Sand control copolymer utilizing charge effect and method of making same

Abstract

The application discloses a sand control copolymer using charge action, which comprises the following components in mass fraction: 20 parts of vinyl pyridine; 35 parts of styrene; 35 parts of butyl acrylate; 10 parts of a coupling agent; 0.1-0.3 parts of an initiator; and 150 parts of a solvent. The application also discloses a preparation method of the sand control copolymer using charge action. The application is suitable for the technical field of chemical sand control. The prepared sand control copolymer is prepared by using tetrahydrofuran and is easy to inject. When entering a stratum, the sand control copolymer changes the polarity of the system by meeting water, controls the precipitation rate of the oil-soluble polymer by using the change of the polarity of the system solvent, and fills the sand particles by the precipitated oil-soluble polymer. The sand control copolymer enhances the adhesion to the sand particles by using the chemical bond action and the physical bond action, and enhances the adhesion between the sand particles by using the charge action. The sand control effect is obvious, the operation is simple, the injection cost is reduced obviously, and the sand control copolymer is easy to be applied in industrialization.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chemical sand control, and specifically relates to a sand control copolymer using charge action and a preparation method thereof. BACKGROUND

[0002] Severe sand production is caused by factors such as oil reservoir geological conditions and oil and gas exploitation, and oil well sand production can cause high production cost and even well plugging. At present, oil field sand control methods mainly include mechanical sand control and chemical sand control, and the chemical sand control is to cement loose sand and gravel with a chemical agent with adhesion to control the problem of formation sand production.

[0003] According to Janning Ning et al. Oilfield Chemical Sand Control Technology Review, the traditional oil and gas well chemical sand control mainly uses a resin consolidated sand system, which can be divided into a phenolic resin sand control agent, a urea-formaldehyde resin sand control agent, and a modified epoxy resin sand control agent. The phenolic resin sand control agent is suitable for strata with less sand production and low clay content, but is not suitable for long-term water injection development. The urea-formaldehyde resin sand control agent is low in price and suitable for sand production oil wells in the high water cut period, but the resin is not firmly bonded with sand particles. The modified epoxy resin sand control agent is suitable for medium and low temperature oil reservoirs. The resin sand control agent has a large molecular weight and high viscosity, which seriously affects the pumpability of the sand control system into the formation, the sand control period is short, and it is basically not suitable for strata with large permeability difference.

[0004] With the increasing requirements for sand control technology and effect, a sand control agent that uses charge attraction and has good sand control effect, long period and easy injection needs to be developed for sandstone potential reservoirs. SUMMARY

[0005] The application aims to overcome the defects of the prior art and provide a sand control copolymer using charge action and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0007] In a first aspect, a sand control copolymer using charge action has the following structural formula:

[0008]

[0009] Preferably, the following components are included in the mass fraction:

[0010] 20 parts of vinylpyridine;

[0011] 35 parts of styrene;

[0012] 35 parts of butyl acrylate;

[0013] 10 parts of a coupling agent;

[0014] 0.1-0.3 parts of an initiator;

[0015] 150 parts of a solvent.

[0016] Preferably, the coupling agent is gamma-methacryloxypropyltrimethoxysilane.

[0017] Preferably, the initiator is azobisisobutyronitrile.

[0018] Preferably, the solvent is tetrahydrofuran.

[0019] In a second aspect, a method for preparing a sand control copolymer using charge effect comprises the following steps:

[0020] S1. A formula amount of vinylpyridine, styrene, butyl acrylate, coupling agent, initiator and solvent are weighed into a reaction vessel, heated to a certain temperature and refluxed until the reaction is completed;

[0021] S2. The prepared polymer is filtered while hot, and after the filtrate is cooled to a certain temperature, it is filtered under reduced pressure;

[0022] S3. The precipitated material is dissolved in ethanol, heated to a certain temperature, and filtered under reduced pressure;

[0023] S4. Step S3 is repeated several times to obtain a weak cationic copolymer sand control agent.

[0024] Preferably, in step S1, the reaction vessel is a three-necked flask.

[0025] Preferably, in step S1, the reaction temperature is 70-80℃ and the reaction time is 6-8h.

