Polymers with interpenetrating network structure and methods of making and using the same

Abstract

This invention provides a polymer with an interpenetrating network structure, its preparation method, and its application. The method includes: polymerizing a polymer backbone with a first monomer; wherein the polymer backbone is a network; the polymer backbone includes structural units derived from a nonionic monomer, structural units derived from an anionic monomer, and structural units derived from a phenolic resin; the first monomer has the structure shown in formula (A); in formula (A), R0 is a C4-C12 alkyl group. The polymer of this invention does not over-spread at high temperatures or over-shrink at high salt conditions, exhibiting excellent temperature and salt resistance, and good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer effectively reduces filtration loss, optimizes lubrication, and enhances suspension.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field drilling technology, specifically to a polymer with an interpenetrating network structure, its preparation method, and its application in drilling fluids and / or completion fluids. Background Technology

[0002] Drilling fluids and completion fluids are the circulating media that come into direct contact with the wellbore during drilling operations, and they are crucial technologies for ensuring a well can be drilled successfully, efficiently, and quickly. Polymer-based treatment agents are the core technology of drilling and completion fluids, playing a vital role in reducing filtration loss, optimizing lubrication, and enhancing suspension. However, in the drilling and development of new geological resources, unknown and unusual formations are often encountered, posing multiple challenges to polymer materials used in drilling and completion fluids, including those related to temperature and salinity. Facing the demands of new energy development, there is an urgent need to optimize and innovate polymer materials for drilling and completion fluids.

[0003] Conventional drilling and completion fluid polymers are primarily multi-component copolymers based on acrylamide and acrylic acid. By introducing cationic, anionic, or other monomers during synthesis, the polymer acquires its main functions in drilling and completion fluids. Furthermore, the hydrophobic and electrostatic interactions between chemical groups within the polymer enhance its temperature and salt resistance. However, conventional polymer molecules have a one-dimensional linear structure, which suffers from poor rigidity and strength. Due to this structural weakness, polymer molecules are prone to decomposition under high formation temperatures and to shrink and fail in high-salt drilling fluids or when exposed to highly saline formation water. Therefore, improving the performance of polymers for drilling and completion fluids requires not only selecting temperature- and salt-resistant reactive monomers but also optimizing the polymer molecular structure. In recent years, by adjusting the synthesis method and increasing the molecular weight, novel polymers for drilling and completion fluids with comb-like, star-shaped, branched, and hyperbranched molecular structures have emerged. The novel molecular structure, based on the original one-dimensional linear molecular morphology, increases the molecular volume of the side chains to form a three-dimensional network structure, thereby improving the rigidity and strength of the molecular chains. This effectively protects the weaker chemical bonds such as ester bonds, amide bonds, and ether bonds that are easily hydrolyzed, thus enhancing the temperature and salt resistance properties of polymers used in drilling and completion fluids. For example, conventional linear drilling fluid polymer flow modifiers have a temperature resistance of only 120℃, while those optimized to a comb-shaped molecular structure can withstand temperatures up to 180℃. However, although the performance of the polymer systems for drilling and completion fluids developed using the above-mentioned optimized molecular structure method has improved, there is still a gap compared to the high-temperature conditions (often exceeding 200℃) and near-saturated saline conditions encountered in new geological resource drilling. Therefore, it is particularly important to further innovate and optimize the molecular structure of polymers for drilling and completion fluids to break through the current limits of polymer temperature and salt resistance.

[0004] Further optimization of the polymer molecular structure for drilling and completion fluids hinges on effectively controlling the thermal motion of molecular chains in solvents under high-temperature and high-salt conditions to maintain relative stability. However, high temperatures in aqueous environments cause molecular chains to primarily expand outwards, while high salinity causes them to primarily contract inwards. These two completely opposite effects cause irreversible damage to the polymer molecular structure, thus determining the performance limits of single-molecule polymer systems. Furthermore, drilling and completion operations often involve mechanical agitation, high-speed shearing of drill bit water jets, and multiple cycles of drilling fluid circulation, resulting in significant temperature differences between the surface and the wellbore. This places even higher demands on the stability of polymer molecular structures used in drilling and completion fluids. Therefore, it is necessary to introduce a second or more structures based on a single polymer molecular structure, forming a complex morphology of multiple interpenetrating and interlocking molecular chains. This leverages the performance advantages of different molecular chains under conditions such as temperature and salinity to synergistically improve the polymer's thermal motion stability in solvents. However, current research reports on polymer systems with multiple interpenetrating molecular structures suitable for drilling and completion fluids are lacking, making it difficult to provide effective reference and guidance. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of excessive spreading of polymers at high temperatures and excessive shrinkage under high salinity, and the urgent need to improve the temperature and salt resistance of polymers. This invention provides a polymer with an interpenetrating network structure, its preparation method, and its application in drilling fluids and / or completion fluids. This polymer does not overspread at high temperatures or shrink excessively under high salinity, exhibits excellent temperature and salt resistance, and has good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer effectively reduces filtration loss, optimizes lubrication, and enhances suspension.

[0006] To achieve the objectives of this invention, one aspect of this invention provides a method for preparing a polymer with an interpenetrating network structure, the method comprising: polymerizing a polymer backbone with a first monomer; wherein the polymer backbone is a network; the polymer backbone comprises structural units derived from a nonionic monomer, structural units derived from an anionic monomer, and structural units derived from a phenolic resin; the first monomer has the structure shown in formula (A);

[0007] Formula (A), wherein R0 is a C4-C12 alkyl group.

[0008] A second aspect of the present invention provides a polymer prepared by the method of the present invention.

[0009] A third aspect of the present invention provides the use of the polymer described herein in drilling fluids and / or completion fluids.

[0010] The polymer with an interpenetrating network structure of the present invention does not spread excessively at high temperatures or shrink excessively under high salinity, exhibiting excellent temperature and salt resistance and good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer has excellent effects in reducing filtration loss, optimizing lubrication, and enhancing suspension. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the preparation process of the polymer of the present invention; Figure 2 A scanning electron microscope image of the skeleton prepared in Example 1 of this invention; Figure 3 A scanning electron microscope image of the skeleton prepared in Example 2 of this invention; Figure 4 A scanning electron microscope image of the skeleton prepared in Example 3 of this invention; Figure 5 A scanning electron microscope image of the skeleton prepared in Example 4 of this invention; Figure 6 This is a scanning electron microscope image of the polymer in Example 1 of the present invention; Figure 7 The images shown are scanning electron microscope (SEM) images (regions 1 and 2) of the polymer in Example 1 of the present invention. Figure 8 This is the Raman spectrum of region 1 in the polymer of Example 1 of the present invention; Figure 9 This is the Raman spectrum of region 2 in the polymer of Example 1 of the present invention; Figure 10 This is a particle size distribution diagram of the hydration kinetics of the polymer in Example 1 in deionized water at room temperature; Figure 11 This is a particle size distribution diagram of the hydration kinetics of the polymer in Example 1 in deionized water at 200°C. Figure 12 This is a particle size distribution diagram of the hydration kinetics of the polymer in Example 1 in salt water at 200°C. Figure 13 The TSI stability index of the polymer in Example 1 and commercially available drilling fluid polymer treatment agents in high-temperature water / salt water; Figure 14 This is a scanning electron microscope image of the polymer of Comparative Example 1 of the present invention; Figure 15 This shows the dispersion of the polymer in water in Comparative Example 1 of the present invention. Detailed Implementation

[0012] The endpoints and any values ​​of the ranges 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0013] This invention provides a method for preparing a polymer with an interpenetrating network structure. The method includes: polymerizing a polymer backbone with a first monomer; wherein the polymer backbone is a network; the polymer backbone includes structural units derived from a nonionic monomer, structural units derived from an anionic monomer, and structural units derived from a phenolic resin; the first monomer has the structure shown in formula (A):

[0014] Formula (A), wherein R0 is a C4-C12 alkyl group.

[0015] A schematic diagram of the preparation process of the polymer with interpenetrating network structure of the present invention is shown below. Figure 1 As shown, a polymer backbone with a network structure is polymerized with monomers to obtain a polymer with an interpenetrating network structure.

[0016] In this invention, the aforementioned preparation methods can all achieve the objectives of this invention. A wide range of other monomers can be selected for use. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the preparation process of the polymer further includes the presence of a second monomer, which has the structure shown in formula (B):

[0017] Formula (B), where R is a C6-C12 alkyl group. The polymer prepared using the aforementioned technical solution does not exhibit excessive spreading at high temperatures or excessive shrinkage under high salinity, demonstrating excellent temperature and salt resistance. It also exhibits good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer demonstrates excellent effects in reducing filtration loss, optimizing lubrication, and enhancing suspension.

[0018] In this invention, as long as the purpose of this invention can be achieved, there are no special requirements for the polymerization conditions during the preparation of the polymer. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the polymerization temperature is 40-60°C.

[0019] In this invention, during the preparation of the polymer, the polymerization time is generally adjusted according to the polymerization temperature, etc., and the range of polymerization time is relatively wide, for example, the polymerization time is 5-8 hours.

[0020] In this invention, the polymerization process is usually carried out under alkaline conditions. The range of alkaline conditions that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the pH of the polymerization is 10-12.

[0021] In this invention, the polymerization process can be carried out in an inert gas during the preparation of the polymer. The range of inert gases that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. For example, the inert gas is nitrogen.

[0022] In this invention, the polymerization process can be carried out dynamically during the preparation of the polymer. The rotation speed is generally adjusted according to the polymerization temperature, time, etc., and the range of selectable rotation speed is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the rotation speed is 600-800 rpm.

[0023] Those skilled in the art will know that in the process of preparing polymers, after polymerization, organic solvents such as anhydrous ethanol are generally used to filter and wash out the product, mainly to remove the reaction solvents, etc., and then the polymer is obtained after drying and pulverizing. This operation is a conventional prior art, and will not be described in detail in this invention.

