Phase change fracturing method

Abstract

A phase change fracturing method is disclosed, comprising: injecting a phase change material liquid into the formation; the phase change material liquid undergoes a phase change under formation conditions to form a honeycomb-shaped solid proppant, thereby completing phase change fracturing. This fracturing method achieves fracturing without the need for additional proppant by injecting the phase change material liquid into the formation, causing the liquid to undergo a phase change and form a honeycomb-shaped solid proppant. Furthermore, the formed honeycomb-shaped solid proppant exhibits high compressive strength, low deformation, and excellent conductivity.

Description

Phase change fracturing method Technical Field

[0001] The present invention relates to the technical field of oil reservoir development, and in particular to a phase change fracturing method. Background Art

[0002] Hydraulic fracturing technology primarily involves pumping fracturing fluid into the formation at high rates to create fractures. Then, a sand-carrying fluid containing proppants is injected to support the fractures and establish oil and gas pathways. To address a series of issues with conventional hydraulic fracturing technology, such as sand plugging, residue damage, equipment wear, and difficulty in effectively supporting the distal ends of the fractures, scholars have conducted extensive research. Regarding fracturing fluids, delayed cross-linking fracturing fluids, low-friction fracturing fluids, clean fracturing fluids, and heat- and shear-resistant fracturing fluids have been developed to reduce pumping pressures, mitigate reservoir damage, and increase proppant suspension capacity. Regarding proppants, low-density proppants are primarily developed to enhance the conductivity of the distal ends of the fractures. Although this research has contributed to improving fracturing effectiveness, it has not yet fully resolved these issues.

[0003] In recent years, Chinese researchers Zhao Liqiang and others have proposed a novel self-supporting fracturing fluid system. This system completely eliminates the concept of "sand entrainment." During the fracturing fluid pumping process, no solid proppant is carried along. Instead, the fracturing fluid and proppant are integrated into one. Once the fluid reaches the target formation, the formation temperature is controlled to transform it from a liquid phase to a solid phase, propping up the fracture. This phase-change fluid assumes the role of proppant in the fracturing fluid. Commonly used proppants for oil fracturing are natural quartz sand, artificial ceramsite, and resin-coated sand, accounting for as much as 99% of total proppant usage. Ideal proppants possess high mechanical strength, high conductivity, low compatibility, low cost, low density, ease of use, and resistance to backflow and embedding. However, these advantages are often difficult to achieve simultaneously. To effectively support and induce fractures under closed pressure conditions, proppants must possess a certain mechanical strength, or compressive resistance. Several high-strength proppants have been developed, including artificial ceramsite and resin-coated proppants. Compared to resin-coated proppants, artificial ceramsite proppants are more expensive, have a higher specific gravity, and are prone to breakage and backflow. Resin-coated proppants are divided into two types: pre-cured resin-coated proppants (RCP) and curable resin-coated proppants (LRS). The difference is that RCP is processed by coating the substrate with resin. No further curing occurs downhole. The cross-linking process of LRS occurs under stress and high temperature conditions within the well formation, and the oil well is closed after fracturing to allow curing. Resin-coated proppants increase the contact area between sand particles and improve the ability of the proppant to resist closure pressure. During fracturing operations, the resin layer on the surface can coat the broken fragments and particles of the broken substrate together, reducing the chance of particle movement and pore clogging, so that the fracture still has a high conductivity. The density of resin-coated proppants is relatively low, which is convenient for carrying and spreading sand, reducing the requirements for fracturing fluid. The resin-coated proppants will deform, increasing the contact area, thereby preventing the proppant from embedding into soft formations. However, resin-coated fracturing fluids also have significant drawbacks: as closure pressure increases, the resin film on the surface of the resin-coated proppant deforms, crushing and rebonding the particles, negatively impacting the fracture's conductivity and permeability. Therefore, when closure pressure reaches a certain value, the resin-coated proppant becomes unsuitable. To address this, phase-change proppants have been modified to address these shortcomings and further eliminate the sand-carrying concept, achieving conditions closer to those of an ideal proppant.

[0004] The proppants in the prior art are basically granular, and the pursuit of sphericity is to improve the flow conductivity. The morphology of the phase change proppant in CN106190086A is beaded. The phase change fluid and the non-phase change fluid are non-miscible, immiscible, and have similar densities. The flow process has independent flow channels. One of the liquids solidifies to form a supporting material after reaching the target position, and the other liquid flows back to leave an oil and gas flow channel. This non-uniform and non-continuous proppant laying form transforms the conventional limited seepage capacity into an infinite seepage capacity. At the same time, the flow of the two liquids can be controlled by the flow ratio to control its flow type, which makes it easier to obtain the ideal proppant laying form.

[0005] The phase change proppant in CN108561111A also has a spherical morphology. The delayed heat generating agent also functions as a pore forming agent, making the spherical shape complete and the structure uniform, and further improving the flow conductivity.

[0006] However, granular or spherical phase change proppants are constantly bearing pressure during the process of solidification from soft to hard, which will cause a very large loss of permeability and even be compacted into a block, making it impossible to achieve the purpose of overall fracturing.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to overcome the problems in the prior art that granular or spherical phase change proppants have low compressive strength and are easily deformed under formation conditions, resulting in poor conductivity. A phase change fracturing method is provided. The fracturing method injects a phase change material liquid into the formation, and the phase change material liquid undergoes a phase change to form a honeycomb solid phase proppant. Fracturing is achieved without adding proppants, and the formed honeycomb solid phase proppant has high compressive strength, low deformation and excellent conductivity.

[0009] In order to achieve the above-mentioned object, the first aspect of the present invention provides a phase change fracturing method, characterized in that the fracturing method comprises:

[0010] Phase change material liquid is injected into the formation, and the phase change material liquid undergoes phase change under formation conditions to form honeycomb solid phase proppant, completing phase change fracturing.

[0011] Through the above technical solution, the phase change fracturing method provided by the present invention achieves the following beneficial effects:

[0012] In the present invention, a phase change material liquid is injected into the formation, a phase change reaction occurs, and a honeycomb solid phase proppant is formed. Without the need to add additional proppant, support for cracks and micro-cracks is achieved. In addition, the honeycomb solid phase proppant has high compressive strength and low deformation degree, and can maintain the high conductivity of the solid phase proppant under formation conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG1 is a photograph of the honeycomb-shaped solidified proppant prepared in Example 1. DETAILED DESCRIPTION

[0014] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0015] A first aspect of the present invention provides a phase change fracturing method, characterized in that the fracturing method comprises:

[0016] Phase change material liquid is injected into the formation, and the phase change material liquid undergoes phase change under formation conditions to form honeycomb solid phase proppant, completing phase change fracturing.

[0017] In the present invention, a phase change material liquid is injected into the formation, a phase change reaction occurs, and a honeycomb solid phase proppant is formed. Without the need to add additional proppant, support for cracks and micro-cracks is achieved. In addition, the honeycomb solid phase proppant has high compressive strength and low deformation degree, and can maintain the high conductivity of the solid phase proppant under formation conditions.

[0018] According to the present invention, there are interconnected channels in the honeycomb solid phase proppant.

[0019] In the present invention, as shown in FIG1 , the honeycomb solid proppant of the present invention has interconnected channels, which enable the solid proppant to support cracks and microcracks while giving the cracks excellent flow conductivity, thereby improving the oil and gas recovery rate.

[0020] According to the present invention, the porosity of the honeycomb solid phase proppant is 1%-40%.

[0021] In the present invention, the honeycomb solid proppant has the above-mentioned specific porosity, which enables the solid proppant to have high conductivity while still maintaining high compressive strength and low deformation.

[0022] In the present invention, the porosity of the honeycomb solid phase proppant is measured using a saturated fluid method.

[0023] In the present invention, the porosity of the honeycomb solid phase proppant is 1%-40%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 20%, 25%, 30%, 35%, 40%, and a range consisting of any two values.

[0024] Furthermore, the porosity of the honeycomb solid phase proppant is 10%-35%, preferably 20%-30%.

[0025] According to the present invention, the pore size of the honeycomb solid phase proppant is 0.1 mm-0.7 mm.

[0026] In the present invention, when the pore size of the honeycomb solid phase proppant meets the above range, the pore size of the honeycomb solid phase proppant is reasonable, the connectivity is good, and the skeleton structure of the honeycomb solid phase proppant can be ensured to remain continuous and complete, so that the honeycomb solid phase proppant can maintain excellent permeability while withstanding high pressure.

[0027] In the present invention, the pore size of the honeycomb solid phase proppant is statistically measured using a stereo microscope. Specifically:

[0028] The honeycomb solid phase proppant was observed under a stereo microscope, and the pore diameter of the honeycomb solid phase proppant was tested within a field of view of 1 cm×1 cm. The pore diameters of 20 pores were tested, and the average value was taken as the pore diameter of the honeycomb solid phase proppant.

[0029] In the present invention, the pore size of the honeycomb solid phase proppant is 0.1 mm-0.7 mm, for example, it can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or a range consisting of any two values.

[0030] Furthermore, the pore size of the honeycomb solid phase proppant is 0.2 mm-0.6 mm, preferably 0.3 mm-0.5 mm.

[0031] According to the present invention, the pore density of the honeycomb solid phase proppant is 20-450.

[0032] In the present invention, when the pore density of the honeycomb solid phase proppant satisfies the above range, it can ensure that the pore structure formed in the honeycomb solid phase proppant is regular and well-connected channels can be formed between the pores, so that the honeycomb solid phase proppant can withstand high pressure while maintaining excellent permeability.

[0033] In the present invention, the pore density refers to the number of pores within a certain size (1 cm×1 cm) of the honeycomb solid phase proppant.

[0034] In the present invention, the pore density of the honeycomb solid phase proppant is statistically measured using a stereo microscope. Specifically:

[0035] The honeycomb solid phase proppant was observed under a stereo microscope. The pore diameter of the honeycomb solid phase proppant was measured within a 1 cm × 1 cm field of view. The pore diameters of 20 pores were tested, and the average value was taken as the pore diameter D (mm) of the honeycomb solid phase proppant. The pore density was calculated using the following formula: pore density = (1 cm × 1 cm) × porosity / pore area, where the pore area is calculated as a circular pore, i.e., pore area = π × (D / 2). 2 , mm 2 .

[0036] In the present invention, the pore density of the honeycomb solid phase proppant is 20-450, for example, it can be 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, and a range consisting of any two values.

