Analysis and Research on Quality Defects of Oil Casing Thread Processing

In the exploration and development of petroleum companies, the processing quality of oil casing threads is directly related to the exploration and development benefits. This is mainly because the thread is the joint part, so it is the weakest link, so it is often the area with high accidents. In the process of oil casing thread processing, there are often quality defects of one kind or another. Based on this background, this paper analyzes the quality defects of oil casing thread processing in combination with its own working practice, and puts forward some points of view on strengthening the thread processing of oil casing.


　　


Oil casing thread; processing quality defect






　　1. Analysis of common quality defects in oil casing thread processing






　　In the processing of oil casing thread, the common quality defects are mainly the following: one is black leather buckle; the second is corrugated; the third is tight distance.






　　As far as the black leather buckle is concerned, the main part is that the thread is partially insufficient in processing amount, resulting in a poor finish, mainly the diameter of the steel pipe itself, the thickness of the pipe wall, the ellipticity and precision, and the straightness of the pipe end. There is an association between degrees. When there is a black leather buckle in the pipe body, it is mainly due to the small outer diameter of the pipe body, the flatness of the pipe end is insufficient, and the ellipticity is large.






　　Moreover, as the black leather buckle appears on the thread, there will be a defect in the partial wall of the thread, which is mainly caused by the thinning of the steel tube and the uneven thickness of the other side. The reason why the thread will be biased is the same as that of the thread forming the black leather buckle, which is caused by the uneven wall thickness of the steel pipe end and the large ellipticity and bending, and the partial processing of the thread processing, and The amount of processing is not properly controlled, resulting in a super negative wall thickness of the wire. Therefore, both are the quality defects of thread processing.






　　The tight distance, the tooth height, the taper and the pitch are the thread parameters, and the connectivity and sealing are often poor due to the excessive parameters. Among them, the tight distance is the comprehensive fluctuation value of many individual parameters in the whole thread, so when any single parameter is unqualified, it will affect its tight distance, so it is not only related to the material of the steel pipe, but also the way of processing. And the type and smoothness of the machine tool being processed are closely related to the precision of the machine itself [1].






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2. Countermeasure analysis of measures to strengthen quality defects






　　2.1 Analysis of treatment measures for threaded black leather buckle






　　The treatment of the quality defect of the threaded black leather buckle is mainly carried out in combination with the reason for its formation. Based on the above reasons, the author proposes the following specific countermeasures.






　　(1) Ensure that the pipe material has a strong verticality. Because the formation of the black leather buckle is mainly caused by the large curvature of the material of the pipe body, when we use the machine tool to machine the casing, in order to better ensure the verticality of the oil casing, the bending degree is different. When processing the pipe material, ensure that the bending range of the pipe body should be determined according to the diameter of the casing to be machined and the type of the machine tool, and should always be lower than this standard value, otherwise the thread will appear. The problem of black leather buckle, so the control of the processing curvature is particularly important, generally within the bending degree of 1.0 mm, in order to better reduce the formation of the black leather buckle, in order to better effectively in the thread processing The occurrence of a defect is minimized, so as to improve the verticality of the pipe material, reduce the impact of the black buckle, and promote its role in the exploration of oil and gas resources.






　　(2) Make sure the workpiece can clamp the center. This is mainly because the difference between the main machine and the auxiliary machine of the machine tool, and the claws are not adjusted, which leads to the problem of the card not being tight, and finally forms a quality defect such as a black leather buckle and a threaded partial wall.






　　In the process of its treatment, the pipe material itself should be removed first. When adjusting the machine tool, ensure that the main machine and the auxiliary machine are concentric. At the same time, the centering claw should be adjusted and the front and rear chucks should be checked. Whether the jaws are worn or not, so that the centering jaws can be better adjusted and checked by clamping and rotating the steel tube to the centering condition. After centering, the accuracy of the rotation of the steel tube should be controlled at 0.5 mm. Within the inside, the front and rear chucks are adjusted to be in a floating working state, so that the slight bending of the steel pipe at the head end can ensure that the centering state meets the actual needs, thereby effectively binding the black leather buckle to the wire. The formation of the buckle wall is minimized [2].






