Rubber powder gel particle

Abstract

The invention relates to a rubber powder gel particle which is prepared from the following components in percentage by weight: 14%-23% of a polymeric monomer, 0.04%-0.08% of a cross-linking agent, 0.3%-0.5% of an initiator, 5%-15% of bentonite, 0.5%-3% of hydrophilic modified rubber powder and the balance of water. In the rubber powder gel particles provided by the invention, the rubber powder is treated by the surfactant and can be uniformly dispersed in a water-based reaction system, and the rubber powder gel particles have the dual advantages of gel particles and rubber powder, so that the viscosity and toughness of the gel particles are obviously enhanced.

Description

Technical Field

[0001] The present invention relates to a rubber powder gel particle, belonging to the technical field of oil exploitation. Background Art

[0002] Water flooding is a commonly used development method in oilfields in China and has achieved good results. However, most oilfields have now entered the middle and late stages of water injection development. The formation of dominant channels leads to poor water flooding effects, greatly affecting the recovery degree of crude oil. Profile control and displacement technology is a commonly used means to improve the water flooding development effect. A commonly used and effective method in profile control and displacement technology is to use chemical reagents, such as inorganic particles, composite particles, pre-crosslinked particles, weak gels, and strong gels, etc., to block the water layer through chemical means. Among them, pre-crosslinked gel particles are a kind of profile control agent for oilfields with a wide application range and large dosage. They have characteristics such as water absorption and swelling, extrusion deformation, etc. They have a good plugging effect on large pores in high-water-cut and high-recovery oilfields, and can greatly improve the recovery degree of crude oil. However, there are problems such as poor viscosity and toughness after water absorption and swelling, easy crushing under extrusion, and weak plugging ability for medium and high-permeability oil reservoirs.

[0003] Rubber powder has strong toughness, is not easy to break, can be extruded and deformed, and is resistant to high temperature and high salinity. In theory, it can become a good profile control and oil displacement agent for oilfields. However, there are two problems in actual application: one is that rubber powder is not hydrophilic and cannot be evenly dispersed in water or water-based profile control agents. It floats on the liquid surface and cannot be injected; the other is that rubber powder is extremely easy to adsorb and aggregate into clusters with each other. After being injected into the wellbore by strong stirring, it aggregates and forms a blockage at the perforation, and the injection pressure rises rapidly, resulting in the suspension of construction and inability to inject deep into the formation.

[0004] The Chinese invention patent application document with the application publication number CN114716993A discloses a solid-core gel particle, its preparation method and application, and provides a solid-core gel particle. The solid-core gel particle includes solid particles and a coating layer coated on the surface of the solid particles. By mass percentage, the solid particles are 15-55%, and the coating layer is 45-85%; the coating layer is a polymer, and the solid particles include rubber powder. However, due to the lack of hydrophilicity of rubber powder, it cannot be evenly dispersed in the water-based solvent. Therefore, ultrasonic dispersion is required during the preparation process, and the operation process of preparing solid-core gel particles by this method is complex and not easy to be widely used on a large scale. Summary of the Invention

[0005] The first object of the present invention is to provide a rubber powder gel particle to solve the problem that in the prior art, rubber powder is not hydrophilic and cannot be evenly dispersed in the water-based system without complicated additional operations, resulting in a complex preparation process of rubber powder gel particles.

[0006] The second object of the present invention is to provide a preparation method of rubber powder gel particles to solve the problem of complex preparation operation process of solid-core gel particles in the prior art.

[0007] The third object of the present invention is to provide the application of rubber powder gel particles in oilfield profile control agents to solve the problems that the pre-crosslinked gel particles in the prior art have poor viscosity and toughness after water absorption and expansion, are easy to break under extrusion, and have weak plugging ability for medium-high permeability oil reservoirs.

[0008] In order to achieve the above objects, the technical solution of a kind of rubber powder gel particles in the present invention is as follows:

[0009] A kind of rubber powder gel particles is made of the following components by weight percentage: 14% - 23% of polymerization monomers, 0.04% - 0.08% of crosslinking agents, 0.3% - 0.5% of initiators, 5% - 15% of bentonite, 0.5% - 3% of hydrophilically modified rubber powder, and the balance is water.

