A high-strength, low-density fracturing organic proppant and its preparation method

Abstract

This invention relates to the field of chemical preparation technology, specifically to a high-strength, low-density fracturing organic proppant and its preparation method, comprising the following raw materials: methyl methacrylate, 2-vinylnaphthalene, divinylbenzene, alkaline earth metal dispersion enhancer, and polyvinyl alcohol; the preparation method is as follows: alkaline earth metal halide and alkali are placed in distilled water, and polyvinyl alcohol is added; methyl methacrylate, 2-vinylnaphthalene, and divinylbenzene are weighed into a beaker, and benzoyl peroxide is added to dissolve them; the solution is added to a dispersion system for reaction; solid particles are obtained by filtration, and the fixed particles are a high-strength, low-density fracturing organic proppant. The prepared high-strength, low-density fracturing organic proppant has the characteristics of high strength, low density, and strong fracture conductivity, solving the problems of sand carrying difficulties and sand blockage that are prone to occur in traditional fracturing proppants containing inorganic particles with high density or low strength.

Description

Technical Field

[0001] This invention relates to the field of chemical preparation technology, and in particular to high-strength, low-density fracturing organic proppant and its preparation method. Background Technology

[0002] Fracturing proppant must be able to support the fractures generated during fracturing under certain formation pressures, and also have a low density to facilitate better placement within the fractures. A common fracturing technique involves injecting high-viscosity fracturing fluid carrying solid proppant into the formation.

[0003] Currently, commonly used traditional proppants include high-strength, lightweight proppants such as quartz sand, ceramsite, and organic composite micro-nano materials. These proppants have high density or low strength, which can easily lead to problems such as difficulty in carrying sand, incomplete gel breaking of high-viscosity fracturing fluid causing damage to the reservoir, sand plugging, and difficulty in pumping, which are not conducive to the progress of construction. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength, low-density fracturing organic proppant and its preparation method, aiming to solve the technical problems in the prior art, such as the proppant having a high density or low strength, which easily leads to difficulties in carrying sand, incomplete gel breaking of high-viscosity fracturing fluid causing damage to the reservoir, sand blockage, and difficulties in pumping, thus hindering the progress of construction.

[0005] To achieve the above objectives, the present invention employs a high-strength, low-density fracturing organic proppant, which is prepared from the following raw materials:

[0006] Methyl methacrylate, 2-vinylnaphthalene, divinylbenzene, alkaline earth metal dispersion enhancer, and polyvinyl alcohol.

[0007] This invention also provides a method for preparing a high-strength, low-density fracturing organic proppant, comprising the following steps:

[0008] Weigh out alkaline earth metal halide and alkali, put alkaline earth metal halide and alkali into distilled water, add polyvinyl alcohol and stir to obtain a dispersion system;

[0009] Weigh methyl methacrylate, 2-vinylnaphthalene, and divinylbenzene into a beaker, add benzoyl peroxide, and stir until dissolved to obtain a solution;

[0010] The solution is added to the dispersion system to carry out the reaction;

[0011] After the reaction is complete, the solid particles are obtained by filtration.

[0012] In the steps of weighing alkaline earth metal halides and alkali, adding alkaline earth metal halides and alkali to distilled water, and adding polyvinyl alcohol and stirring to obtain a dispersion system:

[0013] Add polyvinyl alcohol and heat to 75-85°C while stirring.

[0014] In the step of adding the solution to the dispersion system to carry out the reaction:

[0015] The reaction was carried out at the same rotation speed and temperature.

[0016] In the step of adding the solution to the dispersion system to carry out the reaction:

[0017] The reaction time is 30-50 minutes.

[0018] After the reaction is complete and the solid particles are obtained by filtration:

[0019] Use a drying oven to dry the solid particles.

