A method for preparing a hydrophobic in-situ generated proppant

Abstract

The present application relates to the technical field of fracturing proppant preparation, and specifically provides a preparation method of hydrophobic in-situ generated proppant, comprising the following steps: S1, mixing 15-40 parts of epoxy resin; S2, mixing the epoxy resin prepolymer with 1-3 parts of low surface energy material and 1-5 parts of silane coupling agent, heating at 60 DEG C for 1h to obtain the hydrophobically modified epoxy resin mixture; S3, adding 5-15 parts of curing agent to the A liquid and uniformly mixing to obtain the C liquid; S4, weighing 3-8 parts of polyvinyl alcohol and dissolving in 70-100 parts of water to obtain the D liquid; S5, dropping the D liquid into the C liquid at a speed of 10-60cc / min; S6, continuing to stir after the D liquid is completely added to obtain the hydrophobic self-generated proppant; the present application has excellent hydrophobic effect by hydrophobic modification of the epoxy resin and forming epoxy resin proppant microspheres through in-situ self-generated proppant technology; meanwhile, the in-situ self-generated proppant technology avoids the problems of large density, easy settlement and difficult migration of traditional proppants.

Description

Technical Field

[0001] This invention relates to the field of fracturing proppant preparation technology, specifically to a method for preparing a hydrophobic in-situ generated proppant. Background Technology

[0002] In oil and gas extraction, high-pressure, low-permeability deposits undergo fracturing to open up oil and gas-bearing rock formations. Oil and gas then converge through the channels formed by these fractures. At this point, fluid needs to be injected into the base layer of the rock at pressures exceeding the formation's fracturing strength to create fractures in the surrounding rock strata, forming a channel with high-level flow capacity. To maintain the openness of the fractured formation and allow oil and gas products to flow smoothly, proppant is used during fracturing stimulation in oil and gas fields to enhance the conductivity of the opened formation fractures.

[0003] Conventional proppant materials are quartz sand and ceramsite. Due to their high density, they require high-viscosity fracturing fluid to carry them into the formation during operation. Pumping this proppant-carrying fluid is energy-intensive, and the proppant causes severe erosion and wear on fracturing equipment and downhole tools. Furthermore, conventional proppant materials are difficult to effectively support microfractures smaller than themselves. For these reasons, researchers developed "in-situ self-generated proppant" technology, which allows fracturing fluid to be injected into formation fractures in liquid form, achieving full fracture support.

[0004] The investigation revealed that the proppant microspheres prepared using this technology currently have weak hydrophobicity, and the final sphere formation rate of liquid proppant is generally below 60%, resulting in significant material loss and production waste. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for preparing hydrophobic in-situ proppant, which solves the problems of weak hydrophobicity and low spheroidization rate of proppant microspheres prepared by injecting fracturing fluid into formation fractures in the prior art.

[0006] To achieve the above and other related objectives, the present invention provides a method for preparing a hydrophobic in-situ proppant, comprising the following steps:

[0007] S1. Mix a total of 15-40 parts of epoxy resin to obtain epoxy resin prepolymer;

[0008] S2. Mix epoxy resin prepolymer with 1-3 parts of low surface energy material and 1-5 parts of silane coupling agent, and heat at 60°C for 1 hour to obtain hydrophobically modified epoxy resin mixture, which is liquid A.

[0009] S3. Add 5-15 parts of curing agent to liquid A and mix well to obtain liquid C;

[0010] S4. Weigh 3-8 parts of polyvinyl alcohol and dissolve them in 70-100 parts of water to obtain solution D;

[0011] S5. Add solution D to solution C at a rate of 10-60 cc / min, with the rotation speed set to 500-2000 rpm;

[0012] S6. After the D liquid droplets have been added, continue stirring for 10-40 minutes to obtain a hydrophobic self-supporting agent.

[0013] In one embodiment of the present invention, in step S1, the epoxy resin prepolymer includes E51 epoxy resin, E44 epoxy resin, AG-80 epoxy resin, and AFG-90 epoxy resin.

[0014] In one embodiment of the present invention, in step S2, the low surface energy material includes polydimethylsiloxane, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, and polymethyltriethoxysilane; the silane coupling agent includes KH-550, KH-560, and KH-570.

[0015] In one embodiment of the present invention, in step S3, the curing agent includes one or more of aromatic amine curing agents, alicyclic curing agents, and imidazole curing agents.

[0016] In one embodiment of the present invention, the aromatic amine curing agent includes diaminodiphenyl sulfone, diaminodiphenylmethane, and m-phenylenediamine; the alicyclic curing agent includes Ancamine 2764 and Ancamine 2280; and the imidazole curing agent includes imidazole, 2-methylimidazolium, 2-ethylimidazolium, and 2-ethyl-4-methylimidazolium.

