Quickly Replaceable Measuring Technique And Error Analysis Of Oil-gas Pipes

Offshore oil has been explored for many years in China. There is a need for the oil-gas pipes of the equipments used for offshore drilling, oil-gas-water treating and used on oil production platform nowadays to be repaired and replaced because of corrosion perforation and improvement in technologies. The traditional method used for maintenance and replacement is to isolate, dismantle and clean pipelines under the condition of off production, which involves greater human, material resources and is more time-consuming. As for construction safety, much hidden trouble also exists. Based on the above questions,this paper presents the quick measuring technique of oil-gas pipes according to the principle of laser telemeter.To achieve the quick measurement of oil-gas pipes, the paper puts forward the digital model and measurement scheme based on the analysis of measure elements of oil-gas pipes. Prefabricated Flange pipe sections are practically tested with the help of Laser total station-Nikon DTM-532C, It also introduces the method to turn the measured data back into the original size and the central-line special curve diagram of Flange pipe sections based on the data analysis with the help of matrix transformation and solid geometry knowledge. And then, the results of the experiments will be compared with the data of the original size and the central-line graphs of prefabricated Flange pipe sections to test the accuracy and practicability of the experimental measuring scheme .The paper also analyzes various factors which influence the accuracy of the measurement experiment and gives some suggestions about how to reduce the measurement errors. The main research results of the paper are listed as follows:1)It discusses the current situation in the field of non-contact measurement at home and abroad systematically and introduces the scheme and principle of measuring prefabricated Flange pipe section with the experiments. It analyses the characteristics of Flange pipe section and measure elements, constructs the mathematical model of Flange pipe sections which is composed of the center curve and flange surface of Flange pipe section ,linear and bolt hole location linear and is called the standard curve for short. It theoretically researches how to measure oil-gas pipes with solid geometry and space phase and involves the actual measurement of the laser total stations with Nikon DTM-532C and acquisition of the data of with the help of measurement objects.2) Cartesian three-dimensional coordinate which is useful for further data processing can be obtained after the format conversion of the data acquired with total stations. The key data, such as the three-dimensional coordinate of the standard curve key points of the prefabricated pipelines, the central angle and radius of the standard curve can be gotten by using the spatial relation of measurement objects and Prefabricated Flange pipe sections and transforming coordinates. With these data, the standard curve of prefabricated flange pipe sections can be drawn in AutoCAD, which is introduced to SolidWorks to assemble bend pipes, straight pipes and flange pipes, and the 3D drawing of Flange pipe sections comes into existence. Then the 3D drawing can be transformed into 2D working drawing with the help of the standard orthographic views in SolidWorks. The automatic written dimensions need to be adjusted to be consistent with the construction norms.3) It shows the factors influencing the accuracy of the measurement base on the analysis of the actual measurement of the prefabricated pipelines, including the manufacturing errors of measurement objects and flatness errors of measurement objects and surfaces of flange pipes and puts forward the suggestions to amend the errors.4) It compares the theoretical size of Flange pipe sections with the findings of experimental measurement data analysis to find out the theory is consistent with the experiment findings , which meets the demands of the accuracy for actual measurement of pipes. The paper shows the accuracy and practicability of the measurement model of oil-gas pipes.5) The quick measuring technique of oil-gas pipes pointed out in the paper provides scientific basis for the offshore manufacturing, on-line or half off production quick replacement of pipelines, which can provide a guarantee for reducing field construction enhancing production safety and has great economic and social benefits...