[0020] This invention discloses a high-strength, low-density fracturing organic proppant and its preparation method. Methyl methacrylate and 2-vinylnaphthalene are used as reactant monomers, and alkaline earth metal dispersion enhancer and polyvinyl alcohol are used as mixed dispersants. The preparation process involves: weighing alkaline earth metal halide and alkali, adding them to distilled water, and then adding polyvinyl alcohol and stirring to obtain a dispersion system; weighing methyl methacrylate, 2-vinylnaphthalene, and divinylbenzene in a beaker, adding benzoyl peroxide, and stirring until dissolved to obtain a solution; adding the solution to the dispersion system for reaction; and after the reaction is complete, filtering to obtain solid particles, which are the high-strength, low-density fracturing organic proppant. The prepared high-strength, low-density fracturing organic proppant has the characteristics of high strength, low density, and strong fracture conductivity, solving the problems of sand carrying difficulties and sand blockage that easily occur with traditional fracturing proppants containing inorganic particles due to their high density or low strength. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of the steps in the preparation method of the high-strength, low-density fracturing organic proppant of the present invention.

[0023] Figure 2 This is a flowchart of the steps in Embodiment 1 of the present invention.

[0024] Figure 3 This is a flowchart of the steps in Embodiment 2 of the present invention.

[0025] Figure 4 This is a flowchart of the steps in Embodiment 3 of the present invention.

[0026] Figure 5 This is a flowchart of the steps in Embodiment 4 of the present invention.

[0027] Figure 6 The breakage rate of the support agent under different ratios of 2-vinylnaphthalene and methyl methacrylate according to the present invention.

[0028] Figure 7 This is a diagram showing the conductivity of the proppant containing alkaline earth metal dispersion reinforcing agent and the quartz sand compared to the proppant without alkaline earth metal dispersion reinforcing agent according to the present invention.

[0029] Figure 8 This is a scanning electron microscope image of the proppant without alkaline earth metal dispersion enhancer according to the present invention.

[0030] Figure 9 This is a scanning electron microscope image of the support containing alkaline earth metal dispersion enhancer according to the present invention. Detailed Implementation

[0031] This invention provides a high-strength, low-density fracturing organic proppant, which is prepared from the following raw materials:

[0032] Methyl methacrylate, 2-vinylnaphthalene, divinylbenzene, alkaline earth metal dispersion enhancer, and polyvinyl alcohol.

[0033] Please see Figure 1 This invention provides a method for preparing a high-strength, low-density fracturing organic proppant, comprising the following steps:

[0034] S1: Weigh the alkaline earth metal halide and the alkali, put the alkaline earth metal halide and the alkali into distilled water, add polyvinyl alcohol, heat to 75~85℃ and stir to obtain a dispersion system;

[0035] S2: Weigh methyl methacrylate, 2-vinylnaphthalene, and divinylbenzene into a beaker, add benzoyl peroxide, and stir until dissolved to obtain a solution;

[0036] S3: Add the solution to the dispersion system and react at the same rotation speed and temperature for 30-50 minutes;

[0037] S4: After the reaction is complete, filter to obtain solid particles;

[0038] S5: Use a drying oven to dry the solid particles.

[0039] In this embodiment, methyl methacrylate and 2-vinylnaphthalene are used as reactants, and alkaline earth metal dispersion enhancer and polyvinyl alcohol are used as mixed dispersants. First, alkaline earth metal halide and alkali are weighed and placed in distilled water, and polyvinyl alcohol is added. The mixture is heated to 75-85°C and stirred to obtain a dispersion system. Then, methyl methacrylate, 2-vinylnaphthalene, and divinylbenzene are weighed into a beaker, and benzoyl peroxide is added and stirred until dissolved to obtain a solution. The solution is then added to the dispersion system and reacted at the same speed and temperature for 30-50 minutes. After the reaction is complete, the solid particles are obtained by filtration. Finally, the solid particles are dried in a drying oven. The dried solid particles are the high-strength, low-density fracturing organic proppant, and the resulting high-strength, low-density fracturing organic proppant... Organic proppant possesses high strength, low density, and strong fracture conductivity, solving the problems of sand carrying difficulties and sand blockage that often occur with traditional inorganic particle-containing fracturing proppants due to their high density or low strength. The high-strength, low-density organic fracturing proppant synthesized in this invention incorporates 2-vinylnaphthalene copolymerization into methyl methacrylate. The addition of rigid benzene rings increases the rigidity and strength of the proppant and reduces the breakage rate. An inorganic dispersing agent is used, which, while dispersing the polymerization process, also forms microrods 1-2 micrometers long and approximately 0.1 micrometers in diameter within the proppant, increasing its strength and enhancing fracture conductivity. The density of the prepared high-strength, low-density organic fracturing proppant is significantly lower than that of quartz sand. Furthermore, the polymerization time of the high-strength, low-density organic fracturing proppant is short, and the synthesis process is simple.

