Author(s)

C.N. OKEZUE

Abstract

Hydrodynamic slug flow is the commonest flow regime observed in high viscosity liquid–gas horizontal pipelines over a wide range of different flow conditions.  Hydrodynamic slugging tends to generate large vibrations that may impose structural instability or even damage oil production pipelines. For that reason, there is a need to investigate high viscosity slug flow regime to understand its complex characteristics. This is pertinent when considering that existing slug flow models used in the petroleum industry to design production pipelines are not suitable for predicting the behaviour of high viscosity oil–gas flow. In this study, the effects of liquid viscosity and flow variables on slug flow regime were investigated experimentally through the analysis of two key parameters—slug frequency and slug body liquid holdup, both measured with a gamma densitometer. Comparison of the measured slug parameters to existing correlations revealed that slug body liquid holdup correlations were in close agreement with high viscosity experimental data. However, none of the existing slug frequency correlations used was able to produce accurate predictions. A new empirical correlation for slug frequency was proposed. Compared with existing correlations, the newly proposed correlation performed much better in predict- ing slug frequency of high viscosity liquid–gas flows.

Keywords

Empirical correlation, gamma beam densitometer, hydrodynamic slug flow regime, multiple- linear regression, slug body liquid holdup, slug frequency, two-phase flow.