阅读说明：本技术 一种可溶耐酸铝合金油管及其制备方法及其用铝合金 (Soluble acid-resistant aluminum alloy oil pipe, preparation method thereof and aluminum alloy used by same ) 是由 王鑫 王锋华 董帅 董杰 于 2019-10-29 设计创作，主要内容包括：本发明公开了一种可溶耐酸铝合金油管及其制备方法及其用铝合金,该油管包括油管管材和管材内壁的耐酸涂层,油管管材的材质为铝合金,铝合金以重量百分比计,包括Cu：3.8～4.9％,Mn：0.3～0.9％,Mg：1.2～1.8％,Ni：0.4～0.6％,Fe：0.05～0.1％,其余为Al和杂质。管材制备方法包括以上述成分进行熔炼和精炼获得铸锭；然后将铸锭加热进行均匀化处理；将均匀化处理后的铸锭挤压成管材；对挤压后的管材进行固溶处理；最后对固溶处理后的管材内壁进行耐酸涂层处理。该油管管材在地层水中可以溶解,完全可以避免生产过后的打捞油管任务,而且管材内壁耐酸,避免出现管壁腐蚀断脱的问题,可以作为输送酸液的管道,同时强度满足油井地层及作业中的强度要求。(The invention discloses a soluble acid-resistant aluminum alloy oil pipe, a preparation method thereof and an aluminum alloy used by the oil pipe, wherein the oil pipe comprises an oil pipe and an acid-resistant coating on the inner wall of the pipe, the oil pipe is made of the aluminum alloy, and the aluminum alloy comprises the following components in percentage by weight: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1% and the balance of Al and impurities. The preparation method of the pipe comprises the steps of smelting and refining the components to obtain an ingot; then heating the cast ingot for homogenization treatment; extruding the cast ingot after the homogenization treatment into a pipe; carrying out solution treatment on the extruded pipe; and finally, performing acid-resistant coating treatment on the inner wall of the pipe subjected to the solution treatment. The oil pipe can be dissolved in stratum water, so that the oil pipe salvaging task after production can be completely avoided, the inner wall of the pipe is acid-resistant, the problem that the pipe wall is corroded and broken and is taken off is avoided, the pipe can be used as a pipeline for conveying acid liquor, and meanwhile, the strength of the pipe meets the strength requirements in oil well stratum and operation.)

1. The soluble acid-resistant aluminum alloy oil pipe is characterized by comprising a soluble pipe and a coating on the inner wall of the pipe, wherein the coating is an acid-resistant coating, and the oil pipe is made of materials including: by weight percent, Cu: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1% and the balance of Al and impurities.

2. The soluble acid-resistant aluminum alloy oil pipe as claimed in claim 1, wherein the content of Si in the impurities is not more than 0.10% by weight of the total aluminum alloy.

3. The preparation method of the soluble acid-resistant aluminum alloy oil pipe is characterized by comprising the following steps:

s1: mixing Cu: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1% and the balance of Al and impurities, and carrying out smelting and refining to obtain an ingot;

s2: heating the cast ingot for homogenization treatment;

s3: extruding the ingot after the homogenization treatment into a pipe at the temperature of 420-450 ℃, the extrusion rate of 3-5 mm/s and the extrusion ratio of 5-25;

s4: carrying out solution treatment on the extruded pipe;

s5: and (4) performing acid-resistant coating treatment on the inner wall of the pipe after the solution treatment.

4. The method for preparing the soluble acid-resistant aluminum alloy oil pipe as claimed in claim 3, wherein the homogenizing treatment in the step S2 is to heat the ingot to 430-450 ℃ and then keep the temperature for 6-8 h.

5. The method for preparing the soluble acid-resistant aluminum alloy oil pipe as claimed in claim 3, wherein the solution treatment in the step S4 is carried out at 300-400 ℃, and the holding time of the solution treatment is 3-5 h.

6. The method for preparing the soluble acid-resistant aluminum alloy oil pipe as claimed in claim 3, wherein the step S5 is to perform silver electroplating treatment or polytetrafluoroethylene thermal spraying treatment on the inner wall of the pipe after the solution treatment.

7. The method for preparing the soluble acid-resistant aluminum alloy oil pipe as recited in claim 6, wherein the thickness of the silver plating layer is 10-20 μm.

8. The method for preparing the soluble acid-resistant aluminum alloy oil pipe as recited in claim 6, wherein the polytetrafluoroethylene coating has a thickness of 12-20 μm.

9. An aluminum alloy for a soluble acid-resistant aluminum alloy oil pipe is characterized by comprising the following components in percentage by weight: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1% and the balance of Al and impurities.

