A wellbore jet pump includes a nozzle body with a tapering nozzle passage therein and a pump body with a main passage that receives the nozzle body therein so as to define within the main passage (i) an intake section surrounding the nozzle body, (ii) a mixing section immediately above the nozzle body, and (iii) a diffuser section diverging upwardly from the mixing section. A bypass conduit directs a working fluid downwardly alongside the pump body and upwardly into one of the nozzle passage or the intake section so that produced fluids are drawn into the other one of the nozzle passage or the intake section for subsequent mixing of the working fluid and the produced fluid in the mixing section. In this manner both the working and produced fluids are accelerated before entering the mixing section to increase pump efficiency.