CFD simulation of oil-water flow in a horizontal pipe

Abstract

Water produced along with crude oil during production and transported together in a pipeline is a common occurrence in a petroleum production system. Understanding the behaviour of crude oil-water flow in a pipeline is crucial to many engineering applications, such as design and operation of flowlines and wells, separation systems, logs interpretations and determination of the amount of free water in contact with the wall of the pipes that can render erosion or corrosion problems. Presently, there are only two published papers on two phase flow of Malaysia waxy crude oil-water, namely Ismail et al. (2015b) and Piroozian et al. (2017). Their focuses were on flow pattern, pressure drop, and water holdup of the two phase flow system. All the parameters, working conditions, and simulation for this research work were basically based on the experimental results published by Ismail et al. (2015b) which involved the flow of waxy crude oil-water in a closedloop system of 5.08 cm ID stainless steel horizontal pipeline at ambient condition. The water cut was varied from 10% - 90% with mixture velocities ranging from 0.1 - 0.9 m/s. Five flow patterns have been identified by them; stratified waxy flow, stratified wavy semi dispersed flow at interface and oil film, dispersion of water in oil and oil continuous with emulsion, dispersion of oil in water with water continuous, and the newly found semi dispersed flow semi emulsion at interface and thin oil film. The objective of this study is to simulate and validate the flow pattern, pressure drop and liquid holdup with the experimental results using ANSYS Fluent and CFX-Pre. The volume of fluid (VOF) multiphase flow modeling method was used in Fluent and free surface model was used in CFX-Pre in conjunction with the standard k-e and k-rn schemes to simulate the oil-water flow. The simulation results were found to be in good agreement with the published data. The simulation results can be used as a platform to understand better other more complex cases of waxy crude and water concurrent flow in pipelines.