Perforating gun repairing method

Abstract

The invention provides a perforating gun repairing method, and belongs to the technical field of maintenance and recycling of oil exploitation equipment. The problems of repairing the damaged perforating gun and how to transform the perforating gun into a sandwich gun are solved. According to the method, through the unique blocking piece design, the advanced welding technology and the comprehensive and strict quality detection process, it is ensured that the repaired interlayer gun can meet the high requirements of oil exploitation operation in the aspects of structural strength, sealing performance, electrical performance and the like, the safety risk in perforation operation is effectively reduced, and the repairing efficiency is improved. And the reliability and the stability of operation are improved, smooth proceeding of oil exploitation operation is guaranteed, the operation cost is further reduced for enterprises, and the production efficiency is improved. According to the technology, the original waste perforating gun is successfully converted into the interlayer gun capable of being normally used, the utilization rate of resources is greatly increased, a large amount of equipment purchasing funds are saved for oil exploitation enterprises, the operation cost is reduced, and the concept of sustainable development is met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil exploitation equipment maintenance and recycling, and particularly relates to a process for welding a patch to repair a shot hole of a perforating gun after explosion and transforming the perforating gun into a sandwich gun. BACKGROUND

[0002] Working principle and importance of perforating gun: The perforating gun is a crucial tool in oil exploitation, which generates strong energy through the explosion of an internal perforating charge to form a hole in the gun body and penetrate the casing and cement ring, establishing a channel between the oil and gas layer and the wellbore to enable oil and gas to flow smoothly into the wellbore, thus realizing exploitation operations. However, the particularity of perforating operations determines that the hole site will be subjected to extremely complex and harsh forces after a perforating gun completes a perforating operation.

[0003] Damage to the hole and existing problems: The high temperature generated by the explosion of the perforating charge can reach several thousand degrees Celsius, and the high pressure can reach tens or even hundreds of megapascals, accompanied by strong impact and vibration. These extreme conditions cause severe plastic deformation, changes in the microstructure of the metal material around the hole, and defects such as cracks and holes. Currently, for these damaged perforating guns, if they are directly discarded, not only will it result in high economic costs, but also a large amount of resources will be wasted. Traditional repair methods have many shortcomings, such as the simple repair welding process cannot guarantee the strength and sealing performance of the repaired perforating gun, making it difficult to meet the safety standards for reuse. When attempting to transform the perforating gun into a sandwich gun, due to the lack of a systematic and effective process, the transformed sandwich gun has serious problems in structural stability, sealing performance, and electrical performance, and cannot be reliably applied to oil exploitation operations, limiting the secondary utilization value of the perforating gun. SUMMARY In view of this, in order to solve the problems of repairing damaged perforating guns and transforming them into sandwich guns mentioned in the background, the present application provides a comprehensive and efficient process for successfully repairing damaged perforating guns and transforming them into reliable sandwich guns through the careful design of a patch, the optimization of a welding process, and the perfection of a subsequent processing flow, thereby significantly improving resource utilization and reducing the equipment procurement and operating costs of oil exploitation enterprises, while ensuring safety and stability in oil exploitation operations.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solution: A perforating gun repair method, specifically comprising the following steps: Step 1: Prepare a patch; Step 2: Perforating gun pretreatment: Select a damaged perforating gun after perforating, first use a high-pressure hot water gun to thoroughly flush the surface impurities, then use a sand wheel with a particle size of 80-120 mesh to polish the area around the hole for 5-8 mm, then soak the perforating gun in a rust remover, and then rinse it with clean water; Step 3: Welding repair: accurately align the patch with the hole through the positioning boss, press the positioning boss into the hole, and then perform laser spot welding fixation. After completing each layer of welding, clean the weld surface in time using a high-pressure gas gun and a steel wire brush, carefully check and repair defects; Step 4: Overall strengthening and sealing treatment: after welding, first perform solid solution treatment, slowly heat the perforating gun to 850 - 950℃ at a heating rate of 5 - 10℃ / min, hold at this temperature for 3 - 4 hours, then quench in water, and then perform aging treatment at an aging temperature of 450 - 550℃ for 2 - 3 hours, and then apply sealing glue to the welded area and spray an epoxy zinc-rich paint anticorrosive coating on the surface of the perforating gun; Step 5: Quality inspection: perform appearance inspection, flaw detection, and pressure testing on the repaired and assembled sandwich gun.

