Downhole lift gas injection system

Abstract

A downhole lift gas injection valve is retrievably connected to a downhole hanger device from which a lift gas injection conduit is suspended within a production tubing of a hydrocarbon fluid production well, wherein the valve receives the lift gas from an annular space surrounding the tubing via a side inlet in the production tubing and a tubular packer device is retrievably connected to an upper end of the hanger device to seal the side inlet from a space in the production tubing above the packer device.

1 . A downhole lift gas injection system, wherein:
 a lift gas injection valve is retrievably arranged in a valve chamber in a downhole hanger device from which a lift gas injection conduit is suspended within a production tubing of a hydrocarbon fluid production well,   the lift gas injection valve receives the lift gas from an annular space surrounding the production tubing via a side inlet in the production tubing; and   a tubular packer device is retrievably connected to an upper end of the hanger device to seal the side inlet from a space in the production tubing above the packer device.   
     
     
         2 . The system of  claim 1 , wherein the hanger device comprises a cylindrical body provided with a channel that connects the valve chamber to the lift gas injection conduit, the channel comprising an axial through bore formed in the cylindrical body, and the valve chamber being defined in an upper portion of the through bore. 
     
     
         3 . The system of  claim 1 , wherein the tubular packer device is sealed to the production tubing by a first annular seal, the hanger device is sealed to the production tubing by a second annular seal, and wherein the side inlet is located between the first and second annular seals. 
     
     
         4 . The system of  claim 3 , wherein the hanger device is provided with a polished bore receptacle into which the tubular packer device is received. 
     
     
         5 . The system of  claim 1 , wherein the tubular packer device is retrievable to surface independently of the hanger device. 
     
     
         6 . The system of  claim 1 , wherein the gas lift valve is retrievable from the valve chamber by pulling the gas lift valve out of the valve chamber. 
     
     
         7 . The system of  claim 1 , wherein the valve chamber is formed in an upper portion of the hanger device. 
     
     
         8 . The system of  claim 1 , wherein the side inlet is formed in a side pocket mandrel included in the production tubing. 
     
     
         9 . The system of  claim 1 , wherein, in a second mode of operation, the tubular packer device is temporarily removed from the wellbore and a plug is arranged in the hanger device so as to seal a lower internal space of the production tubing from an upper internal space of the production tubing, and wherein the side inlet is arranged to allow fluid to be circulated from surface through the annular space, the side inlet and the upper internal space back to surface. 
     
     
         10 . The system of  claim 1 , wherein the lift gas injection conduit is provided with a safety valve for isolating the valve chamber from fluid pressure in the wellbore below the hanger device. 
     
     
         11 . The system of  claim 1 , wherein the lift gas injection conduit is adapted to receive a closure element to close the lift gas injection conduit 
     
     
         12 . The system of  claim 1 , wherein the lift gas injection conduit is provided with at least one non-return valve for preventing backflow of fluid from the wellbore into the lift gas injection conduit. 
     
     
         13 . A method of production of hydrocarbon fluid from an earth formation comprising flowing a stream of said hydrocarbon fluid to flow from a reservoir zone into a wellbore wherein using the system of  claim 1  to enhance the production of hydrocarbon fluid from the earth formation. 
     
     
         14 . A method of production of hydrocarbon fluid from an earth formation comprising:
 providing a wellbore formed in an earth formation, comprising a casing cemented in the well bore and a production tubing extending from a wellhead through the casing to a reservoir zone;   lowering a hanger device with a flow passage, and a lift gas injection conduit connected said hanger device, through the production tubing;   after the previous step, lowering a packer device through the production tubing until it is received in a receptacle of the hanger device;   flowing a stream of hydrocarbon fluid from the reservoir zone into the wellbore via perforations in the casing, and into an inlet of the production tubing and through the production tubing to the wellhead, thereby passing through the flow passage of the hanger device and through the packer device.   
     
     
         15 . The method of  claim 14 , whereby preventing inflow of wellbore fluid into the lift gas injection conduit during said lowering of said hanger device. 
     
     
         16 . The method of  claim 14 , whereby pumping lift gas via the lift gas injection conduit into a production zone of the wellbore whereby said lift gas enters the stream of hydrocarbon fluid below an inlet of the production tubing. 
     
     
         17 . The method of  claim 14 , wherein the hanger device further comprises a gas lift valve within a valve chamber, and a latch member provided on the gas lift valve, said method further comprising replacing the gas lift valve, comprising:
 lowering a latching element on a wireline into the production tubing;   latching the latching element to said latch member;   pulling said gas lift valve out of the valve chamber on said wireline;   retrieving the gas lift valve to surface;   lowering a replacement gas lift valve through the production tubing; and   installing the replacement gas lift valve in the valve chamber.