Alpha VS/R Wet-Gas Flowmeter Principle of Operation

Alpha VS/R is based on an extended-throat Venturi, a sonar flowmeter and an optional Red Eye® multiphase water-cut meter. This combination of non nuclear technologies has a wide operating envelope and offers maximum accuracy in dry- and wet-gas streams as well as a stable and predictable response under multiphase flow conditions.

The sonar flowmeter measures the convection of turbulent vortices using an array of dynamic strain sensors. Sonar has the unique ability to measure total flow rate accurately over an extremely wide range of Reynolds numbers (flow rate, fluid types) with a negligible over-reading in wet-gas flows. (Over-reading is the ratio of apparent flow rate to the actual flow rate.)

The Venturi flowmeter is based on the measurement of static pressure drop across a converging pipe section. The pressure drop is proportional to the increase in kinetic energy of the flow stream, i.e., conservation of momentum. Unlike sonar, Venturi flowmeters have a strong and well defined over-reading as a function of wetness or liquid content in the wet-gas stream. The combination of sonar and Venturi in the Alpha VS flowmeter yields total gas and liquid flow rates in real time.

The optional Red Eye multiphase water-cut meter is a filter spectrometer that employs the principle of near-infrared absorption to measure the water content in a liquid or multiphase stream. The Red Eye multiphase meter reports accurate water cut independent of flow regime, flow rates, water salinity and hydrate inhibitors.

The Alpha VS/R is thus a true three-phase wet-gas flowmeter based on three independent primary instruments for the measurement of gas, oil/ condensate and water rates.