[0037] Furthermore, the pore density of the honeycomb solid phase proppant is 50-300, preferably 100-200.

[0038] According to the present invention, the density of the honeycomb solid phase proppant is 0.85 g / cm 3 -0.95g / cm 3 .

[0039] In the present invention, the honeycomb solid proppant has the above-mentioned specific density, which enables the solid proppant to have a density different from that of water and close to that of crude oil, ultimately allowing crude oil to evenly pass through the gaps in the honeycomb solid proppant, thereby achieving the purpose of oil recovery.

[0040] In the present invention, the density of the honeycomb solid phase proppant is 0.85 g / cm 3 -0.95g / cm 3 , for example, it can be 0.85g / cm 3 , 0.86g / cm 3 , 0.87g / cm 3 , 0.88g / cm 3 , 0.89g / cm 3 , 0.90g / cm 3 , 0.91g / cm 3 , 0.92g / cm 3 , 0.93g / cm 3 , 0.94g / cm 3 , 0.95g / cm 3 , and ranges of any two values.

[0041] Furthermore, the density of the honeycomb solid phase proppant is 0.86 g / cm3 -0.93g / cm 3 , preferably 0.88 g / cm 3 -0.91g / cm 3 .

[0042] According to the present invention, within the temperature range of 60-150° C., the compressive strength of the honeycomb solid phase proppant is greater than or equal to 20 MPa.

[0043] In the present invention, the honeycomb solid phase proppant has high compressive strength, which can ensure that the solid phase proppant does not break or be damaged under high temperature and high pressure conditions of the formation, resulting in it being unusable.

[0044] In the present invention, the compressive strength is uniaxial compressive strength. Specifically, the test method is: measuring using a high and low temperature universal material testing machine, and the test sample is cylindrical, with a diameter of 2.4 cm and a height of 4 cm.

[0045] Furthermore, within the range of 60-150° C., the compressive strength of the honeycomb solid phase proppant is greater than or equal to 30 MPa.

[0046] In a specific embodiment of the present invention, at 150° C., the compressive strength of the honeycomb solid proppant is 20 MPa-40 MPa, preferably 30 MPa-40 MPa, and more preferably 40 MPa.

[0047] In the present invention, at 150° C., the compressive strength of the honeycomb solid phase proppant is 20 MPa-40 MPa, for example, 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa, or a range consisting of any two values.

[0048] According to the present invention, at a pressure of 40 MPa and a temperature range of 60-150° C., the deformation rate of the honeycomb solid phase proppant is less than or equal to 8%.

[0049] In the present invention, the honeycomb solid phase proppant has a low deformation rate under high temperature and high pressure conditions, which can ensure that the honeycomb solid phase proppant is not easily deformed during use in the formation, ensure the stable existence of the honeycomb structure, and make the solid phase proppant have excellent flow conductivity.

[0050] In the present invention, at 40 MPa and within the range of 60-150° C., the deformation rate of the honeycomb solid proppant is less than or equal to 8%. For example, the deformation rate may be 8%, 7.5%, 7%, 6.5%, 6%, 5.5%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.5%, 0%, or a range consisting of any two of these values.

[0051] Furthermore, within the range of 40 MPa and 60 - 150 °C, the deformation rate of the honeycomb solid-phase proppant is less than or equal to 6%, preferably 4%.

[0052] According to the present invention, the phase-change material liquid comprises a first component and a second component;

[0053] The first component comprises a water-soluble thermosetting resin, a solvent-based thermosetting resin, and water;

[0054] The second component comprises a curing agent;

[0055] The water-soluble thermosetting resin has a structure shown in Formula I;

[0056] R1 is an alkylene group of C1 - C4;

[0057] A is wherein, R2 and R3 are each independently H, CH3, CF3, or CH2CH3;

[0058] 0 < m1 + m2 ≤ 8;

[0059] M is K or Na.

[0060] In the present invention, the phase-change material liquid contains a water-soluble thermosetting resin having a structure shown in Formula I. The water-soluble thermosetting resin contains hydrophilic sulfonate groups, which can significantly improve the hydrophilicity of the water-soluble resin. When used in combination with a solvent-based thermosetting resin and a curing agent and injected into the formation as the phase-change material liquid, a phase-change reaction can occur under formation conditions to form a honeycomb solid-phase proppant.

[0061] In the present invention, in Formula III, the specific values of m1 and m2 have no particular significance, only indicating that the water-based thermosetting resin shown in Formula III contains SO3M groups. There are no particular limitations on the specific values of m1 and m2 respectively, as long as it is ensured that the water-based thermosetting resin contains SO3M groups.

[0062] In the present invention, 0 < m1 + m2 ≤ 8. For example, m1 + m2 can be 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, and any range composed of two values.

[0063] In a specific embodiment of the present invention, 1 ≤ m1 + m2 ≤ 5.

[0064] In a specific embodiment of the present invention, in Formula I, R1 is an alkylene group of C1 - C3; A is wherein, R2 and R3 are each independently CH3 or H, CF3, or CH2CH3; M is Na.

[0065] According to the present invention, based on the total weight of the water-soluble thermosetting resin, the content of S element is 6-20 wt %.

[0066] In the present invention, when the content of the S element in the water-soluble thermosetting resin satisfies the above range, it indicates that the water-soluble thermosetting resin contains an appropriate content of SO3M, so that the water-soluble thermosetting resin has excellent water solubility. When it is used as a phase change material liquid, the prepared honeycomb solid phase proppant can have an excellent pore structure, and the solid phase proppant can have excellent flow conductivity, high compressive strength and low deformation.

[0067] In the present invention, based on the total weight of the water-soluble thermosetting resin, the content of S element is 6-20wt%, for example, it can be 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, and a range consisting of any two values.

[0068] Furthermore, based on the total weight of the water-soluble thermosetting resin, the content of S element is 10-15 wt %.

[0069] According to the present invention, the epoxy equivalent of the water-soluble thermosetting resin is 100 g / eq-300 g / eq.

[0070] In the present invention, when the epoxy equivalent of the water-soluble thermosetting resin is controlled to meet the above range, the water-soluble thermosetting resin has a curing activity. When used for curing epoxy resin, it can significantly improve the curing strength of the epoxy resin after curing, so that the prepared honeycomb solid phase support has a better pressure bearing capacity.

[0071] In the present invention, the epoxy equivalent of the water-soluble thermosetting resin is 100g / eq-300g / eq, for example, it can be 100g / eq, 110g / eq, 120g / eq, 130g / eq, 140g / eq, 150g / eq, 160g / eq, 170g / eq, 180g / eq, 190g / eq, 200g / eq, 210g / eq, 220g / eq, 230g / eq, 240g / eq, 250g / eq, 260g / eq, 270g / eq, 280g / eq, 290g / eq, 300g / eq, and a range consisting of any two values.

[0072] Furthermore, the epoxy equivalent of the water-soluble thermosetting resin is 150 g / eq-200 g / eq.

[0073] According to the present invention, the weight average molecular weight of the water-soluble thermosetting resin is 2000 g / mol-10000 g / mol.

[0074] In the present invention, the weight average molecular weight of the water-soluble thermosetting resin is 2000 g / mol-10000 g / mol, for example, it can be 2000 g / mol, 2500 g / mol, 3000 g / mol, 4000 g / mol, 5000 g / mol, 6000 g / mol, 7500 g / mol, 8000 g / mol, 9000 g / mol, 10000 g / mol, and a range consisting of any two values.

[0075] Furthermore, the water-soluble thermosetting resin has a weight average molecular weight of 2500 g / mol-8000 g / mol, preferably 3000 g / mol-5000 g / mol.

[0076] In the present invention, preferably, the water-soluble thermosetting resin is prepared according to the following method:

[0077] S1. In the presence of a first catalyst and water, contacting a bisphenol compound with a sulfonating agent to perform a sulfonation reaction to obtain a sulfonated bisphenol compound;

[0078] S2. In the presence of a second catalyst and water, contacting the sulfonated bisphenol compound with the monomer A represented by formula IA to carry out a polycondensation reaction to obtain the water-based thermosetting resin;

[0079] wherein p is an integer of 1-4, and X is Cl or Br.

[0080] In the present invention, a sulfonating agent is brought into contact with a bisphenol compound to achieve sulfonation of the bisphenol compound, and the sulfonated bisphenol compound is subjected to polycondensation with a monomer represented by Formula IA to produce a water-based thermosetting resin containing sulfonic acid groups. The thermosetting resin has excellent hydrophilicity, can be cured in an aqueous environment, and has interconnected pores while maintaining high strength.

[0081] In the present invention, in step S1, the bisphenol compound is at least one selected from bisphenol A, bisphenol S, bisphenol B, bisphenol F and bisphenol AF.

[0082] In the present invention, the sulfonating agent is selected from at least one of concentrated sulfuric acid, chlorosulfonic acid and aminosulfonic acid.

[0083] In the present invention, the first catalyst is Lewis acid.

[0084] In the present invention, the Lewis acid can be a Lewis acid commonly used in the art, such as titanium tetrachloride, ferric chloride, ferric oxide, zirconium oxychloride, aluminum oxide, aluminum chloride, hydrated tin tetrachloride, and the like.

[0085] In the present invention, the molar ratio of the bisphenol compound to the sulfonating agent is 1:1-5.

[0086] In the present invention, the molar ratio of the bisphenol compound to the sulfonating agent satisfies the above range, which can further meet the sulfonation degree requirement of the water-based thermosetting resin.

[0087] In the present invention, the molar ratio of the bisphenol compound to the sulfonating agent is 1:1-5, for example, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, and a range consisting of any two values.

[0088] Furthermore, the molar ratio of the bisphenol compound to the sulfonating agent is 1:2-4.

[0089] According to the present invention, the mass ratio of the bisphenol compound to the first catalyst is 1:0.0001-0.0008.

[0090] In the present invention, the mass ratio of the bisphenol compound to the first catalyst is 1:0.0001-0.0008, for example, it can be 1:0.0001, 1:0.0002, 1:0.0003, 1:0.0004, 1:0.0005, 1:0.0006, 1:0.0007, 1:0.0008, and a range consisting of any two values.

[0091] In the present invention, the mass ratio of the bisphenol compound to the first catalyst satisfies the above range, which can reduce the reaction temperature by 20° C.-30° C. and make the reaction conditions milder.

[0092] Furthermore, the mass ratio of the bisphenol compound to the first catalyst is 1:0.0003-1:0.0005.

[0093] In the present invention, in step S2, in formula IA, p is an integer of 1-3, and X is Cl.

