Performance improvement method for copper-based shape memory alloy and product and application thereof

Abstract

The application discloses a performance improvement method suitable for a copper-based shape memory alloy and a product thereof, and the copper-based shape memory alloy with a proper wire diameter and component is subjected to a dilute crystal degree regulation heat treatment and a graded quenching heat treatment to modulate a phase change temperature and prevent martensite stabilization, and the copper-based shape memory alloy with improved performance is subjected to spiral winding, winding and weaving, cold pressure forming and other steps to obtain a screen pipe material, which has high thermal conductivity and stable shape memory effect and has high recoverable strain at high temperature. The preparation process of the application is simple, the equipment cost and material cost are low, and the reliability is high. The application also discloses a filter pipe assembly and a use method thereof, and has a good application prospect in the field of sand prevention technology for oil and gas drilling and well completion.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil exploitation, and particularly relates to a performance improvement method suitable for a copper-based shape memory alloy and a product thereof, and further relates to a preparation method of a screen pipe material suitable for operation in a high-temperature oil well and a product and application thereof. BACKGROUND

[0002] The process of oil exploitation is generally divided into four steps of exploration-drilling-completion-production, wherein the completion procedure is the last step before the exploitation of the oil reservoir, and the working target is to connect the oil and gas reservoir and the wellbore of the drilling, so that the subsequent exploitation work can be carried out smoothly. However, in the production process, due to the changes in the rock mechanics performance caused by the disturbance of the drilling to the stratum, the pressure difference between the inside and outside of the wellbore pipeline and other factors, the stratum sand inevitably flows into the wellbore during oil production, resulting in problems such as equipment wear, pipeline blockage and even oil well abandonment.

[0003] Among several mainstream completion technologies, the old casing perforation completion method and the open hole completion method are not suitable for preventing the sand production, and thus both of them are only suitable for the stratum with small sand production. In the face of the sand production problem, the traditional solution is to use gravel packing, that is, to fill the wellbore annulus with the gravel slurry to create a gravel packing layer for the oil production pipeline to block the oil reservoir sand from flowing into the oil production pipeline. However, the gravel packing still has many shortcomings. First, the gravel packing layer needs to pump the gravel slurry from the ground downward, which is prone to problems such as jamming, breakage and deformation, and the workover operation is difficult; second, the gravel packing technology needs to use a separately designed packer and needs to run in two pipe columns, and thus the technology is complex; and finally, the gravel packing technology is not mature on the horizontal well pipeline, and for the horizontal well, the collapse is easy to occur during the completion and perforation, and the downhole equipment is damaged.

[0004] In view of the problem of sand production in oil and gas pipelines, the American Baker Hughes Oilfield Technology Service Company developed a kind of intelligent screen pipe material based on porous shape memory polymer (Shape Memory Polymer, SMP) (Shape memory polyurethane foam for downhole sand control filtration devices, US patent 7926565B2, 2011-04-19; Variable Tg Shape memory Polyurethane for wellbore devices US patent, 8365833B2.2013-02-05). The intelligent screen pipe is composed of a porous base pipe in the inner layer and a porous shape memory polymer in the outer layer. Before going down the well, the soft porous shape memory polymer in the outer layer is compressed (50-80% compression), and then it is lowered into the well. The porous shape memory polymer will expand to its original size under the high temperature environment and the assistance of acid in the well, filling the annulus of different sizes of the wellbore, and generating a supporting force on the surrounding well wall, further preventing sand production from the bottom of the well.

[0005] However, the above-mentioned porous shape memory polymer has low recovery stress, and its shape recovery is not complete when encountering obstacles or complex pipelines. In addition, such materials require a large amount of acid to lower their shape memory recovery transition temperature, resulting in high cost. Finally, such materials cannot be used in high temperature conditions, with a maximum use temperature of only 93℃. However, more than 70% of the world's oil resources belong to the range of heavy oil, super heavy oil and bitumen. The exploitation of these oil and gas resources requires the use of thermal recovery methods, resulting in a well bottom temperature of more than 200℃. The performance of the porous shape memory polymer screen pipe is unstable in high temperature environment, and it is prone to creep and large stress relaxation, and even melting failure.

[0006] In order to solve the above problems, the patent document with publication number CN114352239A discloses a kind of ultra-high strain recovery shape memory alloy screen pipe material and preparation method and application. The disclosed NiTi shape memory alloy screen pipe material can be applied in high temperature oil well, but the raw material price of NiTi shape memory alloy screen pipe material is expensive, and the forming pressure required for preparing NiTi memory alloy wire screen pipe material is large, and the cold pressure holding force of the screen pipe material is as high as 2-80kN when it is formed, which further leads to high cost of screen pipe material forming equipment. On the other hand, the thermal conductivity of NiTi alloy does not exceed 20W / (m·K), and it is difficult to achieve the softening of heavy oil at the bottom of the well in the steam drive oil recovery process. The prior art also discloses that the compression stress of 50% is 49.79MPa.

