Modeling Plunger Lift for Water Removal from Tight Gas Wells

Abstract

Abstract Many tight gas wells produce at rates below their potential, due to water loading. Plunger lift is often applied to remove produced (or condensed) water, reduce bottomhole flowing pressure, and increase both gas production rate and ultimate recovery. Previous authors have discussed dynamic models of the plunger lift process. However, these previous models considered only stabilized reservoir production. Because of the assumption that reservoir production is stabilized, these older models have only limited applicability to tight gas wells. This paper presents a study of the application of plunger lift to the problem of water removal from tight gas wells. A numerical simulation model was developed which includes gas flow in the reservoir, wellbore/annulus effects, and dynamic plunger lift cycles. Transient reservoir performance is an important feature of the new model. Transient reservoir performance is a significant factor for tight gas reservoirs, especially as average reservoir pressure decreases during the life of the reservoir. Field data from tight gas wells with plunger lift for water removal can be more thoroughly analyzed using the new simulation model. Calibration of model parameters with field cases allows the plunger lift design to be optimized for a particular well. Improved understanding of the plunger lift process for tight gas wells with water loading problems may lead to more efficient water removal, increased gas production rates and recovery, and longer well life.