Coriolis Principles and Considerations for Entrained Gas in the Upstream Market
Most flow meters directly measure velocity or differential pressure and in turn calculate or infer flow rate. Such devices are Reynolds Number dependent and are affected by changes in temperature and if a gas then pressure too. Coriolis meters are unique because rather than inferring flow from other measurements, they measure mass flow directly. Consequently, Coriolis meters are not concerned with changes in density or velocity profile. Accordingly, no temperature and pressure compensation is necessary as well as long meter runs of straight pipe.
Another advantage of Coriolis meters is that given a small amount of entrained gas, a velocity meter (e.g. Turbine; Electromagnetic; Ultrasonic) will overstate the actual volume by the amount of gas void fraction; whereas a Coriolis meter will measure the mass of the entire fluid stream. Consequently, a Coriolis meter will only overstate the mass of the liquid phase not by the volume of entrained gas but rather by the gas's mass, which is normally inconsequential.
Things get a bit more challenging when gas breaks out of the liquid phase creating pockets or slugs of gas.
What You Will Learn:
- Coriolis and density theory
- Advantages over traditional volumetric meters
- Water cut
- Flow tube geometry relationship to pressure drop, fluid velocity and ultimately to slug flow