[0024] In the preparation of the polymer, any second monomer having the structure shown in the aforementioned formula (B) can achieve the purpose of the present invention. The range of the second monomer is relatively wide. The following is an illustrative description, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the second monomer is selected from one or more of 3,4,5-tris(n-hexanemethoxy)styrene, 3,4,5-tris(n-octanemethoxy)styrene and 3,4,5-tris(dodecanemethoxy)styrene.

[0025] Those skilled in the art will understand that, in the structure shown in formula (B), when R is a C6 alkyl group, the second monomer is 3,4,5-tris(n-hexanemethoxy)styrene; when R is a C8 alkyl group, the second monomer is 3,4,5-tris(n-octanemethoxy)styrene; and when R is a C12 alkyl group, the second monomer is 3,4,5-tris(dodecanemethoxy)styrene. The polymer prepared using the aforementioned technical solution exhibits excellent temperature and salt resistance, without excessive spreading at high temperatures or excessive shrinkage under high salt conditions. It also demonstrates good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer effectively reduces filtration loss, optimizes lubrication, and enhances suspension.

[0026] In this invention, during the preparation of the polymer, any first monomer having the structure shown in the aforementioned formula (A) can achieve the purpose of this invention. The range of options for the first monomer is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the first monomer is selected from one or more of butyl methacrylate, hexyl methacrylate, and lauryl methacrylate.

[0027] Those skilled in the art will understand that in the structure shown in formula (A), when R is a C4 alkyl group, the first monomer is butyl methacrylate; when R is a C6 alkyl group, the first monomer is hexyl methacrylate; and when R is a C12 alkyl group, the first monomer is lauryl methacrylate. The polymer prepared using the aforementioned technical solution exhibits excellent temperature and salt resistance, without excessive spreading at high temperatures or excessive shrinkage under high salt conditions. It also demonstrates good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer effectively reduces filtration loss, optimizes lubrication, and enhances suspension.

[0028] In this invention, the aforementioned preparation methods can all achieve the objectives of this invention. The mass ratio of the polymer backbone to the total amount of added monomers can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the mass ratio of the polymer backbone to the total amount of added monomers is 1:0.5-2. The polymer prepared using the aforementioned technical solutions will not over-spread at high temperatures or over-shrink at high salinity, exhibiting excellent temperature and salt resistance. It also demonstrates good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer exhibits excellent effects in reducing filtration loss, optimizing lubrication, and enhancing suspension.

[0029] In this invention, in order to achieve the purpose of this invention, commonly used materials known to those skilled in the art can be used in the preparation process of the polymer. For example, the polymerization can be carried out in the presence of raw materials such as solubilizer, initiator 1 and crosslinking agent 1. In the preparation process of the polymer, the range of types of raw materials such as solubilizer, initiator 1 and crosslinking agent 1 is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the solubilizer is selected from one or more of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

[0030] In the preparation of the polymer, according to a preferred embodiment of the present invention, the crosslinking agent 1 is selected from one or more of ethylene glycol dimethacrylate and divinylbenzene. The polymer prepared using the aforementioned technical solution exhibits excellent temperature and salt resistance, without excessive spreading at high temperatures or excessive shrinkage under high salinity, and demonstrates good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer effectively reduces filtration loss, optimizes lubrication, and enhances suspension.

[0031] In the preparation of polymers, commonly used initiators can be used in this invention. In this invention, the advantages of the invention are illustrated by the example of initiator 1 being selected from one or more of azobisisobutyronitrile and dimethyl azobisisobutyrate, but this does not limit the scope of the invention.

[0032] In this invention, the objectives of the invention can be achieved by using the aforementioned preparation methods. The range of selectable amounts of the solubilizer and crosslinking agent 1 is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, during the preparation of the polymer, the mass ratio of the total amount of the polymer backbone and monomers to the solubilizer is 1:0.01-0.05.

[0033] According to a preferred embodiment of the present invention, during the preparation of the polymer, the mass ratio of the total amount of the polymer backbone and monomers to the crosslinking agent 1 is 1:0.05-0.2. The polymer prepared using the aforementioned technical solution exhibits excellent temperature and salt resistance, without excessive spreading at high temperatures or excessive shrinkage under high salinity, and demonstrates good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer effectively reduces filtration loss, optimizes lubrication, and enhances suspension.

[0034] As is well known to those skilled in the art, the polymerization process is generally carried out in the presence of a solvent. There are no special requirements for the choice of solvent. Those skilled in the art can make conventional selections based on the raw materials and polymerization conditions of the polymerization reaction. For example, in this invention, the solvent can be water, etc.

[0035] In this invention, there are no special requirements for the amount of solvent used in the preparation process of the polymer. Those skilled in the art can make conventional selections based on the raw materials and polymerization conditions of the polymerization reaction. For example, the amount of solute can be adjusted. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, in the preparation process of the polymer, the mass ratio of the polymer backbone, total monomer, solubilizer and crosslinking agent 1 to the solvent is 1:2-5.

[0036] In this invention, there are no special requirements for the amount of initiator 1 during the preparation of the polymer. For example, it can be adjusted according to the amount of solvent. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of solvent to initiator 1 during the preparation of the polymer is 1:0.001-0.005.

[0037] In this invention, the number-average molecular weight of the polymer backbone used in the preparation process can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the number-average molecular weight of the polymer backbone is 0.5-50,000.

[0038] Polymer skeletons with the aforementioned technical features can all be used in this invention. The range of optional amounts and types of the nonionic monomer, the anionic monomer, and the phenolic resin is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the mass ratio of the nonionic monomer to the anionic monomer is 1:0.2-1.

[0039] According to a preferred embodiment of the present invention, the total mass ratio of the nonionic monomer and the anionic monomer to the phenolic resin is 1:0.2-0.5.

[0040] According to a preferred embodiment of the present invention, the nonionic monomer is selected from one or more of acrylamide, N-hydroxymethylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, vinylpyrrolidone, and vinylcaprolactam.

[0041] According to a preferred embodiment of the present invention, the anionic monomer is selected from one or more of 2-acrylamido-2-methylpropanesulfonic acid and sodium styrenesulfonate.

[0042] According to a preferred embodiment of the present invention, the phenolic resin is a water-soluble phenolic resin, and the phenolic resin contains structural units shown in formula (C) and optionally structural units shown in formula (D):

[0043] Formula (C)

[0044] Formula (D).

[0045] In this invention, phenolic resins having the aforementioned structure can be used to form the polymer backbone required by this invention. The number-average molecular weight of the phenolic resin can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the number-average molecular weight of the phenolic resin is 500-1200.

[0046] In this invention, any phenolic resin possessing the aforementioned technical features can be used to form the polymer skeleton required by this invention. There are no special requirements for the preparation method of the phenolic resin. One embodiment is illustrated, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the preparation method of the phenolic resin includes: reacting raw materials containing phenol and formaldehyde at 40-90°C for 2-6 hours in the presence of an alkaline environment, wherein the molar ratio of phenol to formaldehyde is 1:1.5-3. The polymer prepared using the aforementioned technical solution will not over-spread at high temperatures or over-shrink under high salt conditions, exhibiting excellent temperature and salt resistance, and good dispersion stability in high-temperature water / salt water. When this polymer is applied to drilling fluids and / or completion fluids, it has excellent effects in reducing filtration loss, optimizing lubrication, and enhancing suspension.

[0047] Specifically, for example, the steps for preparing phenolic resin include: first, weighing phenol and stirring it at 40-60℃ to remove oxygen, then adding sodium hydroxide solution dropwise and mixing well, then adding the required amount of formaldehyde solution (the molar ratio of phenol to formaldehyde is 1:1.5-3) dropwise at a temperature of 40-90℃ and mixing well, and reacting under nitrogen conditions for 2-6 hours.

[0048] In this invention, any polymer skeleton with the aforementioned technical features can achieve the purpose of this invention during the preparation of the polymer. There are no special requirements for the preparation method of the polymer skeleton. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the preparation method of the polymer skeleton includes: copolymerizing a nonionic monomer, anionic monomer and phenolic resin to obtain a first polymer, and then freezing the first polymer to form a first polymer dispersion. The freeze-drying step includes: pre-freezing in liquid nitrogen, followed by freeze-drying.

[0049] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer, the range of types of nonionic monomers, anionic monomers, and phenolic resins that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the nonionic monomer used is selected from one or more of acrylamide, N-hydroxymethylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, vinylpyrrolidone, and vinylcaprolactam.

[0050] According to a preferred embodiment of the present invention, the anionic monomer used is selected from one or more of 2-acrylamido-2-methylpropanesulfonic acid and sodium styrene sulfonate.

[0051] According to a preferred embodiment of the present invention, the phenolic resin used is a water-soluble phenolic resin, wherein the phenolic resin contains structural units shown in formula (C) and optionally structural units shown in formula (D):

[0052] Formula (C)

[0053] Formula (D).

[0054] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resins to obtain the first polymer, any phenolic resin having the aforementioned structure can achieve the purpose of this invention. The number-average molecular weight of the phenolic resin can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the number-average molecular weight of the phenolic resin is 500-1200.

[0055] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer, any phenolic resin with the aforementioned technical characteristics can be used in this invention. There are no special requirements for the preparation method of the phenolic resin. One embodiment is illustrated, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the preparation method of the phenolic resin includes: reacting raw materials containing phenol and formaldehyde at 40-90°C for 2-6 hours in the presence of an alkaline environment, wherein the molar ratio of phenol to formaldehyde is 1:1.5-3.

[0056] Specifically, for example, the steps for preparing phenolic resin include: first, weighing phenol and stirring it at 40-60℃ to remove oxygen, then adding sodium hydroxide solution dropwise and mixing well, then adding the required amount of formaldehyde solution (the molar ratio of phenol to formaldehyde is 1:1.5-3) dropwise at a temperature of 40-90℃ and mixing well, and reacting under nitrogen conditions for 2-6 hours.

[0057] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer, the range of selectable amounts of the nonionic monomers, anionic monomers, and phenolic resins is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of the nonionic monomer to the anionic monomer is 1:0.2-1.

