Patent ID: 7276916

Claim:
A method, comprising: performing an on-line measurement of a water fraction in a multi-phase flow of a multi-phase mixture in a pipe by measuring at resonance impedances of coils disposed about said pipe, said impedances varying as a function of a composition of conducting fractions present in the flow, and by employing said coils comprising: a first coil including a first number of turns, said first coil optimized for measuring a continuous mixture of oil/gas, and a second coil including a second different number of turns, said second coil optimized for measuring a continuous mixture of water, wherein said coils are disposed in operation on an outer surface of said pipe, such that the coils are arranged so as to be driven at resonant frequencies of said coils in operation, wherein losses arising in the coils at resonance are determined by alternating from one of the coils to another thereof.