[0094] In the present invention, the second catalyst is a base.

[0095] In the present invention, the base can be a conventional base in the art, for example, NaOH, KOH, Ca(OH)2, etc.

[0096] Furthermore, the second catalyst is more preferably NaOH.

[0097] In the present invention, the mass ratio of the sulfonated bisphenol compound to the monomer A is 1:0.25-0.65.

[0098] In the present invention, the mass ratio of the sulfonated bisphenol compound to the monomer A satisfies the above range, so that the prepared water-based thermosetting resin has a specific epoxy equivalent that meets the requirements, thereby being able to undergo a phase change reaction with the curing agent under formation conditions to form a honeycomb solid phase proppant.

[0099] In the present invention, the mass ratio of the sulfonated bisphenol compound to the monomer A is 1:0.25-0.65, for example, it can be 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, and a range consisting of any two values.

[0100] Furthermore, the mass ratio of the sulfonated bisphenol compound to the monomer A is 1:0.3-1:0.45.

[0101] In the present invention, the mass ratio of the sulfonated bisphenol compound to the second catalyst is 1:0.1-0.5, for example, it can be 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.38, 1:0.4, 1:0.45, 1:0.5, and a range consisting of any two values, preferably 1:0.15-0.38.

[0102] In the present invention, the conditions for the sulfonation reaction include: a reaction temperature of 120-150° C., and a reaction time of 2-6 hours. For example, the conditions for the sulfonation reaction include: a reaction temperature of 120° C., 125° C., 130° C., 135° C., 140° C., 145° C., 150° C., and a range consisting of any two values, and a reaction time of 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, and a range consisting of any two values.

[0103] Furthermore, the conditions of the sulfonation reaction include: reaction temperature of 130-140° C., and reaction time of 2-4 h.

[0104] In the present invention, the conditions for the polycondensation reaction include: a reaction temperature of 40-80°C, and a reaction time of 2-4 hours. For example, the conditions for the polycondensation reaction include: a reaction temperature of 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, and a range consisting of any two values, and a reaction time of 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, and a range consisting of any two values.

[0105] Furthermore, the conditions of the polycondensation reaction include: reaction temperature of 50-70° C., and reaction time of 2-3 h.

[0106] In the present invention, the inventors have found that in the process of preparing water-based thermosetting resin, controlling the oxygen concentration in the system to no more than 3.1 mg / L is conducive to the smooth progress of the reaction and the efficient preparation of water-based thermosetting resin with a specific structure.

[0107] Exemplarily, according to a preferred embodiment of the present invention, the preparation method of the water-based thermosetting resin is as follows:

[0108] S1. In the presence of Lewis acid and water, a bisphenol compound selected from at least one of bisphenol A, bisphenol S, bisphenol B, bisphenol F and bisphenol AF is contacted with a sulfonating agent selected from at least one of concentrated sulfuric acid, chlorosulfonic acid and aminosulfonic acid to carry out a sulfonation reaction, the reaction temperature being 130-140° C. and the reaction time being 2-4 hours to obtain a sulfonated bisphenol compound; wherein the molar ratio of the bisphenol compound to the sulfonating agent is 1:2-3, and the mass ratio of the bisphenol compound to the Lewis acid is 1:0.0003-0.0005.

[0109] S2. Add alkali to deionized water, add a sulfonated bisphenol compound, and dropwise add monomer A represented by formula IA at a temperature not exceeding 60° C. to carry out a polycondensation reaction. The reaction temperature is 50-70° C. and the reaction time is 2-3 hours to obtain a water-based thermosetting resin, wherein the mass ratio of the sulfonated bisphenol compound to the monomer A is 1:0.3-0.45, and the mass ratio of the sulfonated bisphenol compound to the alkali is 1:0.15-0.3.

[0110] According to the present invention, the content N of the hydrophilic groups contained in the resin in the first component is 0.002 mol / g-0.006 mol / g.

[0111] In the present invention, the water solubility of the first component is expressed by the molar content of the hydrophilic group contained in the resin per unit mass of the first component, specifically: N = n / (m1+m2); wherein n represents the amount of the hydrophilic group, mol; m1 is the mass of the water-soluble thermosetting resin, g; m2 is the mass of the solvent-based thermosetting resin, g; and N is the content of the hydrophilic group contained in the resin of the first component, mol / g.

[0112] In the present invention, when the content N of the hydrophilic group contained in the resin of the first component satisfies the above range, it is possible to ensure that the first component has excellent water solubility and maintains a high curing strength after curing the first component, while forming the honeycomb solid phase proppant comprising pores and interconnected channels as described in the present invention.

[0113] In the present invention, the content N of the hydrophilic group contained in the resin in the first component is 0.002 mol / g-0.006 mol / g, for example, it can be 0.002 mol / g, 0.0025 mol / g, 0.003 mol / g, 0.0035 mol / g, 0.004 mol / g, 0.0045 mol / g, 0.005 mol / g, 0.006 mol / g, and a range consisting of any two values.

[0114] Furthermore, the content N of the hydrophilic group contained in the resin in the first component is 0.0025 mol / g-0.004 mol / g.

[0115] According to the present invention, at 25° C., the apparent viscosity of the first component is 100 mPa·s to 400 mPa·s.

[0116] In the present invention, the first component has a low apparent viscosity, which ensures that the phase change material liquid has good injectability and can be fully and evenly injected into the cracks and micro cracks in the formation.

[0117] In the present invention, at 25°C, the apparent viscosity of the first component is 100mPa·s-400mPa·s, for example, it can be 100mPa·s, 150mPa·s, 200mPa·s, 250mPa·s, 300mPa·s, 350mPa·s, 400mPa·s, and a range consisting of any two values.

[0118] Furthermore, at 25° C., the apparent viscosity of the first component is 150-350 mPa·s, preferably 200-300 mPa·s.

[0119] According to the present invention, the mass ratio of the first component to the second component is 1:0.4-0.8.

[0120] In the present invention, when the amounts of the first component and the second component are controlled to meet the above-mentioned ranges, it is possible to ensure that the phase change material liquid has a suitable solidification speed and a suitable solidification time in the formation, which does not affect the injectability of the phase change material liquid and ensures that the phase change material liquid undergoes a phase change reaction in a timely manner to obtain a honeycomb solid phase proppant.

[0121] In the present invention, the mass ratio of the first component to the second component is 1:0.4-0.8, for example, it can be 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.75, 1:0.8, and a range consisting of any two values.

[0122] Furthermore, the mass ratio of the first component to the second component is 1:0.6-0.8.

[0123] According to the present invention, in the first component, the content of the water-soluble thermosetting resin is 55-93 parts by weight, the content of the solvent-based thermosetting resin is 37-56 parts by weight, the content of water is 22-88 parts by weight, and the content of the emulsifier is 5-15 parts by weight.

[0124] In the present invention, when the contents of the various components in the first component are controlled to meet the above-mentioned ranges, a suitable ratio between the water-soluble thermosetting resin and the solvent-based thermosetting resin is achieved, and various forms such as water-in-oil-in-water can be formed. After curing, a honeycomb-shaped solid phase proppant having interconnected pores or interconnected channels can be formed.

[0125] In the present invention, in the first component, the content of the water-soluble thermosetting resin can be 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 93 parts by weight, and a range consisting of any two values; the content of the solvent-based thermosetting resin can be 37 parts by weight, 40 parts by weight, 43 parts by weight, 45 parts by weight, 48 parts by weight, 50 parts by weight, 53 parts by weight, 56 parts by weight, and a range consisting of any two values; the content of water can be 22 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 88 parts by weight, and a range consisting of any two values.

[0126] Furthermore, in the first component, the content of the water-soluble thermosetting resin is 60-80 parts by weight, the content of the solvent-based thermosetting resin is 40-45 parts by weight, the content of water is 25-80 parts by weight, and the content of the emulsifier is 8-13 parts by weight.

[0127] According to the present invention, the solvent-based thermosetting resin is at least one selected from epoxy resin, unsaturated resin and polyimide.

[0128] According to the present invention, the curing agent is at least one selected from water-soluble polymer polyamines, water-soluble polymer polycarboxylic acids, water-soluble phenolic resins, small molecule polyamines and small molecule polycarboxylic acids.

[0129] In one embodiment of the present invention, the water-soluble polymer polyamine comprises structural unit Ia, structural unit IIa and structural unit IIIa;

[0130] The structural unit Ia has a structure shown in Formula 1a, the structural unit IIa has a structure shown in Formula 2a, and the structural unit IIIa has a structure shown in at least one of Formula 3a, Formula 4a, and Formula 5a;

[0131] In formula 1a, R 1a is -H or -CH3, R 2a and R 3a Each independently represents -H or a C1-C18 alkyl group; R 4a -H, A, C1-C20 alkyl or -(CH2) n -OR 21a ; R 21a is -H or a C1-C18 alkyl group, and n is an integer from 0 to 12;

[0132] A has the structure shown in Formula 6a;

[0133] In formula 6a, R 22a and R 23a Each is independently -H or a C1-C18 alkyl group, and m is an integer from 0 to 18;

[0134] In formula 2a, R 5a 、R 6a and R 7a Each is independently -H, C1-C12 alkyl or -(CH2) r -OH, r is an integer from 1 to 12; X is -(CH2) z -, z is an integer from 0 to 5;

[0135] In formula 3a, R 8a is -H or -CH3;

[0136] In formula 4a, R 9a is -H or -CH3;

[0137] In formula 5a, R 10a 、R 11a and R 12a Each is independently -H or -NH2, and at least one is -NH2; R 13a It is -H or -CH3.

[0138] In the present invention, the unsaturated amide copolymer contains the structural unit Ia, structural unit IIa and structural unit IIIa having the above-mentioned specific structure. In particular, due to the introduction of structural unit IIIa, the side groups of the unsaturated amide copolymer have a large number of amino groups. When the curing agent composition containing the copolymer is used to cure the epoxy resin, the epoxy resin can be cured at 90°C-150°C.

[0139] Specifically, the unsaturated amide copolymer of the present invention contains the structural unit IIa represented by formula 2a, which can not only adjust the intrinsic viscosity of the unsaturated amide polymer to meet the requirements of the curing agent for epoxy resin, but also, because the structural unit IIIa contains a rigid group, it can reduce the toughness of the cured product of the curing agent composed of the unsaturated amide polymer and improve the strength of the cured product of the curing agent composed of the unsaturated amide polymer, especially the strength of the epoxy resin.