[0007] The copper-based shape memory alloy has relatively low cost and better heat conduction performance than the NiTi alloy, and has obvious advantages as a screen pipe material of an oil well, but the memory effect of the copper-based shape memory alloy is caused by thermal-elastic martensitic phase change and reverse change, and the martensitic stabilization phenomenon is easy to occur, that is, the thermal-elastic martensite is not easy to reverse, the reversible amount of the martensite is reduced, and even the thermal-elasticity is lost, resulting in loss of the shape memory effect.

[0008] Based on the above, the martensitic stabilization phenomenon seriously damages the memory effect of the copper-based shape memory alloy, and the present application aims to prevent the martensitic stabilization of the copper-based shape memory alloy, improve the reliability of the copper-based shape memory alloy during use, and make the copper-based shape memory alloy be used as a screen pipe material of an oil well and be used in a high-temperature environment. SUMMARY

[0009] In view of the problems in the related art, the present application provides a performance improvement method suitable for a copper-based shape memory alloy, a product and application thereof, to overcome the above technical problems existing in the prior art.

[0010] The technical scheme of the present application is implemented as follows:

[0011] A performance improvement method suitable for a copper-based shape memory alloy, comprising the following steps:

[0012] (1) placing the copper-based shape memory alloy wire in a reaction device for sand bath heating, and then taking out the copper-based shape memory alloy wire for rapid cooling after heat preservation at 600-900 DEG C for 4-30 hours in a vacuum environment or in an inert atmosphere;

[0013] (2) placing the cooled copper-based shape memory alloy wire into the reaction device again for sand bath heating, and then taking out the copper-based shape memory alloy wire for rapid cooling after heat preservation at 750-900 DEG C for 10-30 minutes in a vacuum environment or in an inert atmosphere;

[0014] (3) oil bath heating the cooled copper-based shape memory alloy wire, and then taking out the copper-based shape memory alloy wire for rapid cooling after heat preservation at 120-160 DEG C for 0.5-2 hours, and then cleaning to remove surface oil stains.

[0015] Compared with the prior art, first, the present application improves the crystal fineness of the copper-based shape memory alloy through heat treatment, reduces the number of three-pronged grain boundaries in the copper-based shape memory alloy, and further significantly improves the mechanical properties and shape memory effect of the copper-based shape memory alloy;

[0016] Secondly, the regulation of the crystal fineness can also effectively improve the recovery performance of the screen pipe material containing the copper-based shape memory alloy of the present application, and can be made into different degrees of recoverable strain to meet different needs corresponding to complex and variable conditions in high-temperature oil wells.

[0017] Again, on the basis of the dilute crystal degree regulation, the application adopts a special step quenching heat treatment method to prevent martensite stabilization, so that the copper-based shape memory alloy has excellent and stable shape memory recovery strain, and adjusts the phase change temperature (A f temperature) of the copper-based shape memory alloy in the range of 29.9-99.8℃, that is, the phase change temperature suitable for downhole high temperature working conditions, and further makes the screen pipe material containing the copper-based shape memory alloy of the application reliable and high recovery strain under high temperature conditions (100-350℃).

[0018] Finally, the method for preparing the copper-based shape memory alloy wire of the application is simple and easy to operate, and the raw material cost and processing cost are relatively low compared with the existing NiTi shape memory alloy. On the other hand, the thermal conductivity of NiTi shape memory alloy at 200℃ is about 13.2W / m·K, which is much lower than that of the copper-based shape memory alloy (more than 300W / m·K) of the application. Therefore, the copper-based shape memory alloy prepared by the application has a significant advantage when used for steam-driven oil production to soften the viscosity of the bottom hole reservoir.

[0019] Preferably, in step (1), the copper-based shape memory alloy wire is CuZnAl, wherein the atomic percentage of Cu is 66.02-81.75%, the atomic percentage of Zn is 15.09-24.52%, and the atomic percentage of Al is 3.05-9.88%.

[0020] Preferably, the wire diameter of the copper-based shape memory alloy wire is 0.7-1.2mm.

[0021] Preferably, in steps (1) and (2), the fine sand of the sand bath heating is Al2O3 small balls.

[0022] More preferably, the ball diameter of the Al2O3 small balls is smaller than the wire diameter of the copper-based shape memory alloy wire; specifically, the ball diameter of the Al2O3 small balls is 0.25mm.

[0023] Preferably, in step (3), the oil used for oil bath heating is dimethyl silicone oil.

[0024] Preferably, in step (3), the specific operation of cleaning is: using a 95% alcohol solution with a mass concentration for ultrasonic cleaning for 10-30min.

[0025] Preferably, the application realizes rapid cooling of steps (1) to (3) by water quenching.

[0026] The application further discloses a copper-based shape memory alloy wire prepared by the performance improving method for the copper-based shape memory alloy, and the copper-based shape memory alloy wire is single martensite phase at room temperature.

