High-temperature electric submersible pumps (ESPs) have enabled operators to lower the well drawdown and achieve higher production rate in steam-assisted gravity drainage (SAGD) wells. While theoretically the SAGD process should deliver a single-phase producing stream to the ESP system when bottomhole pressures are reduced to near steam saturation pressures, steam flashing could occur which can result in ESP performance deterioration and wellbore flow regime instability. The essential questions being asked for ESP performance in such SAGD multiphase condition are to identify the boundary at which the ESP and well behavior changes from stable to unstable operations (when is it happening), to determine the effects on ESP deterioration (what are the effects), and to develop solutions to maximize well drawdown with improved well stability (how to manage it).

In this paper, authors will present a new approach to understand ESP multiphase challenges in SAGD operations by using detailed fluid characterization and hydraulic models. The analytical approach identifies phase boundaries (phase envelope), calculates gas-water vapor volume fraction (GWVF) and predicts flow regimes as a function of surface and downhole flowing measurements.

Authors used Soave-Redlich-Kwong for the equation of state (EOS) with the Peneloux volume shift option to compute compositional model and construct pressure-temperature phase diagram for SAGD producing bitumen-gas-water mixture. By coupling the compositional fluid model with a well hydraulic model, one can calculate GWVF and phase splits along the production path and therefore predict flow regimes both upstream and downstream of the ESP. One can also perform pump stage by stage calculations and analyze the pressure contributions as operational stability changes. ESP design and operational recommendations to improve operational stability based on calibrated well model will also be discussed and evaluated in this paper.