[0058] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer, according to a preferred embodiment of the invention, the mass ratio of the total mass of the nonionic monomers and the anionic monomers to the mass of the phenolic resin is 1:0.2-0.5.

[0059] Those skilled in the art will understand that in the process of copolymerizing nonionic monomers, anionic monomers and phenolic resins to obtain the first polymer, commonly used materials known to those skilled in the art can be used. For example, the copolymerization can be carried out in the presence of raw materials such as initiator 2 and crosslinking agent 2. There are no special requirements for the type and amount of raw materials such as initiator 2 and crosslinking agent 2. The following is an illustrative description, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the crosslinking agent 2 is selected from one or more of N,N-methylenebisacrylamide, ethylene glycol diacrylate and polyethyleneimine.

[0060] In the process of copolymerizing nonionic monomers, anionic monomers and phenolic resins to obtain the first polymer, according to a preferred embodiment of the present invention, the initiator 2 is selected from one or more of potassium persulfate and ammonium persulfate.

[0061] In the process of copolymerizing nonionic monomers, anionic monomers and phenolic resin to obtain the first polymer, according to a preferred embodiment of the present invention, the total mass ratio of the nonionic monomers, the anionic monomers and the phenolic resin to the mass ratio of the crosslinking agent 2 is 1:0.001-0.02.

[0062] Those skilled in the art will know that the copolymerization of nonionic monomers, anionic monomers and phenolic resin to obtain the first polymer is generally carried out in the presence of a solvent. There are no special requirements for the choice of solvent. Those skilled in the art can make conventional selections based on the raw materials and conditions of copolymerization. For example, in this invention, the solvent can be water, etc.

[0063] In this invention, there are no special requirements for the amount of solvent used in the process of copolymerizing nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer. Those skilled in the art can make conventional selections based on the raw materials and copolymerization conditions of the copolymerization reaction. For example, the amount of solute can be adjusted. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of the total mass of the nonionic monomer, the anionic monomer, the phenolic resin, and the crosslinking agent 2 to the mass of the solvent is 1:5-10.

[0064] In this invention, during the copolymerization of nonionic monomers, anionic monomers and phenolic resin to obtain the first polymer, there are no special requirements for the amount of initiator 2. For example, it can be adjusted according to the amount of solvent. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of solvent to initiator 2 is 1:0.0005-0.001.

[0065] In this invention, there are no special requirements for the copolymerization conditions during the copolymerization process of nonionic monomers, anionic monomers and phenolic resins to obtain the first polymer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the copolymerization temperature is 60-70°C.

[0066] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer, the copolymerization time is generally adjusted according to the copolymerization temperature, etc., and the range of selectable copolymerization time is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. For example, the copolymerization time is 2-3 hours.

[0067] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer, the copolymerization is usually carried out under alkaline conditions. The range of alkaline conditions that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the pH of the copolymerization is 9-11.

[0068] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer, the copolymerization can be carried out in an inert gas. The range of inert gases that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. For example, the inert gas is nitrogen.

[0069] In this invention, during the copolymerization of nonionic monomers, anionic monomers, and phenolic resin to obtain the first polymer, the copolymerization can be carried out dynamically. The rotation speed is generally adjusted according to the copolymerization temperature, time, etc., and the range of selectable rotation speed is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the rotation speed is 400-600 rpm.

[0070] Those skilled in the art will know that in the process of copolymerizing nonionic monomers, anionic monomers and phenolic resin to obtain the first polymer, the product is generally filtered and washed with an organic solvent such as anhydrous ethanol after copolymerization, mainly to remove the reaction solvent, etc., and then dried and pulverized to obtain the first polymer. This operation is conventional prior art and will not be described in detail in this invention.

[0071] In this invention, during the freeze-drying process after the first polymer forms a first polymer dispersion, There are no special requirements for the freeze-drying conditions. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the freeze-drying conditions include: the solvent of the first polymer dispersion includes alcohol and water, wherein the alcohol is selected from one or more of tert-butanol, ethanol, methanol, and propanol, and the mass ratio of alcohol to water is 1:1-5.

[0072] According to a preferred embodiment of the present invention, the freeze-drying conditions include: in the first polymer dispersion, the mass ratio of solvent to the first polymer is 1:0.01-0.05.

[0073] According to a preferred embodiment of the present invention, the freeze-drying conditions include: pre-freezing in liquid nitrogen for 0.5-2.5 hours.

[0074] According to a preferred embodiment of the present invention, the freeze-drying conditions include a freeze-drying temperature of -60 to -80°C.

[0075] According to a preferred embodiment of the present invention, the freeze-drying conditions include a freeze-drying pressure of 0.5-1.5 Pa.

[0076] In this invention, as long as the first polymer dispersion can be freeze-dried, there are no special requirements for the freeze-drying time. It is generally selected based on the freeze-drying temperature and pressure, for example, the freeze-drying time is 36-60 hours.

[0077] According to a preferred embodiment of the present invention, the freeze-drying conditions include: the solvent of the first polymer dispersion includes tert-butanol, ethanol and water, and the mass ratio of tert-butanol, ethanol and water is 1:1-2:7-8.

[0078] According to a preferred embodiment of the present invention, the freeze-drying conditions include: in the first polymer dispersion, the mass ratio of solvent to the first polymer is 1:0.01-0.02. The polymer prepared using the aforementioned technical solution exhibits excellent temperature and salt resistance, without excessive spreading at high temperatures or excessive shrinkage under high salinity, and demonstrates good dispersion stability in high-temperature water / salt water. When applied to drilling fluids and / or completion fluids, this polymer effectively reduces filtration loss, optimizes lubrication, and enhances suspension.

[0079] This invention provides polymers prepared by the method described herein.

[0080] In this invention, the polymers prepared by the aforementioned methods can all achieve the purpose of this invention. There are no special requirements for the physicochemical properties of the polymers. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the polymer has an approximately spherical morphology, consisting of multiple interwoven and entangled molecular chains, with a rough and dense surface and no obvious filamentous or porous structure.

[0081] According to a preferred embodiment of the present invention, the number-average molecular weight of the polymer is 30,000 to 200,000.

[0082] According to a preferred embodiment of the present invention, the polymer has an average particle size of 200-300 μm in the dry state.

[0083] According to a preferred embodiment of the present invention, the polymer has a hydration kinetic particle size distribution range of 100-400 μm in water at 10-40°C, and an average particle size of 200-300 μm.

[0084] According to a preferred embodiment of the present invention, the polymer has a hydration kinetic particle size distribution range of 100-500 μm in water at 150-250°C, and an average particle size of 200-300 μm.

[0085] According to a preferred embodiment of the present invention, the polymer exhibits a hydration kinetic particle size distribution range of 100-400 μm in brine at 150-250°C and 200,000-400,000 mg / L, with an average particle size of 200-300 μm. The polymer possessing the aforementioned physicochemical properties exhibits excellent temperature and salt resistance, without excessive spreading at high temperatures or excessive shrinkage under high salinity. It also demonstrates good dispersion stability in high-temperature water / salt water. Applying this polymer to drilling fluids and / or completion fluids provides excellent effects in reducing filtration loss, optimizing lubrication, and enhancing suspension.

[0086] This invention provides the application of the polymer described herein in drilling fluids and / or completion fluids.

[0087] The polymer described in this invention is particularly suitable for use in water-based drilling fluids.

[0088] The present invention will be described in detail below through embodiments.

[0089] In the following examples and comparative examples: Scanning electron microscope (SEM) images of the polymer and skeleton were obtained using a FEI Quanta 200F SEM. Before measurement, the sample surface was coated with gold.

[0090] The average particle size of the polymer in its dry state was measured using a scanning electron microscope.

[0091] The number-average molecular weights of the polymer, backbone, and phenolic resin were determined using an integrated gel permeation chromatograph, specifically with tetrahydrofuran as the eluent and a flow rate of 1.0 mL / min.

[0092] The scanning electron microscopy-Raman spectroscopy (SEM-Raman spectroscopy) characterization method for polymers involves examining their microstructure in the SEM field of view, selecting the region to be analyzed, performing Raman scanning on the corresponding region, and outputting the Raman spectrum of the corresponding region.

[0093] The hydration kinetics particle size distribution of the polymer was obtained using a dynamic light scattering (DLS) instrument. Specifically, an ALV / DLS / SLS-5022F DLS instrument from Hosic (Germany) was used, with the sample cell type selected as "Glass" and water selected as the solvent. A 0.05% (w / w) sample solution was injected into the sample cell, and the correlation function of the scattering data was analyzed using the CONTIN method to obtain the particle size distribution information of the sample.

[0094] The test method for polymer dispersion stability is as follows: The TSI stability index of the sample was determined using a Formulaction TurbiScan Lab Expert stability analyzer (France) to characterize the dispersion stability of the sample. 5g of polymer was mixed with 500mL of deionized water, and 5g of polymer gel was mixed with 500mL of a solution with a mineralization of 100,000 mg / L (including Ca²⁺). 2+ Mg 2+ The concentration of divalent ions was 16,000 mg / L, and the concentration was 200,000 mg / L (including Ca). 2+ Mg 2+ The concentration of divalent ions was 33,000 mg / L, and the concentration was 300,000 mg / L (including Ca). 2+ Mg 2+ The content of divalent ions was 50,000 mg / L. The polymer gel-deionized water and polymer gel-salt were mixed and injected into the high temperature and high pressure sample cell, respectively. The temperature was set at 200℃ and the test time lasted for 12,000 minutes.

[0095] The rheological properties, filtration loss reduction properties, and lubrication properties of the polymer were tested and evaluated according to the methods in the national standard GB / T 29170-2012, with the experimental temperature set at 200℃ and hot rolling for 16 hours. The mass of polymer added was calculated as a percentage of the water volume. The preparation method for the water-based drilling fluid was as follows: based on a water volume of 100 mL, 2.0 g of bentonite, 10.0 g of potassium chloride, 20.0 g of sodium chloride, 30.0 g of type I organic salt, and 76.7 g of barite were added to form the water-based drilling fluid.