[0026] Preferably, in step S1, constant temperature oil bath heating is used.

[0027] Preferably, in step S1, nitrogen protection is used before heating.

[0028] Preferably, in step S2, the filtrate is cooled to 25℃ before being filtered under reduced pressure.

[0029] Preferably, in step S3, the temperature is raised to 70-80℃ before being filtered under reduced pressure.

[0030] Preferably, in step S4, step S3 is repeated three times.

[0031] In summary, due to the use of the above technical solutions, the present application has the following advantages:

[0032] In the present application, the prepared sand control copolymer is prepared by using tetrahydrofuran to be easy to inject, and the system polarity is changed after entering the formation to control the precipitation rate of the oil-soluble polymer by using the change of the system solvent polarity, the precipitated oil-soluble polymer can fill between the sand particles, the adhesion to the sand particles is enhanced by using the chemical bonding and physical binding, and the adhesion between the sand particles is enhanced by using the charge effect, the sand control effect is obvious, the operation is simple, the injection cost is significantly reduced, and the industrial application is easy. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a flow chart of a preparation method of the sand control copolymer using charge effect according to the present application. DETAILED DESCRIPTION

[0034] The specific embodiments of the sand control copolymer using charge effect and the preparation method thereof according to the present application are further described below in combination with the examples. The sand control copolymer using charge effect and the preparation method thereof according to the present application are not limited to the description of the following examples.

[0035] Example 1:

[0036] A sand control copolymer using charge effect has the following structural formula:

[0037]

[0038] Further, the following components are included in mass fraction:

[0039] 20 parts of vinylpyridine;

[0040] 35 parts of styrene;

[0041] 35 parts of butyl acrylate;

[0042] 10 parts of a coupling agent;

[0043] 0.1 part of an initiator;

[0044] 150 parts of a solvent.

[0045] Further, the coupling agent is γ-methacryloyloxypropyltrimethoxysilane.

[0046] Further, the initiator is azobisisobutyronitrile.

[0047] Further, the solvent is tetrahydrofuran.

[0048] Example 2:

[0049] A sand control copolymer using charge effect includes the following components in mass fraction:

[0050] 20 parts of vinylpyridine;

[0051] 35 parts of styrene;

[0052] 35 parts of butyl acrylate;

[0053] 10 parts of coupling agent;

[0054] 0.2 parts of initiator;

[0055] 150 parts of solvent.

[0056] Example 3:

[0057] A sand control copolymer using charge effect, comprising the following components by mass fraction:

[0058] 20 parts of vinyl pyridine;

[0059] 35 parts of styrene;

[0060] 35 parts of butyl acrylate;

[0061] 10 parts of coupling agent;

[0062] 0.3 parts of initiator;

[0063] 150 parts of solvent.

[0064] Example 4:

[0065] A sand control copolymer using charge effect, comprising the following steps as shown in the figure: Figure 1

[0066] S1: Take the formula amount of vinyl pyridine, styrene, butyl acrylate, coupling agent, initiator and solvent in the reaction container, heat to a certain temperature and reflux until the reaction is completed;

[0067] S2: Filter the prepared polymer while hot, and after the filtrate is cooled to a certain temperature, reduce the pressure and filter;

[0068] S3: Dissolve the precipitated substance in ethanol, heat to a certain temperature, and reduce the pressure and filter;

[0069] S4: Repeat step S3 several times to obtain a weak cation copolymer sand control agent.

[0070] Further, in step S1, the reaction container is a three-necked flask.

[0071] Further, in step S1, the reaction temperature is 70°C and the reaction time is 6h.

[0072] Further, in step S1, constant temperature oil bath heating is used.

[0073] Further, in step S1, nitrogen protection is used before heating. ​

[0074] Further, in step S2, the filtrate is cooled to 25°C, and then filtered under reduced pressure.

[0075] Further, in step S3, the temperature is raised to 70°C, and then filtered under reduced pressure.

[0076] Further, in step S4, step S3 is repeated three times.

[0077] Example 5:

[0078] A method for preparing a sand control copolymer using charge effect, other steps are similar to those of Example 4, further, in step S1, the reaction temperature is 75°C, and the reaction time is 7h.

