An electrical submersible pump (ESP) completion is used in a reservoir. The ESP completion includes an ESP and a static mixer placed below an intake of the ESP within the reservoir. A two-phase (liquid-gas) mixture flows from the reservoir through a tubing-casing annulus to the static mixer. The static mixer conditions and homogenizes the two phase (liquid-gas) mixture. The mixture flows to a tubing-casing annulus through perforated joints to enter the intake of the pump.