Pipeline Reliability: An Investigation of Pipeline Failure Characteristics and Analysis of Pipeline Failure Rates for Submarine and Cross-Country Pipelines

Abstract

Summary This paper presents an overview of causes and frequency of failures of submarine and cross-country pipelines handling petroleum and natural gas. A breakdown of the causes of failure has been carried out. The most significant causes are: outside-force/ third-party damage, corrosion, and mechanical failures (materials failure and construction defects). The effect on failure frequency of factors such as pipeline age, location, diameter, and commodity pipeline age, location, diameter, and commodity transported have been investigated and discussed. The data have been used for calculating pipeline failure rates. Introduction Pipelines are a safe and reliable mode of transportation. Pipelines are a safe and reliable mode of transportation. Fatalities per ton kilometer transported are much lower than for any other means of transportation. The amount of oil spilled per unit transported is also very low. Pipelines in general therefore represent a small risk to Pipelines in general therefore represent a small risk to human life and to the environment. However, pipelines represent large capital cost, and any pipeline failure has significant economic impact because of the cost of repair and the loss of transportation capacity. For gas pipelines a failure can also directly affect the availability of gas to consumers. The pipeline networks around the world are increasing steadily and new pipelines are being built in new areas. In southeast Asia and Australia there are new gas pipelines under construction and in planning both pipelines under construction and in planning both onshore and offshore. In the North Sea some of the existing pipelines have been designated to handle new pipelines have been designated to handle new transportation requirements and will require a prolonged lifetime. Each year there are hundreds of pipeline failures, resulting in pollution, loss in transportation capacity, loss of gas availability, and costly repair expenses. Of course, most of the failures occur on onshore pipelines, because they cover a much greater area, but failures on offshore lines normally take longer to repair and therefore are more serious in terms of business interruption. A better understanding of the causes and characteristics of pipeline failure will provide important information to improve inspection and maintenance activity for existing pipelines and to aid in selection of design criteria for new pipelines. The purpose of this paper is to compare the failure data from the various pipelines to see if there is a common trend regarding failure rates, causes of failures, aging characteristics, and failure-rate dependence on essential pipeline parameters. A comparison between onshore and pipeline parameters. A comparison between onshore and offshore pipelines is also made to see what experience with onshore pipelines can be applied to offshore lines. Pipeline failures in the U. S., western Europe, the Gulf of Pipeline failures in the U. S., western Europe, the Gulf of Mexico, and the North Sea are examined. In this paper, a pipeline failure is usually defined as an incident that has led to a significant pipeline leak or has otherwise required immediate repair. Failure rates per kilometer year of operating experience--i. e., pipeline length times years in operation--have been calculated for the pipelines where a sufficient data base is available. The paper is based mainly on the results presented in two reports by Det norske Veritas, with some additional information from the original sources. JPT P. 709