An unconventional fracturing sleeve for acidic oil and gas development and its preparation method

Abstract

This invention provides a fracturing sleeve for unconventional acidic oil and gas development and its preparation method. The fracturing sleeve comprises the following chemical composition by mass percentage: C: 0.21%–0.29%, Si: 0.17%–0.37%, Mn: 0.40%–0.60%, P≤0.012%, S≤0.003%, Cr: 1.28%–1.38%, Ni: 0.50%–0.65%, Mo: 0.33%–0.48%, Cu: 0.26%–0.35%, Nb: 0.03%–0.06%, Ce: 0.006%–0.010%, Al: 0.026%–0.035%, Ca: 0.026%–0.035%, N≤0.004%, H≤0.00015%, O≤0.0020%, with the balance being Fe and other unavoidable impurities. The steel grade of this invention reaches 90ksi to 130ksi, with a room temperature yield strength of 718MPa to 996MPa, a tensile strength of 825MPa to 1095MPa, an elongation of 26% to 33%, and a transverse Charpy V-notch impact toughness of 122J to 164J at -20℃. The fracturing sleeve of this invention for unconventional acidic oil and gas development is a non-interventional, unlimited-stage completion fracturing sleeve, which combines comprehensive properties such as strength, toughness, resistance to hydrogen sulfide stress corrosion and hydrogen-induced cracking, and can meet the requirements of unconventional acidic oil and gas development for high-performance fracturing sleeves.

Description

Technical Field

[0001] This invention belongs to the field of fracturing sleeve manufacturing technology, and in particular relates to a fracturing sleeve for unconventional acidic oil and gas development and its preparation method. Background Technology

[0002] With the development of unconventional oil and gas resources, horizontal well fracturing tools have also evolved. In recent years, non-interventional, unlimited-stage fracturing sliding sleeve systems have been developed globally and applied to shale oil and gas horizontal well fracturing, becoming a new type of horizontal well fracturing tool. This technology features stability and efficiency, convenient construction, and precise well stimulation, and is widely used in the development of unconventional oil and gas such as shale oil and gas. To date, this technology has been used in over 300 wells and more than 12,000 fracturing operations both domestically and internationally, achieving excellent results and becoming one of the important technologies for accelerating oil and gas well fracturing.

[0003] The non-interventional, unlimited-level fracturing system mainly consists of an unlimited-level fracturing sliding sleeve, a soluble guided ball and screw clamp, a screw clamp launcher, and a monitoring system. The full-bore sliding sleeve is connected to the mains and inserted into the well along with the mains sleeve. After normal cementing and completion, the system awaits fracturing operations. During fracturing, the soluble guided ball and screw clamp are pumped into the sliding sleeve together. Once the corresponding sliding sleeve is opened, fracturing operations are performed. During fracturing, the screw clamp launcher, under pressure, is remotely operated to pump the screw clamp and soluble ball into the sliding sleeve, enabling continuous, uninterrupted pumping operations. After the screw clamp enters the sliding sleeve, the monitoring system locates its position in real time and determines whether the target sliding sleeve has opened.

[0004] In non-interventional, unlimited-level well completion fracturing sliding sleeve systems, the sliding sleeve, connected to the casing string, is a key structural component. During operation, it withstands complex combined loads including tension, compression, bending, torsion, internal pressure, and external pressure. To ensure its safe and reliable use, it requires high strength and good toughness. However, the strength and toughness of steel materials often exhibit a trade-off: higher strength usually results in lower toughness, and vice versa. For sliding sleeve materials, North America typically uses 4140H medium-carbon Mn-Cr-Mo low-alloy steel, while China typically uses 42CrMo medium-carbon low-alloy steel thick-walled tubing. Both undergo quenching and tempering heat treatment. With a yield strength of approximately 1000 MPa, the Charpy V-notch impact toughness is only 40 J–60 J, with significant differences in longitudinal and transverse toughness, resulting in a high risk of brittle fracture of the sliding sleeve.

[0005] On the other hand, similar to casing for oil and gas wells, fracturing sleeves are prone to sulfide stress corrosion damage in the acidic environment of hydrogen sulfide under the combined effect of corrosive media and working stress, often leading to serious consequences; moreover, the higher the material strength, the greater the probability of sulfide stress corrosion damage.