[0027] The average grain diameter of the copper-based shape memory alloy wire is 0.006-0.51 mm, and the crystal thinness is 0.006-0.51.

[0028] The martensite phase transformation completion temperature M f ≤50.5℃, and the phase transition point A f <100℃.

[0029] Based on the copper-based shape memory alloy wire with improved performance, the application further studies how to prepare the screen pipe material, and specifically, the copper-based shape memory alloy wire is prepared into a spiral roll, wound into a preform and cold-pressed into a screen pipe material through a plurality of processes, the screen pipe material is prepared by intertangling the copper-based shape memory alloy wires with adjusted crystal thinness and phase transition temperature, different crystal thinness brings different performance of the copper-based shape memory alloy wire, so as to adjust the recoverable strain of the screen pipe material, and the preparation method of the screen pipe material is high in reliability and easy to realize mass production.

[0030] The application further discloses a preparation method of the screen pipe material, which comprises the following steps.

[0031] (1) a cylindrical first mandrel is prepared, the copper-based shape memory alloy wire is wound around the first mandrel and stretched, and the copper-based shape memory alloy wire is inclined to the axis of the first mandrel to form a spiral roll;

[0032] (2) the spiral roll prepared in step (1) is embedded and interlocked through winding, laying and weaving to prepare a preform with stable structure;

[0033] (3) the preform prepared in step (2) is placed in a mold for cold-pressing to prepare the screen pipe material.

[0034] Preferably, in step (1), the ratio of the wire diameter of the copper-based shape memory alloy wire to the diameter of the first mandrel is 5-15:1

[0035] Preferably, in step (1), the copper-based shape memory alloy wire is inclined to the axis of the first mandrel to form an included angle of 40-60°, which is defined as a spiral angle.

[0036] Preferably, the specific operation of step (2) is: a cylindrical second mandrel is prepared, the spiral coil prepared in step (1) is inclined to the axis of the second mandrel, the spiral coil is reciprocally wound around the second mandrel until the spiral coil is completely wound, and the end of the spiral coil is embedded and end-capped to lock and prevent disengagement, thereby obtaining a preform.

[0037] Preferably, the diameter of the second mandrel is smaller than the diameter of the first mandrel; the diameter of the first mandrel is 3-10 mm, and the diameter of the second mandrel is 0.5-4 mm.

[0038] Preferably, in step (2), the spiral coil is inclined to the axis of the second mandrel to form an included angle of 40-50°, which is defined as the winding included angle.

[0039] Preferably, in step 3), the loading rate of the cold pressing is 5-12 mm / min, displacement control loading is used during compression, the cold pressing pressure is at least 900 N, and the pressure holding time is 2-15 min. As can be seen from the cold pressing pressure of this step, the cold pressing pressure required for the forming of the screen pipe material of the present application is small, and compared with the forming pressure of 2-80 kN of the NiTi shape memory alloy, the processing cost of the screen pipe material of the present application is relatively low.

[0040] Preferably, the length of the preform prepared in step (2) to the height of the screen pipe material after cold pressing in the cold pressing direction is 2-10:1.

[0041] Preferably, the first mandrel and the second mandrel are both metal mandrels made of stainless steel or carbon steel.

[0042] The present application also discloses a screen pipe material prepared by the above-mentioned method.

[0043] Specifically, the screen pipe material is composed of the above-mentioned copper-based shape memory alloy wires intertwined with each other, the gaps between the wires constitute the pores in the screen pipe material that are interconnected, and the porosity of the screen pipe material is 75-85%.

[0044] The stress corresponding to the compression strain of 50% of the screen pipe material is 2.81-22.67 MPa, which is much lower than the stress 49.79 MPa corresponding to the compression strain of 50% of the NiTi shape memory alloy screen pipe material in the prior art.

[0045] The screen pipe material has excellent high-temperature resistance and heat conduction performance, and the thermal conductivity coefficient is higher than 300 W / m·K, which can be used for sand prevention in oil and gas drilling and completion, and is particularly suitable for thick oil wells with an environmental temperature higher than 200℃ that require high-thermal-conductivity screen pipe materials.

[0046] The shape recovery can be realized spontaneously under high temperature, the recoverable strain can reach 33-50% at 100-350 DEG C, and the use requirement of the recoverable strain of no less than 20.4% in actual production is met; meanwhile, the simple and economical method of adjusting and controlling the crystal thinness is adopted to make the screen pipe material have different recovery performances, and the method is especially suitable for the complicated and changeable high-temperature oil well mining requirement.

[0047] The application further discloses a filter pipe assembly suitable for operation in a high-temperature oil well, which comprises a porous base pipe sleeved outside an oil pipe, and a screen pipe sleeved outside the porous base pipe.

[0048] The height of the screen pipe material in the direction of the cold-pressing pressure is used as the thickness of the screen pipe.

