Failure analysis of oil pipelines

Abstract

Pipelines play significant roles in the major phases of petroleum exploration, drilling, refining and distribution. Pipelines are often subjected to harsh environments which make them to be susceptible to failure, leading to oil leakage and environmental pollution. The objective of this work is to undertake failure analysis of failed schedule 40-inch manifold pipe from Shell Petroleum Development Company, Port Harcourt, Nigeria with a view to ascertaining the causes of failure. Visual examination, chemical and metallographical analyses, and mechanical tests of the failed and standard pipes were carried out. The results revealed that the failed pipe was hard enough (156BHN) to withstand crude abrasion; tough enough (39.73J) to withstand impact shock from the crude, but had a rather low fatigue strength (46.10N/mm2) when compared to the standard. It is suggested that welded joints in pipes be heat-treated and coated on clean substrate pipe in order to enhance material integrity in service.

Keywords: Failure Analysis, Oil Pipeline, Corrosion, Environment, Photomicrograph