[0006] To meet the comprehensive performance requirements of fracturing sleeves in terms of strength, toughness, and resistance to hydrogen sulfide stress corrosion, and to overcome the shortcomings of existing technologies, it is necessary to develop a fracturing sleeve material and preparation process with a reasonable balance of strength and toughness for acidic environments. Summary of the Invention

[0007] In view of this, the present invention aims to propose a fracturing sleeve for unconventional acidic oil and gas development and its preparation method, so as to overcome the shortcomings of the prior art. The fracturing sleeve for unconventional acidic oil and gas development of the present invention is a non-interventional unlimited-stage completion fracturing sleeve, which has comprehensive properties such as strength, toughness, resistance to hydrogen sulfide stress corrosion and hydrogen-induced cracking, and can meet the requirements of unconventional acidic oil and gas development for high-performance fracturing sleeves.

[0008] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0009] A fracturing sleeve for unconventional acidic oil and gas development comprises the following chemical composition by mass percentage: C: 0.21%–0.29%, Si: 0.17%–0.37%, Mn: 0.40%–0.60%, P≤0.012%, S≤0.003%, Cr: 1.28%–1.38%, Ni: 0.50%–0.65%, Mo: 0.33%–0.48%, Cu: 0.26%–0.35%, Nb: 0.03%–0.06%, Ce: 0.006%–0.010%, Al: 0.026%–0.035%, Ca: 0.026%–0.035%, N≤0.004%, O+H+N≤0.007%, with the balance being Fe and other unavoidable impurities.

[0010] Preferably, the chemical composition includes the following percentages by mass: C: 0.21%–0.22%, Si: 0.17%–0.23%, Mn: 0.40%–0.43%, P≤0.012%, S≤0.003%, Cr: 1.28%–1.30%, Ni: 0.50%–0.52%, Mo: 0.33%–0.36%, Cu: 0.26%–0.28%, Nb: 0.03%, Ce: 0.006%, Al: 0.026%–0.028%, Ca: 0.026%–0.028%, N≤0.004%, O+H+N≤0.007%, with the balance being Fe and other unavoidable impurities.

[0011] Preferably, the chemical composition includes the following percentages by mass: C: 0.22%–0.23%, Si: 0.22%–0.24%, Mn: 0.44%–0.46%, P≤0.012%, S≤0.003%, Cr: 1.31%–1.33%, Ni: 0.54%–0.56%, Mo: 0.37%–0.38%, Cu: 0.29%–0.31%, Nb: 0.04%, Ce: 0.007%, Al: 0.029%–0.031%, Ca: 0.029%–0.031%, N≤0.004%, O+H+N≤0.007%, with the balance being Fe and other unavoidable impurities.

[0012] Preferably, the chemical composition includes the following percentages by mass: C: 0.23%–0.25%, Si: 0.25%–0.27%, Mn: 0.47%–0.49%, P≤0.012%, S≤0.003%, Cr: 1.34%–1.35%, Ni: 0.57%–0.59%, Mo: 0.40%–0.42%, Cu: 0.30%–0.32%, Nb: 0.05%, Ce: 0.008%, Al: 0.029%–0.031%, Ca: 0.030%–0.031%, N≤0.004%, O+H+N≤0.007%, with the balance being Fe and other unavoidable impurities.

[0013] Preferably, the chemical composition includes the following percentages by mass: C: 0.25%–0.27%, Si: 0.28%–0.30%, Mn: 0.54%–0.57%, P≤0.012%, S≤0.003%, Cr: 1.33%–1.35%, Ni: 0.60%–0.62%, Mo: 0.43%–0.45%, Cu: 0.30%–0.32%, Nb: 0.06%, Ce: 0.009%, Al: 0.030%–0.032%, Ca: 0.031%–0.032%, N≤0.004%, O+H+N≤0.007%, with the balance being Fe and other unavoidable impurities.

[0014] Preferably, the chemical composition includes the following percentages by mass: C: 0.27%–0.29%, Si: 0.32%–0.37%, Mn: 0.56%–0.60%, P≤0.012%, S≤0.003%, Cr: 1.36%–1.38%, Ni: 0.63%–0.65%, Mo: 0.46%–0.48%, Cu: 0.33%–0.35%, Nb: 0.06%, Ce: 0.010%, Al: 0.033%–0.035%, Ca: 0.033%–0.035%, N≤0.004%, O+H+N≤0.007%, with the balance being Fe and other unavoidable impurities.

[0015] This invention also provides a method for preparing the unconventional acidic oil and gas development fracturing sleeve as described above, comprising the following steps: steelmaking, continuous casting, piercing and hot rolling, heat treatment, hot straightening, stress-relieving tempering, finishing and threading.

[0016] Steelmaking: Batching, electric furnace or oxygen-blown converter steelmaking, ladle refining and vacuum degassing to obtain the above chemical composition, feeding Si-Ca wire to control the deformation of inclusions in the steel.

[0017] Continuous casting: molten steel is poured into a bar-shaped continuous casting billet. Electromagnetic stirring and light reduction techniques are used during the continuous casting process to control the center segregation of the continuous casting billet.

