Methods of increasing efficiency of plunger lift operations

A method of increasing efficiency of a plunger lift operation of a hydrocarbon well, the method comprising:

• monitoring, with an acoustic monitoring system and during a production time period, an acoustic output from the hydrocarbon well as a function of time, wherein the production time period includes:
• (i) an uphole travel time period during which a plunger of the hydrocarbon well travels toward a surface region;
• (ii) a liquid discharge time period during which a liquid, which is above the plunger during the uphole travel time period, is discharged from the hydrocarbon well;
• and
• (iii) a gas discharge time period during which a gas, which is below the plunger during the uphole travel time period, is discharged from the hydrocarbon well, the gas discharge time period being identified by a change in a frequency fingerprint detected in a downsampled plot of the acoustic output;
• calculating a plunger speed of the plunger during the uphole travel time period based, at least in part, on the acoustic output during the uphole travel time period;
• calculating a discharge duration of the liquid discharge time period;
• and
• correlating the plunger speed during the uphole travel time period and the discharge duration to a discharge volume of the liquid discharged from the hydrocarbon well during the liquid discharge time period.