METHOD OF INTERPRETING NMR SIGNALS TO GIVE MULTIPHASE FLUID FLOW MEASUREMENTS FOR GAS/LIQUID SYSTEM Russian patent published in 2018 - IPC G01F1/716 

FIELD: physics.

SUBSTANCE: present invention generally relates to a method and an apparatus for measuring magnetic resonance and analysing multiphase flow regimes in a transport or production pipe. Method for assessing a gas phase in a flowing multi-phase fluid comprises flowing the fluid through magnetic resonance and pre-polarisation modules and applying to the fluid a radio-frequency pulse sequence at least once with and at least once without a magnetic field gradient. Method further includes measuring an NMR signal. Method also includes using calibration between the ratio of slope and intercept of the NMR signal and flow velocity for at least one non-gas phase with the gradient applied to determine that phase's velocity. Calibration between the signal intensity of the liquid phases as a function of flow velocity is used, with and without gradient, to correct the gradient-induced attenuation of the liquid signals and to calculate a gradient-corrected signal intensity of the liquid phases without a magnetic field gradient. Additionally, the method includes subtracting the gradient-corrected signal intensity from the NMR signal to calculate the volumetric fraction of the liquid phase.

EFFECT: higher accuracy of determining the velocity profile of each individual component of a multiphase fluid without using time-of-flight measurements.

9 cl, 5 dwg