[0079] Further, in step S3, the temperature is raised to 75°C, and then filtered under reduced pressure.

[0080] Example 6:

[0081] A method for preparing a sand control copolymer using charge effect, other steps are similar to those of Example 4, further, in step S1, the reaction temperature is 80°C, and the reaction time is 8h.

[0082] Further, in step S3, the temperature is raised to 80°C, and then filtered under reduced pressure.

[0083] Example 7:

[0084] (1) 17.5g of styrene, 10g of vinylpyridine and 17.5g of butyl acrylate were weighed into a three-necked flask, and 0.05g of azobisisobutyronitrile, 5g of KH570 and 50mL of tetrahydrofuran were added, and the mixture was heated under reflux at 70°C for 6h under nitrogen protection;

[0085] (2) The prepared polymer was filtered while hot, and then filtered under reduced pressure after the filtrate was cooled to room temperature; the precipitated substance was dissolved in ethanol, and filtered under reduced pressure after the temperature was raised to 80°C. The above steps were repeated three times to obtain a weak cationic sand control agent.

[0086] The performance of the polymer was determined by preparing solutions of different concentrations using tetrahydrofuran.

[0087] Example 8:

[0088] (1) 17.5g of styrene, 10g of vinylpyridine and 17.5g of butyl acrylate were weighed into a three-necked flask, and 0.05g of azobisisobutyronitrile, 5g of KH570 and 50mL of tetrahydrofuran were added, and the mixture was heated under reflux at 70°C for 6h under nitrogen protection;

[0089] (2) The prepared polymer is filtered while hot, and after the filtrate is cooled to room temperature, it is filtered under reduced pressure; the precipitated substance is dissolved in ethanol, heated to 80°C, and filtered under reduced pressure. The above steps are repeated three times to obtain a weak cationic sand control agent.

[0090] The polymer is prepared into solutions of different concentrations with tetrahydrofuran for performance determination.

[0091] Example 9:

[0092] (1) 17.5 g of styrene, 10 g of vinylpyridine and 17.5 g of butyl acrylate are weighed into a three-necked flask, and 0.1 g of azobisisobutyronitrile, 5 g of KH570 and 75 mL of tetrahydrofuran are added, and the mixture is heated under nitrogen protection in a constant temperature oil bath, and reacted at 80°C for 8 h;

[0093] (2) The prepared polymer is filtered while hot, and after the filtrate is cooled to room temperature, it is filtered under reduced pressure; the precipitated substance is dissolved in ethanol, heated to 80°C, and filtered under reduced pressure. The above steps are repeated three times to obtain a weak cationic sand control agent.

[0094] The polymer is prepared into solutions of different concentrations with tetrahydrofuran for performance determination.

[0095] Example 10:

[0096] (1) 35 g of styrene, 20 g of vinylpyridine and 35 g of butyl acrylate are weighed into a three-necked flask, and 0.1 g of azobisisobutyronitrile, 10 g of KH570 and 150 mL of tetrahydrofuran are added, and the mixture is heated under nitrogen protection in a constant temperature oil bath, and reacted at 70°C for 7 h;

[0097] (2) The prepared polymer is filtered while hot, and after the filtrate is cooled to room temperature, it is filtered under reduced pressure; the precipitated substance is dissolved in ethanol, heated to 80°C, and filtered under reduced pressure. The above steps are repeated three times to obtain a weak cationic sand control agent.

[0098] The polymer is prepared into solutions of different concentrations with tetrahydrofuran for performance determination.

[0099] Example 11:

[0100] (1) 35 g of styrene, 20 g of vinylpyridine and 35 g of butyl acrylate are weighed into a three-necked flask, and 0.3 g of azobisisobutyronitrile, 10 g of KH570 and 150 mL of tetrahydrofuran are added, and the mixture is heated under nitrogen protection in a constant temperature oil bath, and reacted at 75°C for 8 h;

[0101] (2) The prepared polymer is filtered while hot, and after the filtrate is cooled to room temperature, it is filtered under reduced pressure; the precipitated substance is dissolved in ethanol, heated to 80°C, and filtered under reduced pressure. The above steps are repeated three times to obtain a weak cationic sand control agent.