[0140] Furthermore, in one embodiment of the present invention, in Formula 1a, R 1a is -H or -CH3, R 2a and R 3a Each independently represents -H or a C1-C12 alkyl group; R 4a -H, A, C8-C12 alkyl or -(CH2) n -OR 21a ; R 21a is a C1-C12 alkyl group, and n is an integer from 0 to 12. Preferably, R 1a is -H or -CH3, R 2a and R 3a Each independently represents -H, R 4a is -H, C2 alkyl or C12 alkyl; more preferably, R 1a 、R 2a 、R 3a and R 4a All are -H.

[0141] In one embodiment of the present invention, A has the structure shown in Formula 6a;

[0142] In formula 6a, R 22a and R 23a Each independently represents -H or a C1-C12 alkyl group, m is an integer from 1 to 12, preferably, R 22a and R 23a Each is independently -H or C1-C6 alkyl, m is an integer of 1-6, more preferably, R 22a and R 23a Each is independently -H or a C1-C3 alkyl group, and m is an integer of 1-3.

[0143] In one embodiment of the present invention, in Formula 2a, R 5a -(CH2) r -OH or -H, r is an integer of 1-3; R 6a and R 7a Each is independently -H; X is -(CH2) z -, z is an integer from 0 to 2; more preferably, R5a 、R 6a and R 7a Each is independently -H.

[0144] In one embodiment of the present invention, in Formula 3a, R 8a is -H.

[0145] In one embodiment of the present invention, in Formula 4a, R 9a is -H.

[0146] In one embodiment of the present invention, in Formula 5a, R 10a 、R 11a and R 12a Each is independently -H or -NH2, and at least one is -NH2; R 13a is -H.

[0147] According to the present invention, based on the total weight of the unsaturated amide copolymer, the content of the structural unit Ia is 65wt%-85wt%, the content of the structural unit IIa is 5wt%-7wt%, and the content of the structural unit IIIa is 12wt%-27wt%.

[0148] In the present invention, when the content of each structural unit in the unsaturated amide copolymer is controlled to meet the above range, when the curing agent composition containing the copolymer is used to cure the epoxy resin, the curing time is controllable (complete curing within 6 hours), the cured epoxy resin has a large porosity (about 30%), a strong pressure bearing capacity (50MPa), and a high permeability (100 millidarcy-5 darcy).

[0149] In the present invention, based on the total weight of the unsaturated amide copolymer, the content of the structural unit Ia is 65wt%, 68wt%, 70wt%, 73wt%, 75wt%, 78wt%, 80wt%, 72wt%, 85wt%, and a range consisting of any two values; the content of the structural unit IIa is 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, and a range consisting of any two values; the content of the structural unit IIIa is 12wt%, 12.5wt%, 13wt%, 13.5wt%, 14wt%, 14.5wt%, , 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, and a range consisting of any two values.

[0150] Furthermore, based on the total weight of the unsaturated amide polymer, the content of the structural unit Ia is 70 wt%-82 wt%, the content of the structural unit IIa is 5 wt%-6 wt%, and the content of the structural unit IIIa is 12.5 wt%-20 wt%.

[0151] In the present invention, the total content of the structural unit Ia, the structural unit IIa and the structural unit IIIa is 100 wt %.

[0152] In the present invention, the content of each structural unit in the copolymer is calculated based on the feed amount.

[0153] According to the present invention, at 25° C., the intrinsic viscosity of the copolymer is 200 mL / g-1200 mL / g, preferably 900 mL / g-1200 mL / g.

[0154] In one embodiment of the present invention, the water-soluble high molecular weight polycarboxylic acid comprises structural unit Ib, structural unit IIb, structural unit IIIb and structural unit IVb;

[0155] The structural unit Ib has the structure shown in Formula 1b, the structural unit IIb has the structure shown in Formula 2b and / or Formula 3b, the structural unit IIIb has the structure shown in Formula 4b and / or Formula 5b, and the structural unit IVb has the structure shown in at least one of Formula 6b, Formula 7b and Formula 8b;

[0156] Based on the total weight of the unsaturated amide polymer, the content of the structural unit Ib is 30 wt%-50 wt%, the content of the structural unit IIb is 30 wt%-50 wt%, the content of the structural unit IIIb is 4 wt%-10 wt%, and the content of the structural unit IVb is 10 wt%-16 wt%;

[0157] In formula 1b, R 1b is H or CH3, R 2b and R 3b Each independently represents H or a C1-C18 alkyl group; R 4b is H, A or -(CH2) n -OR 21b ; R 21b is a C1-C18 alkyl group, and n is an integer from 0 to 12;

[0158] A has the structure shown in Formula 9b;

[0159] In formula 9b, R 22b and R 23bEach independently represents H, a C1-C18 alkyl group, and m is an integer from 0 to 18;

[0160] In formula 3b, R 5b and R 6b Each is independently H or a C2-C16 alkyl group;

[0161] In formula 4b, R 7b 、R 8b and R 9b are independently H, C1-C11 alkyl, -(CH2) r -OH or -(CH2) q SO3Q, Q is H, Na or K, r is an integer from 0 to 12, q is an integer from 0 to 10; X is -(CH2) z -, z is an integer from 0 to 5;

[0162] In formula 5b, R 10b is H or CH3, M is H, Na or K;

[0163] In formula 6b, R 11b is H or CH3;

[0164] In formula 7b, R 12b is H or CH3;

[0165] In formula 8b, R 13b 、R 14b and R 15b are each independently H, NH2, F or Br; R 16b is H or CH3.

[0166] In the present invention, the unsaturated amide polymer contains the structural unit Ib, structural unit IIb, structural unit IIIb and structural unit IVb having the above-mentioned specific structure. In particular, due to the introduction of structural unit IIb and structural unit IVb, the side groups of the unsaturated amide polymer have a large number of carboxyl groups and amino groups. When the polymer is used as a curing agent for epoxy resin, the epoxy resin can be cured at low temperature (50°C-90°C) or high temperature (90°C-150°C).

[0167] Specifically, the unsaturated amide polymer of the present invention comprising the structural unit IIIb of the structure represented by Formula 4b and / or Formula 5b can not only adjust the molecular weight of the unsaturated amide polymer to meet the requirements of the epoxy resin curing agent, but also, because the structural unit IIIb contains a rigid group, it can reduce the toughness of the product after curing of the unsaturated amide polymer and increase the hardness of the cured product.

[0168] Furthermore, the structural unit IIb comprising the structure represented by Formula 2b and / or Formula 3b in the unsaturated amide polymer of the present invention, due to the introduction of the acid anhydride structure, avoids the loss of carboxylic acid and amine groups due to the easy reaction of carboxylic acid and amine groups to form an intramolecular ring structure, resulting in a decrease in the curing activity of the unsaturated amide polymer when used as a curing agent.

[0169] In the present invention, when the content of each structural unit in the unsaturated amide polymer is controlled to meet the above range, not only can the unsaturated amide polymer have a suitable molecular weight, but also the obtained unsaturated amide polymer can contain suitable rigid groups and active groups. When the unsaturated amide polymer is used as a curing agent for curing epoxy resin, it is ensured that the active groups meet actual needs and the epoxy resin product obtained after curing can be ensured to have high compressive strength, etc.

[0170] In the present invention, based on the total weight of the unsaturated amide polymer, the content of the structural unit Ib is 30 wt%-50 wt%, for example, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, and a range consisting of any two values; the content of the structural unit IIb is 30 wt%-50 wt%, for example, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, and a range consisting of any two values; the content of the structural unit IIIb is 4 wt%-10 wt%, for example, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 9 wt%, 10 wt%, and a range consisting of any two values; the content of the structural unit IVb is 10 wt%-16 wt%, for example, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, and a range consisting of any two values.

[0171] Furthermore, based on the total weight of the unsaturated amide polymer, the content of the structural unit Ib is 30wt%-45wt%, the content of the structural unit IIb is 35wt%-45wt%, the content of the structural unit IIIb is 6wt%-10wt%, and the content of the structural unit IVb is 12wt%-15wt%.

[0172] Furthermore, based on the total weight of the unsaturated amide polymer, the content of the structural unit Ib is 35wt%-45wt%, the content of the structural unit IIb is 40wt%-45wt%, the content of the structural unit IIIb is 8wt%-10wt%, and the content of the structural unit IVb is 14wt%-15wt%.

[0173] In the present invention, the total content of the structural unit Ib, the structural unit IIb, the structural unit IIIb and the structural unit IVb is 100 wt %.

[0174] In the present invention, the content of each structural unit in the polymer is calculated based on the feeding amount of the monomer.

[0175] In a preferred embodiment of the present invention, the structural unit Ib has the structure shown in Formula 1b, the structural unit IIb has the structure shown in Formula 2b, the structural unit IIIb has the structure shown in Formula 4b, and the structural unit IVb has the structure shown in Formula 6b or Formula 8b, preferably having the structure shown in Formula 8b.

[0176] In one embodiment of the present invention, in Formula 1b, R 1b is H or CH3, R 2b and R 3b Each independently represents H or a C1-C12 alkyl group; R 4b is H, A or -(CH2) n -OR 21b ; R 21b is a C1-C12 alkyl group, and n is an integer from 1 to 10. Preferably, R 1b is H or CH3, R 2b 、R 3b and R 4b are each independently H; more preferably, R 1b 、R 2b 、R 3b and R 4b Both are H.

[0177] In the present invention, A has the structure shown in Formula 9b;

[0178] In formula 9b, R 22b and R 23b Each independently represents H or a C1-C12 alkyl group, m represents an integer from 0 to 13, preferably, R 22b and R 23b Each is independently H or a C1-C4 alkyl group, and m is an integer of 0-3.

[0179] In one embodiment of the present invention, in Formula 3, R 5b and R 6b Each independently is H or a C2-C14 alkyl group, preferably, R 5b H, R 6b is C2H5.

[0180] In one embodiment of the present invention, in Formula 4b, R 7b、R 8b and R 9b Each independently represents H or C1-C8 alkyl, -(CH2) r -OH or -(CH2) q SO3Q, Q is H, Na or K, r is an integer from 0 to 10, q is an integer from 0 to 8; X is -(CH2) z -, z is an integer from 0 to 3, preferably, R 7b -(CH2) q SO3Q, Q is H or Na, q is an integer from 0 to 2; R 8b and R 9b Each independently represents H; X b -(CH2) z -, z is 0; preferably, R 7b -(CH2) q SO3Q, Q is Na, q is 0.

