A method for wellhead measurement of at least one well using a Coriolis flowmeter, the method comprising: determining a drive gain threshold; determining an entrained gas severity of the at least one well, where the entrained gas severity is based on the amount of entrained gas corresponding to a measured drive gain that exceeds a determined drive gain threshold, characterized in that: determining the drive gain threshold comprises: storing at least one factory baseline drive gain value during calibration of the Coriolis flowmeter; determining a predetermined drive gain threshold based on the at least one stored factory baseline drive gain value; computing at least one time interval where a measured drive gain is steady and below the predetermined drive gain threshold; setting the drive gain threshold based on the measured drive gain correlating to the at least one time interval; and correcting the drive gain threshold based on a measured water cut and increases in viscosity; wherein the method further comprises: outputting at least one flow variable (221, 222) measurement based on the determined entrained gas severity; and outputting a respective confidence level indicator correlating to the at least one flow variable. determining a drive gain threshold; determining an entrained gas severity of the at least one well, where the entrained gas severity is based on the amount of entrained gas corresponding to a measured drive gain that exceeds a determined drive gain threshold, characterized in that: determining the drive gain threshold comprises: storing at least one factory baseline drive gain value during calibration of the Coriolis flowmeter; determining a predetermined drive gain threshold based on the at least one stored factory baseline drive gain value; computing at least one time interval where a measured drive gain is steady and below the predetermined drive gain threshold; setting the drive gain threshold based on the measured drive gain correlating to the at least one time interval; and correcting the drive gain threshold based on a measured water cut and increases in viscosity; wherein the method further comprises: outputting at least one flow variable (221, 222) measurement based on the determined entrained gas severity; and outputting a respective confidence level indicator correlating to the at least one flow variable. storing at least one factory baseline drive gain value during calibration of the Coriolis flowmeter; determining a predetermined drive gain threshold based on the at least one stored factory baseline drive gain value; computing at least one time interval where a measured drive gain is steady and below the predetermined drive gain threshold; setting the drive gain threshold based on the measured drive gain correlating to the at least one time interval; and correcting the drive gain threshold based on a measured water cut and increases in viscosity; wherein the method further comprises: outputting at least one flow variable (221, 222) measurement based on the determined entrained gas severity; and outputting a respective confidence level indicator correlating to the at least one flow variable. outputting at least one flow variable (221, 222) measurement based on the determined entrained gas severity; and outputting a respective confidence level indicator correlating to the at least one flow variable.