Hydraulically powered downhole piston pump

Abstract

A wellbore pump includes a receptacle for a pump formed into a wellbore production tubing. A pump includes a seal engageable with an interior surface of the receptacle. The seal has a pump rod passing sealingly through the seal. The pump rod has a piston in sealing engagement with an interior of the tubing on each side of the seal. A power fluid line is in hydraulic connection to an interior of the production tubing above and below the seal. A well fluid inlet port is disposed between one of the pistons. A longitudinally spaced apart check valve is disposed in the wellbore production tubing above an upper one of the pistons.

What is claimed is: 
     
         1 . A wellbore pump, comprising:
 a receptacle for a pump formed as part of a wellbore production tubing;   a pump comprising a seal engageable with an interior surface of the receptacle, the seal having a pump rod passing sealingly through the seal, the pump rod having a piston in sealing engagement with an interior of the tubing on each side of the seal, the seal and the piston directly in sealing engagement with an interior surface of the receptacle;   a power fluid line having hydraulic connection to an interior of the production tubing above and below the seal;   a well fluid inlet port disposed between one of the pistons and the seal; and   a longitudinally spaced apart check valve disposed in the wellbore production tubing above the piston disposed above the seal.   
     
     
         2 . The wellbore pump of  claim 1  wherein the check valve is disposed in a piston connected to the pump rod. 
     
     
         3 . The wellbore pump of  claim 1  further comprising a fluid inlet check valve in sealing engagement with the well fluid inlet port. 
     
     
         4 . The wellbore pump of  claim 1  further comprising a filter covering the well fluid inlet port. 
     
     
         5 . The wellbore pump of  claim 1  further comprising a well fluid discharge line in fluid communication with the interior of the production tubing above the longitudinally spaced apart check valve. 
     
     
         6 . The wellbore pump of  claim 5  further comprising an additional check valve disposed in the production tubing above the well fluid discharge line. 
     
     
         7 . The wellbore pump of  claim 6  further comprising well gas inlet ports in the production tubing at a position above the additional check valve. 
     
     
         8 . The wellbore pump of  claim 6  wherein the additional check valve is operable in two fluid flow directions. 
     
     
         9 . The wellbore pump of  claim 1  further comprising well gas inlet ports in the production tubing above the longitudinally spaced apart check valve. 
     
     
         10 . The wellbore pump of  claim 1  further comprising an lower inlet check valve assembly coupled to a bottom end of the production tubing below the pump and arranged such that fluid is drawn into the bottom of the tubing by the pump and is discharged to an additional fluid discharge line in fluid communication with the interior of the tubing above the bottom end of the production tubing. 
     
     
         11 . The wellbore pump of  claim 1  wherein the pump is insertable into and retrievable from the receptacle using at least one of wireline, coiled tubing and a semi-still spoolable rodconveyance. 
     
     
         12 . A wellbore pump, comprising:
 a pump piston disposed in a pump power chamber arranged to be coupled to a wellbore production tubing or wellbore casing, the pump piston comprising check valves and flow passages therein enabling well fluid to be drawn into a pump chamber below the pump piston and a lower pump chamber adapter connecting the power chamber to the production tubing or the wellbore casing, the check valves and flow passages arranged to discharge well fluid into the production tubing above an upper pump chamber adapter connecting the wellbore tubing to the pump chamber, the upper and lower adapters comprising check valves and/or fluid flow passages to alternatingly discharge fluid from the pump chamber into each of the production tubing or wellbore casing and a well fluid return line.   
     
     
         13 . A wellbore pump, comprising:
 a pump power piston and pump piston assembly disposed in a pump body connected to a wellbore production tubing, the pump body comprising an upper cylinder and a lower cylinder disposed on opposed longitudinal sides of a center passage through which a piston may move;   a first control line communication with the upper cylinder between fluid seals and a bottom of the upper piston;   a second hydraulic control line in communication with the lower cylinder;   wiper seals on an exterior of each of the upper piston and the lower piston;. Longitudinal ends of the pump body corresponding pump pistons each may defining a respective upper pump chamber and a lower pump chamber;   check valves configured to admit well fluid to the lower pump chamber when it is expanded and configured to discharge well through a discharge line and into the wellbore tubing; and   corresponding check valves for the upper pump chamber arranged such that enlargement and reduction of the volume of the upper pump chamber by corresponding motion of the upper piston will cause fluid to be drawn into the upper pump chamber and discharged therefrom, respectively.   
     
