Preparation method of high-tungsten alloy oil casing

Abstract

The invention provides a preparation method of a high-tungsten alloy oil casing, which belongs to the technical field of oil casings, and comprises the following steps: cleaning tungsten, chromium, nickel, iron, chromium nitride and yttrium, crushing, vacuumizing, filling argon, heating for smelting, casting, annealing, cooling, and carrying out sand blasting treatment on the inner wall to obtain a pretreated high-tungsten alloy pipe; the preparation method comprises the following steps: uniformly mixing Zn (NO3) 2.6 H2O, pretreated Na2MoO4, methanol and 2-methylimidazole, adding a sodium hydroxide solution and water, stirring, centrifuging, immersing into a Tris-DA solution, centrifuging, and carrying out vacuum drying to obtain MoO4 < 2->-loaded zeolite microcapsules; mixing epoxy modified silicon resin and polyamide, magnetically stirring, adding the MoO4 < 2->-loaded zeolite microcapsule, and slowly stirring to obtain a mixed solution; and immersing the pretreated high-tungsten alloy pipe into the mixed solution, and performing infiltration, preheating and cooling to obtain the high-tungsten alloy oil casing pipe. The carbon fiber reinforced plastic can resist CO2 / H2S corrosion and has certain impact resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of tubing-casing, and particularly relates to a preparation method of a high-tungsten alloy tubing-casing. Background Art

[0002] Tubing-casing is an important part of oil and gas production equipment, and plays the role of supporting the wellbore of oil and gas wells and the oil and gas production channel during the oil and gas production process. CO2 / H2S corrosion is the most common corrosion medium in the oil and gas system. Dry CO2 and H2S have no effect on the corrosion of steel materials, but when CO2 and H2S gases dissolve in water or in produced fluids with water present to form weak acids, they will cause corrosion damage to the tubing-casing made of steel materials, resulting in the corrosion failure of the tubing-casing, which not only causes incalculable economic losses, but also threatens life and environmental safety at all times.

[0003] To cope with CO2 / H2S corrosion, selecting high-alloy corrosion-resistant materials is the first choice for anti-corrosion. However, due to the characteristics of mostly poor oil and low permeability in oil and gas fields, using chromium-based and nickel-based corrosion-resistant materials for tubing-casing not only has a relatively high cost, but also has insufficient impact resistance. The Chinese patent document with the publication number CN110303066A discloses a steel for petroleum casing with high transverse impact energy and its preparation method. In this method, molten steel is smelted, continuously cast into slabs, and then the slabs are heated, rough rolled, finish rolled and laminar cooled in sequence to obtain the finished product. Heat treatment is not used in the method. Through the corresponding rolling process, although the transverse impact energy of the steel is improved, the anti-CO2 / H2S corrosion performance of the tubing-casing is not solved. Rare earths are widely used in seawater corrosion-resistant steel and atmospheric corrosion-resistant steel, but there are few studies and applications in steels for corrosion in high-temperature and high-pressure CO2 / H2S oil and gas fields.

[0004] Therefore, a preparation method of a high-tungsten alloy tubing-casing is needed to solve the problems existing in the above-mentioned prior art. Summary of the Invention

[0005] In view of this, the present invention provides a preparation method of a high-tungsten alloy tubing-casing, which can resist CO2 / H2S corrosion and has a certain impact resistance at the same time.

[0006] To achieve the above object, the present invention provides a preparation method of a high-tungsten alloy tubing-casing, including the following steps:

[0007] S1. Wash, crush tungsten, chromium, nickel, iron, chromium nitride and yttrium, evacuate and fill with argon, raise the temperature for melting, cast, anneal, and cool to obtain a high-tungsten alloy tube, and perform sandblasting treatment on its inner wall to obtain a pretreated high-tungsten alloy tube;

[0008] S2. Mix Zn(NO3)2·6H2O, pretreated Na2MoO4 and methanol to obtain mixture A; mix 2-methylimidazole and methanol to obtain mixture B; mix mixture A and mixture B, add sodium hydroxide solution to adjust the pH, stir magnetically, centrifuge, collect the precipitate, wash it, immerse it in Tris-DA solution, centrifuge, collect the precipitate, wash it, and dry it under vacuum to obtain MoO4-loaded 2- zeolite microcapsules;

[0009] S3. Mix epoxy-modified silicone resin and polyamide, stir magnetically, add MoO4-loaded 2- zeolite microcapsules, stir slowly, sonicate to obtain a mixed solution; immerse the pretreated high-tungsten alloy tube in the mixed solution, soak it, level it, preheat it, keep it warm, and cool it to obtain a high-tungsten alloy oil casing.