[0018] Piercing and hot rolling: The continuously cast billet is heated in an annular heating furnace at a temperature of 1170℃~1200℃ for 90min~120min. It is then hot-pierced at 1160℃~1190℃ and hot-rolled at 930℃~1150℃. The initial rolling temperature is 1150℃ and the final rolling temperature is 930℃. The rolling ratio is controlled to be ≥5. After final rolling, it is air-cooled.

[0019] Heat treatment: Heating in a protective atmosphere furnace is employed, including two quenching processes and high-temperature tempering. The first quenching temperature is controlled at 890℃~910℃, with a holding time of 60min~90min, and internal and external water spray quenching with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 650℃~700℃, and the tempering time is 90min~120min. The second quenching temperature is controlled at 870℃~890℃, with a holding time of 60min~90min, and internal and external water spray quenching with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 600℃~680℃, and the tempering time is 90min~120min. The resulting microstructure is tempered sorbite, followed by water cooling. Through two quenching and tempering heat treatments, a fine and uniform tempered sorbite microstructure with a grain size of 9~10 is obtained. Water cooling after tempering avoids potential temper brittleness.

[0020] Preferably, the temperature for hot straightening is controlled between 550℃ and 630℃;

[0021] Stress-relief tempering: In order to reduce the influence of residual stress on the corrosion resistance of the fracturing sleeve, after hot straightening, it is tempered at 530℃~610℃ for 90min~120min, and then water-cooled.

[0022] Finishing and threading: Finish the sleeves according to standards and / or user requirements, and machine API (American Petroleum Institute) standard threads or special threads, and perform magnetic particle testing on the threads.

[0023] To ensure the comprehensive performance requirements of sliding sleeves in terms of strength, toughness, and resistance to hydrogen sulfide stress corrosion during unlimited-stage well completion fracturing, their chemical composition and manufacturing process must be rationally designed.

[0024] In terms of composition design, this invention proposes to use medium to low C, control Mn, add alloying elements Cr, Ni, Mo, and Cu, micro-alloy Nb, add trace amounts of Ce, control harmful elements such as P, S, O, H, and N in the steel, perform full Al-Si deoxidation, and treat the molten steel with Ca.

[0025] The functions and content ranges of the main elements are as follows:

[0026] Carbon (C) is a major strengthening element in steel. Increased carbon content improves the hardenability of steel, thus increasing its strength; however, excessively high carbon content is detrimental to improving the steel's ductility, toughness, and corrosion resistance. Considering all factors, the carbon content should ideally be controlled within the range of 0.21% to 0.29%.

[0027] Si is a common element in steel and also an important deoxidizer. Its content should be controlled within the range of 0.17% to 0.37%.

[0028] Mn: Mn has a strong tendency to segregate, and excessively high content is detrimental to improving the corrosion resistance of steel, so it needs to be strictly controlled. It is advisable to control it within the range of 0.40% to 0.60%.

[0029] Cr: It is dissolved in steel to improve its hardenability and tempering stability, thereby increasing its strength. However, excessive content will increase costs. Considering all factors, it is advisable to control it within the range of 1.28% to 1.38%.

[0030] Ni: It is dissolved in steel to improve its hardenability and thus its strength. Its addition can also improve the toughness of steel, especially its low-temperature toughness, and reduce the hot brittleness that may be caused by the addition of Cu. However, excessive content will increase costs. Taking all factors into consideration, it is advisable to control it within the range of 0.50% to 0.65%.

[0031] Mo (Mo) is dissolved in steel to improve its hardenability and tempering stability, thereby increasing its strength. Adding Mo can also suppress the segregation of Mn and P, improve uniformity, and enhance the temper brittleness, toughness, and corrosion resistance of the steel. The effect is better when the Mo / P ratio is ≥25, but excessively high content will increase costs. Considering all factors, it is advisable to control the content within the range of 0.33% to 0.48%.

[0032] Cu: The addition of copper helps to form a copper-rich surface layer through selective dissolution and redeposition, effectively inhibiting hydrogen production from H2S decomposition and hindering hydrogen atom penetration into the steel. This significantly improves the steel's resistance to hydrogen sulfide stress corrosion cracking and hydrogen-induced cracking in acidic, humid environments containing H2S. To balance the risk of hot brittleness, the copper content must be strictly controlled and nickel (Ni / Cu ≥ 1) must be added. The synergistic effect of copper with elements such as chromium and molybdenum constitutes the alloying basis for the acid corrosion resistance, especially the resistance to sulfide corrosion cracking, of this type of steel. Considering all factors, the copper content should be controlled within the range of 0.26% to 0.35%.

