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Oil production decreases and water production increases as time goes by in
the life of a hydrocarbon reservoir. The mixture of oil and water is usually
produced as an emulsion. Emulsion formation starts in the two-phase flow inside
the reservoir. The emulsion structure changes as it flows through pipes, pumps
and valves up to the surface facilities. During all stages, large drops of the
dispersed phase break up leading to smaller drops. It is important to know the
droplet size distribution of the dispersed phase in order to design separation units
and predict the pressure drop along the flow. The aim of the this work is to study
the droplets break-up process that takes place in capillaries and in a needle valve
in order to make predictions of the size of the resulting droplets that emerge from
this process. The main challenge is to understand how the different operating flow
parameters affect the break up process. In order to achieve this goal, two
laboratory scale experimental set-ups have been used. In the first experiment, we
conducted a parametric analysis of oil-water emulsion formation in laminar flow
through straight capillaries. The experiments were carried out using two syringe
pumps connected by a double-hubbed capillary pipe. The oil-water emulsion is
forced back and forth through the pipe. The mean diameter and the specific
surface area of the dispersed phase were obtained as a function of flow rate, shear
rate, residence time and rate of energy dissipation at the capillary wall. As
expected, keeping all other variables fixed, the dispersed phase mean diameter
decreases with the shearing time, reaching an asymptotic value, which was a
strong function of the shear rate at the capillary wall. Secondly, we conducted a
parametric analysis of turbulent oil-in-water emulsion flow through a needle
valve. The experiments were carried out using a helicoidal pump to control the
flow rate through the needle valve. The mean diameter and the specific surface
area of the dispersed phase upstream and downstream of the valve were obtained
as a function of the pressure drop in the valve, flow rate, and rate energy
dissipation of the flow. The dispersed phase mean diameter falls and the specific
surface area rises with the pressure drop in the valve until reaching an asymptotic