Corrosion-resistant oil casing liner material and method of making same

Abstract

The application provides a kind of corrosion-resistant oil sleeve lining material and its preparation method, including the components with mass fraction as follows: high-density polyethylene 50-60 parts, ultra-high molecular weight polyethylene 5-10 parts, polytetrafluoroethylene 1-3 parts, modified carbon black 2-6 parts, modified mica powder 5-8 parts, auxiliary agent 0.1-3 parts;Wherein, the modified mica powder is obtained by reaction of acryloxy silane coupling agent, acrylate and mica powder;The modified carbon black is obtained by reaction of silane coupling agent containing polyolefin segment and carbon black.The application takes high-density polyethylene as main component, is compounded with polytetrafluoroethylene and ultra-high molecular weight polyethylene, and at the same time, uses modified mica powder and modified carbon black as filler, which not only has the functions of reinforcing and toughening, and has the function of compatibilizer, greatly improves the combination effect between various components, endows the composite material with high stability, corrosion resistance, high strength and comprehensive performance, and overcomes the deficiencies and defects in the prior art.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a corrosion-resistant oil casing lining material and its preparation method. Background Technology

[0002] Oil casing and tubing are core components in the oil and gas extraction process, primarily used to withstand high pressure within the well and isolate formation media. Their inner walls directly contact corrosive media containing sulfur, acids, and high salt, while also facing complex conditions such as pipe wear and temperature fluctuations. The performance of the lining material directly determines the service life and extraction safety of the oil casing and tubing, making it a key factor in solving corrosion and scaling problems. Currently, non-metallic lining materials are widely used in the oilfield sector to replace traditional metal linings, with polyethylene materials becoming a mainstream choice due to their low cost, ease of processing, and excellent basic corrosion resistance.

[0003] Existing oil casing liners are mostly made of single high-density polyethylene (HDPE) or ultra-high molecular weight polyethylene (UHMWPE). While single HDPE linings have good processability, they lack resistance to strong corrosive media (such as H2S and CO2) and are prone to aging and cracking after long-term use. Single UHMWPE linings, while possessing excellent toughness, are difficult to process, costly, and have poor compatibility with other materials, making it difficult to balance corrosion resistance and processability. To improve corrosion resistance, some technologies use a blend of polytetrafluoroethylene (PTFE) and polyethylene. However, the two still suffer from poor compatibility and insufficient matching effect. PTFE easily forms a dispersed phase, leading to delamination and peeling, failing to fully exert its anti-corrosion effect and offering limited improvement in the toughness of the blended system.

[0004] Existing technologies often incorporate fillers such as carbon black and mica powder to improve material properties. These fillers offer multiple benefits, including oxidation resistance, antistatic properties, high-temperature resistance, enhanced physical barrier properties, and increased system rigidity. However, carbon black and mica powder exhibit strong polarity and hydrophilicity, resulting in poor dispersibility and agglomeration in polyethylene systems. This not only hinders the enhancement of material toughness but may also lead to internal defects, impacting the overall stability and service life of the lining. Therefore, improving the performance of existing polyethylene-filler composite systems to meet the requirements of oilfield development for corrosion resistance, high toughness, good processability, and long-term stability of casing linings has become a pressing technical challenge in this field.

[0005] Therefore, it is necessary to provide a new technical solution to overcome the defects existing in the prior art. Summary of the Invention

[0006] Based on this, the present invention provides a corrosion-resistant oil casing lining material and its preparation method. The present invention uses high-density polyethylene as the main component, compounded with polytetrafluoroethylene and ultra-high molecular weight polyethylene, and uses modified mica powder and modified carbon black as fillers. It not only has the functions of reinforcement and toughening, but also has the function of compatibilizer, which greatly improves the bonding effect between various components and endows the composite material with comprehensive properties of high stability, corrosion resistance and high strength, overcoming the shortcomings and defects of the prior art.

[0007] One object of the present invention is to provide a corrosion-resistant oil casing liner material, the corrosion-resistant oil casing liner material comprising the following components in parts by weight: 50-60 parts of high-density polyethylene 5-10 parts of ultra-high molecular weight polyethylene 1-3 parts of polytetrafluoroethylene 2-6 parts modified carbon black 5-8 parts of modified mica powder Additives: 0.1-3 parts; The modified mica powder is obtained by reacting acryloyloxysilane coupling agent, acrylate and mica powder; The modified carbon black is obtained by reacting a silane coupling agent containing polyolefin segments with carbon black.