[0033] Nb: When added to steel, it combines with C and N in the steel to form NbC and NbN, which inhibit austenite grain growth and refine the grains, thereby improving strength, toughness, and corrosion resistance. However, excessive content will form too many carbonitriding compounds, increasing the brittleness of the steel and leading to increased costs. Considering all factors, it is advisable to control the content within the range of 0.03% to 0.06%.

[0034] Ce has multiple functions, including purifying molten steel, refining grains, modifying inclusions, and alloying. Considering all factors, Ce should be controlled within the range of 0.006% to 0.010%.

[0035] Al: When combined with oxygen or nitrogen, it forms fine and uniformly distributed oxides or nitrides, which can refine grains and improve strength and toughness. It is also an important deoxidizer and nitrogen fixative. However, excessive content will affect the hot working properties of steel. The effect is better when Al / N ≥ 5. Taking all factors into consideration, it is advisable to control it within the range of 0.026% to 0.035%.

[0036] Ca: Adding it to steel can improve the properties and morphology of inclusions, thereby enhancing the steel's plasticity, toughness, and corrosion resistance. The effect is even better when Ca / S ≥ 5. Considering all factors, it is advisable to control it within the range of 0.026% to 0.035%.

[0037] P: A harmful element that mainly affects the plasticity and toughness of steel. P should be controlled to ≤0.012%.

[0038] S: A harmful element that mainly affects the ductility, toughness, and corrosion resistance of steel. S should ideally be controlled to ≤0.003%.

[0039] O, H, and N are harmful elements, mainly affecting the plasticity, toughness, and corrosion resistance of steel. Taking all factors into consideration, the total O+H+N should be controlled to ≤0.007%, with H ≤0.00015% and O ≤0.0020%. Considering the significant impact of N on the strain aging properties of steel, N should be controlled to ≤0.004%.

[0040] Compared with the 4140H medium-carbon Mn-Cr-Mo low-alloy steel and 42CrMo medium-carbon low-alloy steel commonly used in fracturing sleeves, this invention significantly reduces the C content (which is beneficial for improving toughness and corrosion resistance), controls the Mn content (controlling segregation and improving corrosion resistance), appropriately increases the Cr and Mo content (improving hardenability, strength, and toughness, and improving corrosion resistance), adds Ni (improving hardenability, strength, and toughness, and improving process performance) and Cu (improving strength and improving corrosion resistance), adds Nb (refining grains, improving strength, toughness, and corrosion resistance) and Ce (purifying molten steel, refining grains, modifying inclusions, alloying, improving strength and toughness, and improving corrosion resistance), performs Ca treatment, and controls harmful elements such as P, S, O, H, and N in the steel (controlling the properties and morphology of inclusions, and improving toughness and corrosion resistance). These elements, individually and especially in synergy, comprehensively improve the strength, toughness, and corrosion resistance of the sleeve.

[0041] In terms of fracturing sleeve preparation process, the main processes are steelmaking (including ladle refining and vacuum degassing), continuous casting, hot continuous rolling in the austenitic region, and heat treatment, so as to obtain a fine and uniform tempered sorbite microstructure and low residual stress in the material, thereby achieving a reasonable match between the strength, toughness and corrosion resistance of the sleeve material.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] Through optimized chemical composition design, the individual and especially synergistic effects of each alloying element, and unique preparation processes, including improved purity, control of inclusion properties and morphology, segregation control, and rational heat treatment to regulate microstructure, grain size, and residual stress, the strength, toughness, and corrosion resistance of the fracturing sleeve are rationally matched, achieving a steel grade of 90ksi to 130ksi. Its room temperature yield strength is 718MPa to 996MPa, tensile strength is 825MPa to 1095MPa, elongation is 26% to 33%, and transverse Charpy V-notch impact toughness at -20℃ is 122J to 164J. Following the NACE™ 0177 A method, H₂S stress corrosion testing with A solution, at a stress of 85% and / or 95% of the specified minimum yield strength (SMYS), for 720 hours, no cracks or fractures were observed. According to the NACE TM0284 A solution hydrogen-induced cracking (HIC) test for 96 hours, the crack length ratio (CLR) ≤ 15%, the crack thickness ratio (CTR) ≤ 5%, and the crack sensitivity ratio (CSR) ≤ 2%. Under complex loads, it exhibits excellent deformation and fracture resistance, resistance to hydrogen sulfide stress corrosion and hydrogen-induced cracking, long service life, and high safety and reliability. It effectively adapts to the complex working conditions in unconventional acidic oil and gas extraction, improving the efficiency and economic benefits of unconventional oil and gas development. Detailed Implementation

[0044] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art. Unless otherwise specified, the experimental methods described are conventional methods.