[0049] The application further discloses a use method of the filter pipe assembly, which comprises the following steps.

[0050] 1) the screen pipe is sleeved on the porous base pipe, and the initial thickness of the screen pipe is H0;

[0051] 2) the temperature T is controlled to be less than M f , that is, in the low-temperature martensite phase state, a load is applied to the peripheral wall of the screen pipe to deform and constrain the shape, so that the thickness H1 of the screen pipe after being pressed is less than H0;

[0052] 3) the environmental temperature T of the oil well is greater than M a >A f The filter pipe assembly in step 2) is lowered into the oil well, and due to the coupling effect of the structure recovery (pore structure) and the phase change recovery (martensite phase change) of the screen pipe material, the screen pipe can realize great strain recovery, the screen pipe is expanded to the thickness H2 greater than H0, and the installation is completed.

[0053] The microstructure inside the screen pipe material after shape recovery, that is, expansion, is still the alloy wire intertwining each other, and the stable and unique pore structure can ensure that the oil and gas can smoothly enter the oil pipe through the embodiment, and the sand and stone can be effectively blocked. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 It is a whole technological flow chart of the copper-based shape memory alloy wire and the screen pipe material of the application;

[0055] Figure 2 It is a metallographic photo and a grain schematic view of embodiment 1 of the application;

[0056] Figure 3 It is a metallographic photo and a grain schematic view of embodiment 3 of the application;

[0057] Figure 4 Figure 1 is a photomicrograph of the grain structure of Example 5 of the present invention;

[0058] Figure 5 Figure 2 is a schematic of the winding of a spiral wrap of the present invention;

[0059] Figure 6 Figure 3 is a schematic of the structure of a spiral wrap of the present invention;

[0060] Figure 7 Figure 4 is a schematic of the winding of a preform of the present invention;

[0061] Figure 8 Figure 5 is a photograph of a preform of the present invention;

[0062] Figure 9 Figure 6 is a photograph of a screen material of the present invention;

[0063] Figure 10 Figure 7 is a DSC curve of Example 1 of the present invention;

[0064] Figure 11 Figure 8 is a DSC curve of Example 3 of the present invention;

[0065] Figure 12 Figure 9 is a DSC curve of Example 5 of the present invention;

[0066] Figure 13 Figure 10 is one of the cyclic compression curves of Example 2 of the present invention;

[0067] Figure 14 Figure 11 is the second of the cyclic compression curves of Example 2 of the present invention;

[0068] Figure 15 Figure 12 is a plot of the stress required to compress 50% strain for Examples 2, 4 and 6 of the present invention;

[0069] Figure 16 Figure 13 is a plot of the heat and structural recovery strains for 50% strain for Examples 2, 4 and 6 of the present invention;

[0070] Figure 17 Figure 14 is a schematic of the method of using a filter tube assembly of the present invention.

[0071] Reference Numerals

[0072] 1. first mandrel; 2. spiral wrap; 3. second mandrel; 4. porous base pipe; 5. screen. DETAILED DESCRIPTION

[0073] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0074] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0075] As shown in Figure 1 , a schematic diagram of the overall process flow of the copper-based shape memory alloy wire and screen pipe material is shown. Figure 1

[0076] Embodiment 1

[0077] A method for preparing a copper-based shape memory alloy wire, comprising the following steps:

[0078] (1) Select a CuZnAl (Cu at. % 67.85, Zn at. % 23.33, Al at. % 8.83) shape memory alloy wire with a wire diameter of 1.0 mm, a wire length of 5.40 m and a mass of 34.12 g, and place it in a crucible;

[0079] Fill the remaining voids with Al2O3 balls with a diameter of 0.25 mm, and place them in a vacuum tube furnace at 760℃ for 8h, and then water quenching.

[0080] Record the metallographic photos and grain images by metallographic microscope, as shown in Figure 2 .

[0081] (2) Place the copper-based shape memory alloy wire material treated in step (1) in a crucible, fill the remaining voids with Al2O3 balls with a diameter of 0.25 mm, and place them in a vacuum tube furnace at 900℃ for 10min, and then water quenching;

[0082] (3) Place in an oil bath, use dimethyl silicone oil as the oil for oil bath heating, heat at 150℃ for 1h, then water quenching; then place in 95% alcohol solution at 25℃ environment, ultrasonic treatment for 10 minutes to remove oil stains on the surface of the wire material.​

[0083] Example 2

[0084] A method for preparing a screen pipe material, comprising the following steps:

[0085] (1) Refer to Figure 5 , the copper-based shape memory alloy wire prepared in Example 1 is inclined relative to the axis of the first mandrel 1, which is a 304 stainless steel shaft with a diameter of 5 mm, and then is wound around the first mandrel 1 and stretched, to obtain a spiral coil 2 with a spiral angle a of 50° and a coil outer diameter Φ of 8.53 mm, as shown in Figure 6 .