[0096] The synthesis conditions for the water-soluble phenolic resin were as follows: a molar ratio of phenol to formaldehyde of 1:2, a reaction temperature of 75℃, and a reaction time of 4 hours. The specific steps were as follows: Phenol was pre-melted in water at 50℃ in a sealed container. Deionized water was prepared, and a 20% sodium hydroxide solution was prepared. First, the required mass of phenol was weighed into a 250mL four-necked flask according to the desired ratio. The flask was stirred and deoxygenated at 50℃ for 20 minutes. Then, the sodium hydroxide solution was added dropwise to the four-necked flask, and the mixture was stirred for another 20 minutes. The temperature was then set to 75℃. After the temperature stabilized, the required mass of formaldehyde solution was weighed at a molar ratio of phenol to formaldehyde of 1:2 and added dropwise to the four-necked flask at a uniform rate using a constant-pressure dropping funnel. Nitrogen gas was maintained throughout the reaction, and the reaction was allowed to proceed for 4 hours to obtain the phenolic resin. The number-average molecular weight of the obtained phenolic resin was 816.

[0097] Preparation Example 1 8.0 g acrylamide, 2.0 g vinylpyrrolidone, 5 g 2-acrylamido-2-methylpropanesulfonic acid, 5 g water-soluble phenolic resin, 0.1 g N,N-methylenebisacrylamide, and 0.15 g polyethyleneimine were sequentially dispersed in 200 mL of deionized water. The mixture was stirred in an ice-water bath at 5-10°C at a stirring speed of 100 rpm. After uniform dispersion, the solution was added to a three-necked glass flask equipped with a stirrer, a nitrogen purging tube, and a thermometer. Nitrogen gas was purged for 30 min, the pH was maintained at 10, and the temperature was controlled at 65°C. Then, 0.15 g potassium persulfate was added, and the stirring speed was set to 500 rpm. The reaction was allowed to proceed for 3 h. After cooling to room temperature, the product was filtered and washed with anhydrous ethanol, dried, and pulverized to obtain the polymer.

[0098] The 15g polymer obtained above was dispersed in a 1000g mixed solution of tert-butanol / ethanol / deionized water, wherein the mass of tert-butanol in the mixed solution was 100g, the mass of ethanol was 200g, and the mass of deionized water was 700g. After being evenly dispersed, the polymer was frozen in liquid nitrogen for 60min and then freeze-dried at -80℃ and 1Pa for 48h. After being restored to room temperature and normal pressure, the polymer skeleton was obtained.

[0099] The scanning electron microscope image of the obtained skeleton is shown below. Figure 2 As shown in the figure, it has an intertwined and interwoven filamentous structure with pores between the filaments. The pores are widely distributed, and the filaments and pores form a network. The number-average molecular weight of the obtained skeleton is 12,300-24,800, according to the test results.

[0100] Preparation Example 2 5.0 g acrylamide, 1.0 g N-hydroxymethylacrylamide, 1.0 g N-ethylacrylamide, 1.0 g N-isopropylacrylamide, 1.0 g vinylpyrrolidone, 1.0 g vinylcaprolactam, 1 g 2-acrylamido-2-methylpropanesulfonic acid, 1 g sodium styrene sulfonate, 2.4 g water-soluble phenolic resin, 0.05 g N,N-methylenebisacrylamide, and 0.002 g polyethyleneimine were sequentially dispersed in 73 mL of deionized water. The mixture was stirred in an ice-water bath at a temperature controlled at 5-10℃ and a stirring speed of 100 rpm. After the mixture is evenly dispersed, it is added to a three-necked glass bottle equipped with a stirrer, a nitrogen purging tube and a thermometer. Nitrogen gas is purged for 30 min, the pH is controlled at 9 and the temperature is controlled at 65℃. Then, 0.025 g of potassium persulfate and 0.015 g of ammonium persulfate are added. The stirring speed is set to 400 rpm and the reaction is carried out for 2 h. After cooling to room temperature, the product is filtered and washed with anhydrous ethanol. After drying and pulverizing, the polymer is obtained.

[0101] The 10g polymer obtained above was dispersed in a 1000g mixed solution of tert-butanol / ethanol / deionized water, wherein the mass of tert-butanol in the mixed solution was 100g, the mass of ethanol was 100g, and the mass of deionized water was 800g. After being evenly dispersed, the polymer was placed in liquid nitrogen and frozen for 60min, and then freeze-dried at -80℃ and 1Pa for 48h. After being restored to room temperature and normal pressure, the polymer skeleton was obtained.

[0102] The scanning electron microscope image of the obtained skeleton is shown below. Figure 3 As shown in the figure, it has an intertwined and interwoven filamentous structure with pores between the filaments. The pores are widely distributed, and the filaments and pores form a network. The number-average molecular weight of the obtained skeleton is measured to be 0.81-1.35 million.

[0103] Preparation Example 3 8.0 g acrylamide, 2.0 g vinylpyrrolidone, 5 g 2-acrylamido-2-methylpropanesulfonic acid, 5 g sodium styrene sulfonate, 10 g water-soluble phenolic resin, 0.2 g N,N-methylenebisacrylamide, and 0.1 g polyethyleneimine were sequentially dispersed in 300 mL of deionized water. The mixture was stirred in an ice-water bath at 5-10°C at a stirring speed of 100 rpm. After uniform dispersion, the solution was added to a three-necked glass flask equipped with a stirrer, a nitrogen purging tube, and a thermometer. Nitrogen gas was purged for 30 min, the pH was maintained at 11, and the temperature was maintained at 65°C. Then, 0.3 g potassium persulfate was added, and the stirring speed was set to 600 rpm. The reaction was allowed to proceed for 3 h. After cooling to room temperature, the product was filtered and washed with anhydrous ethanol, dried, and pulverized to obtain the polymer.

[0104] The 20g polymer obtained above was dispersed in a 1000g mixed solution of tert-butanol / ethanol / deionized water, wherein the mass of tert-butanol in the mixed solution was 100g, the mass of ethanol was 100g, and the mass of deionized water was 800g. After being evenly dispersed, the polymer was frozen in liquid nitrogen for 60min and then freeze-dried at -80℃ and 1Pa for 48h. After being restored to room temperature and normal pressure, the polymer skeleton was obtained.

[0105] The scanning electron microscope image of the obtained skeleton is shown below. Figure 4 As shown in the figure, it has an intertwined and interwoven filamentous structure with pores between the filaments. The pores are widely distributed, and the filaments and pores form a network. The number-average molecular weight of the obtained skeleton is measured to be 21,200-38,800.

[0106] Preparation Example 4 8.0 g acrylamide, 2.0 g vinylpyrrolidone, 5 g 2-acrylamido-2-methylpropanesulfonic acid, 5 g water-soluble phenolic resin, 0.1 g N,N-methylenebisacrylamide, and 0.15 g polyethyleneimine were sequentially dispersed in 200 mL of deionized water. The mixture was stirred in an ice-water bath at 5-10°C at a stirring speed of 100 rpm. After uniform dispersion, the solution was added to a three-necked glass flask equipped with a stirrer, a nitrogen purging tube, and a thermometer. Nitrogen gas was purged for 30 min, the pH was maintained at 10, and the temperature was controlled at 65°C. Then, 0.15 g potassium persulfate was added, and the stirring speed was set to 500 rpm. The reaction was allowed to proceed for 3 h. After cooling to room temperature, the product was filtered and washed with anhydrous ethanol, dried, and pulverized to obtain the polymer.

[0107] The 15g polymer obtained above was dispersed in a 1000g mixed solution of tert-butanol / ethanol / deionized water, wherein the mass of tert-butanol in the mixed solution was 100g, the mass of ethanol was 200g, and the mass of deionized water was 700g. After being evenly dispersed, the polymer was frozen in a -80℃ refrigerator for 60min and then freeze-dried: the temperature was set at -80℃ and the pressure was set at 1Pa. After drying for 48h, the polymer skeleton was obtained by restoring it to room temperature and normal pressure.

[0108] The scanning electron microscope image of the obtained skeleton is shown below. Figure 5 As shown in the figure, it has a dense, blocky structure, lacking intertwined filaments and porous structures, and does not form a network. Testing revealed that the number-average molecular weight of the obtained framework is 12,000-25,100.

[0109] Preparation Example 5 8.0 g acrylamide, 2.0 g vinylpyrrolidone, 5 g 2-acrylamido-2-methylpropanesulfonic acid, 1.5 g water-soluble phenolic resin, 0.1 g N,N-methylenebisacrylamide, and 0.15 g polyethyleneimine were sequentially dispersed in 200 mL of deionized water. The mixture was stirred in an ice-water bath at 5-10°C at a stirring speed of 100 rpm. After uniform dispersion, the solution was added to a three-necked glass flask equipped with a stirrer, a nitrogen purging tube, and a thermometer. Nitrogen gas was purged for 30 min, the pH was maintained at 10, and the temperature was controlled at 65°C. Then, 0.15 g potassium persulfate was added, and the stirring speed was set to 500 rpm. The reaction was allowed to proceed for 3 h. After cooling to room temperature, the product was filtered and washed with anhydrous ethanol, dried, and pulverized to obtain the polymer.

[0110] The 15g polymer obtained above was dispersed in a 1000g mixed solution of tert-butanol / ethanol / deionized water, wherein the mass of tert-butanol in the mixed solution was 100g, the mass of ethanol was 200g, and the mass of deionized water was 700g. After being evenly dispersed, the polymer was frozen in liquid nitrogen for 60min and then freeze-dried at -80℃ and 1Pa for 48h. After being restored to room temperature and normal pressure, the polymer skeleton was obtained.

[0111] The scanning electron microscope images of the obtained skeleton are similar to those in Preparation Example 1, showing an intertwined and woven filamentous structure with widely distributed pores between the filaments, forming a network. The number-average molecular weight of the obtained skeleton was measured to be 0.96–2.13 million.