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to specific examples. Example

[0046] The chemical composition of the unconventional acidic oil and gas development fracturing sleeves provided in the embodiments of the present invention, with minimum yield strengths of 90 ksi, 95 ksi, 110 ksi, 125 ksi and 130 ksi respectively, is shown in Table 1, with the balance being Fe and unavoidable impurities.

[0047] Table 1 Chemical composition (mass percentage, %) of fracturing sleeves used in unconventional acidic oil and gas development in the examples

[0048] number C Yes Mn P S Cr Ni Mo Cu Nb Yes Al Ca N H 0 1(90ksi) 0.21 0.20 0.42 0.011 0.003 1.29 0.50 0.36 0.26 0.03 0.006 0.026 0.027 0.0039 0.00015 0.0020 2(90ksi) 0.22 0.17 0.43 0.010 0.002 1.30 0.52 0.33 0.28 0.03 0.006 0.028 0.026 0.0037 0.00013 0.0018 3(90ksi) 0.22 0.23 0.40 0.011 0.003 1.28 0.51 0.35 0.27 0.03 0.006 0.027 0.028 0.0038 0.00014 0.0019 4(95ksi) 0.23 0.22 0.44 0.010 0.003 1.32 0.55 0.37 0.30 0.04 0.007 0.030 0.031 0.0036 0.00013 0.0018 5(95ksi) 0.22 0.24 0.46 0.011 0.002 1.31 0.56 0.37 0.29 0.04 0.007 0.029 0.029 0.0038 0.00012 0.0017 6(95ksi) 0.23 0.23 0.45 0.010 0.003 1.33 0.54 0.38 0.31 0.04 0.007 0.031 0.030 0.0037 0.00014 0.0019 7(110ksi) 0.24 0.25 0.48 0.009 0.002 1.35 0.57 0.40 0.30 0.05 0.008 0.030 0.031 0.0036 0.00013 0.0016 8(110ksi) 0.23 0.27 0.49 0.009 0.002 1.34 0.59 0.42 0.32 0.05 0.008 0.031 0.030 0.0035 0.00011 0.0018 9(110ksi) 0.25 0.26 0.47 0.009 0.002 1.35 0.58 0.41 0.31 0.05 0.008 0.029 0.030 0.0037 0.00012 0.0017 10(125ksi) 0.26 0.28 0.54 0.009 0.002 1.33 0.60 0.43 0.31 0.06 0.009 0.031 0.031 0.0036 0.00011 0.0017 11(125ksi) 0.27 0.30 0.57 0.009 0.002 1.35 0.62 0.45 0.30 0.06 0.009 0.030 0.032 0.0034 0.00013 0.0015 12(125ksi) 0.25 0.29 0.55 0.010 0.002 1.34 0.61 0.44 0.32 0.06 0.009 0.032 0.031 0.0035 0.00010 0.0016 13(130ksi) 0.28 0.35 0.60 0.009 0.002 1.36 0.65 0.47 0.33 0.06 0.010 0.035 0.034 0.0035 0.00012 0.0016 14(130ksi) 0.29 0.32 0.56 0.009 0.002 1.38 0.63 0.46 0.35 0.06 0.010 0.033 0.035 0.0033 0.00010 0.0014 15(130ksi) 0.27 0.37 0.58 0.009 0.002 1.37 0.64 0.48 0.34 0.06 0.010 0.034 0.033 0.0034 0.00011 0.0015

[0049] This invention also provides a method for preparing unconventional sour oil and gas development fracturing sleeves with minimum yield strengths of 90 ksi, 95 ksi, 110 ksi, 125 ksi, and 130 ksi, respectively, comprising the following steps:

[0050] ① Steelmaking: Batching, oxygen-blown converter steelmaking, ladle refining and vacuum degassing to obtain the chemical composition shown in Table 1, feeding Si-Ca wire to control the deformation of inclusions in the steel.

[0051] ② Continuous casting: The molten steel is cast into a bar-shaped continuous casting billet. Electromagnetic stirring and light reduction technology are used in the continuous casting process to control the center segregation of the continuous casting billet.

[0052] ③ Piercing and Hot Continuous Rolling: The continuously cast billet is heated in an annular heating furnace at 1190℃ for 120 minutes. Hot piercing is performed at 1160℃~1190℃, followed by hot continuous rolling at 930℃~1150℃. The initial rolling temperature is 1150℃, the final rolling temperature is 930℃, and the rolling ratio is 5. After final rolling, the billet is air-cooled and then cut to the appropriate length.