[0008] Furthermore, the acryloyloxysilane coupling agent is KH-570.

[0009] Furthermore, the acrylate includes fluoroalkyl acrylate and alkyl acrylate.

[0010] Furthermore, the polyolefin is polybutadiene.

[0011] Another object of the present invention is to provide a method for preparing the above-mentioned corrosion-resistant oil casing lining material, wherein the method for preparing the corrosion-resistant oil casing lining material includes the following steps: S1. Acryloyloxysilane coupling agent and mica powder are mixed and heated to obtain double bond modified mica powder. S2. The double-bond modified mica powder, acrylate and initiator are blended and heated and stirred under nitrogen protection to obtain modified mica powder. S3. Silane coupling agent containing polyolefin segments is blended with carbon black and heated to obtain modified carbon black. S4. Add the modified mica powder, modified carbon black and other components to an extruder and extrude to obtain a corrosion-resistant oil casing lining material.

[0012] Furthermore, in step S1, the heating reaction is carried out at a temperature of 50-90°C for 2-10 hours.

[0013] Furthermore, in step S2, the temperature of the heating and stirring reaction is 60-100℃, and the time is 4-8 h.

[0014] Furthermore, in step S2, the mass ratio of the double-bond modified mica powder to acrylate is 1:(0.5-3).

[0015] Furthermore, the acrylate comprises fluoroalkyl acrylate and alkyl acrylate in a mass ratio of 1:(1-10).

[0016] Furthermore, in step S3, the temperature of the heating reaction is 70-100℃.

[0017] The present invention has the following beneficial effects: This invention discloses a corrosion-resistant oil casing lining material containing high-density polyethylene, ultra-high molecular weight polyethylene, polytetrafluoroethylene, modified carbon black, and modified mica powder. The modified mica powder is obtained by copolymerizing mica powder with stearate acrylate and hexafluorobutyl acrylate after introducing double bonds through coupling agent modification. The grafted fluorocarbon segments effectively improve the affinity with PTFE, while the long alkyl segments improve the affinity with the polyethylene matrix. This reduces the polarity and hydrophilicity of the mica powder, improves dispersibility and interfacial bonding, and also functions as a compatibilizer, enhancing the compatibility between HDPE and PTFE, promoting uniform PTFE dispersion, and thus ensuring the material's corrosion resistance and service life. Modified carbon black is carbon black modified with coupling agents containing polybutadiene segments, which improves the dispersion effect of carbon black, while the elastic long chains also have a toughening effect. In addition, mica powder has a micron-sized particle size, which can play a rigid framework and physical barrier role, while carbon black has a nano-sized particle size, which can fill gaps and prevent crack formation and expansion. Furthermore, the introduced polyolefin long chains can further entangle with the carbon chains in polyethylene and modified mica powder to form a more stable network structure, thereby improving the material's comprehensive properties such as impact resistance and corrosion resistance. Detailed Implementation

[0018] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0019] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0020] It should be understood that, except in any operational instance or otherwise indicated, all figures representing the amounts of ingredients used, for example, in the specification and claims, should be understood to be modified in all cases by the term "about". Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximations varying with the desired performance to be obtained according to the invention.

[0021] The raw material components in this embodiment of the invention are as follows: The high-density polyethylene is DGDB2480H.

[0022] The ultra-high molecular weight polyethylene is Daehan Oil & Chemical U050.

[0023] The additives are antioxidant 1010 and polyethylene wax in a 1:1 mass ratio.

[0024] The carbon black is N330 carbon black.

[0025] The mica powder has a particle size of 1000 mesh.

[0026] Polybutadiene-KH570 was prepared in-house, and the preparation method includes the following steps: Add 16 parts KH570 and 0.5 parts benzoyl peroxide to 50 parts xylene to obtain a mixture; 40 parts of liquid polybutadiene rubber (Zhu Zi Chemical ROCEOIL B20) were added to 200 parts of xylene. Under nitrogen protection, the temperature was raised to 89°C, and the mixture was added dropwise (completed in 30 min). Then the temperature was raised to 94°C and reacted for 6 h. After cooling, methanol was added to precipitate the product. After separation and drying, polybutadiene-KH570 was obtained.