[0040] Example 1, please refer to Figure 2 This invention provides a method for preparing a high-strength, low-density fracturing organic proppant, comprising the following steps:

[0041] S11: Weigh 1.5g of alkaline earth metal halide and 0.6g of alkali into a beaker containing 70ml of water, stir to dissolve as an inorganic dispersant. Some of the inorganic particles are encapsulated in the polymer particles during the polymerization reaction, thus also playing a reinforcing role. Then add 0.01g of polyvinyl alcohol as a polymeric dispersant to the beaker, stir thoroughly, and transfer the solution in the beaker to a 250ml three-necked flask. Turn on the stirrer and set the speed to 220r / min, and heat to 85℃ to obtain the dispersion system.

[0042] S12: Weigh 7g of methyl methacrylate as a reactant and 3g of divinylbenzene as a crosslinking agent into a 100ml beaker, add 0.25g of benzoyl peroxide as an initiator, stir to dissolve, and obtain a solution;

[0043] S13: Add the solution to the dispersion system, keep the rotation speed and temperature constant, and stop the reaction after 30~50 minutes;

[0044] S14: Solid particles are obtained by vacuum filtration;

[0045] S15: Dry the solid particles to obtain dry proppant particles A.

[0046] In this embodiment, firstly, 1.5g of alkaline earth metal halide and 0.6g of alkali are weighed into a beaker containing 70ml of water and stirred to dissolve, serving as an inorganic dispersant. Some of the inorganic particles are encapsulated within the polymer particles during the polymerization reaction, thus also contributing to the strengthening effect. Next, 0.01g of polyvinyl alcohol, a high-molecular-weight dispersant, is added to the beaker and stirred thoroughly. The solution is then transferred to a 250ml three-necked flask, and the stirrer is turned on at 220 rpm, and the temperature is raised to 85°C to obtain the dispersion system. Then, 7g of methyl methacrylate is weighed as a reactant monomer and 3g of divinylbenzene is weighed into a 100ml... In a beaker, 0.25g of benzoyl peroxide was added as an initiator and stirred to dissolve, yielding a solution. This solution was then added to a dispersion system, and the reaction was stopped after 30-50 minutes while maintaining constant rotation speed and temperature. The mixture was then filtered to obtain solid particles. Finally, the solid particles were dried to obtain dry proppant particles A. Dry proppant particles A are the high-strength, low-density fracturing organic proppant described above. The prepared high-strength, low-density fracturing organic proppant features high strength, low density, and strong fracture conductivity, solving the problems of sand carrying difficulties and sand blockage that easily occur with traditional inorganic particle-containing fracturing proppants with high density or low strength.

[0047] Example 2, please refer to Figure 3 This invention provides a method for preparing a high-strength, low-density fracturing organic proppant, comprising the following steps:

[0048] S21: Weigh 1.5g of alkaline earth metal halide and 0.6g of alkali into a beaker containing 70ml of water, stir to dissolve, then add 0.01g of polyvinyl alcohol to the beaker, stir thoroughly, transfer the solution in the beaker to a 250ml three-necked flask, turn on the stirrer and set the speed to 220r / min, heat to 85℃ to obtain the dispersion system;

[0049] S21: Weigh 5.25g of methyl methacrylate and 3g of divinylbenzene into a 100ml beaker, then add 1.75g ​​of 2-vinylnaphthalene to the beaker to increase the rigidity of the polymer structure. After dissolving, add 0.25g of benzoyl peroxide, stir to dissolve, and obtain a solution.

