How do multiphase flow meters work for oil and gas production?

Multiphase flow meters (MPFM) measure oil, water, and gas simultaneously without separation. Technologies: gamma-ray densitometry (dual-energy for water cut, total density), venturi (DP for total flow rate), microwave/RF (dielectric for water content), and cross-correlation (velocity measurement). Calculations: phase fractions from density/dielectric, individual phase flow rates from total and fractions. Test separator validation during commissioning. Considerations: flow regime effects (homogeneous vs slug flow), pressure/temperature compensation, and measurement uncertainty (typically 5-10% per phase). Applications: production allocation, well testing, and remote offshore/subsea where test separators impractical. Follow API MPMS Chapter 20.3 guidelines.