[0181] In one embodiment of the present invention, in Formula 5b, R 10b is H, M is Na.

[0182] In one embodiment of the present invention, in Formula 6b, R 11b For H.

[0183] In one embodiment of the present invention, in Formula 7b, R 12b For H.

[0184] In one embodiment of the present invention, in Formula 8b, R 13b 、R 14b and R 15b are each independently H or NH2; R 16b is H or NH, R 17b For H.

[0185] According to the present invention, at 25° C., the intrinsic viscosity of the unsaturated amide polymer is 100 mL / g-1200 mL / g, preferably 800 mL / g-1200 mL / g.

[0186] In one embodiment of the present invention, the water-soluble phenolic resin comprises a structural unit A represented by formula Ic and a structural unit B represented by formula IIc;

[0187] Based on the total weight of the bisphenol-formaldehyde resin, the content of the structural unit A is 0-100 wt %, and the content of the structural unit B is 0-100 wt %.

[0188] In the present invention, the bisphenol novolac resin contains specific structural units Ic and IIc, which can produce a micro-crosslinked structure in the molecular chain of the bisphenol novolac resin, forming a phenolic resin with a micro-network. This makes the molecular chain of the bisphenol novolac resin have a certain rigidity. When it is used as a curing agent for curing epoxy resin, it can significantly improve the compressive strength and flow conductivity of the epoxy resin.

[0189] In the present invention, the permeability of the epoxy resin product at 40 MPa is used to characterize the flow conductivity of the epoxy resin product. That is, the higher the permeability of the epoxy resin product at 40 MPa, the higher the flow conductivity of the epoxy resin product.

[0190] In the present invention, the content of the structural unit A and the content of the structural unit B are not both 0, and the sum of the content of the structural unit A and the content of the structural unit B is 100%.

[0191] According to the present invention, Q is Among them, R 1c 、R 2c Each is independently H or CH3, preferably CH3.

[0192] In the present invention, in order to further improve the water solubility and storage stability of the bisphenol novolac resin, preferably, the bisphenol novolac resin includes both the structural unit A shown in formula Ic and the structural unit B shown in formula IIc. Specifically, based on the total weight of the bisphenol novolac resin, the content of the structural unit A is 70wt%-80wt%, and the content of the structural unit B is 20wt%-30wt%.

[0193] In the present invention, when the contents of structural unit A and structural unit B in the bisphenol-formaldehyde resin meet the above-mentioned specific contents, the sulfonic acid group content in the bisphenol-formaldehyde resin is appropriate, which can ensure that the hydrophilicity of the bisphenol-formaldehyde resin is improved, thereby allowing the epoxy resin product obtained by curing it to maintain a high compressive strength under high-temperature water-containing conditions.

[0194] Furthermore, based on the total weight of the bisphenol-formaldehyde resin, the content of the structural unit A is 72 wt%-77 wt%, and the content of the structural unit B is 23 wt%-28 wt%.

[0195] According to the present invention, the weight average molecular weight of the bisphenol novolac resin is 2000 g / mol-10000 g / mol, preferably 3000 g / mol-5000 g / mol.

[0196] In one embodiment of the present invention, the small molecule polyamine has a structure shown in Formula 1d:

[0197] Wherein, M is a nano-silica particle, x is an integer of 1-4, and R is an alkyl group with 1-4 carbon atoms;

[0198] n is an integer from 0 to 3, m is an integer from 1 to 3, and n+m=3;

[0199] A is a structural unit derived from an acid anhydride compound, and B is a structural unit derived from a polyamino compound.

[0200] In the present invention, by further performing polyamino modification on the nano-silica particles M on the basis of carboxyl modification, a dendritic morphology is exhibited on the surface of the nano-silica particles M. When the nano-silica particles M are added to the epoxy resin, a bonding reaction occurs with the epoxy groups in the epoxy resin, fully utilizing the advantages of both, so that the cured epoxy resin has greater mechanical strength.

[0201] According to the present invention, the acid anhydride compound is at least one selected from maleic anhydride, phthalic anhydride and succinic anhydride.

[0202] According to the present invention, the polyamino compound has a linear polyethylene polyamino compound or a nonlinear polyethyleneimine having a number average molecular weight of 300-3000, which is represented by formula 2d:

[0203] Here, p is an integer from 1 to 6.

[0204] Furthermore, the molecular weight of the nonlinear polyethyleneimine is 1500-2500.

[0205] In the present invention, the polyamino compound is selected from the above compounds, so that the amino content in the modified nano-silica is high, and the curing performance of the epoxy resin is further improved.

[0206] In the present invention, the poly(ethylene)polyamino compound may be triethylenediamine, triethylenetetramine, pentaethylenehexamine or hexaethyleneheptamine.

[0207] According to the present invention, the particle size of the nano-silicon dioxide particles M is 10-500 nm, and the specific surface area is 10-300 m 2 / g.

[0208] In the present invention, the particle size of the nano-silica particles M is 10-500 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, and a range consisting of any two values; the specific surface area is 10-300 m 2 / g, for example, 10m 2 / g,20m2 / g,30m 2 / g,40m 2 / g,50m 2 / g,100m 2 / g,150m 2 / g,200m 2 / g,250m 2 / g,300m 2 / g, and any range of two values.

[0209] Furthermore, the particle size of the nano-silicon dioxide particles M is 30-200 nm, and the specific surface area is 50-200 m 2 / g.

[0210] According to the present invention, the particle size of the modified nano-silica is 10-500nm, and the specific surface area is 50-500m 2 / g.

[0211] In the present invention, when the particle size and specific surface area of ​​the modified nano-silica meet the above ranges, the smaller the particle size, the better the dispersibility in the epoxy resin, thereby improving the curing performance of the epoxy resin.

[0212] In the present invention, the particle size of the modified nano-silica is 10-500nm, for example, it can be 10nm, 20nm, 30nm, 40nm, 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, and a range consisting of any two values; the specific surface area is 50-300m 2 / g, for example, 50m 2 / g,60m 2 / g,70m 2 / g,80m 2 / g,90m 2 / g,100m 2 / g,150m 2 / g,200m 2 / g,250m 2 / g,300m 2 / g,400m 2 / g,500m 2 / g, and any range of two values.

[0213] Furthermore, the particle size of the modified nano-silica is 30-500 nm, and the specific surface area is 50-300 m 2 / g.

[0214] According to the present invention, the amino content of the modified nano-silica is 0.1-5 mmol / g.

[0215] In the present invention, when the amino content of the modified nano-silica satisfies the above range, a dendritic morphology can be presented on the surface of the nanoparticles, thereby increasing the crosslinking speed and crosslinking density of the epoxy resin containing the modified nano-silica.

[0216] In the present invention, the amino content of the modified nano-silica is 0.1-5mmol / g, for example, it can be 0.1mmol / g, 0.2mmol / g, 0.3mmol / g, 0.4mmol / g, 0.5mmol / g, 0.6mmol / g, 0.7mmol / g, 0.8mmol / g, 0.9mmol / g, 1mmol / g, 1.5mmol / g, 2mmol / g, 2.5mmol / g, 3mmol / g, 3.5mmol / g, 4mmol / g, 4.5mmol / g, 5mmol / g, and a range consisting of any two values.

[0217] Furthermore, the amino content of the modified nano-silica is 0.5-5 mmol / g.

[0218] According to the present invention, the emulsifier is selected from cationic emulsifiers and / or anionic emulsifiers.

[0219] In the present invention, the cationic emulsifier and / or cationic emulsifier are selected to further control the pore structure of the solidified proppant, so that the pores and / or connected channels of the solidified proppant are more evenly distributed, thereby further improving the conductivity, compressive strength and deformation resistance of the solidified proppant.

[0220] In the present invention, there is no particular limitation on the specific type of cationic emulsifier, and conventional cationic emulsifiers in the art can be used, for example, at least one of dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, N,N-ethylenedioctadecyldimethylammonium chloride, dodecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride and octadecyldimethylbenzylammonium chloride.

[0221] In the present invention, there is no particular limitation on the specific type of anionic emulsifier, and conventional anionic emulsifiers in the art can be used. Specifically, the anionic emulsifier is at least one selected from sodium stearate, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium oleate, sodium laurate, sodium rosinate, sodium didodecylphenyl ether disulfonate, and sodium dibutylnaphthylsulfonate.

[0222] In the present invention, the second component also includes conventional additives in the art, such as dispersants and curing accelerators. The type and amount of the dispersants and curing accelerators are not particularly limited in the present invention, and conventional dispersants and curing accelerators in the art can be used.

[0223] According to the present invention, the phase change conditions include: phase change pressure of 0-50 MPa, phase change temperature of 70-150° C., and phase change time of 10 min-6 h.

[0224] In the present invention, the honeycomb solid phase proppant is prepared by performing phase change under the above conditions, simulating the formation environment in the laboratory and simulating the process of the phase change material liquid in the formation changing from liquid phase to solid phase.

[0225] Furthermore, the phase change conditions include: phase change pressure of 10MPa-50MPa, phase change temperature of 90°C-150°C, and phase change time of 30min-3h.

[0226] In the present invention, under laboratory conditions, the phase change reaction of the phase change material liquid in the formation is simulated. Under experimental conditions, the fracturing method provided by the present invention can make the phase change material liquid form a honeycomb solid phase proppant. It can be expected that the fracturing method provided by the present invention can also form a honeycomb solid phase proppant in a formation environment to achieve phase change fracturing.

[0227] According to the present invention, the phase change material liquid is 1-20m 3 / min injection into the formation.

[0228] In the present invention, when the injection speed of the phase change material liquid into the formation is controlled to meet the above range, it can be well matched with the field application process and is applicable to existing fracturing equipment.

[0229] Furthermore, the phase change material liquid is 4-20m 3 / min injection into the formation.

[0230] In the present invention, the fracturing method further comprises: injecting fracturing fluid into the formation to generate cracks in the formation, and then injecting phase change material fluid into the formation.

[0231] According to the present invention, preferably, the method further comprises: injecting a free radical scavenger into the formation during the fracturing process.

[0232] In the present invention, by injecting a free radical scavenger into the formation, it is possible to avoid quenching of the active groups (epoxy groups) in the water-soluble thermosetting resin in the first component and the solvent-based thermosetting resin due to residual peroxides and / or persulfides in the plugging agent during the gel breaking process, resulting in the phase change material liquid being unable to form an effective solid phase proppant.