[0005] Further, the patch includes a patch base and a positioning boss connected to each other, the diameter of the patch base is larger than that of the positioning boss, and a through central pressure relief hole is formed in the center of the shaft of the patch base and the positioning boss.

[0006] Further, the diameter of the patch base is 7 - 10mm larger than that of the hole, and the thickness is 5 - 7mm.

[0007] Further, the height of the positioning boss is 1.5 - 2.5mm, and the diameter is 0.4 - 0.6mm smaller than that of the hole.

[0008] Further, the diameter of the central pressure relief hole is 2mm.

[0009] Further, the patch is made of alloy steel material, and the surface of the patch is finely polished to make the surface roughness reach Ra2.5μm.

[0010] Further, in step 3, the laser spot welding adopts friction stir welding, the stirring head rotation speed is 1000 - 1500r / min, the welding speed is 3 - 5mm / s, the stirring head depression amount is 0.5 - 1.0mm, the stirring head shoulder diameter is 15 - 20mm, the stirring needle length is 4 - 6mm, and the diameter is 8 - 10mm.

[0011] Further, in step 3, the laser spot welding is uniformly distributed with 5 - 7 welding points, and the diameter of each welding point is controlled to be 2.5 - 3.5mm.

[0012] Further, in step 4, the sealing glue with a thickness of 0.8 - 1.2mm is applied to the welded area, and the epoxy zinc-rich paint anticorrosive coating with a thickness of 0.3 - 0.5mm is sprayed on the surface of the perforating gun.

[0013] Further, in step 5, no defects are found in appearance inspection, no internal problems are detected in flaw detection, and no abnormalities are found in pressure test at 30MPa for 120 minutes, so it is determined that the sandwich gun is qualified and can be put into actual oil exploitation operation.

[0014] Compared with the prior art, the beneficial effects of the perforating gun repair method are: 1. The present application improves resource utilization: the process of the present application successfully converts the originally discarded perforating gun into a normal sandwich gun, greatly improving the utilization of resources, saving a large amount of equipment procurement funds for oil exploitation enterprises, reducing operating costs, and meeting the concept of sustainable development.

[0015] 2. The present application enhances safety and reliability: through unique patch design, advanced welding process and comprehensive and strict quality detection process, it is ensured that the repaired sandwich gun can meet the high requirements of oil exploitation operation in terms of structural strength, sealing performance and electrical performance, effectively reducing the safety risk in perforating operation, improving the reliability and stability of the operation, ensuring the smooth progress of oil exploitation operation, further reducing the operating costs of enterprises and improving the production efficiency. DETAILED DESCRIPTION

[0016] The accompanying drawings, which form a part of the present application, are used to provide a further understanding of the present application, and the illustrative embodiments thereof and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings: Figure 1 is a structural schematic diagram of the repaired perforating gun body of the present application; Figure 2 is a partial enlarged view of A in Figure 1 ; Figure 3 is a structural schematic diagram of the patch of the present application; Figure 4 is a structural diagram of the repaired perforating gun body used as a sandwich gun; Figure 5 is a bullet hole photo before the perforating gun is repaired; Figure 6 is a bullet hole photo after the perforating gun is repaired; In the drawings: 1-gun body, 2-cartridge assembly, 3-patch. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present application, not all the embodiments.

[0018] Referring to Figures 1-6 The present embodiment is a perforating gun repair process, specifically comprising the following steps: 1. Plug design and material selection Design: The plug 3 adopts a circular structure, which includes a plug base and a positioning boss connected to each other. The diameter of the plug base is 7-10 mm larger than the hole diameter of the perforating gun, and the thickness is 5-7 mm. This size design can not only ensure sufficient contact area between the plug and the hole, but also facilitate welding operation. One side of the plug is provided with an annular positioning boss matched with the hole. The height of the boss is 1.5-2.5 mm, and the diameter is 0.4-0.6 mm smaller than the hole diameter, which ensures that the plug can be precisely embedded into the hole and initially positioned. In the center position of the plug.