10. The aluminum alloy for the soluble acid-resistant aluminum alloy oil pipe as recited in claim 9, wherein the content of Si in the impurities is not more than 0.10% by weight based on the total weight of the aluminum alloy.

Technical Field

The invention belongs to the field of oil pipe manufacturing, and particularly relates to a soluble acid-resistant aluminum alloy oil pipe, a preparation method thereof and aluminum alloy used by the same.

Background

The Tahe oil field is an integrally-installed large carbonate oil-gas reservoir discovered by the northwest oil bureau, and has the advantages of strong heterogeneity, deep burial depth (5400-₃-、CO₃ ²-、OH-、SO₄ ²-、Br-、I-、K+、Na+、Mg²+、Ca²(+) and high temperature (120-160 ℃). Oil wells are naturally produced by a few of the wells encountering karst caves and fracture zones, and most of the wells are transformed by acid fracturing to obtain the production capacity by communicating a well bore with the karst cav-fracture zone.

At present, a pipeline used for conveying acid liquor is a traditional oil-gas resource production pipe column, commonly used corrosion-resistant alloy oil pipes such as a nickel-based alloy oil pipe, an iron-nickel-based alloy oil pipe, a double-phase stainless steel oil pipe, a martensitic stainless steel oil pipe and the like, and at present, an HSJ-1 corrosion inhibitor and a ZJ-1 corrosion inhibition auxiliary agent which is in synergistic action with the corrosion inhibitor are mainly added into the acid liquor to protect the oil pipe from being corroded by the acid liquor. However, due to the reasons of the unsealing failure of the open hole packer, the corrosion and breaking of the pipe column, the collapse of the well wall and the like, the oil pipe cannot be pulled out after one production period is finished, the later sidetracking treatment is difficult, the production time of the production well is delayed, and a large amount of well repairing cost is generated.

Disclosure of Invention

The invention provides a soluble acid-resistant aluminum alloy oil pipe, a preparation method thereof and an aluminum alloy used by the oil pipe, wherein the oil pipe can be dissolved in formation water, can be rapidly and automatically dissolved in a later production stage, can completely avoid the task of fishing the oil pipe after production, has acid-resistant inner wall, meets the requirement of acid liquor transmission in an acid fracturing process, and can be used as a pipeline for conveying acid liquor.

In order to solve the problems, the technical scheme of the invention is as follows:

the utility model provides a soluble acid-fast aluminium alloy oil pipe, includes the coating of soluble tubular product and tubular product inner wall, the coating is acid-fast coating, the material of oil pipe body includes: by weight percent, Cu: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1% and the balance of Al and impurities.

Preferably, the content of Si in the impurities is not more than 0.10% of the total weight of the aluminum alloy.

The invention also provides a preparation method of the aluminum alloy pipe for the soluble acid-resistant aluminum alloy oil pipe, which comprises the following steps:

s1: mixing Cu: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1% and the balance of Al and impurities, and carrying out smelting and refining to obtain an ingot;

s2: heating the cast ingot for homogenization treatment;

s3: extruding the ingot after the homogenization treatment into a pipe at the temperature of 420-450 ℃, the extrusion rate of 3-5 mm/s and the extrusion ratio of 5-25;

s4: carrying out solution treatment on the extruded pipe;

s5: and (4) performing acid-resistant coating treatment on the inner wall of the pipe after the solution treatment.

Preferably, the homogenization treatment in the step S2 is specifically to heat the cast ingot to 430-450 ℃, and then keep the temperature for 6-8 h.

Preferably, the solution treatment in the step S4 is performed at 300-400 ℃, and the heat preservation time of the solution treatment is 3-5 h.

Preferably, the step S5 is to perform silver electroplating treatment or polytetrafluoroethylene thermal spraying treatment on the inner wall of the pipe after the solution treatment.

Preferably, the thickness of the silver coating is 10-20 μm.

Preferably, the thickness of the polytetrafluoroethylene coating is 12-20 μm.

An aluminum alloy for a soluble acid-resistant aluminum alloy oil pipe comprises the following components in percentage by weight: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1% and the balance of Al and impurities.