[0017] In one embodiment of the present invention, in step S4, the polyvinyl alcohol includes type 0588, type 1788, type 1799, and type 2099.

[0018] As described above, the method for preparing the hydrophobic in-situ proppant of the present invention has the following beneficial effects:

[0019] This invention modifies epoxy resin to be hydrophobic and forms epoxy resin proppant microspheres using in-situ self-generated proppant technology. This proppant exhibits excellent hydrophobic properties, which allow it to enter formation fractures and provide higher conductivity channels for oil and gas, increasing oil and gas production and purity. Simultaneously, the in-situ self-generated proppant technology avoids a series of problems associated with traditional proppants, such as high density, easy settling, and difficulty in migration, effectively supporting formation fractures and achieving effective support for the entire fracture network. Furthermore, the hydrophobic in-situ self-generated proppant prepared by this invention has a sphericity rate of over 60%, a surface contact angle exceeding 160°, high strength, low deformation rate under 12-hour load, and long aging resistance. Attached Figure Description

[0020] Figure 1 The image shown is a macroscopic schematic diagram of the particles of the hydrophobic in-situ generated proppant prepared by the method for preparing the hydrophobic in-situ generated proppant disclosed in this invention.

[0021] Figure 2 The image shown is a magnified schematic diagram of the hydrophobic in-situ generated proppant prepared by the method disclosed in this invention.

[0022] Figure 3 The diagram shown is a further enlarged schematic of the hydrophobic in-situ generated proppant prepared by the method for preparing the hydrophobic in-situ generated proppant disclosed in this invention.

[0023] Figure 4 The diagram shown is the Krumbien / Sloss diagram disclosed in Example 5.

[0024] Figure 5 The image shown is a measurement diagram of larger particles of the hydrophobic in-situ generated proppant prepared by the preparation method of the hydrophobic in-situ generated proppant disclosed in this invention. Detailed Implementation

[0025] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0026] Please see Figures 1 to 5 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0027] Example 1

[0028] Please see Figure 1-3 This embodiment provides a method for preparing a hydrophobic in-situ proppant, comprising the following steps:

[0029] S1. Mix a total of 15-40 parts of epoxy resin to obtain an epoxy resin prepolymer; wherein the epoxy resin prepolymer includes E51 epoxy resin, E44 epoxy resin, AG-80 epoxy resin, and AFG-90 epoxy resin.

[0030] S2. Mix the epoxy resin prepolymer with 1-3 parts of a low surface energy substance and 1-5 parts of a silane coupling agent, and heat at 60°C for 1 hour to obtain a hydrophobically modified epoxy resin mixture, which is liquid A; wherein the low surface energy substance includes polydimethylsiloxane, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, and polymethyltriethoxysilane; the silane coupling agent includes KH-550, KH-560, and KH-570;

[0031] S3. Add 5-15 parts of curing agent to solution A and mix thoroughly to obtain solution C; wherein the curing agent includes one or more of aromatic amine curing agents, alicyclic curing agents, and imidazole curing agents; the aromatic amine curing agent includes diaminodiphenyl sulfone, diaminodiphenylmethane, and m-phenylenediamine; the alicyclic curing agent includes Ancamine 2764 and Ancamine 2280; the imidazole curing agent includes imidazole, 2-methylimidazolium, 2-ethylimidazolium, and 2-ethyl-4-methylimidazolium;

[0032] S4. Weigh 3-8 parts of polyvinyl alcohol and dissolve it in 70-100 parts of water to obtain solution D; wherein the polyvinyl alcohol includes type 0588, type 1788, type 1799, and type 2099.

[0033] S5. Add solution D to solution C at a rate of 10-60 cc / min, with the rotation speed set to 500-2000 rpm;

[0034] S6. After the D liquid droplets have been added, continue stirring for 10-40 minutes to obtain a hydrophobic self-supporting agent.

[0035] After being injected into the formation, the hydrophobic self-generated proppant is affected by the formation temperature, causing the epoxy resin to self-cure and form proppant microspheres. This invention modifies the epoxy resin to be hydrophobic and forms epoxy resin proppant microspheres through in-situ self-generated proppant technology. This proppant has excellent hydrophobic properties, which allow it to provide higher conductivity channels for oil and gas after entering the formation fractures, increasing the production and purity of oil and gas. At the same time, the in-situ self-generated proppant technology avoids a series of problems such as high density, easy settling, and difficulty in migration of traditional proppants, fully supporting the formation fractures and achieving effective support for the entire fracture network.

