Multiphase flows are very common in the petroleum, chemical, and nuclear industries,
oftentimes involving harsh media, strict safety regulations, access difficulties, long distances, and
aggressive surroundings; accordingly, there is a need to determine the dispersed phase holdup using
noninvasive fast responding techniques. Moreover, knowledge of the flow structure is essential for the
assessment of the transport processes involved. The ultrasonic technique fulfills these requirements and
could have the capability to provide the information required. In this chapter, the current status of the
ultrasonic technique in the context of multiphase flow metering (MFM) is thoroughly reviewed; the
focus is on multiphase flows of interest in the oil industry. Specific aspects involving the application of
the technique to gas-liquid and gas-liquid-solid flows as well as dispersions and slurries are addressed.
It is expected that this chapter will provide the reader with a clear view of what is already known about
the application of ultrasonics to multiphase flows, its potential, and the research needs so that the
technique could be effectively brought to the field.
Keywords: Multiphase flows, ultrasonic technique, monitoring, flow metering, gas liquid, gas liquid solid,
dispersion, slurries.
