NUMERICAL SIMULATION OF TWO-PHASE SLUG FLOW REGIME IN HORIZONTAL PIPE

Oil and gas offshore production headers frequently experience random trips which
is suspected to be due to liquid carryover issues as a result of sudden slug generation in
the production headers. These slug generations are caused by sudden increase in gas
velocity which provides sufficient drag to allow the free surface wave to grow on gasliquid
interface to a height sufficient to bridge the pipe. This hydrodynamic slugging is
difficult to predict since it can occur over a wide range of gas-liquid flow conditions.
Compounding the complexity is the issue of no standard consensus of applicability of
numerous operational correlations associated with slugging, e.g. pressure gradient,
liquid holdup and slugging frequency. The objective of this study is to investigate oilgas
slug formation in horizontal straight pipe and its associated pressure gradient, slug
liquid holdup and slug frequency. The abrupt change in gas/liquid velocities, which
causes transition of flow patterns was analyzed by using FLUENT 16.1. The
incompressible Volume of Fluid (VOF) method was used to capture the transient
distribution of segregated gas-liquid interface in different flow patterns. The validity of
present model and its methodology was compared using Baker chart for 3.15 inches
diameter horizontal pipe. The numerical solution was also compared quantitatively with
existing experimental data to ensure its correctness. Finally, analyses were carried out
for oil and gas vapor flow, covering substantial region of slug flow regime map.
Concurrently, slug pressure gradient, liquid holdup and frequency were extracted
numerically, and compared to existing empirical correlations. The present results
compares favorably with some correlations and identified some outlier empirical
models, which may not be suitable for operational usage.