Research On Micro-Leakage Detection Technology Of Oil Port Pipeline

Pipeline transportation plays an indispensable role in promoting the development of the national economy.In the process of transportation and construction,the leakage events may occur occasionally due to the internal and external factors of the pipeline.The leakage events may result an economic loss which threatens the life safety of people living around the pipeline,and even leads to the destruction of the ecological environment.Also,there are leakage enents in oil port pipeline.The gas detector meets the requirement for monitoring of pipeline safety,for a large amount of leakage,however,failed to meet the corresponding requirements in minor leakage events caused by aging and corrosion.Therefore,in view of the problem of micro-leakage detection becomes difficulted to be solved,to do research on the leakage detection of it and the estimation of leakage becomes very necessary and meaningful.This thesis analyzes the necessity of detecting micro-leakage events in a background of oil port pipelines.Based on the case of minor leakages caused by corrosion,the study adopts the stress-strain analysis method and tests its feasibility on detection of small leakage and estimation of leakage amount in oil pipelines by theoretical derivation and simulation analysis.On this basis,the pipeline leakage detection experiment platform is built and implemented with a highly sensitive method of electrical measurement,which verifies the simulation results by comparing with the designed experiment.In practical experiment application,it is found that the test results are consistent with the simulation results,which shows the stress-strain state of the pipe wall can effectively reflect the leakage state of the pipeline fluid and the amount of the leakage.Additionally,this method is of good stability,easy maintenance,and high detection sensitivity so that it can be used as an option for small leak detection in oil port pipeline,which achieves a purpose of monitoring the safe operation of pipelines.The study is carried out in the following aspects:(1)Taking the motion equation and continuity equation of pipeline fluid in pipeline operation as the breakthrough point,and the calculation model of leakage and leakage rate of small holes was derived.According to the stress form in which the leaking orifice is pressurized by the internal pressure of the fluid,it is analyzed that the initial operating pressure of the pipeline and the area of the leaking orifice are the main factors affecting the leakage of the pipeline and the stress status of the pipeline.And puts forward the method of oil pipeline based on the analysis of stress-strain from the pipe wall.(2)The pipeline model and boundary conditions which are consistent with the actual test are selected and simulated using ANSYS.Quantitative analysis of the leakage of small holes and the monitoring point of the pipe wall in the course of the initial operating pressure of the pipelines are 0.1 MPa,0.2 MPa,0.3 MPa and 0.4 MPa,with the leakage holes that increasing from 0.6 mm to 2 mm per 0.2 mm interval The law of stress on the change and the mutual reflection of the relationship between them are observed.The simulation results show that the greater the leakage generated by the pipeline,the greater the change in the stress at the monitoring point before the leakage.By monitoring the magnitude of the stress on the pipe wall or the magnitude of the stress change,a decision can be made as to whether or not the pipe is leaking and a preliminary estimate of the amount of leakage.(3)From the point of view of the test comparison,the selection of the electrical measurement method as the method for detecting the stress-strain in the pipe wall during the test,and a platform for the leak detection test of the pipe hole was designed and constructed.On this test platform,it is possible to control the initial operating pressure and different leakage aperture conditions,to complete the leakage of small holes under various leakage conditions and the detection of stress values at the monitoring points on the wall.The obtained multiple sets of the results of the test data were collated,converted and statistically analyzed to determine the leakage status of the pipeline.(4)The orthogonal test design method was used to determine the test scheme for the leak detection test of the pipe with a small hole.Through the analysis of test data results,the conclusion that the results of the test is consistent with the simulation analysis is obtained.That is,the stress state of the pipe wall can reflect the movement state of the fluid in the pipeline,which confirms the feasibility of the leak detection method based on the stress-strain analysis.