[0086] (2) Refer to Figure 7 , the spiral coil 2 prepared in step (1) is inclined relative to the axis of the second mandrel 3, which is a 304 stainless steel shaft with a diameter of 3 mm, and forms a winding included angle β of 45° relative to the axis of the second mandrel 3, and then is reciprocally wound around the second mandrel 3;

[0087] The spiral coil 2 is wound from the middle of the second mandrel 3, and after being wound in one direction to the edge of the second mandrel 3, it is wound back in the opposite direction, i.e. continuously reciprocally wound in the directions of A→B→C→D→E→F and a→b→c→d→e→f, until the spiral coil 2 is completely wound, and finally the end of the spiral coil 2 is embedded inside for end-capping treatment to lock and prevent disengagement, to obtain a preform with a length of 18.85 cm and a diameter slightly less than 30 mm (as shown in Figure 8 ).

[0088] (3) The preform prepared in step (2) is placed in a cylindrical mold with an inner diameter of 30 mm, and cold-pressed at a loading rate of 8 mm / min, using displacement control loading, with a cold-pressing pressure of 920 N and a holding time of 5 min, to obtain a screen pipe material of super-high strain recovery shape memory alloy in the form of a cylinder with a height of 30.64 mm (as shown in Figure 9 ).

[0089] Example 3

[0090] A method for preparing a copper-based shape memory alloy wire, comprising the following steps:

[0091] (1) A CuZnAl (Cu at. % 67.85, Zn at. % 23.33, Al at. % 8.83) shape memory alloy wire with a wire diameter of 1.0 mm, a wire length of 5.40 m and a mass of 34.12 g is selected and placed in a crucible;

[0092] The remaining voids are filled with Al2O3 small balls with a diameter of 0.25 mm, and the assembly is placed in a vacuum tube furnace and held at 760°C for 24 h, and then is water-quenched.

[0093] Metallographic photographs and grain images are recorded using a metallographic microscope, such as Figure 3 As shown.

[0094] (2) Place the copper-based shape memory alloy wire that has been heat-treated in step (1) into a crucible, fill the remaining gaps with Al2O3 balls with a diameter of 0.25 mm, place it in a vacuum tube furnace, keep it at 900℃ for 10 min, and then cool it by water quenching.

[0095] (3) Place it in an oil bath. The oil used for oil bath heating is dimethyl silicone oil. Keep it at 150°C for 1 hour, then cool it with water. Then place it in a 95% alcohol solution at 25°C and sonicate it for 10 minutes to remove the oil stains on the surface of the wire.

[0096] Example 4

[0097] A method for preparing a sieve tube material includes the following steps:

[0098] (1)Reference Figure 5 In Example 1, the copper-based shape memory alloy wire is inclined relative to the axis of the first mandrel 1, and then wound and stretched around the first mandrel 1. The first mandrel 1 is a 304 stainless steel shaft with a diameter of 5 mm. Figure 6 As shown, a spiral coil 2 with a helix angle α of 50° and an outer diameter Φ of 8.53 mm was produced.

[0099] (2)Reference Figure 7 The spiral coil 2 obtained in step (1) is inclined relative to the axis of the second mandrel 3. The second mandrel 3 is a 304 stainless steel shaft with a diameter of 3mm. The spiral coil 2 forms a 45° winding angle β relative to the axis of the second mandrel 3, and then reciprocates around the second mandrel 3.

[0100] The spiral coil 2 begins winding from the middle of the second mandrel 3. After winding in one direction to the edge of the second mandrel 3, the spiral coil 2 winds back in the opposite direction, that is, it continuously winds back and forth in the directions of A→B→C→D→E→F and a→b→c→d→e→f until the spiral coil 2 is completely wound. Finally, the end of the spiral coil 2 is embedded inside for end sealing to lock and prevent unwinding, resulting in a preform with a length of 20.64cm and a diameter slightly less than 30mm (e.g., Figure 8 (As shown).

[0101] (3) The preform prepared in step (2) is placed in a cylindrical mold with an inner diameter of 30 mm and cold-pressed at a loading rate of 8 mm / min. Displacement-controlled loading is used, and the cold-pressing pressure is 922 N for 5 min to obtain a cylindrical screen tube material of ultra-high strain recovery shape memory alloy with a height of 31.44 mm (e.g., Figure 9as shown.

[0102] Example 5

[0103] A method for preparing a copper-based shape memory alloy wire, comprising the following steps:

[0104] (1) Selecting a CuZnAl (Cu at. % 67.85, Zn at. % 23.33, Al at. % 8.83) shape memory alloy wire with a wire diameter of 1.0 mm, a wire length of 5.40 m, and a mass of 34.12 g;

[0105] Recording the metallographic photos and grain images by a metallographic microscope, as shown. Figure 4

[0106] (2) Placing the copper-based shape memory alloy wire material of step (1) in a crucible, filling the remaining gaps with Al2O3 small balls with a diameter of 0.25 mm, placing it in a vacuum tube furnace, and heat treating it at 900°C for 10 min, and then water quenching it;

[0107] (3) Placing it in an oil bath, using dimethyl silicone oil as the oil for oil bath heating, heat treating it at 150°C for 1 h, and then water quenching it; then placing it in a 95% alcohol solution at 25°C, and ultrasonic treating it for 10 min to remove the oil stains on the surface of the wire material.

