Patent ID: 8729893

Claim:
A method of estimating in the petroleum industry, a flow rate in a pipe, of a selected phase of a multiphase fluid, with an NMR spectrometer comprising: obtaining a first velocity distribution of amplitudes from a first set of nuclei in the multiphase fluid from a Nuclear Magnetic Resonance (NMR) signal received from the multiphase fluid in response to a 1 H NMR excitation signal; obtaining a second velocity distribution of amplitudes from a second set of nuclei in the multiphase fluid from an NMR signal received from the multiphase fluid in response to a 13 C NMR excitation signal; estimating a velocity of the selected phase from the first velocity distribution and the second velocity distribution; and in the NMR spectrometer processor: determining a volume fraction and a mean velocity of a water phase and a hydrocarbon phase using said amplitudes obtained from the first velocity distribution; determining a volume fraction and a mean velocity of the hydrocarbon phase using an amplitude obtained from the second velocity distribution; estimating the flow rate of the selected phase, using the determined volume fractions and the estimated velocities, and providing the estimated flow rate of the selected phase to an output storage device of the NMR spectrometer.