[0010] The beneficial effect of the above technical solution is that: through research, it is found that using surfactants to treat rubber powder can modify the rubber powder by its dispersion effect, and the modified rubber powder can be evenly dispersed in the water reaction system of the gel of the present invention. Through experimental verification, the rubber powder gel particles of the present invention have the dual advantages of gel particles and rubber powder, and the strength and viscosity and toughness of the gel particles are significantly improved.

[0011] As a further improvement, the rubber powder is hydrophilically modified with surfactants; the surfactants are sodium alcohol polyoxyethylene ether sulfate with C10 - 16, sodium alkylbenzene sulfonate or sodium alkenyl sulfonate.

[0012] The beneficial effect of the above technical solution is that: through research, it is found that using surfactants to treat rubber powder can modify the rubber powder by its dispersion effect, improve the water solubility of the rubber powder, and lay a foundation for the application of the rubber powder in the aqueous system.

[0013] As a further improvement, 0.5 - 3 g of rubber powder is mixed with 0.06 - 0.1 mL of a surfactant solution with a concentration of 0.08% - 0.1% to obtain hydrophilically modified rubber powder.

[0014] As a further improvement, the initiator is composed of initiator 1 and initiator 2; initiator 1 is one of ammonium persulfate, potassium persulfate or sodium persulfate; initiator 2 is one of sodium bisulfite, ammonium bisulfite or potassium bisulfite.

[0015] The beneficial effect of the above technical solution is that: compared with other types of initiators, selecting persulfate initiators has better stability, water solubility and strong oxidizing property; selecting bisulfate initiators has a faster and more stable gel time.

[0016] As a further improvement, the mass ratio of the initiator 1 to the initiator 2 is 1:1.

[0017] As a further improvement, the polymerization monomer is acrylamide or methacrylamide.

[0018] The beneficial effects of the above technical solution are as follows: Acrylamide and methacrylamide are common polymerization monomers in pre-crosslinked gel particles, which have the advantages of wide sources and low prices, and can effectively reduce the production cost of the industry.

[0019] As a further improvement, the crosslinking agent is one of N,N-methylenebisacrylamide, methylene bisacrylamide or N,N-dimethylacrylamide.

[0020] As a further improvement, the rubber powder gel particles are prepared by a method comprising the following steps:

[0021] S1. Hydrophilic modification of the rubber powder using a surfactant;

[0022] S2. Mixing the hydrophilic modified rubber powder obtained in S1 with a mixture of the main body, crosslinking agent, bentonite and water;

[0023] S3. Adding the initiator 1 and the initiator 2 to the system after mixing in S2, standing and then pulverizing to obtain the product.

[0024] The beneficial effects of the above technical solution are as follows: The preparation method of the rubber powder gel particles of the present invention is simple. After mixing the rubber powder modified with a surfactant with the reaction system of the gel, adding an initiator and allowing it to solidify and pulverize to obtain the product, without complex operation steps and complex instrument support, greatly reducing the production cost.

[0025] As a further improvement, in S2, the initiator 1 is added to the system after mixing in S1, and after dissolution, the initiator 2 solution is added.

[0026] The beneficial effects of the above technical solution are as follows: The initiator 2 will react rapidly after addition, which may lead to uncontrollable reaction rate. Operating in the above manner is conducive to the full reaction of the initiator 1 and can better control the reaction rate.

[0027] In order to achieve the above object, the technical solution of the application of the rubber powder gel particles in the oilfield profile control agent in the present invention is:

[0028] An application of rubber powder gel particles in an oilfield profile control agent.