[0053] ④ Heat Treatment: A protective atmosphere furnace (75% N2 + 25% H2 volume fraction, a nitrogen-hydrogen mixed reducing atmosphere to prevent oxidation and decarburization) is used for heating, followed by two quenchings and high-temperature tempering. The first quenching and tempering heat treatment involves a quenching temperature of 900℃, a holding time of 90 min, internal and external water spray quenching, and a cooling rate ≥30℃ / s; the tempering temperature is 680℃, and the tempering time is 120 min. The second quenching and tempering heat treatment involves a quenching temperature of 880℃, a holding time of 90 min, internal and external water spray quenching, and a cooling rate ≥30℃ / s; the tempering temperature is controlled between 600℃ and 680℃ (adjusted according to different steel grades, see Table 2), and the tempering time is 120 min. The microstructure is tempered sorbite with a grain size of 9–10, and water cooling is performed after tempering.

[0054] ⑤ Hot straightening: After heat treatment, hot straightening is performed at a temperature of 550℃~630℃ (adjusted according to different steel grades, see Table 2), followed by water cooling.

[0055] ⑥ Stress-relieving tempering: After hot straightening, temper at 530℃~610℃ (adjusted according to different steel grades, see Table 2) for 120 minutes, followed by water cooling.

[0056] ⑦ Machining and thread processing: Machining of the sleeve according to standards and user requirements, processing of API standard threads or special threads, and magnetic particle testing of the threads.

[0057] Performance characteristics of the sliding sleeve: The fracturing sliding sleeve for unconventional sour oil and gas development of this invention, after appropriate manufacturing process, possesses excellent comprehensive properties such as strength, toughness, resistance to hydrogen sulfide stress corrosion, and hydrogen-induced cracking (see Table 2 for details). The steel grade reaches 90ksi~130ksi, room temperature yield strength 718MPa~996MPa, tensile strength 825MPa~1095MPa, elongation 26%~33%, and transverse Charpy V-notch impact toughness at -20℃ 122J~164J. It can meet the requirements of unconventional sour oil and gas development for fracturing sliding sleeves with excellent comprehensive performance.

[0058] Among them, the yield strength of the 90ksi grade fracturing sleeve for unconventional acidic oil and gas development reaches 718MPa~723MPa, the tensile strength is 825MPa~831MPa, the elongation is 33%, and the transverse Charpy V-notch impact toughness at -20℃ is 161J~164J.

[0059] The yield strength of the 95ksi grade fracturing sleeve for unconventional acidic oil and gas development reaches 751MPa~755MPa, the tensile strength is 863MPa~868MPa, the elongation is 32%, and the transverse Charpy V-notch impact toughness at -20℃ is 151J~155J.

[0060] The yield strength of the 110ksi grade fracturing sleeve for unconventional acidic oil and gas development reaches 851MPa~855MPa, the tensile strength is 956MPa~961MPa, the elongation is 30%, and the transverse Charpy V-notch impact toughness at -20℃ is 143J~146J.

[0061] The yield strength of the 125ksi grade fracturing sleeve for unconventional acidic oil and gas development reaches 955MPa~960MPa, the tensile strength is 1049MPa~1055MPa, the elongation is 27%, and the transverse Charpy V-notch impact toughness at -20℃ is 129J~133J.

[0062] The yield strength of the 130ksi grade fracturing sleeve for unconventional acidic oil and gas development reaches 992MPa~996MPa, the tensile strength is 1091MPa~1095MPa, the elongation is 26%, and the transverse Charpy V-notch impact toughness at -20℃ is 122J~125J.

[0063] According to the NACE™ 0177 A method, solution A H2S stress corrosion test was conducted: For fracturing sleeves of 90ksi, 95ksi, and 110ksi steel grades used in unconventional sour oil and gas development, with applied stresses of 85% and 95% of the specified minimum yield strength (SMYS) for 720 hours, no cracks or fractures occurred; for fracturing sleeves of 125ksi and 130ksi steel grades used in unconventional sour oil and gas development, with applied stresses of 85% of the specified minimum yield strength (SMYS) for 720 hours, no cracks or fractures occurred. (See Table 2 for specific applied stress levels).

[0064] Hydrogen-induced cracking (HIC) tests were conducted on solution A according to the NACE TM0284 method for 96 hours. The crack length ratio (CLR), crack thickness ratio (CTR), and crack sensitivity ratio (CSR) were all 0.

[0065] The same numbers in Table 1 and Table 2 correspond to the same embodiment.

[0066] Table 2 Key manufacturing processes and performance characteristics of fracturing sleeves for unconventional acidic oil and gas development in the examples.