[0050] S23: Add the solution to the dispersion system, keep the rotation speed and temperature constant, and stop the reaction after 30~50 minutes;

[0051] S24: Solid particles are obtained by vacuum filtration;

[0052] S25: Dry the solid particles to obtain dry proppant particles B.

[0053] In this embodiment, firstly, 1.5g of alkaline earth metal halide and 0.6g of alkali are weighed into a beaker containing 70ml of water and stirred to dissolve. Then, 0.01g of polyvinyl alcohol is added to the beaker and stirred thoroughly. The solution in the beaker is then transferred to a 250ml three-necked flask, and the stirrer is turned on at a speed of 220r / min. The temperature is raised to 85℃ to obtain a dispersion system. Next, 5.25g of methyl methacrylate and 3g of divinylbenzene are weighed into a 100ml beaker, and then 1.75g ​​of... 2-Vinylnaphthalene increases the rigidity and density of the polymer structure. After dissolving, 0.25g of benzoyl peroxide is added and stirred to dissolve, yielding a solution. The solution is then added to the dispersion system, and the reaction is stopped after 30-50 minutes while maintaining constant rotation speed and temperature. The solid particles are then obtained by filtration. Finally, the solid particles are dried to obtain dry proppant particles B. Dry proppant particles B are the high-strength, low-density fracturing organic proppant. The prepared high-strength, low-density fracturing organic proppant has the characteristics of high strength, low density, and strong fracture conductivity, solving the problems of sand carrying difficulties and sand blockage that are prone to occur in traditional fracturing proppants containing inorganic particles with high density or low strength.

[0054] Example 3, please refer to Figure 4 This invention provides a method for preparing a high-strength, low-density fracturing organic proppant, comprising the following steps:

[0055] S31: Weigh 1.5g of alkaline earth metal halide and 0.6g of alkali into a beaker containing 70ml of water, stir to dissolve, then add 0.01g of polyvinyl alcohol to the beaker, stir thoroughly, transfer the solution in the beaker to a 250ml three-necked flask, turn on the stirrer and set the speed to 220r / min, heat to 85℃ to obtain the dispersion system;

[0056] S32: Weigh 3.5g of methyl methacrylate and 3g of divinylbenzene into a 100ml beaker, then add 3.5g of 2-vinylnaphthalene to the beaker and dissolve it. Then add 0.25g of benzoyl peroxide and stir to dissolve to obtain a solution.

[0057] S33: Add the solution to the dispersion system, keep the rotation speed and temperature constant, and stop the reaction after 30~50 minutes;

[0058] S34: Solid particles are obtained by vacuum filtration;

[0059] S35: Dry the solid particles to obtain dry proppant particles C.

[0060] In this embodiment, firstly, 1.5g of alkaline earth metal halide and 0.6g of alkali are weighed into a beaker containing 70ml of water and stirred to dissolve. Then, 0.01g of polyvinyl alcohol is added to the beaker and stirred thoroughly. The solution in the beaker is then transferred to a 250ml three-necked flask, and the stirrer is turned on at a speed of 220r / min. The temperature is raised to 85℃ to obtain a dispersion system. Next, 3.5g of methyl methacrylate and 3g of divinylbenzene are weighed into a 100ml beaker, and then 3.5g of... 2-Vinylnaphthalene was dissolved, and then 0.25g of benzoyl peroxide was added and stirred to dissolve, resulting in a solution. The solution was then added to the dispersion system, and the reaction was stopped after 30-50 minutes while maintaining constant rotation speed and temperature. The solid particles were then obtained by filtration. Finally, the solid particles were dried to obtain dry proppant particles C. Dry proppant particles C are the high-strength, low-density fracturing organic proppant. The prepared high-strength, low-density fracturing organic proppant has the characteristics of high strength, low density, and strong fracture conductivity, which solves the problems of sand carrying difficulties and sand blockage that are prone to occur in traditional fracturing proppants containing inorganic particles with high density or low strength.

