ABSTRACT
Multiphase flow metering (MPFM) is very specific to the oil and gas industry – with the delivery of oil and gas decreasing over the life of the well with a commensurate increase in the delivery of water. A complicating consideration is that the multiphase mixture pressure may vary from almost 0 to 2,000 bar and the temperature can vary from −40°C to 200°C.
The traditional method is to split the multiphase steam into discrete phases, using a test separator with the measurement taking place on a single phase. The compact upstream separation device provides a relatively liquid-free gas stream and a liquid stream – with each metered separately. Because complete phase separation rarely occurs and entrapment of phases within each other is common, alternative in-line MPFM schemes have been devised.
Technologies include a combination of microwave sensor and positive displacement flowmeter, capacitance and inductance sensors, and Venturi tube and nuclear densitometers.
The chapter concludes with a discussion on water-cut meters – the ratio of the water which is produced in a well compared with the volume of the total liquids produced. Water-cut meters employ several technologies including oscillatory, capacitive, microwave dielectric, and infrared.