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　2.2 Analysis of the treatment measures for the problem of excessive thread parameters






　　(1) Strengthen the control of the accuracy of the machine tool itself. When machining the thread, the tool compensation and program adjustment are mainly taken, but the taper of the actual measurement and the change between the tight distance and the measured value are obviously not significant. The root cause is mainly due to the lack of accuracy of the machine tool itself. Caused by. This is mainly due to the fact that the accuracy requirements of some of the wire machines currently in use are difficult to meet the actual needs. Therefore, we must strengthen the control of the accuracy of the machine tool itself, strengthen the elimination of the old wire machine as much as possible, and strengthen its investment and update.






　　In general, the accuracy of the ball screw of the rough and fine turning sleeve and the axial spacing of the machine tool are controlled to 0.10 mm and 0.05 mm, respectively, and the verticality error of the rotating table is controlled at 0.05. Within mm, and by adjusting the NC program, the taper and tightness of the thread are strictly controlled to ensure that it meets the relevant requirements in the API standard, thus ensuring that the accuracy of the machine itself meets the accuracy of the threaded casing. need.






　　(2) Strengthen the adjustment and optimization of the taper and tightness of the thread. Among the many thread parameters, since taper and tightness are the most important factors, we should strengthen the adjustment and optimization. In terms of standard taper, it is mainly a diameter change of 0.0625" (1.5875 mm) per inch. For a full thread portion, the maximum allowable deviation is between 0.061" and 0.067" (1.55 - 1.67 mm). The incomplete thread portion, the maximum deviation allowed is between 0.061" and 0.067" (1.55 - 1.70 mm). When detecting the taper, the thread is the starting point, every 25.4. After mm, the taper value of this point should be measured. A total of three points need to be measured. Combined with the actual measurement, the adjustment of the machine tool is strengthened, and the positioning error of the machine tool should be effectively compensated during the whole adjustment process, thus effectively Adjust the starting point coordinate value during the thread finishing process, and adjust the taper and tight distance by changing the coordinate value of the wire.






　　(3) Fully aware of the necessity of strengthening the precision control of machining. When processing the oil casing, the ovality and verticality of the inner and outer diameters of the material should be strictly controlled to better facilitate the machining. Therefore, in the entire processing process, as a processing personnel, it is necessary to closely combine the thread processing needs of the oil casing, and determine the standards of its various parameters. This requires us to closely integrate the actual situation in the actual processing, determine the impact of its different factors, and focus on the treatment of it, in order to better meet the needs of oil casing processing.






　　In addition, the stability of the processing table should be considered during the processing. Even if it is not stable, it may cause defects in the thread quality of the car. This requires us to pay attention to its processing.






　　(4) When the oil casing thread is processed, the quality of the processing should be inspected and corrected in time. It is strictly forbidden to check after processing, otherwise the quality problem will be caused due to the untimely inspection. At the same time, the accuracy of the inspection tool should also be strictly controlled to better ensure the accuracy of the inspection, so as to better ensure the quality of the processing.






　　For the quality problems that occur in the process, the solution that can be solved should be solved in time. If it cannot be solved, it should be replaced in time, and the cause of the accuracy deviation should be found, so as to better strengthen the future of the oil casing thread processing. The optimization and improvement ensure the precision and quality of its processing, and ensure that its processing quality defects are effectively processed to maximize the exploration benefits of oil companies [3].






　　3, the conclusion






　　In summary, although the defects in the quality of oil casing thread processing are inevitable, we can maximize the quality defects and improve the processing quality as much as possible. This requires us to combine the types of quality defects, targeted The strengthening of its treatment can better meet the needs of exploration and development.