Contribution to integrity assessment of an oil pipeline with the useof corrosion models, flow codes and mechanical properties

Pipelines are becoming an increasingly important means to transport large volumes of hydrocarbons over long distances in the Mediterranean region. If well constructed, carefully monitored and properly maintained, pipelines can be a safe and environmentally/economically sound means of transport; however, pipeline integrity is a growing and challenging problem for oil companies since the age of components is increasing and the responsibility and awareness about environmental protection is increasing too. Procedures and practices to monitor pipeline integrity are an important challenge for operators. Internal corrosion is one of the most active and dangerous damage mechanisms. In the frame of a research project the attempt was made to apply well known models in different sections of a long pipeline, with the objective of obtaining, coupled with flow dynamics properties of the transported fluid, a ranking of corrosion risks along the pipe. Other studies have shown that long term effects on mechanical properties of pipeline steel can be observed in presence of internal corrosion. The results of such studies need an effort towards application, to understand their capability of giving a measure of pipeline integrity. The application to the case of Meleiha-El Hamra pipeline (Agiba Pet. Co.,Egypt) - having a length of 166 km and operating since 1985 to transport oil and condensate from different fields - is discussed in this paper. Hydraulic analysis was performed. Fluid velocity and flow regime as a function of pipeline length were obtained. The run was completed with the application of Water Wetting Models. Obtained results were compared with intelligent pig output to verify the reliability of the proposed procedure. Moreover, on a section of the serviced pipeline provided by Agiba, hydrogen embrittlement effects were assessed to verify the ageing of the pipeline steel, and field applicable technologies to characterize on site mechanical properties of the material were evaluated.