Mechanical-Hydraulic Pumping System

Abstract

Devices and methods for recovering production fluid from a subterranean formation using a mechanical-hydraulic production system. A mechanical-hydraulic production system is described that includes a power fluid pump, a production fluid pump and a hydraulically-actuated motor that is associated with the production fluid pump to actuate the production fluid pump. The power fluid pump is mechanically driven from the surface to fluid hydraulic power fluid to the motor, thereby driving the production fluid pump to pump production fluid.

1 . A mechanical-hydraulic pumping system for use in flowing fluid from a subterranean formation, the system comprising:
 a power fluid pump to be placed in a proximal portion of a wellbore;   a production fluid pump to be placed in a distal portion of a wellbore;   a hydraulically-actuated motor associated with the production fluid pump to actuate the production fluid pump; and   the power fluid pump flowing hydraulic power fluid to the motor to drive the motor and production fluid pump.   
     
     
         2 . The pumping system of  claim 1  further comprising a fluid transmission conduit for flowing production fluid pumped by the production fluid pump from the formation. 
     
     
         3 . The pumping system of  claim 1  wherein the power fluid pump is associated with the motor by:
 a power fluid supply conduit to transmit hydraulic power fluid from the power fluid pump to the motor; and 
 a power fluid return conduit to transmit power fluid from the motor to the power fluid pump. 
 
     
     
         4 . The pumping system of  claim 3  wherein the power fluid supply conduit and the power fluid return conduit are coaxial. 
     
     
         5 . The pumping system of  claim 1  further comprising a fluid accumulator to accommodate thermal expansion and contraction of the hydraulic power fluid. 
     
     
         6 . The pumping system of  claim 3  further comprising a fluid reservoir associated with the power supply and return conduits to permit cooling of power fluid. 
     
     
         7 . The pumping system of  claim 1  further comprising a mechanical driver for operation of the power fluid pump. 
     
     
         8 . The pumping system of  claim 7  wherein the mechanical driver comprises a rod drive unit to rotate a drive rod that actuates the power fluid pump. 
     
     
         9 . The pumping system of  claim 7  wherein the mechanical driver comprises a rod drive unit to axially reciprocate a drive rod that actuates the power fluid pump. 
     
     
         10 . The pumping system of  claim 1  wherein the power fluid pump comprises an electrical submersible pump. 
     
     
         11 . The pumping system of  claim 1  wherein the power fluid pump comprises a progressive cavity pump. 
     
     
         12 . The pumping system of  claim 4  further comprising a transmission conduit for flowing production fluid pumped by the production fluid pump from the formation, the transmission conduit being defined within a shroud that radially surrounds the power fluid supply conduit and power fluid return conduit. 
     
     
         13 . A mechanical-hydraulic pumping system for use in flowing fluid from a subterranean formation, the system comprising:
 a power fluid pump to be placed in a proximal portion of a wellbore;   a production fluid pump to be placed in a distal portion of a wellbore;   a hydraulically-actuated motor associated with the production fluid pump to actuate the production fluid pump;   the power fluid pump flowing hydraulic power fluid to the motor to drive the motor and production fluid pump; and   a fluid transmission conduit for flowing production fluid pumped by the production fluid pump from the formation.   
     
     
         14 . The pumping system of  claim 13  wherein the power fluid pump is associated with the motor by:
 a power fluid supply conduit to transmit hydraulic power fluid from the power fluid pump to the motor; and 
 a power fluid return conduit to transmit power fluid from the motor to the power fluid pump. 
 
     
     
         15 . The pumping system of  claim 14  wherein the fluid transmission conduit is defined within a shroud that radially surrounds the power fluid supply conduit and power fluid return conduit. 
     
     
         16 . A method of recovering production fluid from a subterranean formation comprising the steps of:
 a) disposing a mechanical-hydraulic pumping system within a wellbore formed down to the formation, the pumping system having a power fluid pump, a production fluid pump, a hydraulically-actuated motor associated with the production fluid pump to actuate the production fluid pump;   b) mechanically driving the power fluid pump with a mechanical driver to output hydraulic power fluid;   c) flowing the hydraulic power fluid from the power fluid pump to the motor to drive the motor and production fluid pump, the production fluid pump drawing production fluid from the subterranean formation.   
     
     
         17 . The method of  claim 16  wherein the step of mechanically driving the power fluid pump further comprises rotating a drive rod by a rod drive unit to actuate the power fluid pump. 
     
     
         18 . The method of  claim 16  wherein the step of mechanically driving the power fluid pump further comprises axially reciprocating a drive rod by a rod drive unit to actuate the power fluid pump. 
     
     
         19 . The method of  claim 16  further comprising the step of transmitting production fluid from the production fluid pump to a surface location. 
     
     
         20 . The method of  claim 16  wherein the step of disposing a mechanical-hydraulic pumping system within a wellbore further comprises:
 disposing the power fluid pump in a proximal portion of the wellbore, and 
 disposing the production fluid pump in a distal, deviated portion of the wellbore.