[0112] Example 1 The polymer backbone of Preparation Example 1 was used as the raw material; Disperse 10.0 g of polymer backbone and 0.8 g of sodium dodecyl sulfate in 80 mL of deionized water, maintaining the temperature at 20-25℃ and stirring at 50 rpm. After uniform dispersion, add the mixture to a three-necked glass flask equipped with a stirrer, nitrogen purging tube, and thermometer, and increase the stirring speed to 100 rpm. 2.0 g butyl methacrylate, 2.0 g hexyl methacrylate, 3.0 g lauryl methacrylate, 1.0 g 3,4,5-tris(n-hexanemethoxy)styrene, 1.0 g 3,4,5-tris(n-octanemethoxy)styrene, 1.0 g 3,4,5-tris(dodecanemethoxy)styrene, 1.0 g ethylene glycol dimethacrylate, and 1.0 g divinylbenzene were sequentially added to a three-necked glass flask. Nitrogen gas was purged for 30 min, the pH was controlled at 11, and the temperature was controlled at 50℃. Then, 0.20 g azobisisobutyronitrile and 0.10 g dimethyl azobisisobutyrate were added. The stirring speed was set to 700 rpm, and the reaction was carried out for 6 h. After cooling to room temperature, the product was filtered and washed with anhydrous ethanol, dried, and pulverized.

[0113] The scanning electron microscope image of the obtained polymer is shown below. Figure 6 As shown in the figure, its morphology is approximately spherical, consisting of multiple interwoven and entangled molecular chains. The surface is rough and dense, with no obvious filamentous or porous structure. Tests showed that the average particle size of the obtained polymer in its dry state was approximately 256.3 μm, and the number-average molecular weight was 72,800–111,200.

[0114] The structure and composition of the prepared polymer were characterized using scanning electron microscopy-Raman spectroscopy, such as... Figure 7 As shown, regions 1 and 2, which are intertwined, were selected in the scanning electron microscope field of view. Figure 8 , Figure 9 Raman spectral scans were performed on regions 1 and 2 respectively. The figure shows that the Raman spectrum of region 1 is in the range of 3163-3583 cm⁻¹. -1 The presence of strong peaks within this range indicates the presence of numerous polar groups in the polymer of region 1, suggesting that the polymer in region 1 primarily has a network polymer backbone; the Raman spectrum of region 2 is between 3163 and 3583 cm⁻¹. -1 The absence of obvious absorption peaks within the range indicates that the polymer in region 2 is essentially devoid of polar groups, instead consisting mainly of long hydrocarbon chains and nonpolar groups. This suggests that the polymer in region 2 is primarily another type of polymer. This further confirms that the obtained polymer is in the form of multiple interwoven and entangled molecular chains.

[0115] Hydration kinetics and particle size distribution of the obtained polymer in water / salt solutions at room temperature / high temperature: (1) The hydration kinetics particle size distribution of the obtained polymer in deionized water at room temperature is shown in the figure below. Figure 10 As shown in the figure, the hydration kinetic particle size distribution range is 170.2–310.9 μm in room temperature and deionized water, with an average particle size of 227.3 μm, indicating that it can be effectively dispersed in room temperature and deionized water. (2) The hydration kinetics particle size distribution of the obtained polymer in deionized water at 200℃ is shown in the figure below. Figure 11 As shown in the figure, at 200℃ and in deionized water, its hydration kinetic particle size distribution ranges from 123.1 to 398.6 μm, with an average particle size of 232.9 μm, indicating that it can be effectively dispersed in deionized water at 200℃. (3) The obtained polymer is tested at 200℃ with a mineralization of 300,000 mg / L (including Ca). 2+ Mg 2+ The hydration kinetics particle size distribution diagram of the brine (containing 50,000 mg / L of divalent ions) is shown in the figure below. Figure 12 As shown in the figure, at 200℃ and a mineralization of 300,000 mg / L (including Ca), 2+ Mg 2+ In a solution containing 50,000 mg / L of divalent ions, the hydration kinetic particle size distribution ranged from 160.8 to 281.3 μm, with an average particle size of 213.6 μm, indicating that it can be absorbed at 200℃ and a mineralization of 300,000 mg / L (including Ca). 2+ Mg 2+ The content of divalent ions (e.g., 50000 mg / L) is effectively dispersed in saline solution; Therefore, the dispersion state of the obtained polymer in high temperature and high salt is similar to that in room temperature and deionized water. Its tendency to spread outward when heated and shrink inward when exposed to salt is not obvious, and it has significant advantages in temperature and salt resistance.

[0116] By comparing the TSI stability index of the polymer obtained in this invention with that of commercially available drilling fluid polymer treatment agents SO-1 (Shandong Deshunyuan Company) and Redu200 (Beijing Peikang Company) in high-temperature water / salt water, the dispersion stability of the obtained polymer in high-temperature and high-salt environments was further evaluated. The results are as follows: Figure 13 As shown in the figure, firstly, at 200°C in deionized water, the TSI value of the polymer of the present invention remained stable and the curve remained horizontal for a test time exceeding 10,000 min. The TSI value was 2.12 at 10,800 min, indicating that the polymer maintained good dispersion stability in 200°C and deionized water. Secondly, at 200°C in 100,000 mg / L (containing Ca...)... 2+ Mg 2+The concentration of divalent ions was 16,000 mg / L, and the concentration was 200,000 mg / L (including Ca). 2+ Mg 2+ The concentration of divalent ions was 33,000 mg / L, and the concentration was 300,000 mg / L (including Ca). 2+ Mg 2+ In a saline solution containing 50,000 mg / L of divalent ions, the TSI stability index of the polymer obtained in this invention slowly increased over time. This indicates that under high temperature and high salinity, the stability of the polymer obtained in this invention is slightly lower than that in deionized water at 200°C. Simultaneously, the TSI value of the polymer obtained in this invention also increases with increasing mineralization. Specifically, at 10800 min, the polymer obtained in this invention showed a higher TSI value at 200°C and 100,000 mg / L (containing Ca2+, Mg ... 2+ Mg 2+ The TSI stability index in the brine (containing 16000 mg / L of divalent ions) is 3.64 at 200℃ and 200000 mg / L (including Ca). 2+ Mg 2+ The TSI stability index in the brine (containing 33,000 mg / L of divalent ions) was 8.51 at 200℃ and 300,000 mg / L (including Ca2+). 2+ Mg 2+ The TSI stability index in the brine (containing 50,000 mg / L of divalent ions) was 13.82; this indicates that the mineralization degree had an adverse effect on the dispersion stability of the polymer obtained in this invention, especially Ca. 2+ / Mg 2+ The presence of divalent ions can cause excessive shrinkage of the polymer, leading to loss of dispersibility and sedimentation; third, comparative analysis revealed that the polymer obtained in this invention exhibits better performance at concentrations of 300,000 mg / L (including Ca). 2+ Mg 2+ The dispersion stability of the polymer obtained in this invention in brine (containing 50,000 mg / L of divalent ions) is significantly better than that of commercially available drilling fluid polymer treatment agents SO-1 (Shandong Deshunyuan Company) and Redu200 (Beijing Peikang Company). This indicates that the polymer obtained in this invention has good dispersion stability in high-temperature water / salt water and has outstanding performance advantages in temperature and salt resistance.

[0117] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the obtained polymer are shown in Table 1.

[0118] Example 2 The polymer backbone of Preparation Example 2 was used as the raw material; 10.0 g of the network polymer backbone and 0.15 g of sodium dodecyl sulfate were dispersed in 32 mL of deionized water at a temperature controlled at 20-25℃ and a stirring speed of 50 rpm. After uniform dispersion, the mixture was added to a three-necked glass flask equipped with a stirrer, a nitrogen purging tube, and a thermometer, and the stirring speed was increased to 100 rpm. 1.0 g butyl methacrylate, 1.0 g hexyl methacrylate, 1.5 g lauryl methacrylate, 0.5 g 3,4,5-tris(n-hexanemethoxy)styrene, 0.5 g 3,4,5-tris(n-octanemethoxy)styrene, 0.5 g 3,4,5-tris(dodecanemethoxy)styrene, 0.5 g ethylene glycol dimethacrylate, and 0.26 g divinylbenzene were sequentially added to a three-necked glass flask. Nitrogen gas was introduced for 30 min, the pH was controlled at 10, and the temperature was controlled at 40℃. Then 0.04 g azobisisobutyronitrile was added, the stirring speed was set to 600 rpm, and the reaction was carried out for 5 h. After cooling to room temperature, the product was filtered and washed with anhydrous ethanol, dried, and pulverized.

[0119] The scanning electron microscope image of the obtained polymer is similar to that in Example 1, showing an approximately spherical morphology with multiple interwoven and entangled molecular chains, and a rough and dense surface. Testing revealed that the average particle size of the obtained polymer in its dry state was approximately 281.5 μm, and the number-average molecular weight was 52,100–93,100.

[0120] The scanning electron microscopy-Raman spectroscopy characterization results of the obtained polymer were similar to those in Example 1, which once again proved that the obtained polymer was a morphology of multiple molecular chains intertwined and entangled.

[0121] The hydration kinetics particle size distribution of the obtained polymer in water / salt solutions at room temperature / high temperature is similar to that in Example 1, wherein: (1) In room temperature and deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 159.6 to 331.2 μm, with an average particle size of 242.3 μm, indicating that it can be effectively dispersed in room temperature and deionized water; (2) At 200℃ in deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 110.8 to 421.5 μm, with an average particle size of 256.4 μm, indicating that it can be effectively dispersed in deionized water at 200℃. (3) At 200℃, the mineralization is 300,000 mg / L (including Ca). 2+ Mg 2+In a brine solution containing 50,000 mg / L of divalent ions, the hydration kinetic particle size distribution of the obtained polymer ranged from 149.7 to 361.2 μm, with an average particle size of 249.6 μm. This indicates that it can be synthesized at 200℃ and a salinity of 300,000 mg / L (including Ca2+). 2+ Mg 2+ The content of divalent ions (e.g., 50000 mg / L) is effectively dispersed in saline solution; Therefore, the dispersion state of the obtained polymer in high temperature and high salt is similar to that in room temperature and deionized water. Its tendency to spread outward when heated and shrink inward when exposed to salt is not obvious, and it has significant advantages in temperature and salt resistance.