[0010] The matrix of the present invention adopts a multi-component high-entropy alloy system, and realizes higher corrosion resistance and mechanical properties through the synergistic action of multiple elements. Among them, tungsten is the main element, and the high melting point and hardness of tungsten significantly improve the high-temperature resistance and impact resistance of the alloy. Chromium forms a dense passivation film on the surface by oxidation, blocking the erosion of H2S. At the same time, it forms a composite oxide (Cr2O3-WO3) with tungsten, endowing the passivation film with a certain self-healing ability and further inhibiting the penetration of acidic media (H2CO3 generated by the hydrolysis of CO2). The N element introduced by chromium nitride pre-alloy fills the lattice interstitial, enhancing the stability of the passivation film and inhibiting the anodic dissolution reaction in CO2 corrosion; in addition, yttrium can react with H2S preferentially to generate Y2S3 particles (instead of brittle FeS), reducing the tendency of sulfide stress corrosion, and yttrium can refine the grains in the intermetallic compound. Smaller grains can increase the grain boundary area, thereby improving the impact resistance and toughness of the alloy.

[0011] The present invention prepares MoO4-loaded 2- zeolite microcapsules to achieve the selective release of MoO4 2- anti-corrosion components. As a ligand, 2-methylimidazole can coordinate with Zn 2+ ions to form metal complexes, forming a ZIF-8 zeolite structure, so that the distribution of Na2MoO4 is in the pores of ZIF-8 zeolite or coated inside it, and the outside of the zeolite is coated with polydopamine to achieve dual response release of pH value and reactive oxygen species, and accurately repair corrosion points. When the local pH < 4 due to CO2 corrosion leading to an acidic environment, the polydopamine shell layer degrades and releases MoO4 2- anti-corrosion components, and the H2O2 generated by H2S corrosion triggers the oxidation and rupture of polydopamine, accelerating the release of MoO4 2- anti-corrosion components. MoO4 2- can inhibit the expansion of pitting corrosion, and generate a MoS2 protection layer in an H2S environment, reducing the sensitivity of sulfide stress corrosion cracking; in addition, MoO42- With Fe 2+ Generate FeMoO4 precipitate, which can repair the damaged area of the coating and further improve the anti-corrosion effect and durability.

[0012] The present invention uses epoxy-modified silicone resin as the coating material for oil pipelines. It combines the high adhesion of epoxy resin and the high temperature resistance and corrosion resistance of silicone resin, and can effectively resist corrosive media such as acids, salts, and sulfides that the oil pipeline contacts in different environments. Moreover, the high temperature resistance of the epoxy-modified silicone resin can maintain stability at high temperatures; in addition, it also avoids the problems of coating aging and cracking when exposed to sunlight for a long time. At the same time, this coating also has excellent waterproof performance and can effectively resist the penetration of moisture and water, thereby avoiding corrosion or swelling problems caused by moisture and ensuring the long-term durability of the pipeline.

[0013] Optionally, the high-tungsten alloy tube is prepared by ultrasonic cleaning of tungsten, chromium, nickel, iron, chromium nitride, and yttrium, then crushing, putting them into an electric arc furnace, evacuating to 10 -3 Pa and then filling with argon, heating to 3500 °C and melting for 30 - 120 min, continuously stirring electromagnetically during this period, then casting into a mold, annealing at 700 °C for 10 h, and then air-cooling.

[0014] The present invention uses ultrasonic cleaning to remove impurities on the surface of the base material, and continuously stirs electromagnetically during this period to ensure uniform mixing of each component.

[0015] Optionally, after the high-tungsten alloy tube is prepared in step S1, the inner wall of the high-tungsten alloy tube is sandblasted at 0.6 MPa, wiped with acetone on the inner wall, and dried in hot air at 60 °C for 30 min to obtain a pretreated high-tungsten alloy tube.

[0016] The present invention uses acetone to wipe the inner wall to remove oil stains and dust.

[0017] Optionally, the Tris-DA solution is prepared by dissolving Tris-HCI in deionized water, adjusting the pH to 8.5 with hydrochloric acid, and then adding dopamine hydrochloride and stirring evenly.

[0018] Optionally, the pretreated Na2MoO4 is obtained by ball-milling Na2MoO4 for 12 - 24 h.

[0019] Optionally, the mixture A is prepared by mixing Zn(NO3)2·6H2O, pretreated Na2MoO4, Ce(NO3)3·6H2O, Ga(NO3)3, and methanol evenly and stirring magnetically for 10 - 20 min; the mixture B is prepared by dissolving 2-methylimidazole in methanol and stirring magnetically for 10 - 20 min.

[0020] The present invention prepares the supported MoO42- During the process of zeolite microcapsules, Ce(NO3)3·6H2O and Ga(NO3)3 were also added. Ce 3+ , Ga 3+ coexisted with MoO4 2- in the pores of ZIF-8. Ga 3+ and Ce 3+ formed hydroxide precipitates under alkaline conditions and were coated therein. In a high H2S environment, Ga 3+ and Ce 3+ reacted with H2S to form stable sulfides, further reducing the attack of free S 2- on the substrate.