[0036] Example 2

[0037] Please see Figure 4 Based on Example 1, this example provides a method for preparing a hydrophobic in-situ proppant, comprising the following steps:

[0038] S1. Mix 20 parts of E51 epoxy resin, 10 parts of E44 epoxy resin, and 5 parts of AG-805, for a total of 35 parts of epoxy resin, to obtain an epoxy resin prepolymer.

[0039] S2. Mix epoxy resin prepolymer with 2 parts of polydimethylsiloxane, 1 part of KH-550, 1 part of KH-570, a total of 2 parts of low surface energy material and 2 parts of silane coupling agent, and heat at 60°C for 1 hour to obtain hydrophobically modified epoxy resin mixture, which is liquid A.

[0040] S3. Add 6 parts of diaminodiphenyl sulfone, 1 part of 2-ethyl-4-methylimidazolium, and 3 parts of diaminodiphenylmethane, totaling 10 parts of curing agent, to liquid A and mix evenly to obtain liquid C.

[0041] S4. Weigh out 2 parts of type 0588 polyvinyl alcohol, 3 parts of type 1799 polyvinyl alcohol, and 1 part of type 2099 polyvinyl alcohol, totaling 6 parts of polyvinyl alcohol, and dissolve them in 70-100 parts of water to obtain solution D.

[0042] S5. Add solution D to solution C at a rate of 25cc / min, with the rotation speed set to 700rpm.

[0043] S6. After the D liquid droplets have been added, continue stirring for 10-40 minutes to obtain a hydrophobic self-supporting agent.

[0044] Example 3

[0045] Based on Example 1, this example provides a method for preparing a hydrophobic in-situ proppant, comprising the following steps:

[0046] S1. Mix 25 parts of E51 epoxy resin, 2 parts of E44 epoxy resin, 3 parts of AG-803 parts, and 2 parts of AFG-902 parts of epoxy resin, for a total of 32 parts, to obtain an epoxy resin prepolymer.

[0047] S2. Mix epoxy resin prepolymer with 1 part of polydimethylsiloxane, 1 part of polymethyltriethoxysilane, 1 part of KH-560, 2 parts of KH-570, a total of 1 part of low surface energy material and 4 parts of silane coupling agent, and heat at 60°C for 1 hour to obtain hydrophobically modified epoxy resin mixture, which is liquid A.

[0048] S3. Add 5 parts of diaminodiphenylmethane, 1 part of 2-ethyl-4-methylimidazolium, and 2 parts of Ancamine 2280 to liquid A, totaling 8 parts of curing agent, and mix evenly to obtain liquid C.

[0049] S4. Weigh out 2 parts of type 0588 polyvinyl alcohol, 2 parts of type 1788 polyvinyl alcohol, and 4 parts of type 1799 polyvinyl alcohol, totaling 8 parts of polyvinyl alcohol, and dissolve them in 70-100 parts of water to obtain solution D.

[0050] S5. Add solution D to solution C at a rate of 15cc / min, with the rotation speed set to 900rpm.

[0051] S6. After the D liquid droplets have been added, continue stirring for 10-40 minutes to obtain a hydrophobic self-supporting agent.

[0052] Example 4

[0053] Based on Example 1, this example provides a method for preparing a hydrophobic in-situ proppant, comprising the following steps:

[0054] S1. Mix 30 parts of E51 epoxy resin and 10 parts of AG-801 epoxy resin, for a total of 40 parts, to obtain epoxy resin prepolymer.

[0055] S2. Mix epoxy resin prepolymer with 2 parts of polydimethylsiloxane, 1 part of 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 1 part of polymethyltriethoxysilane, 1 g of KH-560, 3 parts of KH-570, a total of 2 parts of low surface energy material, and 5 parts of silane coupling agent. Heat at 60°C for 1 hour to obtain hydrophobically modified epoxy resin mixture, which is liquid A.

[0056] S3. Add 5 parts of diaminodiphenyl sulfone, 1 part of 2-ethylimidazole, 1 part of 2-ethyl-4-methylimidazole, 1 part of Ancamine 27641 parts, and 1 part of Ancamine 22801 parts, totaling 9 parts of curing agent, to solution A, and mix evenly to obtain solution C.

[0057] S4. Weigh out 2 parts of type 1788 polyvinyl alcohol and 3 parts of type 1799 polyvinyl alcohol, totaling 5 parts of polyvinyl alcohol, and dissolve them in 70-100 parts of water to obtain solution D.

[0058] S5. Add solution D to solution C at a rate of 40cc / min, with the rotation speed set to 800rpm.

[0059] S6. After the D liquid droplets have been added, continue stirring for 10-40 minutes to obtain a hydrophobic self-supporting agent.