[0122] The TSI stability index of the obtained polymer in high-temperature water / salt water shows a similar trend to that in Example 1, wherein: The obtained polymer had a TSI value of 2.06 in deionized water at 200°C and 100,000 mg / L (containing Ca) at 200°C and 10800 min. 2+ Mg 2+ The TSI stability index in the brine (containing 16000 mg / L of divalent ions) is 3.71. At 200℃ and 200000 mg / L (including Ca2+), the TSI stability index is [missing value]. 2+ Mg 2+ The TSI stability index in the brine (containing 33,000 mg / L of divalent ions) was 8.43 at 200℃ and 300,000 mg / L (including Ca2+). 2+ Mg 2+ The TSI stability index in brine (containing 50,000 mg / L of divalent ions) was 14.21; this indicates that the polymer obtained in this invention has good dispersion stability in high-temperature water / salt water and has outstanding performance advantages in temperature and salt resistance.

[0123] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the obtained polymer are shown in Table 2.

[0124] Example 3 The polymer backbone of Preparation Example 3 was used as a raw material; 10.0 g of the network polymer backbone and 1.5 g of sodium dodecyl sulfate were dispersed in 180 mL of deionized water at a temperature controlled at 20-25℃ and a stirring speed of 50 rpm. After uniform dispersion, the mixture was added to a three-necked glass flask equipped with a stirrer, a nitrogen purging tube, and a thermometer, and the stirring speed was increased to 100 rpm. 4.0 g butyl methacrylate, 10.0 g lauryl methacrylate, 3.0 g 3,4,5-tris(n-hexanemethoxy)styrene, 3.0 g 3,4,5-tris(n-octanemethoxy)styrene, 3.0 g ethylene glycol dimethacrylate, and 3.0 g divinylbenzene were sequentially added to a three-necked glass flask. Nitrogen gas was purged for 30 min, the pH was controlled at 12, and the temperature was controlled at 60℃. Then, 0.9 g dimethyl azobisisobutyrate was added, the stirring speed was set to 800 rpm, and the reaction was carried out for 8 h. After cooling to room temperature, the product was filtered and washed with anhydrous ethanol, dried, and pulverized.

[0125] The scanning electron microscope image of the obtained polymer is similar to that in Example 1, showing an approximately spherical morphology with multiple interwoven and entangled molecular chains, and a rough and dense surface. Testing revealed that the average particle size of the obtained polymer in its dry state was approximately 267.2 μm, and the number-average molecular weight was 110,300–152,100.

[0126] The scanning electron microscopy-Raman spectroscopy characterization results of the obtained polymer were similar to those in Example 1, which once again proved that the obtained polymer was a morphology of multiple molecular chains intertwined and entangled.

[0127] The hydration kinetics particle size distribution of the obtained polymer in water / salt solutions at room temperature / high temperature is similar to that in Example 1, wherein: (1) In room temperature and deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 144.7 to 317.6 μm, with an average particle size of 227.6 μm, indicating that it can be effectively dispersed in room temperature and deionized water; (2) At 200℃ in deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 126.8 to 431.5 μm, with an average particle size of 266.3 μm, indicating that it can be effectively dispersed in deionized water at 200℃. (3) At 200℃, the mineralization is 300,000 mg / L (including Ca). 2+ Mg 2+ In a brine solution containing 50,000 mg / L of divalent ions, the hydration kinetics of the resulting polymer showed a particle size distribution ranging from 155.6 to 377.9 μm, with an average particle size of 247.8 μm. This indicates that it can be synthesized at 200℃ and a salinity of 300,000 mg / L (including Ca²⁺ and Mg²⁺). 2+ Mg 2+The content of divalent ions (e.g., 50000 mg / L) is effectively dispersed in saline solution; Therefore, the dispersion state of the obtained polymer in high temperature and high salt is similar to that in room temperature and deionized water. Its tendency to spread outward when heated and shrink inward when exposed to salt is not obvious, and it has significant advantages in temperature and salt resistance.

[0128] The TSI stability index of the obtained polymer in high-temperature water / salt water shows a similar trend to that in Example 1, wherein: The obtained polymer had a TSI value of 2.11 at 200°C and 100,000 mg / L (containing Ca) at 10800 min and 200°C. 2+ Mg 2+ The TSI stability index in the brine (containing 16000 mg / L of divalent ions) is 3.64 at 200℃ and 200000 mg / L (including Ca). 2+ Mg 2+ The TSI stability index in the brine (containing 33,000 mg / L of divalent ions) is 8.57, and it remains stable at 200℃ and 300,000 mg / L (including Ca2+). 2+ Mg 2+ The TSI stability index in brine (containing 50,000 mg / L of divalent ions) is 13.83; this indicates that the polymer obtained in this invention has good dispersion stability in high-temperature water / salt water and has outstanding performance advantages in temperature and salt resistance.

[0129] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the obtained polymer are shown in Table 3.

[0130] Example 4 The method is the same as in Example 1, except that the amount of sodium dodecyl sulfate used is 1.2g, while the other raw materials and methods are the same.

[0131] The scanning electron microscope image of the obtained polymer is similar to that in Example 1, showing an approximately spherical morphology with multiple interwoven and entangled molecular chains, and a rough and dense surface. Testing revealed that the average particle size of the obtained polymer in its dry state was approximately 238.2 μm, and the number-average molecular weight was 68,900–122,100.

[0132] The scanning electron microscopy-Raman spectroscopy characterization results of the obtained polymer were similar to those in Example 1, which once again proved that the obtained polymer was a morphology of multiple molecular chains intertwined and entangled.

[0133] The hydration kinetics particle size distribution of the obtained polymer in water / salt solutions at room temperature / high temperature is similar to that in Example 1, wherein: (1) In room temperature and deionized water, the hydration kinetic particle size distribution of the obtained polymer ranges from 101.2 to 252.3 μm, with an average particle size of 177.6 μm, indicating that it can be effectively dispersed in room temperature and deionized water; compared with Example 1, its dispersion degree is increased.

[0134] (2) At 200°C in deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 53.2 to 265.6 μm, with an average particle size of 159.8 μm, indicating that it could be effectively dispersed in deionized water at 200°C; compared with Example 1, its dispersion degree increased.

[0135] (3) At 200℃, the mineralization is 300,000 mg / L (including Ca). 2+ Mg 2+ In a brine solution containing 50,000 mg / L of divalent ions, the hydration kinetics particle size distribution of the obtained polymer ranged from 79.3 to 175.1 μm, with an average particle size of 125.3 μm. This indicates that it can be synthesized at 200℃ and a salinity of 300,000 mg / L (including Ca2+). 2+ Mg 2+ The divalent ions (containing 50,000 mg / L of divalent ions) were effectively dispersed in saline solution; compared to Example 1, a slight shrinkage phenomenon occurred.

[0136] The TSI stability index of the obtained polymer in high-temperature water / salt water shows a similar trend to that in Example 1, wherein: The obtained polymer had a TSI value of 3.12 at 10800 min in deionized water at 200 °C; and a TSI value of 100000 mg / L (containing Ca) at 10800 min in deionized water at 200 °C. 2+ Mg 2+ The TSI stability index in the brine (containing 16000 mg / L of divalent ions) was 4.36 at 200℃ and 200000 mg / L (including Ca). 2+ Mg 2+ The TSI stability index in the brine (containing 33,000 mg / L of divalent ions) is 9.25. This is consistent with the TSI stability index at 200℃ and a concentration of 300,000 mg / L (including Ca2+). 2+ Mg 2+ The TSI stability index in brine (containing 50,000 mg / L of divalent ions) is 15.96; this indicates that the polymer obtained in this invention has good dispersion stability in high-temperature water / salt water and has outstanding performance advantages in temperature and salt resistance.

[0137] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the prepared polymer are shown in Table 4.

[0138] Example 5 The method is the same as in Example 1, except that the amount of sodium dodecyl sulfate used is 0.1g, while the other raw materials and methods are the same.

[0139] The scanning electron microscope image of the obtained polymer is similar to that in Example 1. Its morphology is approximately spherical, consisting of multiple interwoven and entangled molecular chains, with a rough and dense surface. Testing showed that the average particle size of the obtained polymer in its dry state was approximately 241.5 μm, and the number-average molecular weight was 41,100-64,900.

[0140] The scanning electron microscopy-Raman spectroscopy characterization results of the obtained polymer were similar to those in Example 1, which once again proved that the obtained polymer was a morphology of multiple molecular chains intertwined and entangled.

[0141] The hydration kinetics particle size distribution of the obtained polymer in water / salt solutions at room temperature / high temperature is similar to that in Example 1, wherein: (1) In room temperature and deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 70.2 to 241.1 μm, with an average particle size of 156.6 μm, indicating that it could be effectively dispersed in room temperature and deionized water; compared with Example 1, its dispersion degree increased.

[0142] (2) At 200°C in deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 37.3 to 290.2 μm, with an average particle size of 163.7 μm, indicating that it could be effectively dispersed in deionized water at 200°C; compared with Example 1, its dispersion degree increased.

[0143] (3) At 200℃, the mineralization is 300,000 mg / L (including Ca). 2+ Mg 2+ In a brine solution containing 50,000 mg / L of divalent ions, the hydration kinetics particle size distribution of the obtained polymer ranged from 66.2 to 175.1 μm, with an average particle size of 121.6 μm. This indicates that it can be synthesized at 200℃ and a salinity of 300,000 mg / L (including Ca²⁺ and Mg²⁺). 2+ Mg 2+ The divalent ions (containing 50,000 mg / L of divalent ions) were effectively dispersed in saline solution; compared to Example 1, a slight shrinkage phenomenon occurred.