[0021] Optionally, in step S2, the mixture A and the mixture B were mixed evenly, and a sodium hydroxide solution with a molar concentration of 0.1 mol / L was added to adjust the pH to 10.0. At 25 °C, it was magnetically stirred at a speed of 500 rpm for 12 h, then deionized water was added, and after stirring for 5 - 10 min, it was centrifuged at 8000 rpm for 5 - 15 min. The supernatant was discarded, the precipitate was collected, washed alternately with methanol and deionized water 3 times, then placed in a Tris-DA solution, and continuously contacted with surrounding oxygen at room temperature for 24 h. Subsequently, it was centrifuged at 2000 rpm for 5 - 10 min, the precipitate was collected, then washed with deionized water, and vacuum dried at 40 - 60 °C for 24 h to obtain MoO4 2- -loaded zeolite microcapsules.

[0022] Optionally, in step S3, the epoxy-modified silicone resin and polyamide were mixed and magnetically stirred. The MoO42--loaded zeolite microcapsules were added, and slowly stirred. The time for dropping xylene and the defoaming agent and stirring was 2 - 5 min, and then ultrasonic treatment was carried out to obtain a mixed solution.

[0023] Optionally, in step S3, the magnetic stirring speed was 300 rpm, the time was 5 - 10 min, the slow stirring speed was 100 rpm, the stirring time was 2 - 5 min, the temperature of ultrasonic treatment was 20 °C, the time was 20 - 30 min, and it was paused for 10 s every 5 min during the ultrasonic process.

[0024] Optionally, in step S3, the pretreated high-tungsten alloy tube was fixed on the impregnation machine bracket, vertically immersed in the mixed solution, kept immersed for 30 s, lifted the pipe at a uniform speed of 0.5 m / min, after an interval of 5 min, immersed for another 30 s, then placed horizontally in a dust-free room, leveled at room temperature for 10 - 15 min, preheated at 60 °C for 10 min, then horizontally fixed in a vacuum oven, heated to 80 °C at a rate of 2 °C / min, held for 2 h, and taken out after naturally cooling to 40 °C to obtain high-tungsten alloy oil casing pipes.

[0025] The above technical solutions of the present invention have at least the following beneficial effects:

[0026] 1. Based on the multi-component high-entropy alloy, through the synergistic effect of tungsten, chromium, chromium nitride, and yttrium, excellent corrosion resistance and mechanical properties are achieved. Tungsten improves the high-temperature resistance and impact resistance of the alloy. Chromium forms a dense passivation film to prevent H2S erosion and jointly generates composite oxides with tungsten, having self-healing ability. Chromium nitride introduces N element to enhance the stability of the passivation film and inhibit the anodic dissolution reaction in CO2 corrosion. Yttrium generates Y2S3 particles with H2S, reduces sulfide stress corrosion, and refines the grains of intermetallic compounds, improving the impact resistance and toughness of the alloy.

[0027] 2. The present invention loads MoO4 2- onto zeolite microcapsules, combines 2-methylimidazole ligand with Zn 2+ to form a metal complex, and distributes MoO4 2- in the pores of zeolite or coats the interior. Through the polydopamine shell layer, dual responses of pH value and reactive oxygen species are achieved for release. Under the CO2 acidic environment and the trigger of H2S corrosion, MoO4 2- is accurately released. MoO4 2- can inhibit the propagation of pitting corrosion, generate a MoS2 protective layer, reduce sulfide stress corrosion, repair coating damage, and improve corrosion resistance.

[0028] 3. The present invention uses epoxy-modified silicone resin as the coating material for oil pipelines, combining the high adhesion of epoxy resin and the high-temperature resistance and corrosion resistance of silicone resin, and can effectively resist corrosion media such as acids, salts, and sulfides; its excellent high-temperature performance ensures the stability of the coating at high temperatures, avoiding aging and cracking problems under sunlight exposure; at the same time, the coating has excellent waterproof performance, can prevent moisture and water penetration, avoid corrosion and swelling caused by water, and ensure the long-term durability of the pipeline. Specific Embodiments

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0030] Preparation Work:

[0031] Dissolve 12 parts of Tris-HCI in 100 parts of deionized water, adjust the pH to 8.5 with hydrochloric acid, and then add 20 parts of hydrochloric acid dopamine (DA) and stir evenly to obtain a Tris-DA solution.

[0032] Example 1

[0033] 35 parts of tungsten, 15 parts of chromium, 15 parts of nickel, 23.5 parts of iron, 6 parts of chromium nitride, and 5.5 parts of yttrium are ultrasonically cleaned, then crushed to a particle size of ≤5 mm, placed in an electric arc furnace, evacuated to 10 -3 Pa and then filled with argon, heated to 3500 °C and melted for 80 min, with continuous electromagnetic stirring during this period, and then cast into a mold, annealed at 700 °C for 10 h, and then air-cooled to obtain a high-tungsten alloy tube; the inner wall of the high-tungsten alloy tube is sandblasted at 0.6 MPa, wiped with acetone on the inner wall, and dried in hot air at 60 °C for 30 min to obtain a pretreated high-tungsten alloy tube.

