Plunger lift is a method of artificial lift that uses the well’s own energy to lift fluid from a set depth in the tubing string. It is used to prevent liquid loading once the well drops below critical rate. Plungers act as an interface between fluid and gas. The well’s energy is the driving force that brings the plunger to the surface. Plunger lift focuses on reducing flowing bottom hole pressure to allow in flow from the reservoir. The open cycle is triggered by opening a valve at the surface by blowing of the head gas stored in the tubing. This creates a differential across the plunger allowing the plunger to rise against the path of least resistance and come to the surface.
The plunger then goes into sales, or after-flow, time where gas is sold and fluid flows back into the tubing. After adequate sales time, the plunger then goes into the shut, or fall, cycle. The shut time allows the plunger to travel back to the bottom hole bumper spring to wait until the open cycle begins again. This operation is repeated multiple times per day and is monitored for any necessary adjustments.