[0067]

[0068]

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fracturing sleeve for unconventional acidic oil and gas development, characterized in that: The chemical composition includes the following percentages by mass: C: 0.21%–0.22%, Si: 0.17%–0.23%, Mn: 0.40%–0.43%, P≤0.012%, S≤0.003%, Cr: 1.28%–1.30%, Ni: 0.50%–0.52%, Mo: 0.33%–0.36%, Cu: 0.26%–0.28%, Nb: 0.03%, Ce: 0.006%, Al: 0.026%–0.028%, Ca: 0.026%–0.028%, N≤0.004%, H≤0.00015%, O≤0.0020%, with the balance being Fe and other unavoidable impurities. The preparation method includes the following steps: steelmaking, continuous casting, piercing and hot rolling, heat treatment, hot straightening, stress-relieving tempering, finishing and thread machining. In the piercing and hot rolling process, the furnace temperature is 1170℃~1200℃, the heating time is 90min~120min, hot piercing is performed at 1160℃~1190℃, and hot rolling is performed at 930℃~1150℃. The initial rolling temperature is 1150℃, the final rolling temperature is 930℃, and the rolling ratio is controlled to be ≥5. After final rolling, air cooling is performed. The heat treatment uses a protective atmosphere furnace, including two quenchings and high-temperature tempering. The first quenching temperature is controlled at 890℃~910℃, and the holding time is 60 minutes. The process involves internal and external water quenching for 90-120 minutes, with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 650℃-700℃, and the tempering time is 90-120 minutes. The second quenching temperature is controlled at 870℃-890℃, with a holding time of 60-90 minutes. The process involves internal and external water quenching with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 600℃-680℃, and the tempering time is 90-120 minutes. After tempering, the parts are water-cooled. The hot straightening temperature is controlled at 550℃-630℃. The stress-relief tempering is performed at 530℃-610℃ for 90-120 minutes.

2. A fracturing sleeve for unconventional acidic oil and gas development, characterized in that: The chemical composition includes the following percentages by mass: C: 0.22%–0.23%, Si: 0.22%–0.24%, Mn: 0.44%–0.46%, P≤0.012%, S≤0.003%, Cr: 1.31%–1.33%, Ni: 0.54%–0.56%, Mo: 0.37%–0.38%, Cu: 0.29%–0.31%, Nb: 0.04%, Ce: 0.007%, Al: 0.029%–0.031%, Ca: 0.029%–0.031%, N≤0.004%, H≤0.00015%, O≤0.0020%, with the balance being Fe and other unavoidable impurities. The preparation method includes the following steps: steelmaking, continuous casting, piercing and hot rolling, heat treatment, hot straightening, stress-relieving tempering, finishing and thread machining. In the piercing and hot rolling process, the furnace temperature is 1170℃~1200℃, the heating time is 90min~120min, hot piercing is performed at 1160℃~1190℃, and hot rolling is performed at 930℃~1150℃. The initial rolling temperature is 1150℃, the final rolling temperature is 930℃, and the rolling ratio is controlled to be ≥5. After final rolling, air cooling is performed. The heat treatment uses a protective atmosphere furnace, including two quenchings and high-temperature tempering. The first quenching temperature is controlled at 890℃~910℃, and the holding time is 60 minutes. The process involves internal and external water quenching for 90-120 minutes, with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 650℃-700℃, and the tempering time is 90-120 minutes. The second quenching temperature is controlled at 870℃-890℃, with a holding time of 60-90 minutes. The process involves internal and external water quenching with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 600℃-680℃, and the tempering time is 90-120 minutes. After tempering, the parts are water-cooled. The hot straightening temperature is controlled at 550℃-630℃. The stress-relief tempering is performed at 530℃-610℃ for 90-120 minutes.

3. A fracturing sleeve for unconventional acidic oil and gas development, characterized in that: The chemical composition includes the following percentages by mass: C: 0.23%–0.25%, Si: 0.25%–0.27%, Mn: 0.47%–0.49%, P≤0.012%, S≤0.003%, Cr: 1.34%–1.35%, Ni: 0.57%–0.59%, Mo: 0.40%–0.42%, Cu: 0.30%–0.32%, Nb: 0.05%, Ce: 0.008%, Al: 0.029%–0.031%, Ca: 0.030%–0.031%, N≤0.004%, H≤0.00015%, O≤0.0020%, with the balance being Fe and other unavoidable impurities. The preparation method includes the following steps: steelmaking, continuous casting, piercing and hot rolling, heat treatment, hot straightening, stress-relieving tempering, finishing and thread machining. In the piercing and hot rolling process, the furnace temperature is 1170℃~1200℃, the heating time is 90min~120min, hot piercing is performed at 1160℃~1190℃, and hot rolling is performed at 930℃~1150℃. The initial rolling temperature is 1150℃, the final rolling temperature is 930℃, and the rolling ratio is controlled to be ≥5. After final rolling, air cooling is performed. The heat treatment uses a protective atmosphere furnace, including two quenchings and high-temperature tempering. The first quenching temperature is controlled at 890℃~910℃, and the holding time is 60 minutes. The process involves internal and external water quenching for 90-120 minutes, with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 650℃-700℃, and the tempering time is 90-120 minutes. The second quenching temperature is controlled at 870℃-890℃, with a holding time of 60-90 minutes. The process involves internal and external water quenching with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 600℃-680℃, and the tempering time is 90-120 minutes. After tempering, the parts are water-cooled. The hot straightening temperature is controlled at 550℃-630℃. The stress-relief tempering is performed at 530℃-610℃ for 90-120 minutes.