[0034] 0.5 part of Na2MoO4 is ball-milled for 24 h to obtain pretreated Na2MoO4; 1.2 parts of Zn(NO3)2·6H2O, 0.3 part of pretreated Na2MoO4, 0.1 part of Ce(NO3)3·6H2O, 0.1 part of Ga(NO3)3, and 50 parts of methanol are mixed evenly and magnetically stirred for 15 min to obtain mixture A; 2.6 parts of 2-methylimidazole are dissolved in 50 parts of methanol and magnetically stirred for 20 min to obtain mixture B; after mixture A and mixture B are mixed evenly, sodium hydroxide solution with a molar concentration of 0.1 mol / L is added to adjust the pH to 10.0. At 25 °C, magnetically stirred at a speed of 500 rpm for 12 h, 10 parts of deionized water are added, stirred for 7 min, then centrifuged at 8000 rpm for 12 min, the supernatant is discarded, the precipitate is collected, washed alternately with 20 parts of methanol and 20 parts of deionized water 3 times, placed in Tris-DA solution, and continuously contacted with surrounding oxygen at room temperature for 24 h, then centrifuged at 2000 rpm for 8 min, the precipitate is collected, then washed with deionized water, and vacuum-dried at 50 °C for 24 h to obtain MoO4-loaded 2- zeolite microcapsules.

[0035] 80 parts of epoxy-modified silicone resin and 8 parts of polyamide are mixed, magnetically stirred at 300 rpm for 6 min for premixing, and then 15 parts of MoO4-loaded 2- zeolite microcapsules are added, slowly stirred and dispersed at 100 rpm, 10 parts of xylene and 0.1 part of defoamer are added dropwise, stirred for 5 min, then ultrasonicated at 20 °C for 20 min, paused for 10 s every 5 min to obtain a mixed solution; the mixed solution is poured into an impregnation tank, and the liquid level height covers the area to be coated on the inner wall of the pretreated high-tungsten alloy tube. The pipe is fixed on the impregnation machine bracket and vertically immersed in the mixed solution, kept soaked for 30 s, the pipe is lifted at a uniform speed of 0.5 m / min, after an interval of 5 min, impregnated for another 30 s, horizontally placed in a dust-free room, leveled at room temperature for 15 min, preheated at 60 °C for 10 min, then horizontally fixed in a vacuum oven, heated to 80 °C at a rate of 2 °C / min, held for 2 h, naturally cooled to 40 °C and then taken out to obtain a high-tungsten alloy casing pipe.

[0036] Example 2

[0037] 35 parts of tungsten, 15 parts of chromium, 15 parts of nickel, 23.5 parts of iron, 6 parts of chromium nitride, and 5.5 parts of yttrium were ultrasonically cleaned and then crushed to a particle size of ≤5 mm. They were placed in an electric arc furnace, evacuated to 10 -3 Pa and then filled with argon. The temperature was raised to 3500 °C and melted for 30 min, with continuous electromagnetic stirring during this period. Subsequently, it was cast into a mold, annealed at 700 °C for 10 h, and then air-cooled to obtain a high-tungsten alloy tube. The inner wall of the high-tungsten alloy tube was sandblasted at 0.6 MPa, wiped with acetone, and dried with hot air at 60 °C for 30 min to obtain a pretreated high-tungsten alloy tube.

[0038] 0.5 part of Na2MoO4 was ball-milled for 12 h to obtain pretreated Na2MoO4. 1.2 parts of Zn(NO3)2·6H2O, 0.3 part of the pretreated Na2MoO4, 0.1 part of Ce(NO3)3·6H2O, and 50 parts of methanol were mixed evenly and magnetically stirred for 10 min to obtain mixture A. 2.6 parts of 2-methylimidazole were dissolved in 50 parts of methanol and magnetically stirred for 10 min to obtain mixture B. After mixing mixture A and mixture B evenly, a sodium hydroxide solution with a molar concentration of 0.1 mol / L was added to adjust the pH to 10.0. At 25 °C, it was magnetically stirred at a speed of 500 rpm for 12 h, then 10 parts of deionized water were added, stirred for 5 min, centrifuged at 8000 rpm for 5 min, the supernatant was discarded, the precipitate was collected, washed alternately with 20 parts of methanol and 20 parts of deionized water 3 times, placed in a Tris-DA solution, and continuously contacted with the surrounding oxygen at room temperature for 24 h. Subsequently, it was centrifuged at 2000 rpm for 5 min, the precipitate was collected, then washed with deionized water and vacuum-dried at 40 °C for 24 h to obtain MoO4-loaded 2- zeolite microcapsules.

