Laser cutting of petroleum sieves is one of the typical applications of laser cutting technology in the petrochemical industry. During oil drilling, sand control in loose formations is one of the most critical parts in the design of well completion and production engineering. Generally, a large number of small gaps are processed around the pipe to block most of the sand layer. The important feature of laser cutting is that it can cut gradient slits with wide width and narrow width or narrow width and narrow width, which makes the petroleum sieve pipe have better performance.
Principle of laser cutting machine for petroleum sieve tube Laser cutting of petroleum sieve tube is focused on the sieve tube with a focused high power density laser beam. The high energy of the laser beam plus oxygen assists, which causes the laser to act on the casing surface. The temperature rises sharply, and the workpiece material is partially melted or gasified to form holes. On the one hand, the auxiliary oxygen participates in the laser oxidation cutting, and on the other hand, the slag is blown away to form laser and oxidation cutting. When the sleeve and the laser beam move relative to each other, a slit can be cut in the sleeve.
Compared with traditional mechanical processing methods, laser cutting screens have the following advantages: laser cutting is non-contact processing, so there is no tool wear; cutting is noise-free, and it is easy to automate processing; laser cutting efficiency is high, usually only one seam A few seconds is dozens of times of the machining efficiency and low processing cost. The laser cutting has high processing accuracy and regular seam shape. The laser cutting has a wide processing range. Slots of different specifications such as round holes. The slit width can be reached from 0.2 ± 0.05mm to 0.5 ± 0.05mm.
Performance and specifications Slotted screen pipe: Slotted screen pipe can be divided into two major categories according to the purpose: namely oil slotted pipe and water cutting slotted pipe, which are made of various steel grade pipes. It complies with the requirements of APISpec5CT and China Petroleum Materials & Equipment Corporation's "Supplementary Conditions for Ordering of Tubing Casings", and meets various requirements.
"PRS" screen tube ("PRS" screen tube includes: wire-wound drum screen, straight-wound wire screen, punched (hole) drum screen)
The gap of the wire-wrapped screen tube can be accurately arbitrarily wound on the base pipe (oil, casing), and the width of the slot can be controlled within 0.15-0.5 ± 0.05㎜, which can meet the needs of sand control in the well. Stainless steel wire is resistant to acid, alkali and salt corrosion, and the gap will not widen due to corrosion.
The inside of the filter sleeve of the perforated (hole) cylindrical screen is supported by the base pipe (sleeve, oil pipe), which has sufficient overall strength to resist the compression deformation of the formation. Even if it deforms, the gap in the pressured part will not increase. The shortcomings of the punched screen tube when it is squeezed from the outside are that the gap is reduced or closed by the external force, so the sand control reliability is high.
Inlaid sieve tube: The sieve of the inlaid sieve tube is made of special materials, so the gap is small and evenly distributed. Although it is embedded in the tube and fixed twice, it is easy to fall off.
The key to laser cutting quality defects and analysis of laser cutting screens lies in the reasonable selection of process parameters, mainly including: laser power, focus position, pulse frequency and duty cycle, cutting feed speed, auxiliary gas pressure and cutting head nozzle specifications Wait. If the process parameters used in processing are not reasonable, different processing quality defects will occur. In severe cases, the entire screen tube may be scrapped. The following are several common quality defects in laser processing
1. Burst hole (or match head): The main reasons for this defect are: the laser output power is too high when punching, the pulse frequency is too fast, and the wall thickness of the screen is uneven.
2. Hook head: This kind of defect appears in the process of wide seam processing. The main reason is that the speed of the cutting head at the bend is not adjusted or the linkage between the cutting head and the screen is not coordinated.
3. External slag spraying: The reason for this defect is that the laser power is too low when the hole is punched, the pulse frequency is too fast, and the slag is sprayed back. The laser output power and punching pulse frequency should be adjusted to reduce or avoid slag spraying. For a small number of external slag defects, surface polishing is required.
4. Ultra-wide and slag hanging: The reason for the ultra-wide is that the laser output power is too high during the cutting process, the feed speed is too slow, and the auxiliary gas pressure is too low, which causes the screen substrate to be ablated. Built-in slag is a technical problem that is easy to appear and difficult to solve during the process of cutting the screen. The probability of internal slag is greater when processing trapezoidal seams. The production of internal slag is mainly avoided by increasing the pressure of auxiliary gas and other corresponding technological measures. Laser cutting machine
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brand manufacturer-Dongguan Heli Laser Equipment