![](bg7.png)
because the two-fluid model is mainly used to calculate the stratified flow rate and pressure drop,
while ignoring the pipe wall is surrounded by water friction coefficient decreases ,such as a circular
flow or a two-phase flow in which the wall is prewashed by water.
4. Conclusions
In this paper, the flow characteristics of horizontal and inclined oil-water two-phase annular flow are
studied, and the shear rate, phase-slip ratio and pressure distribution are analyzed. The relationship
between the slip ratio and the oil content of the inlet was analyzed by using the two - fluid model and
the VOF model. The friction pressure drop is calculated by the two-fluid model, the four
homogeneous flow models and the VOF model. The main conclusions are as follows:
1) The slip ratio of annular flow is in increasing relation with the oil content in the inlet, and the
increasing rate is related to both the inlet velocity pipe and the dip, and decreases with the
increase of inlet velocity, and increases with the inclination of the well.
2) The total pressure drop of the annular flow increases with the apparent flow velocity,while
dcreases with pipe inclination. The friction pressure drop of the VOF model is obtained by
using the two-fluid model. Compared with the VOF model and the results of the four
homogeneous flow models, the deviation from the experimental data is the largest, and the
deviation of the friction pressure calculated by the VOF model is the smallest in the middle.
The homogeneous phase flow model is used to predict the pressure drop in a dispersed flow
but the prediction results are better in a toroidal flow where the pipe wall is in contact with
the water phase due to the very simple phase of contact with the pipe wall in the toroidal flow
which is related to Reynolds number and the friction coefficient is stable.
Fund project
National Science and Technology major project "large-scale oil and gas fields and coalbed methane
development" sub-topics (2016ZX05019001-011)
National Natural Science Foundation of China (41374116)
National Natural Science Foundation of China (416774113)
References
[1] Zhai L S, Jin N D, Zong Y B and et al 2015 Experimental flow pattern map, slippage and
time–frequency representation of oil–water two-phase flow in horizontal small
diameter pipes. Int. J. Multiphase Flow 76 p168-186.
[2] Jana A K, Das G and Das P K 2006 Flow regime identification of two-phase liquid–liquid
upflow through vertical pipe. 61 p1500-1515
[3] Lum J Y L, Al-Wahaibi T and Angeli P 2006, Upward and downward inclination oil–
water flows. Int. J. Multiphase Flow 32 p413-435
[4] Rodriguez O M H, Bannwart A C and de Carvalho C H M 2009 Pressure loss in core-
annular flow: Modeling, experimental investigation and full-scale experiments J.
Petrol. Sci. Eng. 65 67-75
[5] Jiang F, Wang Y J, Ou J J andet al 2014 Numerical Simulation of Oil-Water Core Annular
Flow in a U-Bend Based on the Eulerian Model. Chem. Eng. Technol p 659-666
[6] Kumara W, Halvorsen B and Melaaen M C 2009 Velocity and turbulence measurements
of oil-water flow in horizontal and slightly inclined pipes using PIV. Computational
Methods in Multiphase Flow V, p277.
[7] Kumara W A S, Halvorsen B M and Melaaen M C 2010 Particle image velocimetry for
characterizing the flow structure of oil–water flow in horizontal and slightly
inclined pipes. Chem. Eng. Sci. p4332-4349
IWEMSE 2018 - International Workshop on Environmental Management, Science and Engineering
176