[0039] 80 parts of epoxy-modified silicone resin and 8 parts of polyamide were mixed and magnetically stirred at 300 rpm for 5 min for premixing, and then 10 parts of MoO4-loaded 2-Zeolite microcapsules were slowly stirred and dispersed at 100 rpm, 5 parts of xylene and 0.1 part of defoamer were added dropwise. After stirring for 2 min, ultrasonic treatment was carried out at 20 °C for 30 min, pausing for 10 s every 5 min to obtain a mixed solution. The mixed solution was poured into an impregnation tank, and the liquid level height covered the area to be coated on the inner wall of the pretreated high-tungsten alloy tube. The tube was fixed on the support of the impregnation machine and vertically immersed in the mixed solution, maintaining impregnation for 30 s. The tube was lifted uniformly at a speed of 0.5 m / min. After an interval of 5 min, it was impregnated again for 30 s, then horizontally placed in a dust-free room, leveled at room temperature for 10 min, preheated at 60 °C for 10 min, then horizontally fixed in a vacuum oven, heated to 80 °C at a rate of 2 °C / min, held for 2 h, naturally cooled to 40 °C and then taken out to obtain a high-tungsten alloy casing pipe.

[0040] Example 3

[0041] 35 parts of tungsten, 15 parts of chromium, 15 parts of nickel, 23.5 parts of iron, 6 parts of chromium nitride, and 5.5 parts of yttrium were ultrasonically cleaned and then crushed to a particle size of ≤5 mm. They were put into an electric arc furnace, evacuated to 10 -3 Pa and then filled with argon, heated to 3500 °C and melted for 60 min, with continuous electromagnetic stirring during this period. Subsequently, it was cast into a mold, annealed at 700 °C for 10 h, and then air-cooled to obtain a high-tungsten alloy tube. The inner wall of the high-tungsten alloy tube was sandblasted at 0.6 MPa, wiped with acetone on the inner wall, and dried in hot air at 60 °C for 30 min to obtain a pretreated high-tungsten alloy tube.

[0042] 0.5 part of Na2MoO4 was ball-milled for 16 h to obtain pretreated Na2MoO4. 1.2 parts of Zn(NO3)2·6H2O, 0.3 part of pretreated Na2MoO4, 0.1 part of Ce(NO3)3·6H2O, 0.1 part of Ga(NO3)3 and 50 parts of methanol were mixed evenly and magnetically stirred for 15 min to obtain mixture A. 2.6 parts of 2-methylimidazole were dissolved in 50 parts of methanol and magnetically stirred for 15 min to obtain mixture B. After mixing mixture A and mixture B evenly, a sodium hydroxide solution with a molar concentration of 0.1 mol / L was added to adjust the pH to 10.0. At 25 °C, it was magnetically stirred at a speed of 500 rpm for 12 h, then 10 parts of deionized water were added, stirred for 10 min, centrifuged at 8000 rpm for 15 min, the supernatant was discarded, the precipitate was collected, washed alternately with 20 parts of methanol and 20 parts of deionized water 3 times, then placed in a Tris-DA solution and continuously contacted with surrounding oxygen at room temperature for 24 h. Subsequently, it was centrifuged at 2000 rpm for 10 min, the precipitate was collected, then washed with deionized water and vacuum-dried at 60 °C for 24 h to obtain MoO4 2- loaded zeolite microcapsules.

[0043] Mix 80 parts of epoxy-modified silicone resin and 8 parts of polyamide, and premix them with magnetic stirring at 300 rpm for 10 min. Then add 12 parts of MoO4 2- zeolite microcapsules, disperse them with slow stirring at 100 rpm, dropwise add 7 parts of xylene and 0.1 part of defoamer, stir for 3 min, then ultrasonicate at 20 °C for 25 min, pausing for 10 s every 5 min to obtain a mixed solution; pour the mixed solution into an impregnation tank, with the liquid level height covering the area to be coated on the inner wall of the pretreated high-tungsten alloy tube, fix the tube on the impregnation machine bracket, vertically immerse it in the mixed solution, keep it soaked for 30 s, lift the tube at a uniform speed of 0.5 m / min, after an interval of 5 min, impregnate it for another 30 s, place it horizontally in a dust-free room, level it at room temperature for 12 min, preheat it at 60 °C for 10 min, then fix it horizontally in a vacuum oven, heat it up to 80 °C at a rate of 2 °C / min, hold for 2 h, naturally cool to 40 °C and then take it out to obtain a high-tungsten alloy oil casing.

[0044] Example 4

[0045] Ultrasonically clean 35 parts of tungsten, 15 parts of chromium, 15 parts of nickel, 23.5 parts of iron, 6 parts of chromium nitride, and 5.5 parts of yttrium, then crush them to a particle size of ≤5 mm, put them into an electric arc furnace, evacuate to 10 -3 Pa and then fill with argon, heat up to 3500 °C and melt for 100 min, continuously stir magnetically during this period, then cast into a mold, anneal at 700 °C for 10 h, and then air-cool to obtain a high-tungsten alloy tube; perform sandblasting treatment on the inner wall of the high-tungsten alloy tube at 0.6 MPa, wipe the inner wall with acetone, and dry it with hot air at 60 °C for 30 min to obtain a pretreated high-tungsten alloy tube.

