Abstract: A multiphase flow measurement system determines the individual total flow rates of the water, gas, and oil components in a production fluid mixture from a subterranean well. The system includes a mass flow measurement unit which is coupled to the outlet of the well for measuring a total mass flow rate of the production fluid mixture. After the mass flow rate has been measured, a sample portion of the production fluid is supplied to a test separator tank system which is utilized to determine individual sample flow rates of the water, gas, and oil components in the sample portion of the production fluid. A central control unit is responsive to the individual sample flow rates and the mass flow measurement for determining the individual total flow rates of the water, gas, and oil components at the well head.