[0019] Material selection: Alloy steel with similar chemical composition and matched mechanical properties to the material of the perforating gun body is selected as the plug material. For example, when the perforating gun body material is high-strength alloy steel containing specific proportions of nickel (Ni), chromium (Cr), molybdenum (Mo), etc., the proportion of these elements in the plug material is also adjusted accordingly, so that it can be metallurgically combined with the perforating gun body during welding, and has consistent mechanical properties and corrosion resistance in subsequent use, ensuring the stability and reliability of the plug and the perforating gun body working together.

[0020] 2. Perforating gun pretreatment Surface cleaning: First, use a high-pressure hot water gun to preliminarily flush the surface and hole of the perforating gun. The hot water temperature is controlled at 60-80℃, and the pressure is 20-30 MPa. The temperature and pressure of the hot water are used to remove oil stains, sand, debris and other impurities attached to the surface. Then, the area around the hole is further treated by combining mechanical grinding and chemical cleaning. The mechanical grinding uses a sand wheel with a particle size of 80-120 mesh to grind the area around the hole by 5-8 mm, removing the oxidation layer and damaged metal surface, and exposing the fresh and flat metal luster around the hole edge. The chemical cleaning uses a specially prepared rust remover, which mainly contains organic acid, corrosion inhibitor and surfactant. The perforating gun is soaked in the rust remover for 10-15 minutes, and then washed with clean water to further remove residual impurities and oxides, providing a good foundation for subsequent welding.

[0021] Flaw detection: Use ultrasonic flaw detector and phased array flaw detector to detect the overall structure of the perforating gun, especially the area around the perforation. The ultrasonic flaw detector uses pulse echo method, by adjusting the probe frequency and gain parameters, can detect the internal small defects, such as cracks, pores, etc. The phased array flaw detector uses a probe composed of multiple chips, through electronic scanning, multi-angle, full-range detection around the perforation, can more accurately determine the location, shape and size of the defect. For the detected cracks, use the EDM equipment to drill a 1.2-1.8mm diameter, slightly larger than the crack depth of the crack hole at the crack tip, to prevent the crack from further expanding in the subsequent repair and use process, and to ensure the structural integrity of the perforating gun.

[0022] 3. Welding process Positioning and installation: The processed plug is precisely aligned with the perforation of the perforating gun through the positioning boss, and is lightly pressed to be preliminarily fixed in the perforation position. Then, laser spot welding is used to evenly distribute 5-7 welding spots on the edge of the plug, with each welding spot diameter controlled at 2.5-3.5mm. Laser spot welding has the advantages of energy concentration and small heat-affected zone, which can ensure the positioning stability of the plug while reducing the thermal influence on the surrounding metal materials, preventing the change of metal properties caused by local overheating.

[0023] Welding method: Friction stir welding (FSW) process is used for welding. Friction stir welding is a solid-phase joining technology. In the welding process, the stir head rotates at high speed and is pressed down, generating friction heat with the plug and perforating gun materials, making the materials reach a plastic state. Under the stirring action of the stir head, the two materials are mixed and diffused, forming a firm weld. The welding parameters are set as follows: the stir head speed is 1000-1500r / min, the welding speed is 3-5mm / s, and the stir head down pressure is 0.5-1.0mm. The stir head is made of high-strength tool steel, with a shoulder diameter of 15-20mm and a pin length of 4-6mm and a diameter of 8-10mm. By reasonably designing the shape and size of the stir head, it can ensure that the materials are fully stirred during welding, forming a uniform and dense weld.

[0024] 4. Strengthening and sealing treatment Heat treatment: After the welding is completed, the repaired perforating gun is subjected to overall heat treatment. First, solid solution treatment is carried out, the perforating gun is slowly heated to 850-950℃, the heating rate is controlled at 5-10℃ / min, and the temperature is kept for 3-4 hours at this temperature, so that the alloying elements are fully dissolved in the matrix, and then rapid cooling is adopted, such as quenching in water or rapid cooling in high-pressure gas, to obtain a uniform supersaturated solid solution structure, improve the strength and toughness of the material. Then, aging treatment is carried out, the perforating gun is heated to 450-550℃, and kept for 2-3 hours, so that the alloying elements in the supersaturated solid solution gradually precipitate to form fine and dispersed strengthening phases, further improving the strength, hardness and fatigue resistance of the material, and making the patch and the perforating gun body better integrated into a whole.