[0046] Ball mill 0.5 part of Na2MoO4 for 18 h to obtain pretreated Na2MoO4; mix 1.2 parts of Zn(NO3)2·6H2O, 0.3 part of pretreated Na2MoO4, 0.1 part of Ce(NO3)3·6H2O and 50 parts of methanol evenly, and stir magnetically for 18 min to obtain mixture A; dissolve 2.6 parts of 2-methylimidazole in 50 parts of methanol and stir magnetically for 12 min to obtain mixture B; after mixing mixture A and mixture B evenly, add sodium hydroxide solution with a molar concentration of 0.1 mol / L to adjust the pH to 10.0, at 25 °C, stir magnetically at a speed of 500 rpm for 12 h, then add 10 parts of deionized water, stir for 8 min, then centrifuge at 8000 rpm for 12 min, discard the supernatant, collect the precipitate, wash the precipitate alternately with 20 parts of methanol and 20 parts of deionized water 3 times, then place it in a Tris-DA solution and continuously contact with the surrounding oxygen at room temperature for 24 h, then centrifuge at 2000 rpm for 7 min, collect the precipitate, then wash it with deionized water and vacuum dry it at 50 °C for 24 h to obtain MoO4 2- zeolite microcapsules.

[0047] Mix 80 parts of epoxy-modified silicone resin and 8 parts of polyamide. After premixing with magnetic stirring at 300 rpm for 5 min, add 11 parts of MoO4 2- zeolite microcapsules, disperse them with slow stirring at 100 rpm, dropwise add 6 parts of xylene and 0.1 part of defoamer, stir for 4 min, then ultrasonicate at 20 °C for 25 min, pause for 10 s every 5 min to obtain a mixed solution; pour the mixed solution into an impregnation tank, the liquid level height covers the area to be coated on the inner wall of the pretreated high-tungsten alloy tube, fix the tube on the impregnation machine bracket, vertically immerse it in the mixed solution, keep it immersed for 30 s, lift the tube at a uniform speed of 0.5 m / min, after an interval of 5 min, immerse it for another 30 s, place it horizontally in a dust-free room, level it at room temperature for 15 min, preheat it at 60 °C for 10 min, then fix it horizontally in a vacuum oven, heat it up to 80 °C at a rate of 2 °C / min, keep it warm for 2 h, naturally cool it to 40 °C and then take it out to obtain a high-tungsten alloy oil casing.

[0048] Example 5

[0049] Ultrasonically clean 35 parts of tungsten, 15 parts of chromium, 15 parts of nickel, 23.5 parts of iron, 6 parts of chromium nitride, and 5.5 parts of yttrium, then crush them to a particle size of ≤5 mm, put them into an electric arc furnace, evacuate to 10 -3 Pa and then fill it with argon, heat it up to 3500 °C and melt for 80 min, continuously stir magnetically during this period, then cast it into a mold, anneal it at 700 °C for 10 h, and then air-cool it to obtain a high-tungsten alloy tube; carry out sandblasting treatment on the inner wall of the high-tungsten alloy tube at 0.6 MPa, wipe the inner wall with acetone, and dry it with hot air at 60 °C for 30 min to obtain a pretreated high-tungsten alloy tube.

[0050] 0.5 part of Na2MoO4 was ball-milled for 15 h to obtain pretreated Na2MoO4; 1.2 parts of Zn(NO3)2·6H2O, 0.3 part of the pretreated Na2MoO4, 0.1 part of Ce(NO3)3·6H2O, 0.1 part of Ga(NO3)3 and 50 parts of methanol were mixed evenly and magnetically stirred for 20 min to prepare mixture A; 2.6 parts of 2-methylimidazole was dissolved in 50 parts of methanol and magnetically stirred for 12 min to prepare mixture B; after mixture A and mixture B were mixed evenly, sodium hydroxide solution with a molar concentration of 0.1 mol / L was added to adjust the pH to 10.0. At 25 °C, it was magnetically stirred at a speed of 500 rpm for 12 h, then 10 parts of deionized water was added, and after stirring for 6 min, it was centrifuged at 8000 rpm for 14 min. The supernatant was discarded, the precipitate was collected, and the precipitate was alternately washed 3 times with 20 parts of methanol and 20 parts of deionized water, then placed in Tris-DA solution and continuously contacted with surrounding oxygen at room temperature for 24 h. Subsequently, it was centrifuged at 2000 rpm for 9 min, the precipitate was collected, then washed with deionized water, and vacuum dried at 45 °C for 24 h to obtain MoO4 2- zeolite microcapsules.

