Artificial lift method for low pressure sagd wells

Abstract

A pumping system includes a hydraulic motor assembly configured to drive a production pump. The hydraulic motor assembly includes a master pump located on the surface and an electric motor configured to controllably power the master pump. When moved by the electric motor, the master pump discharges a working fluid under pressure. The pressurized working fluid is transferred to a hydraulic turbine located in the wellbore. The hydraulic turbine converts the pressure of the working fluid into torque, which is transferred through a driveline to a production pump. The production pump pressurizes production fluids, which are carried under pressure to the surface.

What is claimed is: 
     
         1 . A pumping system that includes components located on the surface and components located in the wellbore, the pumping system comprising:
 a hydraulic motor assembly; wherein the hydraulic motor assembly comprises:
 a motor located on the surface; 
 a master pump connected to the electric motor, wherein the master pump discharges a working fluid under pressure; and 
 a hydraulic turbine located in the wellbore and driven by the pressurized working fluid discharged from the master pump; 
   a production pump positioned within the wellbore; and   a driveline that connects the hydraulic turbine to the production pump.   
     
     
         2 . The pumping system of  claim 1 , further comprising:
 a seal section connected to the hydraulic turbine; and   a thrust section connected between the seal section and the production pump.   
     
     
         3 . The pumping system of  claim 1 , wherein the hydraulic turbine comprises:
 one or more turbine diffusers;   one or more turbine impellers;   a turbine intake; and   a turbine discharge.   
     
     
         4 . The pumping system of  claim 3 , wherein the feed line is connected to the turbine intake. 
     
     
         5 . The pumping system of  claim 4 , wherein the hydraulic motor assembly further comprises a return line connected to the turbine discharge. 
     
     
         6 . The pumping system of  claim 3 , wherein the production pump comprises:
 a production pump intake;   a production pump discharge;   one or more production pump impellers; and   one or more production pump diffusers.   
     
     
         7 . The pumping system of  claim 6 , wherein each of the one or more turbine impellers has an orientation that is opposite to the orientation of each of the one or more production pump impellers. 
     
     
         8 . The pumping system of  claim 6 , wherein each of the one or more turbine diffusers has an orientation that is opposite to the orientation of each of the one or more production pump diffusers. 
     
     
         9 . The pumping system of  claim 1 , wherein the hydraulic motor assembly further comprises:
 a reservoir connected to the return line; and   a suction line connected between the reservoir and the master pump.   
     
     
         10 . A pumping system configured to transfer production fluids from a subterranean wellbore to surface facilities, the pumping system comprising:
 a production pump, wherein the production pump comprises:
 an intake that receives the production fluids; and 
 a discharge; 
   production tubing connected to the discharge of the production pump; and   a hydraulic motor assembly configured to drive the production pump, wherein the hydraulic motor assembly does not include an electric motor located within the wellbore.   
     
     
         11 . The pumping system of  claim 10 , wherein the hydraulic motor assembly comprises:
 a master pump located on the surface; and   a motor connected to the master pump.   
     
     
         12 . The pumping system of  claim 11 , wherein the hydraulic motor assembly further comprises a hydraulic turbine positioned within the wellbore. 
     
     
         13 . The pumping system of  claim 12 , wherein the production pump is a positive displacement type pump. 
     
     
         14 . The pumping system of  claim 12 , wherein the production pump is a turbomachine that includes a plurality of production pump impellers that are configured in a standard orientation. 
     
     
         15 . The pumping system of  claim 14 , wherein the hydraulic turbine includes a plurality of turbine impellers that are configured in a reverse orientation. 
     
     
         16 . A method for moving production fluids from a subterranean wellbore to surface facilities, the method comprising the steps of:
 pressurizing a working fluid with a master pump;   transferring the pressurized working fluid to a hydraulic turbine positioned in the wellbore;   generating torque by passing the pressurized working fluid through the hydraulic turbine;   transferring the torque from the hydraulic turbine to a production pump;   drawing the production fluids into the production pump through a production pump intake; and   discharging the production fluids from the production pump through production tubing.   
     
     
         17 . The method of  claim 16 , further comprising the step of returning the working fluid from the hydraulic turbine to the master pump. 
     
     
         18 . The method of  claim 16 , further comprising the steps of:
 operating the hydraulic turbine at a first speed to generate a hydraulic turbine thrust; and   operating the production pump at the first speed to generate a production pump thrust that substantially offsets the hydraulic turbine thrust.