[0025] Sealing treatment: After the heat treatment is completed, the welding part of the patch and the hole and the surface of the entire perforating gun are subjected to strict sealing treatment. A layer of high-performance sealing glue with a thickness of 0.8-1.2mm is evenly applied on the welding part, which has excellent high-temperature resistance, high-pressure resistance and chemical corrosion resistance, can effectively fill the small pores of the welding part, and ensure that there is no risk of leakage at the welding part. Then, the surface of the perforating gun is sprayed with a corrosion-resistant coating, the coating is made of high-performance corrosion-resistant materials such as epoxy zinc-rich paint or polyurethane paint, and the coating thickness is controlled at 0.3-0.5mm. By spraying the corrosion-resistant coating, the corrosion resistance of the perforating gun is effectively enhanced, and its service life in harsh working environment is prolonged.

[0026] 5. Quality detection Appearance detection: The repaired and assembled perforating gun is subjected to comprehensive appearance inspection, the surface of the welding seam should be smooth and smooth, without any pores, slag inclusions, cracks and other defects. The welding part of the patch and the hole should be smooth and natural, the sealing glue should be evenly applied, without flowing and missing. The assembly of the outer gun and the inner gun should be neat and firm, the support positioning device should be installed correctly and in place, and the overall appearance should meet the design requirements.

[0027] Flaw detection: The welding part and the entire perforating gun are subjected to deep flaw detection using ultrasonic flaw detector and X-ray flaw detector. Ultrasonic flaw detection is used to detect internal defects, by adjusting the frequency and sensitivity of the flaw detector, internal small defects such as cracks and incomplete welding can be detected. X-ray flaw detection uses X-ray to penetrate the welding seam, which can clearly show that there are no defects such as pores, slag inclusions and incomplete penetration in the welding seam, and there is no safety hazard.

[0028] Pressure test: The perforating gun is installed on a professional simulation test device for sealing pressure test, and the pressure holding time is 120 minutes at 30MPa. During the test, whether the perforating gun has any abnormal conditions such as leakage and deformation is closely observed, and then the pressure test is determined to be qualified. Example 1 The actual example scheme of the perforating gun repair process described in the present application is as follows: Step 1: Preparation of the blocking piece: According to the design requirements, an alloy steel material highly matched with the material of the perforating gun body is selected to carefully process and manufacture a circular blocking piece. The blocking piece includes a blocking piece base and a positioning boss connected to each other, the blocking piece base has a diameter 8 mm larger than the hole and a thickness of 6 mm, the positioning boss has a height of 2 mm and a diameter 0.5 mm smaller than the hole, and the center decompression small hole has a diameter of 2 mm. The surface of the blocking piece is finely polished to make the surface roughness reach Ra2.5 μm, ensuring good welding performance.

[0029] Step 2: Perforating gun pretreatment: Select a damaged perforating gun after perforating. First, use a high-pressure hot water gun to perform overall flushing, with a hot water temperature of 70℃ and a pressure of 25 MPa to remove surface impurities. Then, use a sand wheel with a particle size of 100 mesh to polish the 6 mm area around the hole, and then soak the perforating gun in a rust remover for 12 minutes and rinse it with clean water. Use a flaw detector to detect that there is a 3 mm deep crack at the edge of the hole, and use an electric spark machining device to drill a 1.5 mm diameter and 3.5 mm deep crack stopping hole.

[0030] Step 3: Welding repair: accurately align the blocking piece with the hole through the positioning boss, press the positioning boss into the hole, and then perform laser spot welding to fix it, with 6 evenly distributed welding points. Use friction stir welding, with a stirring head speed of 1200 r / min, a welding speed of 4 mm / s, and a pressing amount of 0.8 mm. After completing each layer of welding, use a high-pressure gas spray gun and a steel wire brush to clean the welding seam surface in time, carefully check and repair defects.

[0031] Step 4: Overall strengthening and sealing treatment: After welding is completed, first perform solid solution treatment, heat to 900℃ at a heating rate of 8℃ / min, and then quench in water after 3.5 hours of holding. Then perform aging treatment at an aging temperature of 500℃ for 2.5 hours. Then apply a 1 mm thick sealing glue to the welded area, and apply a 0.4 mm thick epoxy zinc-rich paint anticorrosive coating to the surface of the perforating gun.