[0061] Example 4, please refer to Figure 5 This invention provides a method for preparing a high-strength, low-density fracturing organic proppant, comprising the following steps:

[0062] S41: Weigh 1.5g of alkaline earth metal halide and 0.6g of alkali into a beaker containing 70ml of water, stir to dissolve, then add 0.01g of polyvinyl alcohol to the beaker, stir thoroughly, transfer the solution in the beaker to a 250ml three-necked flask, turn on the stirrer and set the speed to 220r / min, heat to 85℃ to obtain the dispersion system;

[0063] S42: Weigh 1.75g ​​of methyl methacrylate and 3g of divinylbenzene into a 100ml beaker, then add 5.25g of 2-vinylnaphthalene to the beaker and dissolve it. Then add 0.25g of benzoyl peroxide and stir to dissolve to obtain a solution.

[0064] S43: Add the solution to the dispersion system, keep the rotation speed and temperature constant, and stop the reaction after 30~50 minutes;

[0065] S44: Solid particles are obtained by vacuum filtration;

[0066] S45: Dry the solid particles to obtain dry proppant particles D.

[0067] In this embodiment, firstly, 1.5g of alkaline earth metal halide and 0.6g of alkali are weighed into a beaker containing 70ml of water and stirred to dissolve. Then, 0.01g of polyvinyl alcohol is added to the beaker and stirred thoroughly. The solution in the beaker is then transferred to a 250ml three-necked flask, and the stirrer is turned on at a speed of 220r / min. The temperature is raised to 85℃ to obtain a dispersion system. Next, 1.75g ​​of methyl methacrylate and 3g of divinylbenzene are weighed into a 100ml beaker, and then 5.25g of... 2-Vinylnaphthalene was dissolved, and then 0.25g of benzoyl peroxide was added and stirred to dissolve, resulting in a solution. The solution was then added to the dispersion system, and the reaction was stopped after 30-50 minutes while maintaining constant rotation speed and temperature. The solid particles were then obtained by filtration. Finally, the solid particles were dried to obtain dry proppant particles D. Dry proppant particles D are the high-strength, low-density fracturing organic proppant. The prepared high-strength, low-density fracturing organic proppant has the characteristics of high strength, low density, and strong fracture conductivity, which solves the problems of sand carrying difficulties and sand blockage that are prone to occur in traditional fracturing proppants containing inorganic particles with high density or low strength.

[0068] Performance testing of high-strength, low-density fracturing organic proppant:

[0069] Table 1 shows the density tests of 2-vinylnaphthalene (N) and methyl methacrylate (MMA) at different ratios;

[0070] Serial Number (N:MMA) <![CDATA[Apparent density (g / cm 3 ).]]> <![CDATA[Apparent density (g / cm 3 )]]> A (0:4) 1.1750 0.66 B (1:3) 1.1592 0.57 C (1:1) 1.0946 0.63 D (3:1) 1.0152 0.65 Quartz sand 2.5858 0.99

[0071] Table 1

[0072] As can be seen from Table 1, the density of the high-strength, low-density proppant synthesized in this invention is much lower than that of quartz sand. Figure 6 Data analysis showed that an increase in naphthalene content resulted in a decrease in breakage rate (breakage rate was measured at 69 MPa).

[0073] Depend on Figure 7 Data analysis showed that proppants containing alkaline earth metal dispersion reinforcing agents had higher conductivity than proppants without alkaline earth metal dispersion reinforcing agents under a certain closing pressure.

