Strain Analysis of Oil and Gas Pipeline with Dents Based on ILI Data

Abstract

Dents in an oil and gas pipeline can be detected by In-line-Inspection (ILI), and structure integrity analysis of the pipe with theses reported dents is important for the safe operation. Strain analysis of the dented pipe is a way of fine assessment and ASME B31.8 has established the strain assessment code and its acceptable range. However, the method of strain assessment is rarely used due to the difficulty of strain calculation for a buried pipe. In this study, features of ILI data are investigated to elaborate the necessary of filtering analysis for strain analysis of the dent with ILI data. Then typical filtering methods are used to smooth the ILI data, and strain analysis are carried out with the smoothed data to study the practicability of strain assessment. Profile and strain of a dent in D813 pipe were obtained by Finite Element Method (FEM). Then different filtering methods were used to smooth the simulated ILI data of the dent which were selected from FEM profile. Strain of the dent were also calculated by smoothed data with the latest ASME B31.8 code, and compared with it from FEM at last to prove the feasibility and validity of the filtering methods with ASME B31.8 code.

Modeling and strain analysis of pipeline dent based on geometric in-line-inspection data

“…Although pipeline integrity assessment has gained achievements in the pipeline industry practices, there is still a lack of a process from data collection to model establishment of the pipeline integrity assessment [3] . In recent years, there are many studies focus on dent assessment with ILI data and FEM analysis, such as the studies done by Katina Tinacos [4] , Race J M [5] , Lei Z [6,7] , Xian-Kui Zhu [8] and Brian Leis [9] . But these studies did not establish the modeling of the pipe based on ILI data in the FEM simulation and strain analysis.…”