[0108] Example 6

[0109] A method for preparing a screen pipe material, comprising the following steps:

[0110] (1) Referring to Figure 5 , the copper-based shape memory alloy wire prepared in Example 1 is inclined relative to the axis of the first mandrel 1, and then wound and stretched around the first mandrel 1, which is a 304 stainless steel shaft with a diameter of 5 mm, as shown. Figure 6

[0111] (2) Referring to Figure 7 , the spiral roll 2 prepared in step (1) is inclined relative to the axis of the second mandrel 3, which is a 304 stainless steel shaft with a diameter of 3 mm, and the spiral roll 2 forms a winding included angle β of 45° relative to the axis of the second mandrel 3, and then reciprocally wound around the second mandrel 3.

[0112] ​​The spiral coil 2 is wound from the middle of the second mandrel 3, and after being wound in one direction to the edge of the second mandrel 3, the spiral coil 2 is wound in the opposite direction, i.e. continuously reciprocating in the directions of A→B→C→D→E→F and a→b→c→d→e→f until the spiral coil 2 is completely wound, and finally the end of the spiral coil 2 is embedded in the inside for end-capping treatment to lock and prevent disengagement, thereby obtaining a preform with a length of 19.84 cm and a diameter slightly smaller than 30 mm (as shown in Figure 8 ).

[0113] (3) The preform prepared in step (2) is placed in a cylindrical mold with an inner diameter of 30 mm, and cold pressing is performed at a loading rate of 8 mm / min, displacement control loading is adopted, the cold pressing pressure is 922 N and the pressure is maintained for 5 min, thereby obtaining a cylindrical sieve pipe material of super-high strain recovery shape memory alloy with a height of 24.16 mm (as shown in Figure 9 ).

[0114] Performance test

[0115] (1) Dilute crystal degree determination

[0116] The calculation formula of the dilute crystal degree of the wire is d / D, d represents the average grain size of the alloy, and D represents the diameter of the wire. The average grain size d is calculated as the average value of all radial lines passing through the center of the grain.

[0117] According to the above method, all the grains in Figure 2 can be obtained, the average grain diameter d of example 1 is 0.19 mm, the diameter D of the wire prepared in example 1 is 1 mm, and the dilute crystal degree d / D of the wire prepared in example 1 is 0.19.

[0118] According to the above method, all the grains in Figure 3 can be obtained, the average grain diameter d of example 3 is 0.51 mm, the diameter D of the wire prepared in example 3 is 1 mm, and the dilute crystal degree d / D of the wire prepared in example 3 is 0.51.

[0119] According to the above method, all the grains in Figure 4 can be obtained, the average grain diameter d of example 5 is 0.006 mm, the diameter D of the wire prepared in example 5 is 1 mm, and the dilute crystal degree d / D of the wire prepared in example 5 is 0.006.

[0120] (2) Differential scanning calorimetry analysis and thermal conductivity test

[0121] The differential scanning calorimetry (DSC) analysis of example 1, example 3 and example 5 is performed, and at the same time, the element distribution ratio of the sample is obtained by EDS test, and the thermal conductivity is calculated.

[0122] The DSC curve of example 1 is shown in Figure 10 , the Mf M s A s and A f The temperatures were 39.7℃, 67.8℃, 72.3℃ and 97.1℃, respectively; the thermal conductivity was 317.3 W / m·K.

[0123] The DSC curve of Example 3 is as follows: Figure 11 As shown, M in Example 3 f M s A s and A f The temperatures were 49.5℃, 74.2℃, 73.2℃ and 94.9℃, respectively; the thermal conductivity was 320.0 W / m·K.

[0124] The DSC curve of Example 5 is as follows: Figure 12 As shown, M in Example 5 f M s A s and A f The temperatures were 41.1℃, 56.8℃, 62.1℃ and 86.6℃, respectively; the thermal conductivity was 348.3 W / m·K.

[0125] The DSC curves of Examples 1, 3, and 5, along with the above-mentioned dilution degree determination, reveal that the phase transition temperature of copper-based shape memory alloys can be controlled by adjusting the dilution degree, thus adapting to different application requirements. Furthermore, the A values ​​of Examples 1, 3, and 5... f The temperature is below 100℃, and the transformation is complete under high temperature conditions (100~350℃). The phase transformation temperature is suitable for use in high temperature environments. On the other hand, through the special graded quenching heat treatment method of this invention, copper-based shape memory alloys with different dilution degrees avoid martensite stabilization and can exhibit a stable shape memory effect under high temperature conditions (100~350℃). This indicates that the screen material containing the copper-based shape memory alloy of this invention can be used in high-temperature oil well bottom environments and achieve spontaneous shape recovery. It is suitable for high-temperature heavy oil wells above 200℃ that require high thermal conductivity screen materials.