[0029] The beneficial effects of the above technical solution are as follows: Through experimental verification, the rubber powder modified by the surfactant in the present invention can be evenly dispersed in the gel particles, effectively solving the problem that the rubber powder cannot be injected deep in practical applications. Moreover, the rubber powder gel particles have the dual advantages of gel particles and rubber powder, significantly enhancing the viscosity and toughness of the gel particles, meeting the requirements of efficient and economic development of oilfields, and reducing environmental pollution. Description of the Drawings

[0030] Figure 1 Dispersion comparison of rubber powder with or without surfactant pretreatment in solution (the left beaker in the figure is normal rubber powder, and the right beaker is rubber powder treated with surfactant (0.08%));

[0031] Figure 2 Gel before comminution in Example 1;

[0032] Figure 3 Gel before comminution in Example 2;

[0033] Figure 4 Gel before comminution in Example 3. Detailed Embodiments

[0034] Through experiments, the present invention found that the rubber powder without hydrophilicity can improve its hydrophilicity after being treated with a surfactant, enabling the rubber powder to be evenly dispersed in water. The specific operations are as follows:

[0035] Take 3 g of rubber powder and add 0.1 mL of C10-C16 alkylbenzene sulfonate solutions with different concentrations (the concentrations are 0.02%, 0.04%, 0.06%, 0.08%, and 0.1%) respectively, and stir to make them evenly mixed. Add the rubber powder treated with C10-C16 alkylbenzene sulfonate and normal rubber powder into water. It is found that the rubber powder treated with C10-C16 alkylbenzene sulfonate can be evenly dispersed in water, while the normal rubber powder cannot be evenly dispersed in water after being added to water. Moreover, through experiments, it is found that when the concentration is 0.08%, the dispersion effect is the best, which can better wet the rubber powder and has a better modification effect. The dispersion comparison of the rubber powder treated with 0.08% C10-C16 alkylbenzene sulfonate and normal rubber powder in solution is as Figure 1 shown.

[0036] Subsequently, through experiments, the present invention verified that after treating the rubber powder with C10-C16 alkenyl sulfonate or C10-C16 alcohol polyoxyethylene ether sulfate, the rubber powder can be evenly dispersed in water, and the modification effect is better.

[0037] In the early stage of the present invention, an attempt was also made to add rubber powder to water and then add a surfactant for treatment. However, it was found that compared with the method of modifying the rubber powder first, when treating the same mass of rubber powder, the amount of surfactant added was as high as 130 times that of the above method, and the rubber powder still could not be uniformly dissolved in water.

[0038] The following further describes the present invention in conjunction with specific embodiments. It should be noted that on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments. The equipment, raw materials, etc. used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are all conventional methods in the art unless otherwise specified.

[0039] The CAS number of sodium C10-16 alkylbenzenesulfonate used in the present invention is 68081-81-2, the CAS number of sodium C10-16 alkenylsulfonate solution is 68439-57-6, and the CAS number of sodium C10-16 alcohol polyoxyethylene ether sulfate is 68891-38-3.

[0040] Example 1 Rubber powder gel particle 1 and its preparation method

[0041] The rubber powder gel particle 1 of this example is specifically operated as follows:

[0042] The rubber powder gel particle 1 is made of the following components by weight percentage: 14% acrylamide, 0.08% N,N-methylenebisacrylamide, 0.25% ammonium persulfate, 0.25% sodium bisulfite, 15% bentonite, 3% rubber powder, 0.1% surfactant, and the balance is water.

[0043] The preparation method is as follows:

[0044] (1) Surface pretreatment of rubber powder: Add 0.1 mL of 0.08% sodium C10-C16 alkylbenzenesulfonate (CAS number 68081-81-2) solution (diluted with water) to 3 g of rubber powder, stir to make it evenly mixed, so as to modify the rubber powder to obtain hydrophilic modified rubber powder (the surface of the rubber powder is wetted by the surfactant), enabling it to be evenly dispersed in the reaction system;

[0045] (2) At room temperature, dissolve 14 g of acrylamide, 0.08 g of N,N-methylenebisacrylamide, and 15 g of bentonite in 67.42 mL of water;

[0046] (3) Add the 3 g of rubber powder pretreated in (1) to the mixed solution obtained in step (2) while stirring;

[0047] (4) While stirring, add 0.25 g of ammonium persulfate to the solution in step (3). After complete dissolution, while stirring, add an aqueous solution containing 2.5 mL of 0.1 g / mL sodium bisulfite. The solution gradually becomes thick. Let it stand for about three hours to obtain a gel. As can be seen from Figure 2 it can be seen that the rubber powder is uniformly dispersed in the gel. After crushing the gel, it becomes rubber powder gel particles 1.

