Downhole well pump assembly

Abstract

Downhole well pump assembly (1) having first and second pump units (7a, 7b) with first and second bellows (31) connected to inlet and outlet check valves. A drive fluid assembly (5) with first and second hydraulic drive lines (9a, 9b) communicates with the bellows. Hydraulic fluid is provided to the first and second hydraulic drive lines. A drive fluid distribution valve (11) is arranged between a drive pump (17) and the drive lines. It has a drive fluid inlet and outlet (113, 115), and first and second drive ports. The distribution valve (11) interchanges between a first mode, where the drive fluid inlet communicates with the first drive port and the drive fluid outlet (115) communicates with the second drive port; and a second mode, wherein the drive fluid inlet communicates with the second drive port, and the drive fluid outlet communicates with the first drive port.

1 . A downhole well pump assembly comprising:
 a first pump unit and a second pump unit, each pump unit having a compressible metal bellows arranged in a housing, the housing being connected to an inlet check valve and an outlet check valve;   a drive fluid assembly with a first hydraulic drive line in communication with the inner volume of the metal bellows of the first pump unit and a second hydraulic drive line in communication with the inner volume of the metal bellows of the second pump unit, the drive fluid assembly further comprising a drive fluid pump providing hydraulic fluid to the first and second hydraulic drive lines, wherein the drive fluid pump is mechanically connected to a drive motor which is powered by a power line and which drives the drive fluid pump; and,   wherein a drive fluid distribution valve is arranged between the drive fluid pump and the first and second hydraulic drive lines, the drive fluid distribution valve comprising a drive fluid inlet, a drive fluid outlet, a first drive port and a second drive port, and wherein the drive fluid distribution valve is interchangeable between;   a first mode, in which the drive fluid inlet is in communication with the first drive port, and the drive fluid outlet is in communication with the second drive port; and   a second mode, in which the drive fluid inlet is in communication with the second drive port, and the drive fluid outlet is in communication with the first drive port.   
     
     
         2 . The downhole well pump assembly according to  claim 1 , wherein the drive fluid pump comprises a rotating output which is functionally connected to the drive fluid distribution valve, wherein rotation of the rotating output governs the changing of the drive fluid distribution valve between the first mode and the second mode. 
     
     
         3 . The downhole well pump assembly according to  claim 1 , wherein a bypass channel is arranged between the first hydraulic drive line and the second hydraulic drive line. 
     
     
         4 . The downhole well pump assembly according to  claim 1 , wherein the compressible bellows in the first and second pump units comprises a collapse restriction means, wherein the collapse restriction means has a drive fluid valve member which is interchangeable between an open and a closed position. 
     
     
         5 . The downhole well pump assembly according to  claim 4 , wherein the drive fluid valve member is arranged at a drive fluid inlet and outlet end of the compressible bellows, and that a bellows closure flange is arranged at the opposite end of the compressible bellows, wherein an actuation member, which is connected to the bellows closure flange, protrudes axially into compressible bellows and is configured to abut and thereby move the drive fluid valve member into the closed position upon movement of the bellows closure flange towards the drive fluid inlet and outlet end. 
     
     
         6 . The downhole well pump assembly according to  claim 1 , wherein the drive fluid distribution valve comprises:
 a housing;   a first distribution chamber communicating with the drive fluid outlet;   a second distribution chamber communicating with the drive fluid inlet;   a first drive channel arranged between the first drive port and the first and second distribution chambers, and a second drive channel arranged between the second drive port and the first and second distribution chambers;   a rotatable first distribution member which is arranged between the first distribution chamber and the first and second drive channels and which has a distribution aperture, and a rotatable second distribution member which is arranged between the second distribution chamber and the first and second drive channels, and which has a distribution aperture; and   wherein each distribution aperture of the first distribution member and the second distribution member is adapted to align with both and opposite first and second drive channels, depending on the rotational position of the first and second distribution members.   
     
     
         7 . The downhole well pump assembly according to  claim 2 , wherein:
 the first and second distribution members are connected to a common shaft;   the shaft is connected to a reduction gear; and   that the reduction gear is connected to the rotating output.   
     
     
         8 . A fluid distribution valve comprising:
 a housing;   a drive fluid inlet;   a drive fluid outlet;   a first drive port;   a second drive port;   a first distribution chamber in fluid communication with the drive fluid outlet;   a second distribution chamber in fluid communication with the drive fluid inlet;   a first drive channel arranged between the first drive port and the first and second distribution chambers, and a second drive channel between the second drive port and the first and second distribution chambers;   a rotatable first distribution member which is arranged between the first distribution chamber and the first and second drive channels and which has a distribution aperture, and a rotatable second distribution member which is arranged between the second distribution chamber and the first and second drive channels, and which has a distribution aperture; and   wherein each distribution aperture of the first distribution member and the second distribution member is adapted to align with both and opposite first and second drive channels, depending on the rotational position of the first and second distribution members.   
     
     
         9 . The fluid distribution valve according to  claim 8 , comprising:
 wherein the first and second distribution members are arranged on opposite sides of a partition wall comprising a first partition wall bore and a second partition wall bore which constitute part of the first and second drive channels; and   wherein the first and second distribution members are connected to a common shaft which extends through the partition wall.   
     
     
         10 . The fluid distribution valve according to  claim 9 , comprising a main body within which the following are arranged:
 the first and second distribution chamber;   the partition wall;   the first and second drive channels;   an output channel and a first distribution chamber mouth which connect the first distribution chamber to the drive fluid output; and   an input channel and a second distribution chamber mouth which connect the second distribution chamber to the drive fluid input.   
     
     
         11 . The fluid distribution valve according to  claim 8 , comprising a bypass channel which connects the first drive port with the second drive port. 
     
     
         12 . A collapsible metal bellows which has a cylindrical shape, is axially collapsible, and at one axial end has a drive fluid inlet and outlet end and which at the opposite axial end has a bellows closure flange, the collapsible metal bellows comprising:
 a collapse restriction means comprising:   at the drive fluid inlet and outlet end a drive fluid valve member movable between an open valve position and a closed valve position, and which is biased towards the open valve position; and   at the opposite axial end an actuation member which protrudes with an axial distance into the metal bellows, and which upon axial movement of the bellows closure flange towards the drive fluid inlet and outlet end is configured to abut and move the drive fluid valve member towards the closed valve position.   
     
     
         13 . The collapsible metal bellows according to  claim 12 , wherein the drive fluid valve member exhibits a valve member opening constituting fluid communication between the interior and exterior of the metal bellows, wherein the valve member opening is partially closed when the fluid valve member is in an intermediate valve position.