Preferably, the content of Si in the impurities is not more than 0.10% of the total weight of the aluminum alloy.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects:

the aluminum alloy of the invention adopts high-content Cu and Mg, and the Cu is an important alloy element in the aluminum alloy for the aluminum alloy oil pipe. Cu may form a strengthening phase S phase (Al) with Al and Mg₂CuMg) has an additional strengthening effect on the aluminum alloy, and the strength of the aluminum alloy pipe is improved. Cu can improve the dispersity of the precipitated phase and improve the intergranular structure, such as the intergranular precipitated phase and the intergranular non-existenceA ribbon is precipitated. The addition of Cu has the tendency of generating intergranular corrosion and pitting corrosion, and is beneficial to the design of soluble materials, and the weight percentage of Cu is 3.8-4.9 percent based on the design;

magnesium can improve the mechanical property of the Al-Cu alloy after natural aging, particularly the improvement of the strength property of the Al-Cu alloy after artificial aging is particularly obvious, the medium Mg content (1.2-1.8%) is an alpha (A1) + theta + S three-phase eutectic, and the S phase in the eutectic is increased along with the increase of the Mg content;

manganese is an economic strengthening element in aluminum alloys for aluminum alloy oil pipes. Mn can refine crystal grains, prevent matrix crystal grains from growing and recrystallizing and improve the strength of the aluminum alloy pipe under the condition of not reducing the plasticity and the toughness of the aluminum alloy;

a small amount of nickel is added into the aluminum alloy, so that the needle-shaped beta (Al-Fe-Si) brittle phase is transformed to form a new phase, and the mechanical property of the material is improved; the addition of nickel element can ensure the excellent high-temperature performance;

silicon is an inevitable impurity in aluminum alloys for aluminum alloy oil pipes, mainly from raw materials, tools and equipment used in smelting and casting; the mechanical properties of the aluminum alloy are not greatly influenced by trace silicon, A1₃The potential difference between Fe and the aluminum matrix is large, thereby providing a weak link of corrosion, accelerating the corrosion of the matrix and being beneficial to the design of soluble materials.

The aluminum alloy oil pipe comprises a soluble pipe and an acid-resistant coating on the inner wall of the pipe, wherein the optimized alloy component proportion of the alloy is obtained by researching different proportions of Cu, Mg, Mn, Ni and Fe in the pipe, the pipe obtained by deformation of an extrusion process is subjected to solution treatment, the yield strength change amplitude is 300-350 MPa and the tensile strength change amplitude is 420-490 MPa at high temperature (150 ℃), and the strength requirements in oil well stratum and operation can be effectively met; meanwhile, the inner wall of the pipe is acid-resistant by adopting a surface treatment mode, the requirement of conveying acid liquor for corrosion resistance can be met, the pipe is made of aluminum alloy, and the outer wall of the pipe is exposed, so that the pipe is damaged by adopting a drilling mode after a production period is finished, the aluminum alloy material for the aluminum alloy oil pipe can be automatically degraded in formation water, the time for completely dissolving is less than 2 years, the task of fishing the oil pipe after production can be completely avoided, and the operation difficulty and the cost are greatly reduced.

Drawings

FIG. 1 is a flow chart of a method for preparing a soluble acid-resistant aluminum alloy oil pipe provided by the invention;

FIG. 2 is a metallographic structure diagram of the pipe in example 1 after the extrusion solution treatment.

Detailed Description

The following will explain in detail the aluminum alloy for soluble acid-resistant aluminum alloy oil pipe and the method for preparing the pipe thereof according to the present invention with reference to the accompanying drawings and specific examples. Advantages and features of the present invention will become apparent from the following description and from the claims.

It is to be noted that an oil well needs to convey acid liquor in the early stage and then oil, a pipeline needs to be replaced after a production cycle is completed, the pipeline can be damaged by sidetracking and then taken out, the pipeline used for conveying the acid liquor at present is a traditional oil-gas resource production pipe column, and commonly used corrosion-resistant alloy oil pipes such as a nickel-based alloy oil pipe, an iron-nickel-based alloy oil pipe, a dual-phase stainless steel oil pipe, a martensitic stainless steel oil pipe and the like, and the acid-resistant means mainly adopts the steps of adding an HSJ-1 corrosion inhibitor and a ZJ-1 corrosion inhibition auxiliary agent which has a synergistic effect with the corrosion inhibitor into the acid liquor, but the oil pipes are corroded by the acid liquor, and the oil pipes cannot be taken out in the later stage due to the. Therefore, the invention provides the aluminum alloy oil pipe which can meet the strength requirement, can resist acid and can be automatically degraded in underground water and the preparation method thereof, so that the oil pipe does not need to be taken out after a production period is finished, and the oil pipe only needs to be damaged and then automatically degraded underground and then replaced by a new oil pipe.

The utility model provides a soluble acid-fast aluminium alloy oil pipe, includes the acid-fast coating of soluble tubular product and tubular product inner wall, and the material of oil pipe body includes: by weight percent, Cu: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1%, and the balance of Al and inevitable impurities. Wherein the impurities are mainly Si, and the content of Si is not more than 0.10 percent of the total weight of the aluminum alloy.

