A submersible well pump assembly in a wellbore; the pump assembly includes a liquid lift pump and a booster pump for pumping a two-phase mixture of gas and liquid. A shroud with an opening at its upper end partially encloses the pump assembly. An annulus is formed between the shroud and the wellbore inner circumference. Two phase fluid from the booster pump exits the shroud through a port and flows up the annulus to the shroud opening. Liquid in the two-phase flow separates from the gas and flows into the shroud opening and onto the liquid lift pump. The gas continues to flow up the wellbore, past the shroud opening, to the wellbore entrance.