Plunger Lift Dynamic Characteristics in Single Well and Network System for Tight Gas Well Deliquification

Abstract

AbstractThis paper presents a study for plunger lift characteristics to dewater tight-gas wells operated in the Piceance basin of Rocky Mountains with multiple-well pads and surface pipeline network. The wells’ TVDs are about 6000 ft with deviated paths, and the water-gas-ratio (WGR) is 40~80 stb/MMscf. The objective is to understand the optimal operating conditions for reasonably controlling deliquification without severe liquid surge while maintaining maximum gas production.The IPR and reservoir depletion are based on tight gas model, which considers the transient IPR due to very low matrix permeability, hydraulic-fractures and drainage radius. A transient dynamic multiphase flow analysis has been performed to investigate the plunger lift effectiveness, performance and optimization for different scenarios. Simulation runs were performed for early, middle and late field life which corresponds to different reservoir pressure and productivity index. It shows that liquid loading becomes severe and production becomes unstable (heading) with decreased reservoir pressure and increased water influx. Eventually the well production can stop due to liquid loading. Plunger lift helps to maintain the production and reduce the instability. A network model with 22 wells on a pad has been built to study the interaction of the system and the liquid surge control strategy.Plunger-lift process for tight gas wells with liquid loading problems needs integrated dynamic modeling for both reservoir and wellbore systems. The philosophy of optimization is that, the reservoir and wellbore system should be the "master" for production optimization, and surface control should serve as a "slave" system.