[0051] 80 parts of epoxy-modified silicone resin and 8 parts of polyamide were mixed and magnetically stirred at 300 rpm for 10 min for premixing, then 14 parts of MoO4 2- zeolite microcapsules were added and slowly stirred and dispersed at 100 rpm. 10 parts of xylene and 0.1 part of defoamer were added dropwise, and after stirring for 5 min, it was ultrasonically treated at 20 °C for 20 min, pausing for 10 s every 5 min to prepare a mixed solution; the mixed solution was poured into an impregnation tank, and the liquid level height covered the area to be coated on the inner wall of the pretreated high-tungsten alloy tube. The tube was fixed on the impregnation machine bracket and vertically immersed in the mixed solution, kept immersed for 30 s, the tube was lifted at a uniform speed of 0.5 m / min, after an interval of 5 min, it was impregnated for another 30 s, horizontally placed in a dust-free room, leveled at room temperature for 12 min, preheated at 60 °C for 10 min, then horizontally fixed in a vacuum oven, heated to 80 °C at a rate of 2 °C / min, kept warm for 2 h, naturally cooled to 40 °C and then taken out to obtain a high-tungsten alloy oil casing.

[0052] The present invention also carried out comparative examples and related tests.

[0053] Comparative Example 1

[0054] Compared with Example 5, the difference was only that chromium nitride was not added during the preparation of the high-tungsten alloy tube, and other components and preparation methods were exactly the same. Finally, a high-tungsten alloy oil casing was prepared.

[0055] Comparative Example 2

[0056] Compared with Example 5, the difference is only that yttrium is not added during the preparation of the high-tungsten alloy tube, and other components and preparation methods are exactly the same. Finally, a high-tungsten alloy oil casing is prepared.

[0057] Comparative Example 3

[0058] Compared with Example 5, the difference is only that the MoO4 2- zeolite microcapsules are not prepared, and other components and preparation methods are exactly the same. Finally, a high-tungsten alloy oil casing is prepared.

[0059] Performance detection test

[0060] For Examples 1-5 and Comparative Examples 1-3, the yield strength, tensile strength, elongation, yield ratio, and -10°C impact energy were tested with reference to the national standard of GB / T37701-2019. The specific test results are shown in Table 1.

[0061] Table 1

[0062]

[0063] As can be seen from Table 1, the relevant properties of Examples 1-5 are significantly better than those of Comparative Examples 1-3. Among them, chromium nitride was not added in Comparative Example 1, and the yield strength and tensile strength were significantly lower than those of Example 1. Yttrium was not added in Comparative Example 2, and the impact energy decreased significantly compared with Example 1. The addition of yttrium can refine the grains and adsorb sulfides by forming Y2O3 nanoparticles, significantly improving the low-temperature toughness.

[0064] To better test the CO2 / H2S corrosion resistance of Examples 1-5 and Comparative Examples 1-3, specimens were prepared according to the full immersion test method for uniform corrosion of metal materials in the laboratory of JB / T7901-2023. The specimens were fixed on the fixture and placed in the autoclave, 4L of oilfield simulated solution was injected and sealed, the solution was deoxygenated with N2 for more than 4h, and after deoxygenation, the temperature was raised. When the temperature in the autoclave reached the predetermined temperature, the test gas was introduced to the test pressure according to the test conditions of a test temperature of 70°C, pH = 5, CO2 partial pressure of 2.0MPa, H2S of 2.0MPa, and an experimental period of 120h, and then N2 was introduced to boost the pressure to the total pressure required for the test, and the timing started. After the test was completed, N2 was introduced for at least 2h to remove the remaining gas in the autoclave, and then the samples were taken out for analysis.

[0065] After taking out the samples, the corrosion products on the surface of the samples were removed with the stripping solution, then rinsed with flowing water, dehydrated with alcohol, and dried with cold air. Subsequently, the samples were weighed with an electronic balance accurate to 0.001g. The uniform corrosion rate was calculated using the following formula.

[0066]

[0067] In the formula, r cis the uniform corrosion rate, mm / a; W is the mass difference of the specimen before and after the experiment, g; S is the total area of the scraping, cm 2 ; ρ is the density of the scraping material, g / cm 3 ; t is the experimental time, h. The anti-CO2 / H2S corrosion performance was evaluated according to the uniform corrosion rate of the specimen and the appearance of the specimen after testing. The results are shown in Table 2.

[0068] Table 2

[0069] Project Uniform corrosion rate (mm / a) Appearance Example 1 0.016 No obvious corrosion signs Example 2 0.018 No obvious corrosion signs Example 3 0.015 No obvious corrosion signs Example 4 0.019 No obvious corrosion signs Example 5 0.014 No obvious corrosion signs Comparative Example 1 0.085 Corrosion occurred and the passivation film peeled off Comparative Example 2 0.086 Corrosion occurred and obvious cracks appeared Comparative Example 3 0.088 Corrosion occurred and the coating surface peeled off

[0070] As can be seen from Table 2, the uniform corrosion rates of Examples 1-5 are significantly lower than those of Comparative Examples 1-3, which indicates that the addition of chromium nitride, yttrium, and supported MoO4 2- zeolite microcapsules can effectively block the erosion of CO2 / H2S, significantly improving the anti-CO2 / H2S corrosion performance of the samples. In addition, there are no obvious corrosion signs on the surfaces of the specimens of Examples 1-5 after testing, which further demonstrates that the high-tungsten alloy oil casing prepared by the test method of the present invention has excellent anti-CO2 / H2S corrosion resistance.