[0126] (3) Porosity determination

[0127] The mass m, diameter D, and height H of the samples were measured in Examples 2, 4, and 6. V is the apparent volume of the sample. The density of the copper-based shape memory alloy wire is known to be ρ. s =8.05g / cm 3 The porosity P of Examples 2, 4, and 6 was calculated using the following formula, where... This refers to the relative density.

[0128]

[0129]

[0130] The porosity of Example 2 is calculated to be 80.4%, the porosity of Example 4 is 80.9%, and the porosity of Example 6 is 75.2%. The suitable porosity is combined with the shape memory effect of the wire material to achieve the high recovery characteristics of the present application, and it is also proved that the preparation process of the present application can control the porosity to adapt to the filtering precision requirement in the oil and gas exploitation process.

[0131] (4) Compression test

[0132] (4-1) The compression test is carried out at room temperature according to the ASTM E9-89a standard, the test equipment is INSTRON 5984 universal material testing machine, displacement control loading is adopted, the loading rate is 0.5 mm / min, and the compression performance test of Example 2 is carried out by sequentially compressing 20%, 30%, 40% and 50% compression strain, and the loading and unloading test of 50% compression strain is directly carried out on Example 4 and Example 6.

[0133] The test results of Example 2 are shown in Figure 13 and Figure 14 It can be seen from the figure that the stress values of Example 2 under 20%, 30%, 40% and 50% strain are 3.50 MPa, 5.03 MPa, 7.95 MPa and 16.14 MPa respectively.

[0134] After Example 2 experiences 20% and 30% compression strain loading, the shape can completely recover to the state before loading, which indicates that the recoverable strain of Example 2 caused by the structure at room temperature reaches 30%, which is far more than the maximum recoverable strain of copper-based shape memory alloy itself, which shows that the present application can effectively improve the comprehensive performance of copper-based shape memory alloy.

[0135] The stress required when Example 2, Example 4 and Example 6 are compressed by 50% strain is shown in Figure 15 .

[0136] The stress corresponding to the compression strain of 50% of Example 2 is 16.14 MPa, the stress corresponding to the compression strain of 50% of Example 4 is 2.81 MPa, and the stress corresponding to the compression strain of 50% of Example 6 is 22.67 MPa, that is, the stress (2.81-22.67 MPa) corresponding to the compression strain of 50% of the screen pipe material prepared by the present application is much lower than the stress 49.79 MPa corresponding to the compression strain of 50% of the NiTi shape memory alloy screen pipe material in the prior art.

[0137] (4-2) After experiencing 50% compressive strain, Examples 2, 4 and 6 were placed in a 200°C water bath for 8 hours to test the structural recovery strain and thermal recovery strain.

[0138] The results are as follows Figure 16 As shown. Example 2 produced a phase change driven springback strain of 21.3% (phase change recovery, i.e., shape memory recovery strain), and its recoverable strain (i.e., the sum of structural recovery and phase change recovery) reached 33.2%; Example 4 produced a phase change driven springback strain of 24.4%, and its recoverable strain reached 48.7%; Example 6 produced a phase change driven springback strain of 16.6%, and its recoverable strain reached 35.2%, indicating that the screen tube material prepared by the present invention meets and far exceeds the actual production and use requirement of 20.4% recoverable strain.

[0139] Example 7

[0140] like Figure 17 As shown, a filter pipe assembly includes a porous base pipe 4 sleeved on the outside of the oil production pipe, and a screen pipe 5 sleeved on the porous base pipe 4. The screen pipe 5 is a pipe fitting pressed by embodiment 4.

[0141] In Example 4, the height in the pressure direction after cold pressing is the thickness of the screen tube 5.

[0142] The method of using the filter tube assembly includes the following steps:

[0143] 1) The sieve tube 5 is sleeved on the porous base tube 4, and the initial thickness of the sieve tube 5 is H0;

[0144] 2) Control the temperature T <M f That is, in the low-temperature martensitic phase state, a load is applied to the outer peripheral wall of the sieve tube 5 to deform it and constrain its shape, so that the thickness H1 of the pressurized sieve tube 5 is... <H0;

[0145] 3) Ambient temperature T inside the oil well a >A f The filter tube assembly from step 2) is lowered into the oil well. Due to the coupling effect of structural recovery (pore structure) and phase transformation recovery (martensitic phase transformation) of the screen tube material, the screen tube 5 can achieve a large strain recovery. The screen tube 5 expands and recovers until the thickness H2>H0, thus completing the installation.

