Research On Integrity Assessment Of X80Pipeline

The integrity assessment of pipeline is a kind of quantitative method, by which the fitness-for-service of the pipeline containing defect can be determined. And not only could the incident ratio of pipeline be reduced greatly, but the unnecessary replacement and maintenance could be avoided. With the need for the overall consideration of the safety and cost for the pipeline engineering, there are many technique and method questions need to be improved and developed. Especially, the construction of API X80pipeline engineering brings forward a new demand and challenge for the integrity technique.In this paper, on the basis of the mechanical property test, the fracture toughness of the X80base material, weld joint and heat affected zone (HAZ) had been test, and the failure assessment curve fitting equations of these3kinds of material were established. Furthermore, the Charpy impact energy (CVN) of X80was collected and analyzed, and the stray data of the test sample was removed, and the probabilistic distribution mode of X80line pipe was established. Besides that, the empirical equation between CVN and the fracture toughness of X80was provided. Comparing with the equation recommended in the API579, the equation established in this paper is more reliable.This paper also assessed the reliability of the2nd West-East gas pipeline, and the scatter character of material mechanical property and the fluctuation of the operating pressure were considered. And the assessment results indicated that the reliability of the2nd West-East can meets the need for the target reliability recommended in the DNV RP F101.