Optimization of Well Start-Up Using Integrated Well and Electrical Submersible Pump Modeling

An integrated multiphase flow well and electrical submersible pump model was used to optimize operating procedures for initial well clean-up and ramp up to production for a major deepwater production system before first oil. An integrated modeling approach was crucial to create and test start-up scenarios given uncertainty in the amount of completion fluid in tubing, uncertainty in density of near wellbore fluid and lack of prior experience in ESP operation. The model was used to simulate numerous well start-up scenarios:Well BS&W rate profiles as a function of frac pack fluid recovery percentageWell unloading profiles as a function of injected base volumeNatural flowing well start-up profilesChemical injection volumes and associated surface injection pressuresPressure surging across the completion during ESP start-upsNumber of "A" annulus bleeds required during initial start-up Accurately simulating such highly transient scenarios requires integrating multiphase flow phenomena in tubing to reservoir inflow and dynamic pump behavior. The integrated model proved to be very valuable in finalizing well start-up procedure with a high degree of confidence. This fully dynamic model can estimate phase, pressure, temperature and flow anywhere in the tubing including effect of well choke operations, pump pressure and temperature dynamics based on speed, effect of downhole conditions, and reservoir inflow. The transient behavior in tubing and annulus upon switching on or off ESP pump during well operation is also accurately represented. In this paper, we will present how the integrated model was developed, how it was used to simulate various scenarios and how the results were used to create and validate well start-up procedure. The methodology presented here is applicable to any well using ESP artificial lift methods. This model is a very useful tool not only for engineering simulation, but for operator training and real-time surveillance as well.