Production equipment and process for acid-resistant low-carbon alloy coiled tubing with different steel grades

Abstract

The invention relates to the field of petroleum engineering, in particular to production equipment and process for acid-resistant low-carbon alloy coiled tubing of different steel grades, and the process comprises the steps of cleaning, processing and forming of the coiled tubing, primary heat treatment, secondary heat treatment and air cooling. The production equipment comprises cleaning equipment, oil pipe continuous processing equipment, simulated normalizing equipment, spray cooling equipment, tempering treatment equipment and air cooling equipment which are arranged in sequence. The corrosion resistance and the mechanical property of the acid-resistant coiled tubing can be achieved at the same time, and acid-resistant coiled tubing of different steel grades can be produced under the condition that the proportion of alloy elements is not changed.

Description

Technical Field

[0001] The invention relates to the field of petroleum engineering, and in particular to production equipment and technology for acid-resistant low-carbon alloy continuous oil pipes of different steel grades. Background Art

[0002] In an acidic environment, conventional coiled tubing has insufficient corrosion resistance and is prone to problems such as stress corrosion cracking and hydrogen-induced cracking. Currently, most existing coiled tubing materials use medium carbon or low carbon alloy steel, which has excellent performance in high strength and wear resistance, but poor corrosion resistance in an acidic environment. The steel grade of the coiled tubing material that meets the API industry standard and adds corrosion-resistant alloy elements such as chromium (Cr), nickel (Ni), and molybdenum (Mo) to the low carbon steel matrix is ​​inversely proportional to the corrosion resistance. It is impossible to simultaneously produce a coiled tubing with strong corrosion resistance and high steel grade that meets the chemical composition requirements of the industry standard. Therefore, in order to improve the acid resistance, an external anti-corrosion coating or an internal coating method is usually adopted, but this increases the cost and complexity, and the long-term stability of the coating is also problematic. In addition, different operating environments have different requirements for steel strength and toughness, and a single material is difficult to meet diverse needs. Therefore, the present invention proposes a manufacturing and production process of acid-resistant low-carbon alloy coiled tubing of different steel grades, which meets the production and manufacturing of coiled tubing with high corrosion resistance and variable steel grades that meet the chemical composition requirements of the API industry standard. Summary of the invention

[0003] Based on the above problems, the purpose of the present invention is to provide a production equipment and process for acid-resistant low-carbon alloy coiled tubing of different steel grades. The present invention adopts the following technical solutions:

[0004] The present invention provides a production process of acid-resistant low-carbon alloy coiled tubing of different steel grades, comprising the following steps:

[0005] Step 1: Cleaning: Use ultrasonic degreasing and organic solvent mixed degreasing to clean the surface of the acid-resistant alloy steel strip;

[0006] Step 2: Processing and forming the coiled tubing: processing the acid-resistant alloy steel strip into the coiled tubing;

[0007] Step 3, primary heat treatment: the coiled tubing is immediately spray-cooled to 15-35°C after simulated normalizing at 890°C-960°C;

[0008] Step 4: Secondary heat treatment: Temper the coiled tubing at a temperature ranging from 500 to 750°C.

[0009] Step 5, air cooling: precool the air to 15-25°C and then cool the coiled tubing to 25-30°C.

[0010] Preferably, when the tempering temperature is controlled to be 580°C, the produced coiled tubing is of CT100 steel grade;

[0011] When the tempering temperature is controlled at 680℃, the produced coiled tubing is CT90 steel grade;

[0012] When the tempering temperature is controlled at 750℃, the produced coiled tubing is of CT80 steel grade.

[0013] The present invention also provides a production device for acid-resistant low-carbon alloy coiled tubing of different steel grades, which is used to realize the production process of acid-resistant low-carbon alloy coiled tubing of different steel grades described above; it is characterized in that: the production device comprises a cleaning device, a tubing continuous processing device, a simulated normalizing device, a spray cooling device, a tempering treatment device, and an air cooling device arranged in sequence;

[0014] The simulated normalizing equipment includes a normalizing induction heating coil and an induction heating device, wherein the induction head of the induction heating device is directly opposite to the weld of the coiled tubing;

[0015] The spray cooling equipment includes a circulating water tank and an air blowing nozzle. The circulating water tank is arranged below the coiled oil pipe. Two spray heads are arranged above the circulating water tank. The spray heads are connected to the circulating water tank through a water supply system. The air blowing nozzle is located behind the circulating water tank and connected to the air supply equipment.

