Fluid lifting system to be placed in a fluid production well, related fluid production installation and process

A fluid lifting system to be placed in a fluid production well, comprising:

• a fluid pump, having a pump stator and a pump rotor defining an intermediate fluid pumping space, the pump rotor having an impeller received in the intermediate fluid pumping space, the pump rotor being rotatable around a longitudinal rotation axis,
• a gas turbine comprising a turbine rotor having blades and a turbine stator defining a gas expansion chamber with the turbine rotor,
• a gas injection duct, configured to receive a gas flow from an external gas source and to introduce the gas flow in the gas expansion chamber to drive the turbine rotor in rotation around the longitudinal rotation axis,
• the turbine rotor being rotatable around the longitudinal rotation axis, the turbine rotor and the pump rotor being mechanically coupled such that the rotation of the turbine rotor produced by gas injection from the gas injection duct drives in rotation the pump rotor
• wherein the turbine rotor and the pump rotor are at least partly in longitudinal overlap in projection on the rotation axis.