TABLE OF CONTENTS The major parts of the TopFlow meter are the Venturi insert and the electrodes inside the Venturi throat. The flow rates of oil, water, and gas are calculated based on the measurements performed by the electrodes and the measurement of the differential pressure across the Venturi inlet.
The TopFlow meter utilizes a capacitance sensor for oil-continuous liquid mixtures, where the capacitance caused by the dielectric constant of the fluid mixture is measured in the throat of the Venturi. Similarly it utilizes a four-electrode conductance sensor for water-continuous liquid mixtures, where the conductance is caused by the conductivity of the fluid mixture. All the necessary electrodes are incorporated within a Venturi that is somewhat modified. Advanced data processing is utilized to have continuous readings of the flow rates of oil, water, and gas.
The Venturi has a minimum of pressure drop. Nearly all multiphase meter vendors use a Venturi in one way or the other, and the reason is that this is probably the most reliable device for multiphase measurement because it measures the mass flow rate independent of what happens. One objection is the relatively limited turndown ratio that is specified, especially for single-phase measurements within fiscal uncertainties. However, because most wells produce in the high GVF range, where the total mass flow rate does not vary much, there is no general problem connected to the use of this device. Especially when installing one meter at each single well and not having to...
