Experimental study on two phase oil-water dispersed flow

Abstract

The present work reports the study of oil-water dispersed flows experimentally. Small scale experiments using small diameter pipe flow loops or rheometers are commonly used for the characterization of oil-water flows in the industry. These small scale techniques offer a relatively simple and low cost alternative. However, the applicability of these small scale results in large scale real systems remains uncertain.

The objective of the present work is to have a better understanding on the scale up of oil-water dispersed pipe flow. To this aim a combination of dispersed oil-water flow experiments with unstable and stable mineral oil mixtures as well as with real crude oils was carried out. The experiments were performed in different pipe diameters using different experimental setups depending of the stability of the oil-water mixtures. An existing flow loop at the Statoil Research Centre was used for the crude oil experiments. Unstable dispersions were tested in the Multiphase Flow loop at NTNU. Major modifications had to be made to this facility for the experiments with stable oil-water mixtures in different pipe diameters. Mineral oils with special additives that resemble real crudes, available as part of the FACE consortium, were used here.

The qualification of small scale characterization methods was also part of the initial plan. Nevertheless, the pipe diameter effect results with stable dispersions required additional experiments which took additional time. Therefore, the small scale characterization techniques were not properly qualified.

Appropriate instrumentation is of key importance when studying complex flow structures as in dispersed oil-water two phase flow. A feasibility study for the development of a multiple beam two energy gamma densitometer was also performed as part of the present work. An instrument capable of providing the cross sectional distribution of the phases in the pipe would certainly have added interesting information if used in the present work. The development of this instrument will be extremely useful for future work in this field.