Systems and methods for measuring an interface level in a multi-phase fluid composition

A method for measuring a level of a mixture of fluids in a vessel, the method comprising:

• detecting a set of signals from a resonant sensor system at a plurality of locations in the vessel, wherein the resonant sensor system comprises at least an electrically resonant transducer;
• converting the set of signals to values of real and imaginary parts of the impedance spectra for the plurality of locations;
• storing the values of the real and imaginary parts of the impedance spectra and frequency values;
• and
• determining a fluid phase inversion point from the independent values of the real and imaginary parts of the impedance spectra.

A method for determining a composition of a mixture of oil and water in a vessel comprising:

• determining a set of complex impedance spectrum values and conductivity values of the mixture of oil and water as a function of a height in the vessel with an electrically resonant transducer, wherein the set of complex impedance spectrum values and conductivity values include real and imaginary parts of the impedance spectra;
• determining a fluid phase inversion point from each of the independent values of real and imaginary parts of the impedance spectra;
• applying an oil phase model to the set of complex impedance spectrum values, and conductivity values above the fluid phase inversion point;
• and
• applying a water phase model to the set of complex impedance spectrum values and conductivity values below the fluid phase inversion point.

A method for determining a composition of a mixture of a first fluid and a second fluid in a vessel comprising:

• determining, with a sensor system, a set of complex impedance spectrum values of the mixture of the first fluid and the second fluid as a function of a height in the vessel, wherein the set of complex impedance spectrum values include real and imaginary parts of the impedance spectra;
• determining a fluid phase inversion point from the independent values of the real and imaginary parts of the impedance spectra;
• applying a phase model of the first fluid to the set of complex impedance spectrum values above the fluid phase inversion point;
• and
• applying a phase model of the second fluid to the set of complex impedance spectrum values below the fluid phase inversion point.