The oil pipe provided by the invention is made of aluminum alloy, the oil pipe is prepared by matching high-content Cu and Mg, and the Cu is an important alloy element in the aluminum alloy for the aluminum alloy oil pipe. Cu may form a strengthening phase S phase (Al) with Al and Mg₂CuMg) has an additional strengthening effect on the aluminum alloy, and the strength of the aluminum alloy pipe is improved. Cu can improve the dispersity of the precipitated phase and improve the intercrystalline structure, such as a grain boundary precipitated phase and a grain boundary precipitation-free zone. The addition of Cu has the tendency of generating intergranular corrosion and pitting corrosion, and is beneficial to the design of soluble materials, so that the weight percentage of Cu is 3.8-4.9%;

magnesium can improve the mechanical property of the Al-Cu alloy after natural aging, particularly the improvement of the strength property of the Al-Cu alloy after artificial aging is particularly obvious, the medium Mg content (1.2-1.8%) is an alpha (A1) + theta + S three-phase eutectic, and the S phase in the eutectic is increased along with the increase of the Mg content;

the aluminum alloy is an economic strengthening element in the aluminum alloy for the aluminum alloy oil pipe. Mn can refine crystal grains, prevent matrix crystal grains from growing and recrystallizing and improve the strength of the aluminum alloy pipe under the condition of not reducing the plasticity and the toughness of the aluminum alloy;

a small amount of nickel is added into the aluminum alloy, so that the needle-shaped beta (Al-Fe-Si) brittle phase is transformed to form a new phase, and the mechanical property of the material is improved; the addition of nickel element can ensure the excellent high-temperature performance;

silicon is an inevitable impurity in aluminum alloys for aluminum alloy oil pipes, mainly from raw materials, tools and equipment used in smelting and casting; the mechanical properties of the aluminum alloy are not greatly influenced by trace silicon, A1₃The potential difference between Fe and the aluminum matrix is large, thereby providing a weak link of corrosion, accelerating the corrosion of the matrix and being beneficial to the design of soluble materials.

Referring to fig. 1, the invention also provides a preparation method of the soluble acid-resistant aluminum alloy oil pipe, which comprises the following steps:

s1: mixing Cu: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1% and the balance of Al and impurities, and carrying out smelting and refining to obtain an ingot;

s2: heating the cast ingot for homogenization treatment, improving the crystal structure in the alloy, eliminating casting stress and reducing segregation;

s3: extruding the ingot after the homogenization treatment into a pipe at the temperature of 420-450 ℃, the extrusion rate of 3-5 mm/s and the extrusion ratio of 5-25;

s4: carrying out solution treatment on the extruded pipe;

s5: and (4) performing acid-resistant coating treatment on the inner wall of the pipe after the solution treatment.

The aluminum alloy oil pipe comprises a soluble pipe and an acid-resistant coating on the inner wall of the pipe, wherein the optimized alloy component proportion of the alloy is obtained by researching different proportions of Cu, Mg, Mn, Ni and Fe in the pipe, the pipe obtained by deformation of an extrusion process is subjected to solid solution treatment, the structure of the pipe forms a thin line along the deformation direction macroscopically, a fiber structure appears, the extruded crystal grains are still in an equiaxial crystal state, the crystal grains are elongated along the extrusion direction, the crystal structure is uniform, the variation amplitude of the yield strength is 300-350 MPa and the variation amplitude of the tensile strength is 420-490 MPa at high temperature (150 ℃), and the strength requirements in oil well stratum and operation can be effectively met. Meanwhile, the inner wall of the pipe is acid-resistant by adopting a surface treatment mode, so that the requirement of corrosion resistance in acid liquor conveying can be met, the quality of the inner wall is basically not lost after the pipe is soaked in HCl with the temperature of 100 ℃ and the concentration of 20 percent for 4 hours, and the pipe can be effectively acid-resistant, so that the pipe column can be prevented from being corroded and broken in the current acid fracturing operation production process. Because the pipe material is aluminum alloy and the outer wall of the pipe material is exposed, the pipe material is damaged in a drilling mode after a production period is finished, the aluminum alloy material for the aluminum alloy oil pipe can be automatically degraded in formation water, the time for completely dissolving is less than 2 years, the task of fishing the oil pipe after production can be completely avoided, and the operation difficulty and the cost are greatly reduced.

Further, the homogenization treatment in the step S2 is specifically heating the cast ingot to 430-450 ℃, and then preserving heat for 6-8 hours.

Further, the solution treatment in step S4 is performed at 300-400 ℃, and the heat preservation time of the solution treatment is 3-5 h.

