Reinforcing Composite Materials To Repair The Research To Oil And Gas Pipelines

A lot of defects of China’s numerous in-service oil and gas pipeline are generated due to corrosion, mechanical damage and external loads in the service process. These defects reduce the strength of the pipe, so that the carrying capacity can not achieve the original designed pressure capacity. These defects are serious threat to the safe operation of pipelines. The radial expansion is produced in the wall of the ring to the tensile stress because of the internal pressure. The stress concentration happens in the thinning area of pipe wall (such as corrosion place). The stress concentration in the wall thinning area (such as corrosion Office), The site will rupture failure and leakage when the stress is greater than the tensile strength limit.There are more than50,000kilometers’existing pipelines are in service in China, how to ensure the integrity and the safe operation of the pipe become an urgent need of petrochemical industry. Using composite material to repair pipelines greatly reduces the replacement cost and time, which is recognized an accepted method in the industry. This paper mainly research on how to repair pipelines by using composite material more economically and effectively, in order to achieve the maximum safe operation purpose:1) For not repaired pipeline with defects, calculate the residual strength according to the AP1579standards and finite element method respectively. Discuss the influnence of depth and length of defects to the ultimate bearing capacity of pipeline.2) For repaired pipelines with defects by using composite materials, calculate the ultimate bearing capacity according to the ASME criterion, discuss the failure of the finite element method in the pipeline criterion, observe and analyze the stress changes of ultimate bearing capacity of the pipeline, and compare these with not repaired pipe.3) Introduces the blast test of prepared pipeline with composite materials, simulates the teststatus by using ANSYS, study the test results to verify the reliability of the test model. Finally, this paper also summarizes the main research work, and points out needed further research.