[0102] The polymer is prepared into different concentration solutions with tetrahydrofuran for performance determination.

[0103] Example 12:

[0104] (1) 35 g of styrene, 20 g of vinylpyridine and 35 g of butyl acrylate are weighed into a three-necked flask, and 0.3 g of azobisisobutyronitrile, 10 g of KH570 and 150 mL of tetrahydrofuran are added, and the mixture is heated under nitrogen protection using a constant temperature oil bath, and the reaction is carried out at 80℃ for 8h;

[0105] (2) The prepared polymer is filtered while hot, and after the filtrate is cooled to room temperature, it is extracted under reduced pressure; the precipitated substance is dissolved in ethanol, and the temperature is raised to 80℃, and then extracted under reduced pressure. The above steps are repeated for 3 times, and a weak cationic sand control agent can be obtained.

[0106] The polymer is prepared into different concentration solutions with tetrahydrofuran for performance determination.

[0107] The weak cationic sand control agent of the application is an oil-soluble polymer, and the application uses the monomers commonly used in synthetic resins, such as styrene, vinylpyridine and butyl acrylate, as monomers, and a coupling agent γ-methacryloyloxypropyl trimethoxysilane (KH570) is used for preparation by free radical polymerization reaction, and the experimental conditions of monomer ratio, initiator and coupling agent are optimized to obtain a better process synthesis route. The anti-erosion and compression resistance of the sand control agent prepared in Example 12 are tested as follows:

[0108] (1) Anti-erosion performance research

[0109] The coarse sand is filtered with a screen, and the sand particles with a particle size of 0.3mm to 0.45mm are selected, and the sand particles are mixed uniformly with crude oil at a mass ratio of 7:1, and 250g of sand particles are added uniformly to a surface dish to obtain a sand pile model with consistent shape, and different concentrations of sand control agent are sprayed on the sand pile model at a spraying amount of 1L / m 2 The sand control agent is dried to form a consolidated layer, and then an electric fan is used to simulate natural wind to blow the sand pile model from the front, and whether the consolidated layer is damaged is observed, and the mass of the sand pile is recorded after half an hour. The results are shown in Table 1.

[0110] Table 1 Anti-erosion strength of sand control agent

[0111]

[0112] (2) Compression resistance

[0113] The coarse sand is filtered by a screen, sand particles with a particle size of 0.3 mm to 0.45 mm are selected, the sand particles are mixed uniformly at a mass ratio of 7:1 of the sand particles to crude oil, 250 g of the oil sand is weighed and mixed uniformly with 20 g of the sand inhibiting agent solution, a mold with a size of 4.0 cm in height and 7 cm in diameter is added, and the sand column model is obtained after ramming and drying. The sand column model is placed into a material mechanics testing machine for compression until the sand model is broken, and the test speed is 5 mm / min. The results are shown in Table 2.

[0114] Table 2: Compressive strength of the sand inhibiting agent

[0115]

[0116] As shown above, with the increase of the mass concentration of the sand inhibiting agent, the wind erosion resistance and the compressive strength are both improved.

[0117] By adopting the technical scheme, the following advantages are achieved:

[0118] An oil-soluble polymer sand inhibiting agent is prepared by emulsion copolymerization of vinyl pyridine, styrene and butyl acrylate. The monomer vinyl pyridine in the polymer provides weak cations, which can form charge attraction with the multiple hydroxyl anions on the surface of sandstone, thereby increasing the adhesion work between the sand inhibiting agent and the sandstone. The styrene and butyl acrylate provide hydrophobic structures, and the butyl acrylate provides alkyl structures, which can be easily incorporated into the oil film. Meanwhile, the coupling agent γ-methacryloyloxypropyltrimethoxysilane (KH-570) can strengthen the adhesion to the sand particles. A solution with a concentration of 10-20% is prepared by using the solvent tetrahydrofuran, which is easy to inject into the formation. Then, water is used to incorporate tetrahydrofuran to change the polarity of the solution, so that the polymer is precipitated to fill the sand particles, thereby achieving effective sand inhibition. The operation is simple, the injection cost is significantly reduced, and the industrial application is facilitated.