     
         14 . The wellbore pump of  claim 13  wherein one of the check valves for the lower pump chamber is disposed in an adapter coupled to a lower end of the wellbore pump. 
     
     
         15 . The wellbore pump of  claim 13  wherein a fluid discharge line couples an outlet of the lower pump chamber to the production tubing located above the wellbore pump. 
     
     
         16 . The wellbore pump of  claim 13  wherein one of the check valves for the lower pump chamber is disposed in an upper adapter coupling the wellbore pump to the production tubing. 
     
     
         17 . The wellbore pump of  claim 16  wherein one of the check valves for the upper pump chamber is disposed in the upper adapter. 
     
     
         18 . A wellbore fluid pump, comprising:
 a first pump housing coupled to a production tubing by an upper adapter, the upper adapter comprising a check valve disposed therein or in fluid communication therewith, the upper adapter having an internal passage connecting a pumped fluid discharge line to an interior of a check valve seat whereby fluid discharged through the pumped fluid discharge line flows through an internal passage to the check valve and upwardly through the production tubing;   a power chamber defined within the first pump housing longitudinally between the upper adapter and a power fluid inlet port through the wall of the pump housing, a part of the first pump housing corresponding to the power chamber having an enlarged internal diameter section corresponding to a length of the power chamber;   a piston disposed within the first pump housing, an upper end of the piston in fluid communication with hydraulic power fluid moved under pressure into the pump housing above the top of the piston through a power fluid passage in the upper adapter;   a first hydraulic control line coupled to the power fluid passage to enable moving the piston downwardly in the first pump housing;   a bottom end of the piston comprising a similar fluid seal; and   a pump chamber defined between the bottom end of the piston within the first pump housing and a lower adapter coupled to a lower end of the pump housing, the lower adapter comprising an intake check valve and a discharge check valve disposed in the lower adapter or in fluid communication therewith.   a bore through the piston at an upper end to a position on the exterior surface of the piston below dynamic seals on the piston, the bore comprising a relief valve in the bore proximate a top of the piston whereby hydraulic power fluid pressure on a second control line used to move the piston upward in the first pump housing when increased to a pressure higher than operating pressure after the piston reaches the upper end of the pump housing lifts the relief valve followed by opening a corresponding relief valve in the upper adapter to cause trapped gas to exit from the power chamber, through the piston and the relief valves  1710 A,  1704 A, and then into the production tubing above the upper adapter.
 Should we add a claim referring to this claim that check valves can be hydraulically coupled to the adapters, but necessarily not mechanically coupled to said adapter? (Thinking that if someone move check valves away from the adapters, but still use such check valves, it is easy to not be in breach with this claim.) 
 Also, should the gas relief function be removed from this claim, as it is included below in claim  20 ? 
   
     
     
         19 . The wellbore pump of  claim 18  further comprising at least one additional pump comprising an upper adapter, a second pump housing, a piston and a lower adapter and check valves coupled at or in fluid communication with the upper adapter to a lower end of the first pump housing. 
     
     
         20 . The pump of  claim 18  further comprising a gas dump valve coupled hydraulically to a wellbore pump discharge chamber, the gas dump valve operable to release trapped gas by applying hydraulic pressure to the first and second control lines as a pressure above an operating pressure to move the piston. 
     
     
         21 . The wellbore pump of  claim 18 , further comprising a bore through the piston at an upper end to a position on the exterior surface of the piston below dynamic seals on the piston, the bore comprising a relief valve in the bore proximate a top of the piston whereby hydraulic power fluid pressure on a second control line used to move the piston upward in the first pump housing when increased to a pressure higher than operating pressure after the piston reaches the upper end of the pump housing lifts the relief valve followed by opening a corresponding relief valve in the upper adapter to cause trapped gas to exit from the power chamber, through the piston and the relief valves, and then into the production tubing above the upper adapter.