the technical requirements specified by the comparative examples of TX-6, TX-7, TX-8, TX-9 and the standard, and the heterogeneous oil displacement system based on the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent, which is formed by the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent, the polyacrylamide emulsion and the nano oil displacement agent, has good viscosity of the water dispersion system, elastic modulus of the water dispersion system and oil washing rate. Experiments prove that the indexes of the viscosity, the elastic modulus and the oil washing rate of the heterogeneous oil displacement system formed by the three components are superior to the sum of any component, and the obvious synergistic effect is embodied. Taking TX-1 as an example, the viscosity of a single 800mg/L polyacrylamide emulsion 20C aqueous dispersion is 12.5mPa.s, the viscosity of a single 500mg/L temperature-resistant and salt-resistant viscoelastic particle oil displacement agent JX-1 aqueous dispersion is 21.6mPa.s, the sum of the two is 34.1mPa.s, and the viscosity of the TX-1 aqueous dispersion is measured to be 65.5mPa.s > 34.1mPa.s through experiments; taking TX-2 as an example, the elastic modulus of a single 1000mg/L polyacrylamide emulsion 30C water dispersion system is 19.4Pa, the elastic modulus of a single 800mg/L temperature-resistant salt-resistant viscoelastic particle oil displacement agent JX-2 solution water dispersion system is 10.4Pa, the sum of the elastic modulus and the elastic modulus is 29.8Pa, and the elastic modulus of the TX-2 water dispersion system is measured to be 38.7Pa to 29.8Pa by experiments; taking TX-6 as an example, PPG is used for replacing the temperature-resistant and salt-resistant viscoelastic particle oil displacement agent in the example 1 in the comparative example 1, and the temperature resistance and salt resistance of PPG are relatively poor, so that the viscosity and modulus of a heterogeneous oil displacement system formed by PPG and polyacrylamide emulsion 20C are relatively poor, and deep profile control is difficult to perform by sufficient migration, so that the wave volume at the deep part of a stratum is difficult to fully expand, and the nano oil washing agent is difficult to fully penetrate into fine gaps to play a strong oil washing effect, so that the oil washing rate of TX-6 is 25.58 percent to 38.17 percent.

It can be understood that, in comparative example 2TX-7, the polyacrylamide emulsion 30C is replaced by the polyacrylamide dry powder for III type displacement of reservoir oil, and the polyacrylamide for III type displacement of reservoir oil is white granular dry powder and cannot be sufficiently dissolved within 15min, so that when the polyacrylamide for III type displacement of reservoir oil is in heterogeneous displacement with the temperature-resistant and salt-resistant viscoelastic particle displacement agent and the nano-oil washing agentThe viscosity and modulus of the oil system TX-7 are relatively poor. Oil detergent AE for comparative example 3TX-8₁The nanometer oil-washing agent KPS-4 in the embodiment 4 is replaced, and the particle size is large, so that the nanometer oil-washing agent KPS-4 is difficult to penetrate into small cracks of a low-permeability reservoir to exert a strong oil-washing effect, and therefore the synergistic effect of the nanometer oil-washing agent KPS-4 in the low-permeability reservoir of a heterogeneous oil reservoir is difficult, and the oil-washing effect is poor. Compared with the prior art, the temperature-resistant salt-tolerant viscoelastic particle oil displacement agent is not added in the comparative example 4TX-9, a heterogeneous oil displacement system cannot be formed with the polyacrylamide emulsion 30C and the nano oil washing agent KPS-2, and the synergistic effect cannot be exerted, so that the viscosity of the water dispersion system, the elastic modulus of the water dispersion system and the oil washing rate of the binary oil displacement system formed by the polyacrylamide emulsion 30C and the nano oil washing agent KPS-2 are poor.

Claims

1. The preparation method of the heterogeneous oil displacement system based on the temperature-resistant salt-resistant viscoelastic particle oil displacement agent is characterized by comprising the following steps of:

the stirring speed is adjusted to 380-.

2. The method according to claim 1, wherein the mass of the polyacrylamide emulsion added is m_aWherein m is_a0.24g to 0.36 g; the mass of the added temperature-resistant salt-resistant viscoelastic particle oil displacement agent is m_bWherein m is_b0.15g to 0.3 g; the mass of the added nano oil washing agent solution is 300-m_a-m_b g。

3. The preparation method according to claim 1 or 2, wherein the median diameter of the nano oil washing agent is in the range of 20-50 nm.

4. The preparation method according to claim 1 or 2, wherein the temperature-resistant salt-tolerant viscoelastic particle oil displacement agent is prepared by the following steps:

5. The method according to claim 4, wherein the mass ratio of the added acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and deionized water is (0.1 to 0.3): (0.01-0.05): (0.15-0.5): 1.

6. the preparation method according to claim 4, wherein the mass of the added crosslinking agent N, N-dimethylacrylamide accounts for 1% to 3% of the total mass of the reaction system.

7. The preparation method according to claim 4, wherein the pH in the reaction kettle is adjusted to 8-10.

8. The method according to claim 4, wherein the ratio of the multimetal heteropolyacid salt of molybdenum in the initiating system: the mass ratio of the polyhydric alcohol is (0.05-0.1): 1, and the initiating system accounts for 0.1 to 0.3 percent of the total mass of the reaction system.

9. The method of claim 8, wherein the multimetal heteropolyacid salt of molybdenum in the initiating system is selected from [ Bmim [ ]]₃[SiMo₁₂O₄₀]、[Hmim]₃[SiMo₁₂O₄₀]、[Dhmim]₃[SiMo₁₂O₄₀]、[Hpy]₃[SiMo₁₂O₄₀]At least one of (1).

10. The method according to claim 8, wherein the polyol in the initiation system is at least one selected from the group consisting of ethylene glycol, glycerol, and pentaerythritol.

11. The heterogeneous oil displacement system based on the temperature-resistant salt-tolerant viscoelastic particle oil displacement agent prepared by the preparation method according to any one of claims 1 to 10.

12. The use of the heterogeneous oil displacement system based on the temperature-resistant and salt-tolerant viscoelastic particle oil displacement agent according to claim 11 in the exploitation of high-temperature and high-salinity reservoirs, heterogeneous reservoirs and polymer oil displacement reservoirs with the temperature of less than or equal to 90 ℃ and the degree of mineralization of less than or equal to 32848 mg/L.

13. The application of claim 12, wherein when the heterogeneous oil displacement system is applied, the viscosity of an aqueous dispersion system of a solution is more than or equal to 65.5mPa & s at 90 ℃ and the mineralization degree of 32848 mg/L; the elastic modulus of the aqueous dispersion system of the solution is more than or equal to 31.6Pa at the temperature of 35 ℃ and the mineralization degree of 32848 mg/L; the oil washing rate of the solution is more than or equal to 37.22 percent at 50 ℃ and the mineralization degree of 32848 mg/L.