[0119] In summary, the present application has the following advantages:

[0120] (1) In the present application, commonly used monomers such as styrene, vinyl pyridine with weak cation characteristics, butyl acrylate providing alkyl structures, and coupling agent γ-methacryloyloxypropyltrimethoxysilane (KH570) are used to prepare a lipophilic polymer sand inhibiting agent with weak cations through free radical polymerization. The monomer vinyl pyridine in the polymer provides weak cations, which can form charge attraction with the multiple hydroxyl anions on the surface of sandstone, thereby increasing the adhesion work between the sand inhibiting agent and the sandstone. The styrene and butyl acrylate provide hydrophobic structures, and the butyl acrylate provides alkyl structures, which are easy to enter the oil film. KH-570 can strengthen the adhesion to the sand particles. The reaction conditions of the experimental scheme are easy to control, and the reaction process is simple.

[0121] (2) In the present application, the copolymer with weak cationic characteristics can balance the negative charge on the surface of sandstone and enhance the adhesion between particles. It avoids the self-repulsion between particles caused by high cationic concentration in conventional sand control agents, and reduces the rock adsorption phenomenon of strong cationic polymers during injection.

[0122] (3) In the present application, the prepared sand control copolymer is prepared with tetrahydrofuran to facilitate injection. When it enters the formation, it changes the polarity of the system by encountering water, controls the precipitation rate of oil-soluble polymers by changing the polarity of the system solvent, and the precipitated oil-soluble polymers can fill the space between sand particles, enhance the adhesion to sand particles by chemical bonding and physical binding, and enhance the adhesion between sand particles by charge effect. The sand control effect is obvious, and the operation is simple and easy to industrialize.

[0123] The above is a further detailed description of the present application in combination with specific preferred embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, a number of simple deductions or substitutions can be made without departing from the concept of the present application, and all of them should be considered as falling within the protection scope of the present application.

Claims

1. A sand control copolymer utilizing charge effect, characterized in that, By mass fraction, comprising the following components: 20 parts of vinylpyridine; 35 parts of styrene; 35 parts of butyl acrylate; 10 parts of coupling agent; 0.1-0.3 parts of initiator; 150 parts of solvent; The coupling agent is γ-methacryloyloxypropyltrimethoxysilane; The solvent is tetrahydrofuran; Its preparation method, Comprising the following steps: S1. Take the formula amount of vinylpyridine, styrene, butyl acrylate, coupling agent, initiator and solvent in a reaction vessel, heat to a certain temperature and reflux until the reaction is completed; S2. Filter the prepared polymer while hot, and after the filtrate is cooled to a certain temperature, reduce pressure and filter; S3. Dissolve the precipitated substance in ethanol, heat to a certain temperature, and reduce pressure and filter; S4. Repeat step S3 several times to obtain a weak cation copolymer sand control agent.

2. A sand control copolymer utilizing charge effect according to claim 1, wherein, The initiator is azobisisobutyronitrile.

3. A sand control copolymer utilizing charge effect according to claim 1, wherein the copolymer is a copolymer of a monomer having a hydrophilic group and a monomer having a hydrophobic group. In the step S1, the reaction vessel is a three-necked flask.

4. A sand control copolymer utilizing charge effect according to claim 1, wherein, In the step S1, the reaction temperature is 70-80℃, and the reaction time is 6-8h.

5. A sand control copolymer utilizing charge effect according to claim 1, wherein the copolymer is a copolymer of a monomer having a hydrophilic group and a monomer having a hydrophobic group. In the step S1, constant temperature oil bath heating is used.

6. A sand control copolymer utilizing charge effect according to claim 1, wherein, In the step S1, nitrogen protection is used before heating.

7. A sand control copolymer utilizing charge effect according to claim 1, wherein the copolymer is a copolymer of a monomer having a hydrophilic group and a monomer having a hydrophobic group. In the step S2, the filtrate is cooled to 25℃ before being reduced pressure and filtered.

8. A sand control copolymer utilizing charge effect according to claim 1, wherein, In the step S3, heat to 70-80℃, and reduce pressure and filter.

9. A sand control copolymer utilizing charge effect according to claim 1, wherein, In the step S4, step S3 is repeated three times.

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