Analytical-numerical Investigation of Factors Influencing Overall Heat Transfer Coefficient of Multiphase Petroleum Fluids in Horizontal Subsea Pipelines

摘要

This paper aims to identify the factors which influence overall heat transfer coefficient, U, in subsea petroleum pipelines. For this purpose, first, factors that influence fluid temperature in pipelines, i.e. properties of pipe, insulation and fluid, are divided into two groups. Group 1 (2) factors affect temperature solely (possibly) through influencing U. Examples are pipe thickness for group 1 and ambient temperature for group 2. Group 1 factors definitely impact on U. The dependence of U on group 2 factors is unclear. To resolve this ambiguity in subsea pipelines, a combined analysis of theoretically derived relationships and OLGA software results is proposed for horizontal subsea pipelines carrying multiphase petroleum fluids in steady state. Outcomes show that, in group 2, U only depends on input fluid temperature and pipe diameter. These two alongside group 1 form an inclusive list of factors influencing U. Such a list is essential to develop an accurate mathematical model to estimate overall heat transfer coefficient to be used in thermal analysis of the pipeline.