A Dynamic Plunger Lift Model for Gas Wells

Abstract

Summary Many low-volume gas wells produce at suboptimum rates because of liquid loading caused by an accumulation of liquids in the well-bore that creates additional backpressure on the reservoir and reduces production. Plunger lift is an artificial lift method which can use reservoir energy to remove these accumulated liquids from the wellbore and improve production. Lacking a thorough understanding of plunger lift systems leads to disappointing results in many applications. This study develops a plunger lift model that couples the dynamic nature of the mechanical plunger lift system with the reservoir performance. The model takes advantage of previous work and incorporates frictional effects of the liquid slug and the expanding gas above and below the plunger. The model considers separator and flowline effects and includes modeling of transient production behavior after the liquid slug has arrived at the surface. An improved understanding of plunger lift dynamics can lead to improved efficiency, increased production and recovery, and extended well life.