Determining phase fractions by flowing multiphase fluid through a resonant cavity in which certain resonance modes are suppressed or enhanced

摘要

A multiphase meter for use in the quantification of the individual phase fractions of a multiphase flow has a resonant cavity 12 through which, in use, a multiphase fluid flows from an inlet 13 to an outlet 14. A signal generator applies electromagnetic energy at a range of frequencies to the cavity via probes 22. The phase fractions can be determined by analysing peaks in the measured response spectrum. Desired resonance modes are enhanced and/or undesirable interference modes suppressed to improve the quality of the measurement. This is done using physical structures 26 within the cavity 12, preferably using conductive elements embedded in a ceramic material 18. The structures may be of various shapes, such as flat, rectangular, circular, annular, arched, spherical, cylindrical, ovoidal, saw-toothed, sinusoidal, castellated and leaf-shaped. The method is particularly suitable for streams from oil/gas wells which include a mixture of hydrocarbons and salt water.