2.2 Cleaning of the barrel 3 welding process 3.1 Welding methods and equipment Table 1 Welding parameters Table 2 Temperature and pressure resistance test Table 3 Simulated well perforation test 5 Conclusion (1) The barrel repaired by the above process is tested by the temperature and pressure resistance and the simulated well perforation test, and the quality fully meets the design requirements, which proves that the repair process is feasible. About the Author: Dai Yuanxiong, born in 1960, welding technician. Previous page Window Hardware,Window And Door Hardware,Casement Window Hardware,Casement Hinges Hardware SANHUI HARDWARE COMPANY LTD. , https://www.sanhui-1.com
After the perforating operation, the barrel is often accompanied by a thick layer of dirt formed by crude oil and sand. It should be thoroughly removed before welding and carefully cleaned within 2.03 m of the groove to expose the metallic luster. The groove processed on the drilling machine and the blocking plate processed on the lathe are inevitably stained with oil. It can be cleaned with a cleaning agent. After cleaning, it must be dried immediately and transferred to the next process as soon as possible to prevent rust.
When repairing the barrel, it is best to use a skilled and flexible manual arc welding method due to the particularity of the groove form. In order to prevent burn-through and soldering, it can also be primed by hand TIG welding, and then filled and covered by hand arc welding. At the same time, in order to meet the strict welding process requirements and obtain excellent welded joints, the United States Miller DC power supply is selected.
3.2 Welding materials
The root of the groove is 35CrMoA+Q235 dissimilar steel welded joint. The strength grades are different, and the welding is difficult. In order to make the weld metal have good crack resistance, the welded joint is obtained. E4315 electrode is used for bottoming and filled with E5015 electrode. And cover. After the electrode is baked (350 ~ 450) ° C × 2 h, put it in a 100 ° C incubator for heat preservation, use it with the use, you must use the insulation tube.
3.3 Welding parameters
According to the shape of the groove and the performance of the welded joint, the process parameters as shown in Table 1 are selected, and the lower limit of the parameter is selected as much as possible, and the polarity of the power source is reversed by DC. Welding rod diameter
d/mm Welding current
I/A Arc voltage
U/V Welding speed
Mm . mm -1 2.5 60～70 23~24 100～120 3.2 90～100 25~26 120～140
(1) When welding, if it is hot summer, or when the ambient temperature is ≥30°C, the wall thickness of the barrel is thin (δ<8mm), the structure is simple, and the cooling rate of HAZ is slow, so it can be preheated, but Slow cooling and heat treatment measures must be taken. In winter, the welding environment is bad, the temperature difference between the molten pool and the base metal is large, the cooling speed of the welded joint is fast, and the crack and hardening tendency of the weld are serious. To prevent the occurrence of cold cracks, preheating measures are needed to reduce the cooling rate. Reduce the welding stress to ensure the structure and performance of the welded joint. Considering the wall thickness of the barrel and the actual factors of the structure, the weldment can be preheated in the temperature range of (250-300) °C, and slow cooling and heat treatment measures are taken. When conditions are met, it is best to place the barrel on a long hot iron stove. After the tube and the furnace are hot (250 ~ 300 °C), the welding is carried out directly. When welding, the room is not allowed to wear the wind, so as not to speed up the cooling. Promote the formation and stability of high-carbon martensite in the heat-affected zone, increase brittleness and cause cracks.
(2) In the welding, in order to prevent burn-through, first use the E4315 welding rod of φ2.5 mm to make the bottoming, and in the case of no arc extinction, make the rounding strip with the diameter gradually decreasing along the outer diameter of the blocking plate. In order to prevent liquefaction cracks, the solder layer should be flat and thin, and the arc pit should be filled and then extinguished. When the weld is slightly blackened, knock the slag and clean it with a wire brush. Immediately increase the welding current at the interlayer temperature of (250-300) °C, and replace it with the E5015 electrode of φ3.2 mm. Fillet layer welding is performed at the flat climbing slope. In order to ensure the arc heat concentration, slow down the cooling rate, and eliminate the inclusions and hydrogen holes in the weld, theoretically, a larger welding line energy should be used, but in order to avoid overheating of the austenite in the overheated zone and improve the austenite Body stability, and avoid the formation of coarse martensite, to improve the performance of the superheat zone and reduce the embrittlement of the superheat zone, reasonably use a small (<1.5 kJ / mm) welding line energy, short arc Straight line or "∞" shaped strip, the welding meat should be flat and thin, press one by one, and at the same time, tap the tube with a hammer to reduce internal stress and avoid cracks. The cover layer is quickly welded while ensuring the interlayer temperature. When starting the arc, it should be staggered from the arcing point of the upper road. When the strip is to the edge of the groove, the residence time should not be too long, so as to avoid the peak temperature of the arc burning the matrix alloy element and increasing the fusion ratio of the welded joint, resulting in the chromium in the heat affected zone. The weld is hardened and the crack tends to increase. Welding should be continuously welded.
(3) In order to ensure the quality of welding, welders or senior welders and technicians who hold the boiler pressure vessel and high-pressure steam pipe welding qualification certificate must be welded, and the test and on-site trial conditions should be recorded in detail and kept for record.
4 post weld inspection
(2) According to the design requirements, the barrel is subjected to 100 ° C temperature resistance and 30 MPa withstand voltage test. The results are shown in Table 2. Pilot projects Temperature t/°C Pressure P/MPa Hold time t/min Design requirements 100 (no leakage of the barrel) 30 (no deformation of the gun body) 30 test results 100 (no leakage of the barrel) 31 (no deformation of the gun body) 30 Pilot projects Shooting ratio of gun perforation and blind hole φ (%) The maximum expansion of the outer diameter of the gun body is z/mm One-side longitudinal maximum crack length of gun body hole a/mm Non-hole crack The gun body is split and broken. Standard or design requirements ≥85 ≤ 5 ≤40 No crack Crack free test results 100 5 0 No crack Crack free
(2) According to the above repair process, we have welded and repaired the scrap barrels of nearly 300 m, and successively put them into the perforating operation of oil and gas wells, which have good effect and can be reused at least 2 times (by the outer diameter of the gun body). The limit of the maximum expansion value), the annual perforating barrel of the Bureau consumes more than a kilometer, and its economic benefits are considerable.
Author unit: Dai Yuanxiong Liaohe Petroleum Exploration Bureau Oil Construction Second Company (Panjin City 124012)
Xu Yongheng Liaohe Petroleum Exploration Bureau Oil Construction Second Company (Panjin City 124012)
Li Qing Liaohe Petroleum Exploration Bureau Oil Construction Second Company (Panjin City 124012)
Repair characteristics and technology of perforating barrel in oil and gas field (2)
3.4 Process operation points
(1) After welding, after visual inspection, ultrasonic flaw detection, no cracks, and 30 MPa hydrostatic test with a test machine, and kept for 30 min, no leakage.
(3) On the simulated well with a well temperature of 50 °C and a well pressure of 10 MPa, the SL52YD-1 type perforating projectile with a single charge of 37.7 g was used, and the total number of loaded bombs was 32, and the barrel was simulated. Hole test, the results are shown in Table 3.