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

Abstract

The fluid lifting system comprises a fluid pump, having a pump stator and a pump rotor being rotatable around a longitudinal rotation axis, a gas turbine comprising a turbine rotor and a turbine stator defining a gas expansion chamber, a gas injection duct, to introduce a gas flow in the gas expansion chamber to drive the turbine rotor in rotation. The turbine rotor is rotatable around the 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. The turbine rotor and the pump rotor are at least partly in longitudinal overlap in projection on the rotation axis.

1 . 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.   
     
     
         2 . The fluid lifting system according to  claim 1 , wherein the fluid pump is motorless, the rotation of the pump rotor being driven exclusively by rotation of the turbine rotor. 
     
     
         3 . The fluid lifting system according to  claim 1 , wherein the turbine rotor and the pump rotor are directly mechanically coupled such that rotation of the turbine rotor at a given angular rotation speed around the longitudinal rotation axis drives the pump rotor in rotation at the same angular rotation speed around the rotation axis. 
     
     
         4 . The fluid lifting system according to  claim 1 , comprising a mechanical decoupler, inserted between the pump rotor and the turbine rotor, the rotation of the turbine rotor at a first given angular rotation speed driving in rotation the pump rotor at a second given angular rotation speed, different from the first angular rotation speed. 
     
     
         5 . The fluid lifting system according to  claim 4 , wherein the mechanical decoupler comprises a non-Newtonian fluid, an epicyclical gear or/and a magnetic coupler inserted between the turbine rotor and the pump rotor. 
     
     
         6 . The fluid lifting system according to  claim 1 , comprising a radial gas passage fluidly connecting the expansion chamber to the intermediate fluid pumping space. 
     
     
         7 . The fluid lifting system according to  claim 1 , wherein the impeller of the pump rotor defines gas mixing through holes. 
     
     
         8 . The fluid lifting system according to  claim 1 , wherein the turbine rotor and the pump rotor have a full longitudinal overlap in projection on the rotation axis. 
     
     
         9 . The fluid lifting system according to  claim 1 , wherein the pump rotor is received within the turbine rotor. 
     
     
         10 . The fluid lifting system according to  claim 9 , wherein the turbine stator receives the turbine rotor, the turbine rotor receiving the pump rotor and being mechanically coupled to the pump rotor, the pump rotor receiving the pump stator. 
     
     
         11 . The fluid lifting system according to  claim 1 , wherein the impeller of the pump rotor has vanes protruding radially towards the longitudinal rotation axis, the blades of the pump rotor protruding radially apart from the rotation axis. 
     
     
         12 . A fluid production installation, comprising a fluid production well comprising:
 a production tubing inwardly defining an inner production canal and outwardly defining an outer annular space being connected to a gas source at the surface of the well, the production tubing delimiting a gas injection inlet extending between the outer annular space and the production canal, and   a fluid lifting system according to  claim 1 , the gas injection duct being connected to the gas injection inlet   
     
     
         13 . A fluid lifting process, comprising:
 providing a fluid lifting system according to  claim 1  in a fluid production well;   providing a gas flow from an external gas source to the gas injection duct, and introducing the gas flow in the gas expansion chamber to drive the turbine rotor in rotation around the longitudinal rotation axis, and   jointly driving the pump rotor with the turbine rotor to pump fluid through the intermediate fluid pumping space.   
     
     
         14 . The fluid lifting process according to  claim 13 , comprising transferring expanded gas from the expansion chamber to the intermediate fluid pumping space to mix the expanded gas with the pumped liquid. 
     
     
         15 . The fluid lifting process according to  claim 13 , comprising producing a first negative thermal power in the gas turbine by expansion of gas in the gas chamber and producing a second positive thermal power in the fluid pump by pumping fluid through the intermediate pumping space, and providing heat exchange between the gas turbine and the fluid pump to at least partly compensate the second thermal power with the first thermal power. 
     
     
         16 . The fluid lifting system according to  claim 4 , wherein the rotation of the turbine rotor at a first given angular rotation speed drives in rotation the pump rotor at a second given angular rotation speed smaller than the first angular rotation speed.