[0233] According to the present invention, the free radical scavenger is selected from quinone compounds and / or phenolic compounds.

[0234] According to the present invention, the injection amount of the free radical scavenger is 1-20m 3 .

[0235] In one embodiment of the present invention, the fracturing method comprises the following steps:

[0236] S1. Injecting fracturing fluid into the formation to generate cracks in the formation;

[0237] S2, 1-10m 3 The free radical scavenger is injected into the formation;

[0238] S3, after mixing the first component and the second component in the phase change material liquid at a ratio of 1:0.4-0.6, 3 After injecting into the formation at a speed of / min, inject 1-10m 3 The free radical scavenger is injected into the displacement fluid and the machine is shut down for 6h-8h after completion.

[0239] In the present invention, under laboratory conditions, the phase change reaction of the phase change material fluid in the formation is simulated. Specifically, the method includes the following steps:

[0240] (1) injecting a fracturing fluid containing peroxide and / or persulfide into an aging tank so that the fracturing fluid is located at the bottom of the aging tank;

[0241] (2) optionally, injecting a free radical scavenger into the aging tank such that the free radical scavenger is located above the hydraulic fracture;

[0242] (3) After mixing the first component and the second component in the phase change material liquid, inject it into the aging tank. Optionally, inject the free radical scavenger and then inject the displacement liquid. After completion, shut down the machine.

[0243] In the present invention, based on the total weight of the fracturing fluid, the content of the peroxide and / or persulfide is 0.02 wt%-0.06 wt%.

[0244] In the present invention, there is no particular limitation on the amount of the free radical scavenger. Excessive amounts of the free radical scavenger are added to prevent quenching of epoxy groups caused by the presence of peroxides and / or persulfides. For example, the amount of the free radical scavenger is 10-50 parts by weight relative to 1 part by weight of the peroxides and / or persulfides.

[0245] The present invention will be described in detail below by way of examples.

[0246] The porosity of honeycomb solid proppants is measured using the osmotic pressure differential method. The specific test method is as follows: A sample with dimensions of 24 mm in diameter and 40 mm in length is solidified. The solidified sample is placed in the permeameter, ensuring there is no leakage between the sample column and the permeameter. After assembly, a certain pressure differential is applied, and the volume and time of the fluid flowing through the permeameter are recorded. Finally, the permeability is calculated.

[0247] The calculation formula is: K g =2Q2LμP0 / A(P1 2 -P2 2 )

[0248] Among them, K g To measure the permeability, μm 2 ; Q2 is the fluid flow rate at the core outlet, ml / s; L is the core length, cm; A is the core cross-sectional area, cm 2 ; P0 is atmospheric pressure, MPa; P1 is the absolute pressure at the core inlet, MPa; P2 is the absolute pressure at the outlet, MPa; μ is the fluid viscosity, mPa﹒s.

[0249] The pore size of the honeycomb solid phase proppant was statistically measured using a stereo microscope. Specifically:

[0250] The honeycomb resin product is observed under a stereo microscope, and the pore diameter of the honeycomb resin product is tested within a field of view of 1 cm×1 cm. The pore diameters of 20 holes are tested, and the average value is the pore diameter of the honeycomb resin product.

[0251] The pore density of the honeycomb solid phase proppant was statistically measured using a stereo microscope. Specifically:

[0252] The honeycomb resin product was observed under a stereo microscope, and the pore diameter of the honeycomb resin product was measured within a 1 cm × 1 cm field of view. The pore diameters of 20 pores were tested, and the average value was taken as the pore diameter D (mm) of the honeycomb resin product. The pore density was calculated using the following formula: pore density = (1 cm × 1 cm) × porosity / pore area, where the pore area is calculated as a circular pore, i.e., pore area = π × (D / 2) 2 , mm 2 .

[0253] The compressive strength of the honeycomb solid phase proppant was measured using a high and low temperature universal material testing machine. Specifically, the test sample was cylindrical, with a diameter of 2.4 cm and a height of 4 cm.

[0254] The density of the honeycomb solid phase proppant is measured by determining the mass and volume, specifically:

[0255] The deformation rate of the honeycomb solid phase proppant is measured according to the following method:

[0256] At normal pressure and 25°C, the diameter of the honeycomb solid phase proppant tested is D0. After the honeycomb solid phase proppant is extruded at 40 MPa and 150°C using a high and low temperature universal material testing machine, the diameter of the honeycomb solid phase proppant after extrusion is D1. The deformation rate = (D0-D1) / D0×100%.

[0257] The apparent viscosity of the phase change material liquid was measured using a six-speed rotational viscometer. Specifically, 300 ml of the phase change material liquid was placed in the sample chamber, the temperature was set at 25° C., the rotation speed was set at 100 rad / min, and the apparent viscosity value was read after 1 minute.

[0258] The weight average molecular weight of the water-soluble thermosetting resin is measured by gel chromatography. Specifically, a certain amount of resin is dissolved in chromatographically pure tetrahydrofuran (THF) to prepare a test solution, the mobile phase is THF, and the reference substance is polystyrene. The weight average molecular weight of the water-soluble thermosetting resin is measured.

[0259] The content of S element in the water-soluble thermosetting resin and the amount of hydrophilic group contained in the resin of the first component are measured by an elemental analyzer. Specifically, the test is performed according to the oxygen bottle combustion method.

[0260] The epoxy equivalent of water-soluble thermosetting resins is measured using the hydrochloric acid-pyridine method. Specifically, 0.5 g of sample is added to 25 mL of hydrochloric acid-acetone solution and reacted at 45°C for 3.5 hours. Pipette 25 mL of hydrochloric acid-acetone solution, add 3 drops of mixed indicator, and perform a blank titration (titration must be completed within 30 seconds). The endpoint is the volume of NaOH standard solution consumed after 5 seconds without fading. Pipette the mixed solution, add three drops of mixed indicator (30 seconds), and titrate with sodium hydroxide after 5 seconds without fading. Record the amount of 0.5 mol / L NaOH consumed, recorded as V, mL. Calculate according to the following formula:

[0261] Where EV = epoxy equivalent, mol / 100g; V0 = volume of sodium hydroxide standard solution consumed in the blank experiment, mL; V = volume of sodium hydroxide standard solution consumed in the test sample, mL; C = concentration of NaOH standard solution, mol / L; m = test mass, g.

[0262] Water-soluble phenolic resin: resol phenolic resin, commercially available.

[0263] Water-soluble polycarboxylic acid: oxalic acid, commercially available.

[0264] Water-soluble polyamine: polyethylene polyamine, commercially available.

[0265] Other raw materials used in the examples and comparative examples are all commercially available.

[0266] Preparation Example 1

[0267] Water-soluble thermosetting resin EP1-sulfonated bisphenol A epoxy resin

[0268] (a) 57 g of bisphenol A, 0.02 g of ferric chloride, and 50 g of concentrated sulfuric acid were contacted for sulfonation reaction at a reaction temperature of 130° C. for a reaction time of 3 h to obtain a sulfonated bisphenol compound BPAS-1; wherein the molar ratio of bisphenol A to concentrated sulfuric acid was 1:2, and the mass ratio of bisphenol A to ferric chloride was 1:0.00035.

[0269] (b) 8 g of NaOH was dissolved in deionized water, 48 g of BPAS-1 was added, and 18 g of epichlorohydrin was added dropwise at 50°C for 3 h to carry out a polycondensation reaction to obtain a water-soluble thermosetting resin EP1. The mass ratio of BPAS-1 to NaOH was 1:0.17. The mass ratio of BPAS-1 to epichlorohydrin was 1:0.375.

[0270] The water-soluble thermosetting resin EP1 has an S content of 10.8 wt %, an epoxy equivalent weight of 110 g / eg, and a weight-average molecular weight of 2659 g / mol. R1 is a C1 alkylene group, R2 is 1, R3 is 1, M is Na, and m1+m2 is 2.

[0271] Preparation Example 2

[0272] Water-soluble thermosetting resin EP2-sulfonated bisphenol A epoxy resin

[0273] A water-soluble thermosetting resin was prepared according to the method of Preparation Example 1, except that the amount of concentrated sulfuric acid added was 70.4 g, and the molar ratio of bisphenol A to concentrated sulfuric acid was 1:2.3.

[0274] The content of S element in the water-soluble thermosetting resin EP2 is 12.8 wt %, the epoxy equivalent is 190 g / eg, the weight average molecular weight is 4568 g / mol, and m1+m2 is 2.3.

[0275] Preparation Example 3

[0276] Water-soluble thermosetting resin EP3-sulfonated bisphenol A epoxy resin

[0277] A water-soluble thermosetting resin was prepared according to the method of Preparation Example 1, except that the amount of concentrated sulfuric acid added was 100 g, and the molar ratio of bisphenol A to concentrated sulfuric acid was 1:3.3.

[0278] The content of S element in the water-soluble thermosetting resin EP3 is 14.7 wt %, the epoxy equivalent is 238 g / eq, the weight average molecular weight is 6800 g / mol, and m1+m2 is 3.3.

[0279] Preparation Example 4

[0280] Water-soluble thermosetting resin EP4-sulfonated bisphenol S epoxy resin

[0281] A water-soluble thermosetting resin was prepared according to the method of Preparation Example 1, except that 57 g of bisphenol A was replaced by 64.5 g of bisphenol A, and the molar ratio of bisphenol A to concentrated sulfuric acid was 1:1.8.

[0282] The content of S element in the water-soluble thermosetting resin EP4 is 8.3 wt %, the epoxy equivalent is 170 g / eq, the weight average molecular weight is 5907 g / mol, and m1+m2 is 1.8.

[0283] Preparation Example 5

[0284] Water-soluble thermosetting resin EP5-sulfonated bisphenol F epoxy resin

[0285] A water-soluble thermosetting resin was prepared according to the method of Preparation Example 1, except that 57 g of bisphenol A was replaced with 48.5 g of bisphenol F, and the molar ratio of bisphenol F to concentrated sulfuric acid was 1:2.5.

[0286] The content of S element in the water-soluble thermosetting resin EP5 is 11.2 wt %, the epoxy equivalent is 150 g / eq, the weight average molecular weight is 4650 g / mol, and m1+m2 is 2.5.

[0287] Preparation Example 6

[0288] Water-soluble thermosetting resin EP6-bisphenol AF epoxy resin

[0289] A water-soluble thermosetting resin was prepared according to the method of Preparation Example 1, except that 57 g of bisphenol A was replaced with 84 g of bisphenol AF, and the molar ratio of bisphenol AF to concentrated sulfuric acid was 1:2.4.

