A method and system operates a well having an outer casing, a tubing positioned inside the outer casing, and a plunger moveable within the tubing to periodically draw out a liquid slug. A chemical to slug size ratio is set by the operator. Thereafter, the gas flow rate is monitored and the well is shut-in when the gas flow rate drops below a predetermined threshold. After well shut-in, a calculated amount of chemical foaming agent is injected. The size of the liquid slug is calculated and then the well is opened, drawing the plunger and liquid slug up to the surface. The calculated amount of chemical foaming agent is calculated based on one or more previous liquid slug size determinations and the set chemical to slug size ratio.