[0016] The tempering treatment equipment comprises a tempering induction heating coil and a heat preservation induction heating coil, the number of the tempering induction heating coils is three, and the number of the heat preservation induction heating coil is one;

[0017] The air cooling device comprises two air coolers, the two air coolers are connected via an air pump, and the air cooler located at the rear is connected to a cooling nozzle via a pipeline.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are:

[0019] The present invention can ensure that the acid-resistant coiled tubing has both corrosion resistance and mechanical properties, and can produce acid-resistant coiled tubing of different steel grades without changing the proportion of alloy elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] Figure 1 The production process flow chart of the acid-resistant low-carbon alloy coiled tubing of different steel grades of the present invention;

[0022] Figure 2 It is a production equipment layout diagram of acid-resistant low-carbon alloy coiled tubing of different steel grades of the present invention;

[0023] Figure 3 It is a structural schematic diagram of the simulated normalizing equipment of the present invention;

[0024] Figure 4 It is a structural schematic diagram of the spray cooling device of the present invention;

[0025] Figure 5 It is a structural schematic diagram of the tempering treatment equipment of the present invention;

[0026] Figure 6 It is a schematic structural diagram of the air cooling device of the present invention.

[0027] Description of reference numerals: 1. Cleaning equipment; 2. Continuous processing equipment for oil pipes; 3. Simulated normalizing equipment; 301. Normalizing induction heating coil; 302. Induction heating device; 4. Spray cooling equipment; 401. Circulating water tank; 402. Air blowing nozzle; 403. Spray head; 5. Tempering equipment; 501. Tempering induction heating coil; 502. Insulation induction heating coil; 6. Air cooling equipment; 601. Air cooler; 602. Air pump; 603. Cold blowing nozzle; DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0029] like Figure 1 As shown, this embodiment discloses a production process of acid-resistant low-carbon alloy coiled tubing of different steel grades, and the process includes the following steps:

[0030] Step 1, cleaning: The surface of the acid-resistant alloy steel strip is cleaned by ultrasonic degreasing and organic solvent mixed degreasing. The organic solvent is a mixed solution of trichloroethylene, acetone and thickener, with a trichloroethylene content of 65%wt, an acetone content of 25%wt, and the rest being thickener. The material of the acid-resistant alloy steel strip is carbon steel low alloy steel.

[0031] Step 2: Processing and forming of the continuous oil pipe: processing the acid-resistant alloy steel strip into the continuous oil pipe.

[0032] Step 3, primary heat treatment: After the coiled tubing is simulated normalized at 890℃~960℃, it is immediately spray-cooled to 15~35℃. Simulated normalizing can dissolve carbides in the steel and refine the grains. It should be noted that in the heat treatment process, normalizing is defined as "cooling in still air", and in the production process of coiled tubing, the product is continuously moving in the air, so this normalizing process is called "simulated normalizing".

[0033] Step 4: Secondary heat treatment: The coiled tubing is tempered at a temperature of 500-750°C. The tempering process can eliminate the stress of the tubing and generate tempered troostite, which makes the overall tubing have good strength, hardness and toughness. At the same time, it avoids the inconsistency of tubing diameter and the change of tubing length caused by long-term heating, ensures the uniformity of tubing outer diameter, and thus increases the service life of the coiled tubing.

[0034] Step 5, air cooling: precool the air to 15-25°C and then cool the coiled tubing to 25-30°C.

[0035] For example, when the tempering temperature is controlled at 580°C, the produced coiled tubing is CT100 steel grade; when the tempering temperature is controlled at 680°C, the produced coiled tubing is CT90 steel grade; when the tempering temperature is controlled at 750°C, the produced coiled tubing is CT80 steel grade (the same normalizing temperature is used for the above three steel grades, and the temperature of the coiled tubing after spray cooling is specifically 22-25°C; the temperature of the coiled tubing after air cooling is 25-30°C).

[0036] like Figures 2 to 6 As shown, this embodiment also discloses a production equipment for acid-resistant low-carbon alloy continuous oil pipes of different steel grades, and the production equipment is used in the above production process. The production equipment includes a cleaning device 1, an oil pipe continuous processing device 2, a simulated normalizing device 3, a spray cooling device 4, a tempering treatment device 5, and an air cooling device 6 arranged in sequence. The cleaning device 1 is an ultrasonic cleaning device. The oil pipe continuous processing device 2 mainly includes a steel pipe preliminary forming device, an optical fiber winding device, a laser welding device, a non-destructive flaw detection device, a steel pipe drawing device, and a traction device. The cleaning device 1 and the oil pipe continuous processing device 2 belong to the prior art, and their structures are not repeated here.