[0290] The content of S element in the water-soluble thermosetting resin EP6 is 10.8 wt %, the epoxy equivalent is 123 g / eq, the weight average molecular weight is 3059 g / mol, and m1+m2 is 2.4.

[0291] Preparation Example 7

[0292] Water-soluble thermosetting resin EP7-bisphenol B epoxy resin

[0293] A water-soluble thermosetting resin was prepared according to the method of Preparation Example 1, except that 57 g of bisphenol A was replaced with 60.5 g of bisphenol B, and the molar ratio of bisphenol B to concentrated sulfuric acid was 1:2.4.

[0294] The content of S element in the water-soluble thermosetting resin EP7 is 11 wt %, the epoxy equivalent is 170 g / eq, the weight average molecular weight is 4383 g / mol, and m1+m2 is 2.4.

[0295] Example 1

[0296] S1. 55 parts by weight of a water-soluble thermosetting resin EP1, 37.2 parts by weight of an epoxy resin (E51), 3.6 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 2 parts by weight of an emulsifier N',N-ethylenedioctadecyldimethylammonium chloride, and 27 parts by weight of water were stirred uniformly to obtain a first component. Testing showed that the content N of the hydrophilic group contained in the first component resin was 0.003 mol / g, and the apparent viscosity of the first component was 390 mPa·s.

[0297] S2. Add 66.4 parts by weight of the second component, water-soluble phenolic resin (curing agent), to the first component, and mix thoroughly to obtain a phase change material liquid, wherein the mass ratio of the first component to the second component is 1:0.53.

[0298] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A1 having a honeycomb structure, a porosity of 16.5%, a pore diameter of 0.6 mm, a pore density of 58, and a density of 0.930 g / cm 3 , at 40MPa and 150℃, its deformation rate is 5%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0299] FIG1 is a photograph of a honeycomb solid phase proppant A1. As can be seen from FIG1 , the negative proppant has a honeycomb structure with interconnected channels.

[0300] Example 2

[0301] S1. 93 parts by weight of a water-soluble thermosetting resin EP1, 55.8 parts by weight of an epoxy resin (E51), 7.9 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 7 parts by weight of an emulsifier N',N-ethylenedioctadecyldimethylammonium chloride, and 60 parts by weight of water were stirred uniformly to obtain a first component. Testing showed that the content N of the hydrophilic group contained in the first component resin was 0.0032 mol / g, and the apparent viscosity of the first component was 219 mPa·s.

[0302] S2. Add 90 parts by weight of water-soluble phenolic resin (curing agent) to the first component and mix thoroughly to obtain a phase change material liquid, wherein the mass ratio of the first component to the second component is 1:0.4.

[0303] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A2 having a honeycomb structure, a porosity of 21.6%, a pore diameter of 0.4 mm, a pore density of 172, and a density of 0.872 g / cm 3 , at 40MPa and 150℃, its deformation rate is 3%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0304] Example 3

[0305] S1. 65 parts by weight of a water-soluble thermosetting resin EP1, 42 parts by weight of an epoxy resin (E51), 6 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of an emulsifier N',N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water were stirred uniformly to obtain a first component. Testing showed that the content N of the hydrophilic group contained in the first component resin was 0.0031 mol / g, and the apparent viscosity of the first component was 333 mPa·s.

[0306] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin (curing agent), to the first component, and mix thoroughly to obtain a phase change material liquid, wherein the mass ratio of the first component to the second component is 1:0.72.

[0307] S3: The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A3 having a honeycomb structure, a porosity of 28.6%, a pore diameter of 0.3 mm, a pore density of 405, and a density of 0.885 g / cm 3 , at 40MPa and 150℃, its deformation rate is 1%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0308] Example 4

[0309] S1. 65 parts by weight of a water-soluble thermosetting resin EP2, 42 parts by weight of an epoxy resin (E51), 6 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of an emulsifier N′N-ethylenedioctadecyldimethylammonium chloride, and 60 parts by weight of water are stirred uniformly to obtain a first component. Testing shows that the content N of the hydrophilic group contained in the first component resin is 0.0039 mol / g, and the apparent viscosity of the first component is 363 mPa·s.

[0310] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin (curing agent), to the first component and mix thoroughly to obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0311] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A4 having a honeycomb structure, a porosity of 28.6%, a pore diameter of 0.5 mm, a pore density of 146, and a density of 0.888 g / cm 3 , at 40MPa and 150℃, its deformation rate is 2%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0312] Example 5

[0313] S1, 65 parts by weight of a water-soluble thermosetting resin EP3, 42 parts by weight of an epoxy resin (E51), 6 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of an emulsifier N′N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water are stirred evenly to obtain a first component. After testing, the content N of the hydrophilic group contained in the first component resin is 0.0044 mol / g, and the apparent viscosity of the first component is 393 mPa·s.

[0314] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin (curing agent), to the first component and mix thoroughly to obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0315] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A5 having a honeycomb structure, a porosity of 23.1%, a pore diameter of 0.65 mm, a pore density of 70, and a density of 0.889 g / cm 3 , at 40MPa and 150℃, its deformation rate is 5%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0316] Example 6

[0317] S1, 65 parts by weight of water-soluble thermosetting resin EP4, 42 parts by weight of epoxy resin (E51), 6 parts by weight of emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of emulsifier N'N-ethylenedioctadecyldimethylammonium chloride, 50 parts by weight of water, are stirred evenly to obtain a first component. After testing, the content N of the hydrophilic group contained in the first component resin is 0.0029 mol / g, and the apparent viscosity of the first component is 165 mPa·s.

[0318] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin (curing agent), to the first component, mix thoroughly, and obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.7.

[0319] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A6 having a honeycomb structure, a porosity of 19.1%, a pore diameter of 0.58 mm, a pore density of 72, and a density of 0.900 g / cm 3 , at 40MPa and 150℃, its deformation rate is 5.5%. At 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0320] Example 7

[0321] S1, 65 parts by weight of a water-soluble thermosetting resin EP5, 42 parts by weight of an epoxy resin (E51), 6 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of an emulsifier N′N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water are stirred evenly to obtain a first component. After testing, the content N of the hydrophilic group contained in the first component resin is 0.0034 mol / g, and the apparent viscosity of the first component is 144 mPa·s.

[0322] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin, to the first component, mix thoroughly, and obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0323] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A7 having a honeycomb structure, a porosity of 24.1%, a pore diameter of 0.44 mm, a pore density of 159, and a density of 0.886 g / cm 3 , at 40MPa and 150℃, its deformation rate is 4.8%. At 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0324] Example 8

[0325] S1. 65 parts by weight of a water-soluble thermosetting resin EP6, 42 parts by weight of an epoxy resin (E51), 6 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of an emulsifier N′N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water are stirred uniformly to obtain a first component. Testing shows that the content N of the hydrophilic group contained in the first component resin is 0.003 mol / g, and the apparent viscosity of the first component is 154 mPa·s.

[0326] S2. Add 120 parts by weight of the second component, aqueous polyamine (polyethylene polyamine), to the first component, and mix thoroughly to obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0327] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A8 having a honeycomb structure, a porosity of 22.1%, a pore diameter of 0.38 mm, a pore density of 195, and a density of 0.889 g / cm 3 , at 40MPa and 150℃, its deformation rate is 5.3%. At 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0328] Example 9

[0329] S1, 65 parts by weight of water-soluble thermosetting resin EP7, 42 parts by weight of epoxy resin (E51), 6 parts by weight of emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of emulsifier N'N-ethylenedioctadecyldimethylammonium chloride, 50 parts by weight of water, are stirred evenly to obtain a first component. After testing, the content N of the hydrophilic group contained in the first component resin is 0.003 mol / g, and the apparent viscosity of the first component is 234 mPa·s.

[0330] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin, to the first component, mix thoroughly, and obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0331] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A9 having a honeycomb structure, a porosity of 27%, a pore diameter of 0.45 mm, a pore density of 170, and a density of 0.880 g / cm 3 , at 40MPa and 150℃, its deformation rate is 5.6%. At 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0332] Example 10

[0333] S1, 65 parts by weight of water-soluble thermosetting resin EP7, 42 parts by weight of epoxy resin (E51), 6 parts by weight of emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of emulsifier N'N-ethylenedioctadecyldimethylammonium chloride, 50 parts by weight of water, are stirred evenly to obtain a first component. After testing, the content N of the hydrophilic group contained in the first component resin is 0.003 mol / g, and the apparent viscosity of the first component is 363 mPa·s.

[0334] S2. Add 120 parts by weight of the second component, water-soluble polyamine, to the first component, mix thoroughly, and obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0335] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A10 having a honeycomb structure, a porosity of 15%, a pore diameter of 0.7 mm, a pore density of 39, and a density of 0.940 g / cm 3 , at 40MPa and 150℃, its deformation rate is 4%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0336] Example 11

[0337] S1, 65 parts by weight of water-soluble thermosetting resin EP7, 42 parts by weight of unsaturated resin 901, 6 parts by weight of emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of emulsifier N'N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water are stirred uniformly to obtain a first component. After testing, the content N of hydrophilic groups contained in the first component resin is 0.003 mol / g, and the apparent viscosity of the first component is 297 mPa·s.

[0338] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin, to the first component, and mix thoroughly to obtain a phase change material liquid.

[0339] S2. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A11 having a honeycomb structure, a porosity of 18%, a pore diameter of 0.7 mm, a pore density of 47, and a density of 0.910 g / cm 3 , at 40MPa and 150℃, its deformation rate is 5%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 35MPa.

[0340] Example 12

[0341] S1, 65 parts by weight of a water-soluble thermosetting resin EP7, 42 parts by weight of an epoxy resin E44, 6 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of an emulsifier N′N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water are stirred uniformly to obtain a first component. Testing shows that the content N of hydrophilic groups contained in the first component resin is 0.003 mol / g, and the apparent viscosity of the first component is 366 mPa·s.

[0342] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin, to the first component, mix thoroughly, and obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0343] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A12 having a honeycomb structure, a porosity of 38%, a pore diameter of 0.59 mm, a pore density of 139, and a density of 0.851 g / cm 3 , at 40MPa and 150℃, its deformation rate is 8.1%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 20MPa.

[0344] Example 13

[0345] S1, 65 parts by weight of water-soluble thermosetting resin EP7, 42 parts by weight of epoxy resin F51, 6 parts by weight of emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of emulsifier N'N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water are stirred evenly to obtain a first component. After testing, the content N of the hydrophilic group contained in the first component resin is 0.003 mol / g, and the apparent viscosity of the first component is 186 mPa·s.

