Analysis of possible applications of dual ESPs - a reservoir engineering perspective

Relatively few field installations of a dual-electric submersible-pump (DESP) completion have been reported. In general, the purpose of the second pump was either to increase the pumping capacity, or to act as a backup to improve the reliability of the pumping system. However, DESPs potentially can address a much wider range of reservoir management challenges. This paper will analyze the performance of a DESP in a range of reservoir scenarios. It will show how DESP performance can be modeled by use of commercially available, coupled, well-performance and reservoir-simulation tools. Four DESP applications were analyzed. Where possible, the robustness of the numerical-modeling results will be compared with analytical predictions. DESPs gave improved oil production and recovery in reservoirs with strong aquifer support and became progressively more attractive in a layered-reservoir scenario as the pressure difference between the production zones increased. However, while DESPs had no significant advantages in a long, horizontal well placed in a homogeneous reservoir, they can increase recovery in a tilted, layered reservoir. A slim, deepwater well completed with a lower-capacity downhole pump and a larger (multiwell) seabed booster pump was shown to be a potentially attractive solution for some reservoir developments. This work provides a comparison of the drivers for the choice of a single electric submersible pump (SESP) and a DESP in the scenarios studied. It illustrates a modeling methodology and provides DESP-selection guidelines, thus aiding the increased application of this technology.