[0037] The simulated normalizing equipment 3 includes a normalizing induction heating coil 301 and an induction heating device 302. The normalizing induction heating coil 301 is located in the front of the induction heating device 302. The induction head of the induction heating device 302 is directly opposite to the weld of the coiled tubing.

[0038] The spray cooling equipment 4 uses a dual-circulation cooling device to ensure the cooling effect. The spray cooling equipment 4 includes a circulating water tank 401 and an air blowing nozzle 402. The circulating water tank 401 is arranged below the continuous oil pipe. Two spray heads 403 are arranged above the circulating water tank 401. The spray heads 403 are connected to the circulating water tank 401 through a water supply system. The water supply system generally includes components such as a water pump and a pipe. The air blowing nozzle 402 is located behind the circulating water tank 401 and is connected to the air supply equipment. After the production pipeline is spray-cooled, the air blowing nozzle 402 is used to blow away the water droplets on the surface of the pipe.

[0039] The tempering treatment device 5 includes a tempering induction heating coil 501 and a heat preservation induction heating coil 502 . There are three tempering induction heating coils 501 and one heat preservation induction heating coil 502 . The heat preservation induction heating coil 502 is located behind the last tempering induction heating coil 501 .

[0040] The air cooling device 6 compresses the air to pre-cool it to 15-25°C and then blows out the air flow for cooling through the regulating valve and the nozzle. Compared with conventional air cooling, the cooling rate and cooling time can be controlled more stably. Specifically, the air cooling device 6 includes two air coolers 601, which are connected by an air pump 602. The air cooler 601 located in the front pre-cools the air. The air cooler 601 in the front uses water as a cooling medium, and the air cooler 601 located in the rear uses compressed nitrogen as a cooling medium. The air cooler 601 located in the rear is connected to the cooling nozzle 603 through a pipeline.

[0041] It should be noted that the air cooler 601 has the same structural principle as a heat exchanger, and exchanges heat between the cooling medium and the air, thereby reducing the air temperature.

[0042] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A production process for acid-resistant low-carbon alloy coiled tubing of different steel grades, characterized in that: The following steps are involved: Step 1: Cleaning: Use ultrasonic degreasing and organic solvent mixed degreasing to clean the surface of the acid-resistant alloy steel strip; Step 2: Processing and forming the coiled tubing: processing the acid-resistant alloy steel strip into the coiled tubing; Step 3, primary heat treatment: the coiled tubing is immediately spray-cooled to 15-35°C after simulated normalizing at 890°C-960°C; Step 4: Secondary heat treatment: Temper the coiled tubing at a temperature ranging from 500 to 750°C. Step 5, air cooling: precool the air to 15-25°C and then cool the coiled tubing to 25-30°C.

2. The production process of acid-resistant low-carbon alloy coiled tubing of different steel grades according to claim 1, characterized in that: When the tempering temperature is controlled at 580℃, the produced coiled tubing is CT100 steel grade; When the tempering temperature is controlled at 680℃, the produced coiled tubing is CT90 steel grade; When the tempering temperature is controlled at 750℃, the produced coiled tubing is of CT80 steel grade.

3. A production device for acid-resistant low-carbon alloy coiled tubing of different steel grades, used to implement the production process of acid-resistant low-carbon alloy coiled tubing of different steel grades as claimed in claim 1; characterized in that: The production equipment comprises a cleaning device (1), an oil pipe continuous processing device (2), a simulated normalizing device (3), a spray cooling device (4), a tempering treatment device (5), and an air cooling device (6) which are arranged in sequence; The simulated normalizing equipment (3) comprises a normalizing induction heating coil (301) and an induction heating device (302), wherein the induction head of the induction heating device (302) is directly opposite to the weld of the coiled tubing; The spray cooling device (4) comprises a circulating water tank (401) and an air blowing nozzle (402), wherein the circulating water tank (401) is arranged below the coiled oil pipe, and two spray heads (403) are arranged above the circulating water tank (401), and the spray heads (403) are connected to the circulating water tank (401) through a water supply system; the air blowing nozzle (402) is located behind the circulating water tank (401) and is connected to the air supply device; The tempering treatment equipment (5) comprises a tempering induction heating coil (501) and a heat preservation induction heating coil (502), the number of the tempering induction heating coils (501) is three, and the number of the heat preservation induction heating coil (502) is one; The air cooling device (6) comprises two air coolers (601), the two air coolers (601) are connected via an air pump (602), and the air cooler (601) located at the rear is connected to a cooling nozzle (603) via a pipeline.

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