Further, step S5 is to perform silver electroplating treatment or thermal spraying polytetrafluoroethylene on the inner wall of the tube after the solution treatment.

Specifically, the silver electroplating treatment specifically comprises the following steps:

s5011, carrying out chemical oil removal and water washing on the tube subjected to the solution treatment by using an oil remover, and then carrying out alkali etching treatment by using 80-1000 g/L NaOH at the temperature of 60-70 ℃ for 0.5-1.0 min to remove dirt on the surface of the aluminum alloy and activate the inner wall matrix of the tube;

s5012: further 500ml/LHNO₃60ml/LHF with the mass fraction of 40 percent is subjected to light extraction treatment for 5-10 seconds at the temperature of 20-30 ℃, and an oxide layer on the surface of the aluminum alloy is removed;

s5013: galvanizing the bright-dipping pipe by a chemical galvanizing method, adopting an ODM ZINCEX-40 zinc dipping agent with the volume fraction of 400mL/L, the temperature of 25 ℃, the zinc dipping time of 90S, and shaking the workpiece in the zinc dipping process;

s5014: performing secondary zinc plating on the pipe, wherein 35-45 g/L ZnO, 70-90 g/L NaCN, 60-70 g/L NaOH, 5 ml/L95 zinc plating opener, 3-5 ml/L zinc plating brightener, temperature of 5-45 ℃, and current density of 0.5-3A/dm²The time is 2-5 min;

s5015: soaking the secondary galvanized pipe in a mixed solution of 55-85 g/L CuCN, 10-15 g/L NaCN and 1.0-1.2 ml/L991 brightener, and carrying out chemical copper plating for 10-15 min at the temperature of 55-65 ℃; the surface of the substrate needs to be plated with a transition layer in the steps so as to improve the binding force between the silver and the inner wall of the pipe;

s5016: the copper plated pipe is treated at 20-40 g/L KAg (CN)₂Performing silver electroplating treatment in 90-150 g/LKCN and 5-10 g/LKOH electrolyte at 10-30 deg.C and current density of 0.3-0.5A/dm²And the time is 10-15 min, so that the acid-resistant dissolvable aluminum alloy oil pipe is obtained.

Preferably, the thickness of the silver coating is 10 to 20 μm.

Preferably, the thermal sprayed polytetrafluoroethylene is in particular:

s5021: adding a filler and an auxiliary agent into the polytetrafluoroethylene concentrated solution to prepare a polytetrafluoroethylene coating;

s5022: carrying out sand blasting treatment on the inner wall of the pipe subjected to solution treatment, using quartz sand with more edges and proper hardness and 80 meshes as an abrasive, using 0.5-0.6 MPa dry clean compressed air as power, spraying the abrasive onto the surface of a sample at a high speed, and thoroughly cleaning and roughening the surface of the sample, wherein the spraying distance is 150mm, and the spraying angle is 30-75 ℃;

s5023: spraying the prepared coating on the inner wall of an oil pipe by adopting a thermal spraying technology, atomizing the coating by using 0.4-0.5 MPa of clean and dry compressed air, keeping a spray gun vertical to the inner wall of the pipe, keeping the spray distance between the spray gun and the inner wall of the pipe to be 200-250 mm, keeping the spray angle to be 30-75 degrees, and keeping the moving speed of the spray gun to be 6-8 m/min; the spray gun is introduced into acetylene, oxygen and compressed air, respectively, by siphon, and mixes the acetylene and the oxygen to generate a combustion flame at the outlet of the nozzle, and the flame is continuously supplied through the center of the nozzle, heated and melted in the flame. The compressed air forms a conical high velocity air stream through the air cap and atomizes the molten coating into fine particles, driven by the flame and the high velocity air stream. Spraying the molten particles onto a surface of a pretreated substrate to form a coating;

s5024: and (3) putting the sprayed oil pipe into a constant-temperature drying box, heating to 110-130 ℃, preserving heat for 15-25 min, taking out, putting into a box-type resistance furnace for plasticizing at 365-375 ℃ for 20min, and immersing the plasticized sample into cold water to obtain the acid-resistant soluble aluminum alloy oil pipe.

Preferably, the thickness of the polytetrafluoroethylene coating is 12-20 μm.

The invention also provides an aluminum alloy for the soluble acid-resistant aluminum alloy oil pipe, which comprises the following components in percentage by weight: 3.8-4.9%, Mn: 0.3-0.9%, Mg: 1.2-1.8%, Ni: 0.4-0.6%, Fe: 0.05-0.1 percent of Al and inevitable impurities of Si, wherein the content of Si is not more than 0.10 percent of the total weight of the aluminum alloy.