Integrity Management for Wrinklebends and Buckles

Overview

Main Objective

Validation of the newly available direct assessment methodologies for both external corrosion and stress-corrosion cracking; development of improved modules for assisting operators with controlling the parameters that cause stress-corrosion cracking; approaches for improving the integrity of systems with wrinklebends and buckles; and a viable approach to running fracture that should help operators minimize its consequences when ruptures occur. Goals: (1) Broaden the utility of severity assessment criteria to cover pipelines with diameters from 12" to 36" in Grades from B thru X60, for wall thickness typical of products and natural gas transport, and operational histories for such service, and validate by full-scale test; (2) Quantify effects of corrosion pitting on the corrosion-fatigue resistance of line pipe steels, and combine with analysis of the effects of ID and OD corrosion on wrinklebends, and modify assessment criteria. (3) Quantify effects of pipe restraint applied local to the wrinkle or globally near the wrinkle, and assess implications for fieldwork on or nearby wrinklebends; (4) Quantify differences in hot-formed vs. cold-formed wrinkles in regard to fatigue resistance of line pipe and shape of the wrinkle; (5) Update severity assessment criteria to embed effects of corrosion, constraint, and forming temperature; and (6) Evaluate differences between wrinkles and large-scale buckles. This is a consolidated project with Project No 162, Project No 163, and Project No 165.

Public Abstract

The Pipeline and Hazardous Materials Safety Administration is keenly interested in ensuring the safety of the nation's pipeline infrastructure. Battelle proposes a broad program that addresses several key elements of the complex but related issues that impact pipeline integrity to help meet this need. It is known that external and internal corrosion of buried pipelines receives much attention from operators. Stress-corrosion cracking and external corrosion have been implicated in several field failures. Consequently, Battelle has invested considerable effort to both understand and mitigate future related failures. We have also focused on other mechanisms that undermine integrity of vintage systems such as wrinklebends. Finally, ruptures occur occasionally when preventive measures taken to optimize pipeline integrity fail. In the worst of those cases, rupture propagates rapidly along the pipeline ("running fracture"), whose length controls the consequences of failure. Our proposal combines these elements into one project to provide higher value-added to the Government. Battelle's program comprises five projects previously submitted as separate white papers combined within the task structure of one program. The scope includes: validation of the newly available direct assessment methodologies for both external corrosion and stress-corrosion cracking; development of improved modules for assisting operators with controlling the parameters that cause stress-corrosion cracking; approaches for improving the integrity of systems with wrinklebends and buckles; and a viable approach to running fracture that should help operators minimize its consequences when ruptures occur.

Relevant Files & Links