[0144] The TSI stability index of the obtained polymer in high-temperature water / salt water shows a similar trend to that in Example 1, wherein: The obtained polymer had a TSI value of 3.36 at 200°C and 100,000 mg / L (containing Ca) at 10800 min and 200°C. 2+ Mg 2+ The TSI stability index in the brine (containing 16000 mg / L of divalent ions) is 4.58. At 200℃ and 200000 mg / L (including Ca2+), the TSI stability index is [missing value]. 2+ Mg 2+ The TSI stability index in the brine (containing 33,000 mg / L of divalent ions) was 9.63 at 200℃ and 300,000 mg / L (including Ca2+). 2+ Mg 2+ The TSI stability index in brine (containing 50,000 mg / L of divalent ions) was 15.71; this indicates that the polymer obtained in this invention has good dispersion stability in high-temperature water / salt water and has outstanding performance advantages in temperature and salt resistance.

[0145] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the prepared polymer are shown in Table 5.

[0146] Example 6 The method is the same as in Example 1, except that the mass of ethylene glycol dimethacrylate is 0.4 g and the mass of divinylbenzene is 0.4 g, while the other raw materials and methods are the same.

[0147] The scanning electron microscope image of the obtained polymer is similar to that in Example 1, showing an approximately spherical morphology with multiple interwoven and entangled molecular chains, and a rough and dense surface. Testing revealed that the average particle size of the obtained polymer in its dry state was approximately 252.3 μm, and the number-average molecular weight was 49,100-73,100.

[0148] The scanning electron microscopy-Raman spectroscopy characterization results of the obtained polymer were similar to those in Example 1, which once again proved that the obtained polymer was a morphology of multiple molecular chains intertwined and entangled.

[0149] The hydration kinetics particle size distribution of the obtained polymer in water / salt solutions at room temperature / high temperature is similar to that in Example 1, wherein: (1) In room temperature and deionized water, the hydration kinetic particle size distribution of the obtained polymer ranges from 126.1 to 281.6 μm, with an average particle size of 203.5 μm, indicating that it can be effectively dispersed in room temperature and deionized water; compared with Example 1, its dispersion degree is increased.

[0150] (2) At 200°C in deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 70.3 to 320.1 μm, with an average particle size of 196.4 μm, indicating that it could be effectively dispersed in deionized water at 200°C; compared with Example 1, its dispersion degree increased.

[0151] (3) At 200℃, the mineralization is 300,000 mg / L (including Ca). 2+ Mg 2+ In a brine solution containing 50,000 mg / L of divalent ions, the hydration kinetics particle size distribution of the obtained polymer ranged from 95.4 to 240.9 μm, with an average particle size of 167.8 μm. This indicates that it can be synthesized at 200℃ and a salinity of 300,000 mg / L (including Ca2+). 2+ Mg 2+ The divalent ions (containing 50,000 mg / L of divalent ions) were effectively dispersed in saline solution; compared to Example 1, a slight shrinkage phenomenon occurred.

[0152] The TSI stability index of the obtained polymer in high-temperature water / salt water shows a similar trend to that in Example 1, wherein: The obtained polymer had a TSI value of 3.42 at 200°C and 100,000 mg / L (containing Ca) at 10800 min and 200°C. 2+ Mg 2+ The TSI stability index in the brine (containing 16000 mg / L of divalent ions) was 4.36 at 200℃ and 200000 mg / L (including Ca). 2+ Mg 2+ The TSI stability index in the brine (containing 33,000 mg / L of divalent ions) was 10.08 at 200℃ and 300,000 mg / L (including Ca2+). 2+ Mg 2+ The TSI stability index in brine (containing 50,000 mg / L of divalent ions) is 15.56; this indicates that the polymer obtained in this invention has good dispersion stability in high-temperature water / salt water and has outstanding performance advantages in temperature and salt resistance.

[0153] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the prepared polymer are shown in Table 6.

[0154] Example 7 The method is the same as in Example 1, except that the amount of polymer backbone is 15 g, the amount of butyl methacrylate is 1 g, the mass of hexyl methacrylate is 1 g, the mass of lauryl methacrylate is 1.5 g, the mass of 3,4,5-tris(n-hexanemethoxy)styrene is 0.5 g, the mass of 3,4,5-tris(n-octanemethoxy)styrene is 0.5 g, and the mass of 3,4,5-tris(dodecanemethoxy)styrene is 0.5 g. All other raw materials and methods are the same.

[0155] The scanning electron microscope image of the obtained polymer is similar to that in Example 1, showing an approximately spherical morphology with multiple interwoven and entangled molecular chains, and a rough and dense surface. Testing revealed that the average particle size of the obtained polymer in its dry state was approximately 241.6 μm, and the number-average molecular weight was 44,100-65,900.

[0156] The scanning electron microscopy-Raman spectroscopy characterization results of the obtained polymer were similar to those in Example 1, which once again proved that the obtained polymer was a morphology of multiple molecular chains intertwined and entangled.

[0157] The hydration kinetics particle size distribution of the obtained polymer in water / salt solutions at room temperature / high temperature is similar to that in Example 1, wherein: (1) In room temperature and deionized water, the hydration kinetic particle size distribution of the obtained polymer ranges from 110.2 to 285.0 μm, with an average particle size of 197.5 μm, indicating that it can be effectively dispersed in room temperature and deionized water; compared with Example 1, its dispersion degree is increased.

[0158] (2) At 200°C and in deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 25.6 to 318.2 μm, with an average particle size of 171.8 μm, indicating that it could be effectively dispersed in deionized water at 200°C; compared with Example 1, its dispersion degree increased.

[0159] (3) At 300,000 mg / L (wherein, including Ca 2+ Mg 2+ In a saline solution containing 50,000 mg / L of divalent ions, the hydration kinetic particle size distribution of the obtained polymer ranged from 93.2 to 243.8 μm, with an average particle size of 168.8 μm. This indicates that it can be synthesized at 200℃ and a salinity of 300,000 mg / L (including Ca2+). 2+ Mg 2+ The divalent ions (containing 50,000 mg / L of divalent ions) were effectively dispersed in saline solution; compared to Example 1, a slight shrinkage phenomenon occurred.

[0160] The TSI stability index of the obtained polymer in high-temperature water / salt water shows a similar trend to that in Example 1, wherein: The obtained polymer had a TSI value of 3.56 at 200°C and 100,000 mg / L (containing Ca) at 10800 min and 200°C. 2+ Mg 2+ The TSI stability index in the brine (containing 16000 mg / L of divalent ions) was 4.63 at 200℃ and 200000 mg / L (including Ca). 2+ Mg 2+ The TSI stability index in the brine (containing 33,000 mg / L of divalent ions) was 10.84 at 200℃ and 300,000 mg / L (including Ca2+). 2+ Mg 2+ The TSI stability index in brine (containing 50,000 mg / L of divalent ions) was 16.11; this indicates that the polymer obtained in this invention has good dispersion stability in high-temperature water / salt water and has outstanding performance advantages in temperature and salt resistance.

[0161] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the prepared polymer are shown in Table 7.

[0162] Example 8 The polymer backbone of Preparation Example 5 was used as the raw material; 10.0 g of the network polymer backbone and 0.15 g of sodium dodecyl sulfate were dispersed in 32 mL of deionized water at a temperature controlled at 20-25℃ and a stirring speed of 50 rpm. After uniform dispersion, the mixture was added to a three-necked glass flask equipped with a stirrer, a nitrogen purging tube, and a thermometer, and the stirring speed was increased to 100 rpm. 1.0 g butyl methacrylate, 1.0 g hexyl methacrylate, 1.5 g lauryl methacrylate, 0.5 g 3,4,5-tris(n-hexanemethoxy)styrene, 0.5 g 3,4,5-tris(n-octanemethoxy)styrene, 0.5 g 3,4,5-tris(dodecanemethoxy)styrene, 0.5 g ethylene glycol dimethacrylate, and 0.26 g divinylbenzene were sequentially added to a three-necked glass flask. Nitrogen gas was introduced for 30 min, the pH was controlled at 10, and the temperature was controlled at 40℃. Then 0.04 g azobisisobutyronitrile was added, the stirring speed was set to 600 rpm, and the reaction was carried out for 5 h. After cooling to room temperature, the product was filtered and washed with anhydrous ethanol, dried, and pulverized.

[0163] The scanning electron microscope image of the obtained polymer is similar to that in Example 1, showing an approximately spherical morphology with multiple interwoven and entangled molecular chains, and a rough and dense surface. Testing revealed that the average particle size of the obtained polymer in its dry state was approximately 249.5 μm, and the number-average molecular weight was 66,500–102,100.

[0164] The scanning electron microscopy-Raman spectroscopy characterization results of the obtained polymer were similar to those in Example 1, which once again proved that the obtained polymer was a morphology of multiple molecular chains intertwined and entangled.

[0165] The hydration kinetics particle size distribution of the obtained polymer in water / salt solutions at room temperature / high temperature is similar to that in Example 1, wherein: (1) In room temperature and deionized water, the hydration kinetic particle size distribution of the obtained polymer ranged from 93.6 to 238.4 μm, with an average particle size of 166.3 μm, indicating that it could be effectively dispersed in room temperature and deionized water; compared with Example 1, its dispersion degree increased. (2) In deionized water at 200°C, the hydration kinetic particle size distribution of the obtained polymer ranged from 40.3 to 274.5 μm, with an average particle size of 157.8 μm, indicating that it could be effectively dispersed in deionized water at 200°C; compared with Example 1, its dispersion degree increased. (3) At 200℃, the mineralization is 300,000 mg / L (including Ca). 2+ Mg 2+ In a saline solution containing 50,000 mg / L of divalent ions, the hydration kinetic particle size distribution of the obtained polymer ranged from 70.2 to 158.3 μm, with an average particle size of 114.3 μm. This indicates that it can be synthesized at 200℃ and a salinity of 300,000 mg / L (including Ca2+). 2+ Mg 2+ The sample was effectively dispersed in saline solution containing 50,000 mg / L of divalent ions; compared to Example 1, it exhibited slight shrinkage. Therefore, the dispersion state of the obtained polymer in high temperature and high salt is similar to that in room temperature and deionized water. Its tendency to spread outward when heated and shrink inward when exposed to salt is not obvious, and it has significant advantages in temperature and salt resistance.