[0048] Example 2 Rubber powder gel particles 2 and its preparation method

[0049] The rubber powder gel particles 2 of this example are specifically implemented as follows:

[0050] The rubber powder gel particles 2 are made of the following components by weight percentage: 23% of methylacrylamide, 0.04% of methylenebisacrylamide, 0.15% of potassium persulfate, 0.15% of ammonium bisulfite, 5% of bentonite, 0.5% of rubber powder, 0.06% of surfactant, and the balance is water.

[0051] The preparation method is as follows:

[0052] (1) Surface pretreatment of rubber powder: Add 0.06 mL of a 0.08% solution of C10-C16 alkenyl sulfonate (CAS No. 68439-57-6) (diluted with water) to 0.5 g of rubber powder, and stir to make it uniformly mixed, thereby modifying the rubber powder to obtain hydrophilically modified rubber powder (the surface of the rubber powder is wetted by the surfactant), so that it can be uniformly dispersed into the reaction system;

[0053] (2) At room temperature, dissolve 23 g of methylacrylamide, 0.04 g of methylenebisacrylamide, and 5 g of bentonite in 71.1 mL of water;

[0054] (3) While stirring, add 0.5 g of the pretreated rubber powder in (1) to the mixed solution obtained in step (2);

[0055] (4) While stirring, add 0.15 g of potassium persulfate to the solution in step (3). After complete dissolution, while stirring, add an aqueous solution containing 1.5 mL of 0.1 g / mL ammonium bisulfite. The solution gradually becomes thick. Let it stand for about three hours to obtain a gel. As can be seen from Figure 3 it can be seen that the rubber powder is uniformly dispersed in the gel. After crushing the gel, it becomes rubber powder gel particles 2.

[0056] Example 3 Rubber powder gel particles 3 and its preparation method

[0057] The rubber powder gel particles 3 of this example are specifically implemented as follows:

[0058] The rubber powder gel particles 3 are made of the following components by weight percentage: 18% acrylamide, 0.06% methylene bisacrylamide, 0.2% potassium persulfate, 0.2% ammonium bisulfite, 10% bentonite, 2% rubber powder, 0.08% surfactant, and the balance is water.

[0059] The preparation method is as follows:

[0060] (1) Surface pretreatment of the rubber powder: Add 0.06 mL of a 0.08% solution of C10-C16 alcohol polyoxyethylene ether sulfate (CAS No. 68891-38-3) (diluted with water) to 2 g of rubber powder, stir to make it evenly mixed, thereby modifying the rubber powder to obtain hydrophilically modified rubber powder (the surface of the rubber powder is wetted by the surfactant), so that it can be evenly dispersed in the reaction system;

[0061] (2) At room temperature, dissolve 18 g of acrylamide, 0.06 g of N,N-methylenebisacrylamide, and 10 g of bentonite in 69.45 mL of water;

[0062] (3) Add the 2 g of rubber powder pretreated in (1) to the mixture obtained in step (2) while stirring;

[0063] (4) Add 0.2 g of sodium persulfate to the solution in step (3) while stirring, and after complete dissolution, add an aqueous solution containing 2 mL of 0.1 g / mL potassium bisulfite while stirring. The solution slowly becomes thick, and let it stand for about three hours to obtain the gel. As Figure 4 can be seen, the rubber powder is evenly dispersed in the gel. After the gel is crushed, it becomes the rubber powder gel particles 3.

[0064] Gel particles of Comparative Example 1

[0065] The gel particles of this comparative example are made of the following components by weight percentage: 14% acrylamide, 0.08% N,N-methylenebisacrylamide, 0.25% ammonium persulfate, 0.25% sodium bisulfite, 15% bentonite, and the balance is water.

