Modeling Transient Inflow Performance in Artifical-Lift Systems
This thesis presents a transient inflow-performance relationship (IPR) model for wells under a periodic varying well-flowing pressure. A wellbore model is coupled to accurately depict the well deliverability encountered in an artificial-lift system (ALS), such as intermittent gas lift and plunger lift. The commercial simulators allowed verification of model results and field data validated the solution approach. This model successfully reproduced transient profiles obtained from an analytical model using commercial software. Errors associated with the simplified transient model are well within engineering accuracy. Field data for plunger lift operations validated the transient-IPR model presented in this thesis. Results show high-frequency oscillation translates into a large error between the traditional IPR model and the actual transient-IPR model. This finding suggested the need for a transient-IPR model in ALS to express the realistic rates and pressures to combat failures due to significant pressure fluctuations or higher than expected rates.