[0346] S2. Add 120 parts by weight of the second component, water-soluble phenolic resin, to the first component, mix thoroughly, and obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0347] S3. The phase change material liquid was heated in an aging tank at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A13 having a honeycomb structure, a porosity of 30%, a pore diameter of 0.59 mm, a pore density of 110, and a density of 0.870 g / cm 3 , at 40MPa and 150℃, its deformation rate is 7.8%. At 150℃, the compressive strength of the honeycomb solid phase proppant is 15MPa.

[0348] Example 14

[0349] S1, 65 parts by weight of water-soluble thermosetting resin EP7, 42 parts by weight of epoxy resin E51, 6 parts by weight of emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of emulsifier N'N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water are stirred evenly to obtain a first component. After testing, the content N of hydrophilic groups contained in the first component resin is 0.003 mol / g. After testing, the apparent viscosity of the first component is 387 mPa·s.

[0350] S2. Add 120 parts by weight of the second component, water-soluble polycarboxylic acid (oxalic acid), to the first component, and mix thoroughly to obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0351] S3. The phase change material liquid was placed in an aging tank and heated at 40 MPa and 120°C for 6 h to obtain a solid phase proppant A14 having a honeycomb structure, a porosity of 26%, a pore diameter of 0.48 mm, a pore density of 144, and a density of 0.881 g / cm 3 , at 40MPa and 150℃, its deformation rate is 6.5%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 18MPa.

[0352] Example 15

[0353] S1. 65 parts by weight of a water-soluble thermosetting resin EP1, 42 parts by weight of an epoxy resin (E51), 6 parts by weight of an emulsifier octadecyltrimethylammonium chloride, 3 parts by weight of an emulsifier N',N-ethylenedioctadecyldimethylammonium chloride, and 50 parts by weight of water were stirred uniformly to obtain a first component. Testing showed that the content N of the hydrophilic group contained in the first component resin was 0.0031 mol / g, and the apparent viscosity of the first component was 333 mPa·s.

[0354] S2. Add 66.4 parts by weight of water-soluble phenolic resin (curing agent) to the first component and mix thoroughly to obtain a phase change material liquid. The mass ratio of the first component to the second component is 1:0.72.

[0355] S3. Fracturing fluid (100 g of 1% polyacrylamide fracturing fluid and 0.04 g of ammonium persulfate) was injected into the aging tank. The fracturing fluid was located at the bottom of the aging tank. The phase change material liquid was heated in the aging tank at 40 MPa and 120° C. for 6 h to obtain solid phase proppant A15, which had a honeycomb structure, a porosity of 38%, a pore diameter of 0.8 mm, a pore density of 76, and a density of 0.852 g / cm 3 , at 40MPa and 150℃, its deformation rate is 26%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 7MPa.

[0356] Example 16

[0357] The method of Example 15 is different in that step S3 is different, specifically:

[0358] S3. Inject fracturing fluid (100 g of 1% polyacrylamide fracturing fluid and 0.04 g of ammonium persulfate) into an aging tank, with the fracturing fluid located at the bottom of the aging tank. Inject 10 parts by weight of a 10 wt% aqueous solution of sulfonated p-benzodiquinone into the aging tank, so that the free radical scavenger is located above the fracturing fluid. Heat the phase change material liquid in the aging tank at 40 MPa and 120° C. for 6 h to obtain a solid phase proppant A16 having a honeycomb structure, a porosity of 28%, a pore diameter of 0.5 mm, a pore density of 143, and a density of 0.880 g / cm 3, at 40MPa and 150℃, its deformation rate is 1%, and at 150℃, the compressive strength of the honeycomb solid phase proppant is 40MPa.

[0359] As can be seen from the above embodiments, the fracturing method provided by the present invention can cause the phase change material liquid to undergo a phase change under conditions simulating the formation, forming a honeycomb solid phase proppant with a specific pore structure. The honeycomb solid phase proppant has a low deformation rate under high temperature and high pressure conditions, and has high compressive strength under high temperature conditions, which can meet the requirements for the use of proppants in oil reservoir development.

[0360] Test Case

[0361] The permeabilities of honeycomb solid proppants A1-A16, quartz sand, and ceramsite sand were tested using a high-pressure displacement device in accordance with Sinopec Shengli Oilfield Administration corporate standard Q / SH1020, "Method for Determining the Permeability of High-Permeability Consolidated Cores." The results are shown in Table 1.

[0362] Table 1

[0363] *In the present invention, the 5000 mD in the test example does not represent the upper limit of the permeability, but only the upper limit of the high-pressure displacement device test instrument.

[0364] 1- The particle size of quartz sand is 400-800μm.

[0365] 2- The particle size of ceramsite sand is 400-800μm.

[0366] As can be seen from Table 1, the honeycomb solid proppant provided by the present invention exhibits similarly excellent permeability compared to quartz sand and ceramsite sand. In particular, under high-pressure conditions, the honeycomb solid proppant provided by the present invention exhibits even superior permeability compared to quartz sand and ceramsite sand. This indicates that the honeycomb solid proppant provided by the present invention can be used as a proppant in oil reservoir development, and during the fracturing process, there is no need to add additional quartz sand or ceramsite sand as a proppant.

[0367] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A phase change fracturing method, characterized in that, The phase change fracturing method includes: Injecting a phase change material liquid into the formation, and the phase change material liquid undergoes a phase change under formation conditions to form a honeycomb solid proppant, completing the phase change fracturing.

2. The phase change fracturing method according to claim 1, wherein, There are connected channels in the honeycomb solid proppant.

3. The phase change fracturing method according to claim 1 or 2, wherein, The porosity of the honeycomb solid proppant is 1%-40%, preferably 20%-30%; Preferably, the pore diameter of the honeycomb solid proppant is 0.1 mm - 0.7 mm; preferably 0.2 - 0.6 mm; Preferably, the pore density of the honeycomb solid proppant is 20 - 450, preferably 50 - 300.

4. The phase change fracturing method according to any one of claims 1-3, wherein, The density of the honeycomb-shaped solid-phase proppant is 0.85 g / cm 3 - 0.95 g / cm 3 , preferably 0.86 g / cm 3 - 0.93 g / cm 3 .

5. The phase change fracturing method according to any one of claims 1-4, wherein, In the range of 60 - 150 °C, the compressive strength of the honeycomb solid proppant is greater than or equal to 20 MPa, preferably greater than or equal to 30 MPa; Preferably, under 40 MPa and in the range of 60 - 150 °C, the deformation rate of the honeycomb solid proppant is less than or equal to 8%, preferably less than or equal to 4%.

6. The phase change fracturing method according to any one of claims 1-5, wherein, The phase change material liquid includes a first component and a second component; The first component includes a water-soluble thermosetting resin, a solvent-based thermosetting resin, an emulsifier, and water; The second component includes a curing agent; The water-soluble thermosetting resin has a structure represented by Formula I; R1 is an alkylene group of C1-C4; A is Wherein, R2 and R3 are each independently H, CH3, CF3 or CH2CH3; 0 < m1 + m2 ≤ 8; M is K or Na.

7. The phase change fracturing method according to claim 6, wherein, R1 is an alkylene group of C1-C3; Preferably, A is Wherein, R2 and R3 are each independently CH3, H, CF3 or CH2CH3; M is Na.

8. The phase change fracturing method according to claim 6 or 7, wherein, Based on the total weight of the water-soluble thermosetting resin, the content of S element is 6 - 20 wt%, preferably 10 - 15 wt%; Preferably, the epoxy equivalent of the water-soluble thermosetting resin is 100 g / eq - 300 g / eq, preferably 150 g / eq - 200 g / eq; Preferably, the weight average molecular weight of the water-soluble thermosetting resin is 2000 g / mol - 10000 g / mol, preferably 3000 g / mol - 5000 g / mol.

9. The phase change fracturing method according to any one of claims 6-8, wherein, The content N of the hydrophilic groups contained in the resin in the first component is 0.002 mol / g - 0.006 mol / g, preferably 0.0025 mol / g - 0.004 mol / g.

10. The phase change fracturing method according to any one of claims 6-9, wherein, At 25 °C, the apparent viscosity of the first component is 100 mPa·s - 400 mPa·s, preferably 200 mPa·s - 300 mPa·s.

11. The phase change fracturing method according to any one of claims 6-10, wherein, The mass ratio of the first component to the second component is 1:0.4 - 0.8, preferably 1:0.6 - 0.

8.

12. The phase change fracturing method according to any one of claims 6-11, wherein, In the first component, the content of the water-soluble thermosetting resin is 55 - 93 parts by weight, the content of the solvent-based thermosetting resin is 37 - 56 parts by weight, the content of water is 22 - 88 parts by weight, and the content of the emulsifier is 5 - 15 parts by weight; Preferably, in the first component, the content of the water-soluble thermosetting resin is 60 - 80 parts by weight, the content of the solvent-based thermosetting resin is 40 - 45 parts by weight, the content of water is 25 - 80 parts by weight, and the content of the emulsifier is 8 - 13 parts by weight.

13. The phase change fracturing method according to any one of claims 6-12, wherein, The solvent-based thermosetting resin is selected from at least one of epoxy resin, unsaturated resin and polyimide; Preferably, the curing agent is selected from at least one of water-soluble polymer polyamine, water-soluble polymer polycarboxylic acid, water-soluble phenolic resin, small molecule polyamine and small molecule polycarboxylic acid.

14. The phase change fracturing method according to any one of claims 6-13, wherein, The emulsifier is selected from cationic emulsifiers and / or anionic emulsifiers, preferably cationic emulsifiers.

15. The phase change fracturing method according to any one of claims 1-14, wherein, The conditions for the phase change include: The phase change pressure is 0 MPa - 50 MPa, the phase change temperature is 70 °C - 150 °C, and the phase change time is 10 min - 6 h.

16. The phase change fracturing method according to any one of claims 1-15, wherein, The phase change material liquid is injected into the formation at a rate of 1-20 m 3 / min.

17. The phase change fracturing method according to any one of claims 1-16, wherein, The fracturing method further includes injecting a radical scavenger into the formation; Preferably, the injection amount of the radical scavenger is 1-20 m 3 .

18. The phase change fracturing method according to claim 17, wherein, The radical scavenger is selected from quinone compounds and / or phenolic compounds.

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