[0027] In the embodiments of this invention, "parts" refers to parts by mass. Example 1

[0028] A corrosion-resistant oil casing liner material, wherein the corrosion-resistant oil casing liner material comprises the following components in parts by weight: 50 parts of high-density polyethylene 5 parts of ultra-high molecular weight polyethylene 1 part polytetrafluoroethylene 3 parts modified carbon black 5 parts modified mica powder Two parts of the auxiliary agent; The preparation method of the corrosion-resistant oil casing lining material includes the following steps: S1. Using a mixture of water and ethanol at a mass ratio of 1:9 as a solvent, acetic acid was added to adjust the pH to 4.0. Then, KH570 and mica powder at a mass ratio of 0.2:1 were mixed and reacted at 60℃ for 4 h. After filtration, washing and drying, double bond modified mica powder was obtained. S2. Using ethyl acetate as solvent, the double bond modified mica powder, stearate acrylate, hexafluorobutyl acrylate and azobisisobutyronitrile in a mass ratio of 10:5:2:0.1 were mixed and stirred at 70°C for 6 h under nitrogen protection. After filtration, washing and drying, the modified mica powder was obtained. S3. Using xylene as solvent, polybutadiene-KH570 and carbon black were mixed in a mass ratio of 0.15:1 and reacted at 80°C for 3 hours. The mixture was then filtered, washed, and dried to obtain modified carbon black. S4. According to the above-mentioned mass proportions, the modified mica powder, modified carbon black and the remaining components are added to a twin-screw extruder and extruded and granulated at 180-200℃ to obtain a corrosion-resistant oil casing lining material. Example 2

[0029] A corrosion-resistant oil casing liner material, wherein the corrosion-resistant oil casing liner material comprises the following components in parts by weight: 55 parts of high-density polyethylene 5.8 parts of ultra-high molecular weight polyethylene 1.1 parts polytetrafluoroethylene 3.5 parts modified carbon black 6 parts modified mica powder Two parts of the auxiliary agent; The preparation method of the corrosion-resistant oil casing lining material includes the following steps: S1. Using a mixture of water and ethanol at a mass ratio of 1:9 as a solvent, acetic acid was added to adjust the pH to 4.0. Then, KH570 and mica powder at a mass ratio of 0.2:1 were mixed and reacted at 60℃ for 4 h. After filtration, washing and drying, double bond modified mica powder was obtained. S2. Using ethyl acetate as solvent, the double bond modified mica powder, stearate acrylate, hexafluorobutyl acrylate and azobisisobutyronitrile in a mass ratio of 10:5:2:0.1 were mixed and stirred at 70°C for 6 h under nitrogen protection. After filtration, washing and drying, the modified mica powder was obtained. S3. Using xylene as solvent, polybutadiene-KH570 and carbon black were mixed in a mass ratio of 0.15:1 and reacted at 80°C for 3 hours. The mixture was then filtered, washed, and dried to obtain modified carbon black. S4. According to the above-mentioned mass proportions, the modified mica powder, modified carbon black and the remaining components are added to a twin-screw extruder and extruded and granulated at 180-200℃ to obtain a corrosion-resistant oil casing lining material. Example 3

[0030] A corrosion-resistant oil casing liner material, wherein the corrosion-resistant oil casing liner material comprises the following components in parts by weight: 60 parts of high-density polyethylene 6.4 parts of ultra-high molecular weight polyethylene 1.2 parts polytetrafluoroethylene 4 parts modified carbon black 6.5 parts modified mica powder Two parts of the auxiliary agent; The preparation method of the corrosion-resistant oil casing lining material includes the following steps: S1. Using a mixture of water and ethanol at a mass ratio of 1:9 as a solvent, acetic acid was added to adjust the pH to 4.0. Then, KH570 and mica powder at a mass ratio of 0.2:1 were mixed and reacted at 60℃ for 4 h. After filtration, washing and drying, double bond modified mica powder was obtained. S2. Using ethyl acetate as solvent, the double bond modified mica powder, stearate acrylate, hexafluorobutyl acrylate and azobisisobutyronitrile in a mass ratio of 10:5:2:0.1 were mixed and stirred at 70°C for 6 h under nitrogen protection. After filtration, washing and drying, the modified mica powder was obtained. S3. Using xylene as solvent, polybutadiene-KH570 and carbon black were mixed in a mass ratio of 0.15:1 and reacted at 80°C for 3 hours. The mixture was then filtered, washed, and dried to obtain modified carbon black. S4. According to the above-mentioned mass proportions, the modified mica powder, modified carbon black and the remaining components are added to a twin-screw extruder and extruded and granulated at 180-200℃ to obtain a corrosion-resistant oil casing lining material.