[0060] Example 5: This example provides a method for detecting the hydrophobic self-supporting agent obtained in Schemes 1-3;

[0061] 1. Ball formation rate test: The mass of the material used before curing is m1, and the mass of the material remaining after drying and curing is m2. Then the ball formation rate M = (m2 / m1)*100%.

[0062] 2. Particle size and breakage rate detection: 1) The most widely used method for determining roundness and sphericity is the Krumbien / Sloss chart. (Refer to...) Figure 5 Where X represents roundness and Y represents sphericity;

[0063] 2) Spread the sample flat in a flat container, about the thickness of one particle, and then observe the sample with a low magnification (10x to 40x). If the support is light-colored, choose a dark background, and vice versa.

[0064] 3) Randomly select at least 20 proppant particles to evaluate particle sphericity;

[0065] 5) Refer to the Krumbien / Sloss chart to determine the sphericity of each selected particle and record the given sphericity number corresponding to each particle;

[0066] Average the recorded sphericity numbers and report the closest average particle sphericity with an accuracy of 0.1 graphic units.

[0067] 3. Contact angle test: Prepare experimental instruments, including glass dishes and contact angle measuring instrument (DSA100);

[0068] 2) The hydrophobic in-situ self-generated proppant prepared in Examples 1-3 was spread in a glass dish and leveled. The contact angle of formation water on the surface of the hydrophobic proppant was measured at room temperature using a contact angle measuring instrument.

[0069] The test results are shown in the table below:

[0070]

[0071] As shown in the table above, the hydrophobic in-situ self-generated proppant prepared by Examples 1-3 all have a sphericity rate of over 60%, a surface contact angle of over 160°, high proppant strength, low deformation rate under 12h load, and long aging resistance.

[0072] In summary, this invention modifies epoxy resin to be hydrophobic and forms epoxy resin proppant microspheres using in-situ self-generated proppant technology. This proppant exhibits excellent hydrophobic properties, which allow it to enter formation fractures and provide higher conductivity channels for oil and gas, increasing oil and gas production and purity. Simultaneously, the in-situ self-generated proppant technology avoids a series of problems associated with traditional proppants, such as high density, easy settling, and difficulty in migration, effectively supporting formation fractures and achieving effective support for the entire fracture network. Furthermore, the hydrophobic in-situ self-generated proppant prepared by this invention has a sphericity rate of over 60%, a surface contact angle exceeding 160°, high strength, low deformation rate under 12-hour load, and long aging resistance. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0073] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing a hydrophobic in-situ generated proppant, characterized in that, Includes the following steps: S1. Mix a total of 15-40 parts of epoxy resin to obtain epoxy resin prepolymer; S2. Mix the epoxy resin prepolymer with 1-3 parts of a low surface energy substance and 1-5 parts of a silane coupling agent, and heat at 60°C for 1 hour to obtain a hydrophobically modified epoxy resin mixture, which is liquid A. The low surface energy substance includes polydimethylsiloxane, 1,3-bis(3-aminopropyl)tetramethyldisiloxane or polymethyltriethoxysilane; the silane coupling agent includes KH-550, KH-560 or KH-570. S3. Add 5-15 parts of curing agent to liquid A and mix well to obtain liquid C; S4. Weigh 3-8 parts of polyvinyl alcohol and dissolve them in 70-100 parts of water to obtain solution D; S5. Add solution D to solution C at a rate of 10-60 cc / min, with the rotation speed set to 500-2000 rpm; S6. After the D liquid droplets have been added, continue stirring for 10-40 minutes to obtain a hydrophobic self-supporting agent.

2. The method for preparing the hydrophobic in-situ proppant according to claim 1, characterized in that: In step S1, the epoxy resin prepolymer includes E51 epoxy resin, E44 epoxy resin, AG-80 epoxy resin, or AFG-90 epoxy resin.

3. The method for preparing the hydrophobic in-situ proppant according to claim 1, characterized in that: In step S3, the curing agent includes one or more of aromatic amine curing agents, alicyclic curing agents, and imidazole curing agents.

4. The method for preparing the hydrophobic in-situ proppant according to claim 3, characterized in that: The aromatic amine curing agent includes diaminodiphenyl sulfone, diaminodiphenylmethane, or m-phenylenediamine; the alicyclic curing agent includes Ancamine 2764 or Ancamine 2280; the imidazole curing agent includes imidazole, 2-methylimidazolium, 2-ethylimidazolium, or 2-ethyl-4-methylimidazolium.

5. The method for preparing the hydrophobic in-situ proppant according to claim 1, characterized in that: In step S4, the polyvinyl alcohol includes type 0588, type 1788, type 1799, or type 2099.

Images