[0066] The preparation method is as follows:

[0067] (1) At room temperature, dissolve 14 g of acrylamide, 0.08 g of N,N-methylenebisacrylamide, and 15 g of bentonite in 70.42 mL of water;

[0068] (2) Add 0.25 g of ammonium persulfate to the solution in step (1) while stirring, and after complete dissolution, add an aqueous solution containing 2.5 mL of 0.1 g / mL sodium bisulfite while stirring. The solution slowly becomes thick, and let it stand for about three hours to obtain the gel. Figure 2It can be seen that the rubber powder is evenly dispersed in the gel. After the gel is crushed, it becomes gel particles.

[0069] Performance Test of Experimental Example 1

[0070] The rubber powder gel particles of Examples 1 to 3 and the gel particles of Comparative Example 1 were tested in accordance with the enterprise standard Q / SH3135 454—2018 "Technical Requirements for Gel Plugging Agents" of Henan Oilfield Company, SINOPEC and the enterprise standard Q / SH1025 0426—2009 "Technical Conditions for Pre-crosslinked Particle Profile Control Agents" of Zhongyuan Petroleum Exploration Bureau. The specific results are shown in Table 1.

[0071] Table 1 Performance Test Results of Rubber Powder Gel Particles 1 to 3 and Gel Particles of Comparative Example 1

[0072] Coefficient of thermal expansion Temperature resistance / °C Tensile strength / kPa Gel particles of rubber powder 1 5 95 700 Gel particles of rubber powder 2 4.5 98 720 Gel particles of rubber powder 3 4.5 96 760 Gel particles (Comparative Example 1) 2.6 85 420

[0073] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention is subject to the claims. All equivalent structural changes made by using the content of the specification of the present invention should, by the same token, be included in the protection scope of the present invention.

Claims

1. A rubber powder gel particle, characterized in that: It is made of the following components by weight percentage: 14% - 23% of polymerization monomer, 0.04% - 0.08% of crosslinking agent, 0.3% - 0.5% of initiator, 5% - 15% of bentonite, 0.5% - 3% of hydrophilically modified rubber powder, and the balance is water.

2. The rubber powder gel particle according to claim 1, characterized in that: The hydrophilically modified rubber powder is obtained by hydrophilically modifying rubber powder with a surfactant; the surfactant is sodium alcohol polyoxyethylene ether sulfate with C10 - 16, sodium alkyl benzene sulfonate or sodium alkenyl sulfonate.

3. The rubber powder gel particle according to claim 2, characterized in that: 0.5 - 3 g of rubber powder is mixed with 0.06 - 0.1 mL of surfactant solution with a concentration of 0.08% - 0.1% to obtain the hydrophilically modified rubber powder.

4. The rubber powder gel particle according to claim 1, characterized in that: The initiator consists of initiator 1 and initiator 2; initiator 1 is one of ammonium persulfate, potassium persulfate or sodium persulfate; initiator 2 is one of sodium bisulfite, ammonium bisulfite or potassium bisulfite.

5. The rubber powder gel particle according to claim 4, characterized in that: The mass ratio of initiator 1 to initiator 2 is 1:

1.

6. The rubber powder gel particle according to claim 1, characterized in that: The polymerization monomer is acrylamide or methacrylamide.

7. The rubber powder gel particle according to claim 1, characterized in that: The crosslinking agent is one of N,N - methylene bisacrylamide, methylene bisacrylamide or N,N - dimethylacrylamide.

8. The rubber powder gel particle according to any one of claims 1 to 7, characterized in that: The rubber powder gel particles are prepared by a method including the following steps: S1. Hydrophilically modify the rubber powder with a surfactant; S2. Mix the hydrophilically modified rubber powder obtained in S1 with the mixture of the main body, crosslinking agent, bentonite and water; S3. Add initiator 1 and initiator 2 to the system after mixing in S2, and obtain the product after standing and pulverizing.

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