[0031] Comparative Example 1 The difference between this comparative example and Example 1 is that stearate acrylate and hexafluorobutyl acrylate in step S2 are replaced with butyl acrylate of equal mass; other components and preparation methods are the same as in Example 1.

[0032] Comparative Example 2 The difference between this comparative example and Example 1 is that step S3 is modified as follows: Using xylene as a solvent, KH570 and carbon black were blended at a mass ratio of 0.1:1 and reacted at 80℃ for 3 h. After filtration, washing and drying, the solid product and liquid polybutadiene rubber were mixed at a mass ratio of 1:0.1 to obtain modified carbon black. The other components and preparation methods are the same as in Example 1.

[0033] Test case The samples prepared in the examples and comparative examples were subjected to performance tests.

[0034] Test method: Performance tests were conducted in accordance with the provisions of GB / T 1040, GB / T 18743, and GB / T 11547 (corrosion resistance was tested by immersion in 0# diesel oil at 70℃ for 8 weeks, and the notched impact strength after immersion was tested).

[0035] The test results are shown in Table 1.

[0036] Table 1 Performance Test Results

[0037] As shown in Table 1, the corrosion-resistant oil casing lining material prepared in the embodiments of the present invention has good mechanical properties, ensuring toughness and impact resistance. Furthermore, after long-term immersion at high temperatures, the notched impact strength retention rate can reach 90%, demonstrating excellent corrosion resistance. Comparative Example 1 uses butyl acrylate reacted with double-bond modified mica powder. The compatibility with polyethylene is insufficiently improved, and it is difficult to intertwine and combine with other components. It also cannot adjust the compatibility between HDPE and PTFE, resulting in significant interfacial bonding defects and a marked reduction in mechanical properties and corrosion resistance. Comparative Example 2 uses KH570 to modify carbon black and then physically blends it with polybutadiene. The presence of polybutadiene alone has a poor effect on improving mechanical properties, while the modified carbon black surface lacks elastic long chains, making it difficult to synergistically toughen and reinforce with other components. Therefore, the performance is lower than that of the embodiments.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A corrosion-resistant oil casing lining material, characterized in that, The corrosion-resistant oil casing lining material comprises the following components in parts by weight: 50-60 parts of high-density polyethylene 5-10 parts of ultra-high molecular weight polyethylene 1-3 parts of polytetrafluoroethylene 2-6 parts modified carbon black 5-8 parts modified mica powder Additives: 0.1-3 parts; The modified mica powder is obtained by reacting acryloyloxysilane coupling agent, acrylate and mica powder; The modified carbon black is obtained by reacting a silane coupling agent containing polyolefin segments with carbon black. The preparation method of the corrosion-resistant oil casing lining material includes the following steps: S1. Acryloyloxysilane coupling agent and mica powder are mixed and heated to obtain double bond modified mica powder. S2. The double-bond modified mica powder, acrylate and initiator are blended and heated and stirred under nitrogen protection to obtain modified mica powder. S3. Silane coupling agent containing polyolefin segments is blended with carbon black and heated to obtain modified carbon black. S4. Add the modified mica powder, modified carbon black and other components to an extruder and extrude to obtain a corrosion-resistant oil casing lining material. The acrylates include fluoroalkyl acrylates and alkyl acrylates; The polyolefin is polybutadiene.

2. The corrosion-resistant oil casing lining material according to claim 1, characterized in that, The acryloyloxysilane coupling agent is KH-570.

3. The corrosion-resistant oil casing lining material according to claim 1, characterized in that, In step S1, the heating reaction is carried out at a temperature of 50-90°C for 2-10 hours.

4. The corrosion-resistant oil casing lining material according to claim 1, characterized in that, In step S2, the heating and stirring reaction is carried out at a temperature of 60-100℃ for 4-8 hours.

5. The corrosion-resistant oil casing lining material according to claim 1, characterized in that, In step S2, the mass ratio of the double-bond modified mica powder to acrylate is 1:(0.5-3).

6. The corrosion-resistant oil casing lining material according to claim 1, characterized in that, The acrylate comprises fluoroalkyl acrylate and alkyl acrylate in a mass ratio of 1:(1-10).

7. The corrosion-resistant oil casing lining material according to claim 1, characterized in that, In step S3, the temperature of the heating reaction is 70-100℃.

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