[0074] The microstructures of proppants containing alkaline earth metal dispersion enhancers and proppants without dispersion enhancers were investigated using scanning electron microscopy. The results are shown in [Figure number missing]. Figure 8 and Figure 9 The proppant containing alkaline earth metal dispersing agents contains microrods 1-2 micrometers long and about 0.1 micrometers in diameter, which provide a reinforcing effect. The proppant without dispersing agents does not have microrod-like structures.

[0075] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for preparing a high-strength, low-density fracturing organic proppant, characterized in that, Weigh 1.5g of alkaline earth metal halide, 0.6g of alkali, and 70ml of water, and stir to dissolve as an inorganic dispersant. Then add 0.01g of polyvinyl alcohol, stir thoroughly, set the rotation speed to 220r / min, and heat to 85℃ to obtain a dispersion system. Next, weigh 7g of methyl methacrylate as a reactant monomer and 3g of divinylbenzene as a crosslinking agent, add 0.25g of benzoyl peroxide as an initiator, and stir to dissolve to obtain a solution. Add the solution to the dispersion system, maintain the rotation speed and temperature, and stop the reaction after 30-50min. Then filter to obtain solid particles. Finally, dry the solid particles to obtain dried proppant particles, which are the high-strength, low-density fracturing organic proppant.

2. A method for preparing a high-strength, low-density fracturing organic proppant, characterized in that, Weigh 1.5g of alkaline earth metal halide, 0.6g of alkali, and 70ml of water, stir to dissolve, then add 0.01g of polyvinyl alcohol to a beaker, stir thoroughly, set the stirring speed to 220r / min, and heat to 85℃ to obtain a dispersion system; then weigh 5.25g of methyl methacrylate and 3g of divinylbenzene, add 1.75g ​​of 2-vinylnaphthalene, dissolve, then add 0.25g of benzoyl peroxide, stir to dissolve, and obtain a solution; The solution is then added to the dispersion system, and the rotation speed and temperature are maintained. The reaction is stopped after 30-50 minutes. The solid particles are then obtained by filtration. Finally, the solid particles are dried to obtain dry proppant particles, which are the high-strength, low-density fracturing organic proppant.

3. A method for preparing a high-strength, low-density fracturing organic proppant, characterized in that, Weigh 1.5g of alkaline earth metal halide, 0.6g of alkali, and 70ml of water, stir to dissolve, then add 0.01g of polyvinyl alcohol to a beaker, stir thoroughly, set the stirring speed to 220r / min, and heat to 85℃ to obtain a dispersion system; then weigh 3.5g of methyl methacrylate and 3g of divinylbenzene, add 3.5g of 2-vinylnaphthalene, dissolve, then add 0.25g of benzoyl peroxide, stir to dissolve, and obtain a solution; The solution is then added to the dispersion system, and the rotation speed and temperature are maintained. The reaction is stopped after 30-50 minutes. The solid particles are then obtained by filtration. Finally, the solid particles are dried to obtain dry proppant particles, which are the high-strength, low-density fracturing organic proppant.

4. A method for preparing a high-strength, low-density fracturing organic proppant, characterized in that, Weigh 1.5g of alkaline earth metal halide, 0.6g of alkali, and 70ml of water, stir to dissolve, then add 0.01g of polyvinyl alcohol to a beaker, stir thoroughly, set the speed to 220r / min, and heat to 85℃ to obtain a dispersion system; Then weigh 1.75g ​​of methyl methacrylate and 3g of divinylbenzene, add 5.25g of 2-vinylnaphthalene to a beaker, dissolve it, then add 0.25g of benzoyl peroxide, stir to dissolve, and obtain a solution; The solution is then added to the dispersion system, and the rotation speed and temperature are maintained. The reaction is stopped after 30-50 minutes. The solid particles are then obtained by filtration. Finally, the solid particles are dried to obtain dry proppant particles, which are the high-strength, low-density fracturing organic proppant.

5. The method for preparing the high-strength, low-density fracturing organic proppant according to any one of claims 1 to 4, characterized in that, After the reaction is complete, and the solid particles are obtained by filtration: Use a drying oven to dry the solid particles.

Images