[0032] Step 5: Quality detection: Perform appearance inspection, flaw detection, and pressure test on the repaired and assembled sandwich gun. No defects are found in the appearance inspection, no internal problems are detected in the flaw detection, and no abnormalities are found in the pressure test at 1.5 times (45 MPa) the actual use pressure for 30 minutes, determining that the sandwich gun is qualified and can be put into actual oil exploitation operation.

[0033] The above disclosed embodiments of the present application are only used to help explain the present application. The embodiments do not describe all the details of the present application, and the present application is not limited to the specific embodiments described. According to the content of the present specification, many modifications and changes can be made. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application.

Claims

1. A method for repairing a perforating gun, characterized in that: Specifically, the following steps are included: Step 1: Prepare the blocking plate (3); Step 2: Perforation gun pretreatment: Select a perforation gun that has been damaged after perforation. First, use a high-pressure hot water gun to thoroughly rinse it to remove surface impurities. Then, use an 80-120 grit grinding wheel to grind the area 5-8mm around the hole. Next, soak the perforation gun in rust remover and then rinse it clean with water. Step 3: Welding repair: The plug (3) is accurately aligned with the hole through the positioning boss. After pressing the positioning boss into the hole, it is fixed by laser spot welding. After each layer of welding is completed, the weld surface is cleaned in time with a high-pressure gas spray gun and a wire brush. Defects are carefully inspected and repaired. Step 4: Overall strengthening and sealing treatment: After welding, solution treatment is performed first. The perforating gun is slowly heated to 850-950℃, with the heating rate controlled at 5-10℃ / min. After holding at this temperature for 3-4 hours, it is quenched in water. Then, aging treatment is performed at 450-550℃ for 2-3 hours. After that, sealant is applied to the welded parts, and epoxy zinc-rich paint anti-corrosion coating is sprayed onto the surface of the perforating gun. Step 5: Quality Inspection: Perform visual inspection, flaw detection and pressure test on the repaired and assembled sandwich gun.

2. The method for repairing a perforating gun according to claim 1, characterized in that: The plug (3) includes a plug base and a positioning boss connected to each other. The diameter of the plug base is larger than the diameter of the positioning boss. The plug base and the positioning boss have a through central pressure relief hole on their axes.

3. The method for repairing a perforating gun according to claim 2, characterized in that: The diameter of the plug base is 7-10 mm larger than the hole, and the thickness is 5-7 mm.

4. The method for repairing a perforating gun according to claim 2, characterized in that: The height of the positioning boss is 1.5-2.5mm, and its diameter is 0.4-0.6mm smaller than the diameter of the hole.

5. The method for repairing a perforating gun according to claim 2, characterized in that: The diameter of the central pressure-reducing orifice is 2 mm.

6. The method for repairing a perforating gun according to claim 1, characterized in that: The plug (3) is made of alloy steel and the surface of the plug is finely polished to achieve a surface roughness of Ra2.5μm.

7. The method for repairing a perforating gun according to claim 1, characterized in that: In step 3, the laser spot welding adopts friction stir welding, the stirring head rotation speed is 1000-1500 r / min, the welding speed is 3-5 mm / s, the stirring head pressure is 0.5-1.0 mm, the stirring head shoulder diameter is 15-20 mm, the stirring pin length is 4-6 mm, and the diameter is 8-10 mm.

8. The method for repairing a perforating gun according to claim 1, characterized in that: In step 3, 5-7 weld points are evenly distributed by laser spot welding, and the diameter of each weld point is controlled between 2.5 and 3.5 mm.

9. The method for repairing a perforating gun according to claim 1, characterized in that: In step 4, apply a sealant with a thickness of 0.8-1.2mm to the welding area, and spray an epoxy zinc-rich paint anti-corrosion coating with a thickness of 0.3-0.5mm onto the surface of the perforating gun.

10. The method for repairing a perforating gun according to claim 1, characterized in that: In step 5, no defects were found in the visual inspection, no internal problems were detected in the flaw detection, and no abnormalities were found in the pressure test at 30MPa for 120 minutes. Therefore, the sandwich gun was deemed qualified and could be used in actual oil extraction operations.

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