[0146] Even after shape recovery and expansion, the internal microstructure of the screen material remains an intertwined structure of alloy wires, maintaining a stable through-hole pore structure. This stable and unique pore structure ensures that oil and gas can smoothly pass through the production pipe in this embodiment, while effectively blocking sand and gravel.

[0147] Those skilled in the art can make various modifications and changes to the above embodiments in light of the teachings and disclosure of this specification, therefore, the above disclosed and described embodiments shall not be regarded as limiting the application, and some modifications and changes to the application shall fall into the protection scope of the claims of the application. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description, and do not constitute any limitation to the application.

Claims

1. A method for performance enhancement of copper-based shape memory alloys, characterized in that, Comprising the following steps: (1) Put the copper-based shape memory alloy wire into the reaction device for sand bath heating, and keep the temperature at 600-900 ℃ for 4-30 h in a vacuum environment or in an inert atmosphere, then take out the copper-based shape memory alloy wire for rapid cooling; (2) Put the cooled copper-based shape memory alloy wire into the reaction device for sand bath heating again, and keep the temperature at 750-900 ℃ for 10-30 min in a vacuum environment or in an inert atmosphere, then take out the copper-based shape memory alloy wire for rapid cooling; (3) Perform oil bath heating on the cooled copper-based shape memory alloy wire, keep the temperature at 120-160 ℃ for 0.5-2 h, then take out the copper-based shape memory alloy wire for rapid cooling; and clean; In step (1), the copper-based shape memory alloy wire is CuZnAl, wherein the atomic percentage of Cu is 66.02-81.75%, the atomic percentage of Zn is 15.09-24.52%, and the atomic percentage of Al is 3.05-9.88%; The diameter of the copper-based shape memory alloy wire is 0.7-1.2 mm.

2. The method for performance enhancement of copper-based shape memory alloys according to claim 1, characterized in that, In steps (1) and (2), the sand for sand bath heating is Al2O3 small balls; The diameter of the Al2O3 small balls is smaller than the diameter of the copper-based shape memory alloy wire.

3. The method for performance enhancement of copper-based shape memory alloys according to claim 1, characterized in that, In step (3), the oil used for oil bath heating is dimethyl silicone oil.

4. A copper-based shape memory alloy wire, characterized by, Prepared by the performance improvement method for copper-based shape memory alloy according to any one of claims 1-3.

5. A method of making a screen material, characterized by, Comprising the following steps: (1) Prepare a first core shaft in a columnar shape, and wind and stretch the copper-based shape memory alloy wire according to claim 4 around the first core shaft, and the copper-based shape memory alloy wire is inclined relative to the axis of the first core shaft to form a spiral roll; (2) The spiral roll prepared in step (1) is embedded and interlocked by winding, laying and weaving to prepare a preform with stable structure; (3) Put the preform prepared in step (2) into a mold for cold pressing forming to prepare a screen pipe material.

6. The method of claim 5, wherein the screen material is prepared by the steps of: In step (1), the copper-based shape memory alloy wire is inclined relative to the axis of the first core shaft to form an included angle of 45-55°, which is defined as a spiral angle; The specific operation of step (2) is as follows: prepare a second core shaft in a columnar shape, and the spiral roll prepared in step (1) is inclined relative to the axis of the second core shaft, the spiral roll is reciprocally wound around the second core shaft until the winding of the spiral roll is completed, and the end of the spiral roll is embedded into the interior for end sealing treatment to lock and prevent disengagement, thereby preparing a preform; In step (2), the spiral roll is inclined relative to the axis of the second core shaft to form an included angle of 40-50°, which is defined as a winding included angle; In step 3), the loading rate of cold pressing is 5-12 mm / min, displacement control loading is adopted during compression, the cold pressing pressure is at least 900 N, and the pressure holding time is 2-15 min; The length of the preform prepared in step (2) is 2-10 times the height of the screen pipe material in the cold pressing direction after cold pressing.

7. A screen material characterized by, Prepared by the preparation method of the screen pipe material according to claim 5 or 6.

8. A filter string assembly adapted for use in high temperature oil wells, characterised in that, Comprising a sleeve outside the oil extraction pipe a porous base pipe, which is covered with a screen pipe, the screen pipe being a pipe pressed from the screen pipe material of claim 7; the height of the screen pipe material in the direction of the cold pressing pressure after the cold pressing serves as the thickness of the screen pipe.

9. A method of using a filter tube assembly according to claim 8, wherein, comprising the following steps: (1) covering the porous base pipe with a screen pipe, the initial thickness of the screen pipe being H0; (2) cold pressing the screen pipe to a thickness of H1, wherein H1 < H0. (2) Control temperature T < M f applying a load to the outer peripheral wall of the screen pipe to make the thickness H1 of the pressurized screen pipe < H0; (3) Ambient temperature T in the oil well a > A f The filter pipe assembly of step 2) is lowered into the oil well, the screen pipe is expanded to return to a thickness H2>H0, and the installation is completed.

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