4. A fracturing sleeve for unconventional acidic oil and gas development, characterized in that: The chemical composition includes the following percentages by mass: C: 0.25%–0.27%, Si: 0.28%–0.30%, Mn: 0.54%–0.57%, P≤0.012%, S≤0.003%, Cr: 1.33%–1.35%, Ni: 0.60%–0.62%, Mo: 0.43%–0.45%, Cu: 0.30%–0.32%, Nb: 0.06%, Ce: 0.009%, Al: 0.030%–0.032%, Ca: 0.031%–0.032%, N≤0.004%, H≤0.00015%, O≤0.0020%, with the balance being Fe and other unavoidable impurities. The preparation method includes the following steps: steelmaking, continuous casting, piercing and hot rolling, heat treatment, hot straightening, stress-relieving tempering, finishing and thread machining. In the piercing and hot rolling process, the furnace temperature is 1170℃~1200℃, the heating time is 90min~120min, hot piercing is performed at 1160℃~1190℃, and hot rolling is performed at 930℃~1150℃. The initial rolling temperature is 1150℃, the final rolling temperature is 930℃, and the rolling ratio is controlled to be ≥5. After final rolling, air cooling is performed. The heat treatment uses a protective atmosphere furnace, including two quenchings and high-temperature tempering. The first quenching temperature is controlled at 890℃~910℃, and the holding time is 60 minutes. The process involves internal and external water quenching for 90-120 minutes, with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 650℃-700℃, and the tempering time is 90-120 minutes. The second quenching temperature is controlled at 870℃-890℃, with a holding time of 60-90 minutes. The process involves internal and external water quenching with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 600℃-680℃, and the tempering time is 90-120 minutes. After tempering, the parts are water-cooled. The hot straightening temperature is controlled at 550℃-630℃. The stress-relief tempering is performed at 530℃-610℃ for 90-120 minutes.

5. A fracturing sleeve for unconventional acidic oil and gas development, characterized in that: The chemical composition includes the following percentages by mass: C: 0.27%–0.29%, Si: 0.32%–0.37%, Mn: 0.56%–0.60%, P≤0.012%, S≤0.003%, Cr: 1.36%–1.38%, Ni: 0.63%–0.65%, Mo: 0.46%–0.48%, Cu: 0.33%–0.35%, Nb: 0.06%, Ce: 0.010%, Al: 0.033%–0.035%, Ca: 0.033%–0.035%, N≤0.004%, H≤0.00015%, O≤0.0020%, with the balance being Fe and other unavoidable impurities. The preparation method includes the following steps: steelmaking, continuous casting, piercing and hot rolling, heat treatment, hot straightening, stress-relieving tempering, finishing and thread machining. In the piercing and hot rolling process, the furnace temperature is 1170℃~1200℃, the heating time is 90min~120min, hot piercing is performed at 1160℃~1190℃, and hot rolling is performed at 930℃~1150℃. The initial rolling temperature is 1150℃, the final rolling temperature is 930℃, and the rolling ratio is controlled to be ≥5. After final rolling, air cooling is performed. The heat treatment uses a protective atmosphere furnace, including two quenchings and high-temperature tempering. The first quenching temperature is controlled at 890℃~910℃, and the holding time is 60 minutes. The process involves internal and external water quenching for 90-120 minutes, with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 650℃-700℃, and the tempering time is 90-120 minutes. The second quenching temperature is controlled at 870℃-890℃, with a holding time of 60-90 minutes. The process involves internal and external water quenching with a cooling rate ≥30℃ / s. The tempering temperature is controlled at 600℃-680℃, and the tempering time is 90-120 minutes. After tempering, the parts are water-cooled. The hot straightening temperature is controlled at 550℃-630℃. The stress-relief tempering is performed at 530℃-610℃ for 90-120 minutes.

Images