Abstract:
Multiphase flows are of great interest to a large variety of industries because flows of two
or more immiscible liquids are encountered in a diverse range of processes and
equipment. However, the advent of high viscosity oil requires more investigations to
enhance good design of transportation system and forestall its inherent production
difficulties.
Experimental and numerical studies were conducted on water-sand, oil-water and oilwater-
sand respectively in 1-in ID 5m long horizontal pipe. The densities of CYL680 and
CYL1000 oils employed are 917 and 916.2kg/m3 while their viscosities are 1.830 and
3.149Pa.s @ 25oC respectively. The solid-phase concentration ranged from 2.15e-04 to
10%v/v with mean diameter of 150micron and material density of 2650kg/m3.
Experimentally, the observed flow patterns are Water Assist Annular (WA-ANN),
Dispersed Oil in Water (DOW/OF), Oil Plug in Water (OPW/OF) with oil film on the
wall and Water Plug in Oil (WPO). These configurations were obtained through
visualisation, trend and the probability density function (PDF) of pressure signals along
with the statistical moments. Injection of water to assist high viscosity oil transport
reduced the pressure gradient by an order of magnitude. No significant differences were
found between the gradients of oil-water and oil-water-sand, however, increase in sand
concentration led to increase in the pressure losses in oil-water-sand flow.
Numerically, Water Assist Annular (WA-ANN), Dispersed Oil in Water (DOW/OF), Oil
Plug in Water (OPW/OF) with oil film on the wall, and Water Plug in Oil (WPO) flow
pattern were successfully obtained by imposing a concentric inlet condition at the inlet of
the horizontal pipe coupled with a newly developed turbulent kinetic energy budget
equation coded as user defined function which was hooked up to the turbulence models.
These modifications aided satisfactory predictions.