[0166] The TSI stability index of the obtained polymer in high-temperature water / salt water shows a similar trend to that in Example 1, wherein: The obtained polymer had a TSI value of 4.20 at 200°C and 100,000 mg / L (containing Ca) at 10800 min and 200°C. 2+ Mg 2+The TSI stability index in the brine (containing 16000 mg / L of divalent ions) is 5.33 at 200℃ and 200000 mg / L (including Ca). 2+ Mg 2+ The TSI stability index in the brine (containing 33,000 mg / L of divalent ions) was 12.67 at 200℃ and 300,000 mg / L (including Ca2+). 2+ Mg 2+ The TSI stability index in brine (containing 50,000 mg / L of divalent ions) is 18.06; this indicates that the polymer obtained in this invention has good dispersion stability in high-temperature water / salt water and has outstanding performance advantages in temperature and salt resistance.

[0167] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the obtained polymer are shown in Table 8.

[0168] Comparative Example 1 Same as Example 1, except that the polymer backbone of Preparation Example 4 was used as the raw material, and all other raw materials and conditions were the same. Scanning electron microscope image of the obtained polymer is shown below. Figure 14 As shown in the figure, it has a dense, blocky structure and does not exhibit the morphology of multiple interwoven or entangled molecular chains. Tests revealed that the number-average molecular weight of the obtained polymer ranged from 73,100 to 112,100.

[0169] The resulting polymer cannot be dispersed in deionized water and floats on the surface of the water, such as Figure 15 As shown, it is speculated that this is because the polymer skeleton of Preparation Example 4 does not have a network structure. During polymerization, the monomer cannot enter the interior of the polymer skeleton and can only undergo polymerization on the surface of the polymer skeleton to form a coating structure. Furthermore, due to the hydrophobicity of the monomer, the resulting polymer cannot be dispersed in water and floats on the surface of the water.

[0170] The results of performance tests on the rheological properties, filtration loss reduction properties, and lubrication properties of the obtained polymer are shown in Table 9.

[0171] Table 1

[0172] Table 2

[0173] Table 3

[0174] Table 4

[0175] Table 5

[0176] Table 6

[0177] Table 7

[0178] Table 8

[0179] Table 9

[0180] As can be seen from the table, the polymer of the present invention has the characteristics of low plastic viscosity (PV), high dynamic shear force (YP), and suitable initial and final shear under high temperature and high salt conditions, exhibiting outstanding rheological and thixotropic properties. It can provide good support for the dynamic carrying of rock cuttings and static suspension of solid phases in the system, while also having excellent effects in reducing filtration loss and optimizing lubrication.

[0181] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a polymer with an interpenetrating network structure, characterized in that, The method includes: The polymer backbone is polymerized with the first monomer; wherein... The polymer backbone is a network structure; the polymer backbone includes structural units derived from nonionic monomers, structural units derived from anionic monomers, and structural units derived from phenolic resins. The first monomer has the structure shown in formula (A): Formula (A), wherein R0 is a C4-C12 alkyl group.

2. The method according to claim 1, characterized in that, The method also includes being carried out in the presence of a second monomer having the structure shown in formula (B): Formula (B), where R is a C6-C12 alkyl group.

3. The method according to claim 1 or 2, characterized in that, The polymerization temperature is 40-60℃; and / or The polymerization time is 5-8 hours; and / or The polymerization occurs at a pH of 10-12; and / or Polymerization is carried out in an inert gas; and / or The polymerization is carried out dynamically at a speed of 600-800 rpm.

4. The method according to claim 2, characterized in that, The second monomer is selected from one or more of 3,4,5-tris(n-hexanemethoxy)styrene, 3,4,5-tris(n-octanemethoxy)styrene and 3,4,5-tris(dodecanemethoxy)styrene.

5. The method according to claim 1 or 2, characterized in that, The first monomer is selected from one or more of butyl methacrylate, hexyl methacrylate, and lauryl methacrylate; and / or The mass ratio of the polymer backbone to the total amount of added monomers is 1:0.5-2; and / or The polymerization is carried out in the presence of a solubilizer, initiator 1, and crosslinking agent 1; in, The solubilizer is selected from one or more of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate; and / or The crosslinking agent 1 is selected from one or more of ethylene glycol dimethacrylate and divinylbenzene; and / or The initiator 1 is selected from one or more of azobisisobutyronitrile and dimethyl azobisisobutyrate.

6. The method according to claim 5, characterized in that, The mass ratio of the total polymer backbone, total monomers, and solubilizer is 1:0.01-0.05; and / or The mass ratio of the total amount of polymer backbone and monomers to crosslinking agent 1 is 1:0.05-0.

2.

7. The method according to claim 1 or 2, characterized in that, The number-average molecular weight of the polymer backbone is 0.5-50,000; and / or The mass ratio of the nonionic monomer to the anionic monomer is 1:0.2-1; and / or The total mass ratio of the nonionic monomer and the anionic monomer to the phenolic resin is 1:0.2-0.5; and / or The nonionic monomer is selected from one or more of acrylamide, N-hydroxymethylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, vinylpyrrolidone, and vinylcaprolactam; and / or The anionic monomer is selected from one or more of 2-acrylamido-2-methylpropanesulfonic acid and sodium styrene sulfonate; and / or The phenolic resin is a water-soluble phenolic resin, and the phenolic resin contains structural units shown in formula (C) and optionally structural units shown in formula (D): Formula (C) Formula (D).

8. The method according to claim 1 or 2, characterized in that, The number average molecular weight of the phenolic resin is 500-1200; and / or The method for preparing the phenolic resin includes: reacting raw materials containing phenol and formaldehyde at 40-90℃ for 2-6 hours in the presence of an alkaline environment, wherein the molar ratio of phenol to formaldehyde is 1:1.5-3.

9. The method according to claim 1 or 2, characterized in that, The method for preparing the polymer backbone includes: The first polymer is obtained by copolymerizing nonionic monomers, anionic monomers and phenolic resin. The first polymer is then formed into a first polymer dispersion and freeze-dried. The freeze-drying steps include: pre-freezing in liquid nitrogen and then freeze-drying.

10. The method according to claim 9, characterized in that, The nonionic monomer is selected from acrylamide, N-hydroxymethylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, vinylpyrrolidone, vinylcaprolactam; and / or The anionic monomer is selected from one or more of 2-acrylamido-2-methylpropanesulfonic acid and sodium styrene sulfonate; and / or The phenolic resin is a water-soluble phenolic resin, and the phenolic resin contains structural units shown in formula (C) and optionally structural units shown in formula (D): Formula (C) Formula (D).

11. The method according to claim 9, characterized in that, The number average molecular weight of the phenolic resin is 500-1200; and / or The method for preparing the phenolic resin includes: reacting raw materials containing phenol and formaldehyde at 40-90℃ for 2-6 hours in the presence of an alkaline environment, wherein the molar ratio of phenol to formaldehyde is 1:1.5-3; and / or The mass ratio of the nonionic monomer to the anionic monomer is 1:0.2-1; and / or The total mass ratio of the nonionic monomer and the anionic monomer to the phenolic resin is 1:0.2-0.

5.

12. The method according to claim 9, characterized in that, The copolymerization is carried out in the presence of initiator 2 and crosslinking agent 2; in, Crosslinking agent 2 is selected from one or more of N,N-methylenebisacrylamide, ethylene glycol diacrylate, and polyethyleneimine; and / or Initiator 2 is selected from one or more of potassium persulfate and ammonium persulfate; and / or The total mass ratio of the nonionic monomer, the anionic monomer, and the phenolic resin to the crosslinking agent 2 is 1:0.001-0.02; and / or The copolymerization temperature is 60-70℃; and / or The co-polymerization time is 2-3 hours; and / or The copolymerization pH is 9-11; and / or Copolymerization is carried out in an inert gas; and / or The copolymerization was carried out dynamically at a speed of 400-600 rpm.

13. The method according to claim 9, characterized in that, The freeze-drying conditions include: The solvent of the first polymer dispersion includes an alcohol and water, wherein the alcohol is selected from one or more of tert-butanol, ethanol, methanol, and propanol, and the mass ratio of alcohol to water is 1:1-5; and / or In the first polymer dispersion, the mass ratio of solvent to the first polymer is 1:0.01-0.05; and / or Pre-freeze in liquid nitrogen for 0.5–2.5 h; and / or The freeze-drying temperature is -60 to -80℃; and / or The freeze-drying pressure is 0.5-1.5 Pa; and / or The freeze-drying time is 36-60 hours.

14. The method according to claim 13, characterized in that, The freeze-drying conditions include: The solvent for the first polymer dispersion includes tert-butanol, ethanol, and water, wherein the mass ratio of tert-butanol, ethanol, and water is 1:1-2:7-8; and / or In the first polymer dispersion, the mass ratio of solvent to the first polymer is 1:0.01-0.

02.

15. A polymer, characterized in that, The polymer is prepared according to the method described in any one of claims 1-14.

16. The polymer according to claim 15, characterized in that, The polymer has an approximately spherical morphology, consisting of multiple interwoven and entangled molecular chains, with a rough and dense surface, and no obvious filamentous or porous structures; and / or The polymer has a number-average molecular weight of 30,000 to 200,000; and / or The polymer has an average particle size of 200-300 μm in the dry state; and / or The polymer exhibits a hydration kinetic particle size distribution range of 100-400 μm in water at 10-40℃, with an average particle size of 200-300 μm; and / or The polymer exhibits a hydration kinetic particle size distribution range of 100-500 μm in water at 150-250 °C, with an average particle size of 200-300 μm; and / or The polymer exhibits a hydration kinetic particle size distribution range of 100-400 μm in 150-250℃, 200000-400000 mg / L saline solution, with an average particle size of 200-300 μm.

17. The application of a polymer in drilling fluids and / or completion fluids, characterized in that, The polymer is the polymer described in any one of claims 15 and 16.

18. The application according to claim 17, characterized in that, Application of the polymer in water-based drilling fluids.

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