Method for non-linear high salinity water cut measurements

A method for determining a water cut value and a salinity value for a hydrocarbon composition, the method comprising the steps of:

• obtaining the hydrocarbon composition, where the hydrocarbon composition has the water cut value and the salinity value;
• inducing, by a capacitance probe, a set of frequency values into the hydrocarbon composition in a range of from a first frequency value to a second frequency value, the capacitance probe in fluid contact with the hydrocarbon composition;
• detecting, by the capacitance probe, a set of mixture permittivity values of the hydrocarbon composition at the set of induced frequency values, the capacitance probe operable to form an associated signal for the set of mixture permittivity values;
• inducing, by the capacitance probe, a normalization frequency value into the hydrocarbon composition;
• detecting, by the capacitance probe, a reference mixture permittivity value at the induced normalization frequency value;
• determining, at a computer coupled to the capacitance probe, a set of ratiometric mixture permittivity values using the reference mixture permittivity value and the set of detected mixture permittivity values, the computer comprising a signal processing device operable to receive the associated signal;
• deriving, at the computer, a first set of ratiometric mixture permittivity values at the set of induced frequency values, a first set of salinity values and a first water cut value, where the first set of ratiometric mixture permittivity values is normalized at a first reference mixture permittivity value determined at the induced normalization frequency value;
• deriving, at the computer, a second set of ratiometric mixture permittivity values at the set of induced frequency values, a second set of salinity values and a second water cut value, where the second set of ratiometric mixture permittivity values is normalized at a second reference mixture permittivity value determined at the induced normalization frequency value and where the first water cut value and the second water cut value are not the same;
• and
• determining, at a signal processing device, the water cut value and the salinity value of the hydrocarbon composition by comparing the set of determined ratiometric mixture permittivity values to the first set of derived ratiometric mixture permittivity values and the second set of derived ratiometric mixture permittivity values at the set of induced frequency values;
• calibrating a water cut meter based on the determined water cut value;
• and
• using the water cut meter in an enhanced oil recovery (EOR) operation.