[0071] The above are the preferred embodiments of the present invention. Without departing from the principle of the present invention, those of ordinary skill in the art can also make several improvements and refinements, which should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a high-tungsten alloy oil casing pipe, characterized in that, It includes the following steps: S1. Clean, crush tungsten, chromium, nickel, iron, chromium nitride and yttrium, evacuate and fill with argon, heat up for melting, cast, anneal, and cool to obtain a high-tungsten alloy tube, and perform sandblasting treatment on its inner wall to obtain a pretreated high-tungsten alloy tube; S2. Mix Zn(NO3)2·6H2O, pretreated Na2MoO4 and methanol to obtain mixture A; mix 2-methylimidazole and methanol to obtain mixture B; mix mixture A and mixture B, add sodium hydroxide solution to adjust the pH, stir magnetically, centrifuge, collect the precipitate, wash it, immerse it in Tris-DA solution, centrifuge, collect the precipitate, wash it, and dry it under vacuum to prepare MoO4 2- zeolite microcapsules; S3. Mix epoxy-modified silicone resin and polyamide, stir magnetically, add MoO4-loaded 2- zeolite microcapsules, stir slowly, perform ultrasonic treatment to obtain a mixed solution; immerse the pretreated high-tungsten alloy tube in the mixed solution, let it soak, level, preheat, keep warm, and cool to obtain a high-tungsten alloy oil casing.

2. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, The high-tungsten alloy tube is prepared by ultrasonic cleaning of tungsten, chromium, nickel, iron, chromium nitride and yttrium, crushing them, putting them into an electric arc furnace, evacuating to 10 -3 Pa and then filling with argon, heating to 3500 °C and melting for 30 to 120 minutes, continuously carrying out electromagnetic stirring during this period, then casting into a mold, annealing at 700 °C for 10 hours, and then air-cooling to obtain it.

3. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, After obtaining the high-tungsten alloy tube in step S1, perform sandblasting treatment on the inner wall of the high-tungsten alloy tube at 0.6 MPa, wipe the inner wall with acetone, and dry it with hot air at 60 °C for 30 min to obtain a pretreated high-tungsten alloy tube.

4. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, The Tris-DA solution is prepared by dissolving Tris-HCl in deionized water, adjusting the pH to 8.5 with hydrochloric acid, and then adding dopamine hydrochloride and stirring evenly.

5. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, The pretreated Na2MoO4 is obtained by ball-milling Na2MoO4 for 12 - 24 h.

6. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, The mixture A is prepared by mixing Zn(NO3)2·6H2O, the pretreated Na2MoO4, Ce(NO3)3·6H2O, Ga(NO3)3, and methanol evenly and magnetically stirring for 10 - 20 min; the mixture B is prepared by dissolving 2-methylimidazole in methanol and magnetically stirring for 10 - 20 min.

7. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, In step S2, mixture A and mixture B are mixed evenly, and a sodium hydroxide solution with a molar concentration of 0.1 mol / L is added to adjust the pH to 10.

0. At 25 °C, magnetic stirring is carried out at a speed of 500 rpm for 12 h. Then, deionized water is added, and after stirring for 5 - 10 min, centrifugation is carried out at 8000 rpm for 5 - 15 min. The supernatant is discarded, and the precipitate is collected. The precipitate is washed alternately with methanol and deionized water three times, then placed in a Tris-DA solution, and continuously contacted with surrounding oxygen at room temperature for 24 h. Subsequently, centrifugation is carried out at 2000 rpm for 5 - 10 min, and the precipitate is collected. Then, after washing with deionized water, vacuum drying is carried out at 40 - 60 °C for 24 h to obtain MoO4-loaded 2- zeolite microcapsules.

8. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, In step S3, mix epoxy-modified silicone resin and polyamide, magnetically stir, add MoO42--loaded zeolite microcapsules, slowly stir, and the stirring time for adding xylene and defoaming agent is 2 - 5 min, then perform ultrasonic treatment to obtain a mixed solution.

9. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, In step S3, the magnetic stirring speed is 300 rpm, the time is 5 - 10 min, the slow stirring speed is 100 rpm, the temperature of ultrasonic treatment is 20 °C, the time is 20 - 30 min, and it pauses for 10 s every 5 min during ultrasonic treatment.

10. The preparation method of a high-tungsten alloy oil casing according to claim 1, characterized in that, In step S3, fix the pretreated high-tungsten alloy tube on the impregnator bracket, vertically immerse it in the mixed solution, keep it immersed for 30 s, lift the pipe at a uniform speed of 0.5 m / min, after an interval of 5 min, immerse it for another 30 s, then place it horizontally in a dust-free room, level it at room temperature for 10 - 15 min, preheat it at 60 °C for 10 min, then fix it horizontally in a vacuum oven, heat it up to 80 °C at a rate of 2 °C / min, keep it warm for 2 h, naturally cool to 40 °C and then take it out to obtain a high-tungsten alloy oil casing.

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