Borehole production boosting system

Abstract

Method and apparatus for assisting the flow of production fluid from a hydrocarbon wellbore ( 4 ) to a remote host facility ( 16 ) including a separation facility ( 6 ) situated close to the wellbore ( 4 ). Jetting fluid is supplied initially from the host facility ( 16 ) to a downhole jet pump ( 14 ) via the separation facility ( 6 ) for assisting the flow of production fluid from the wellbore ( 4 ) to the separation facility ( 6 ) where the resulting mixture enters one of two parallel gravity separation chambers ( 32 ). Separated jetting fluid ( 60 ) is recirculated to the jet pump ( 14 ) via a pump ( 38 ) and production fluid is routed to the host facility via a production pipeline ( 18 ). A jetting fluid supply pipe ( 20 ) can be of relatively small diameter and the production pipeline ( 18 ) does not have to be enlarged to accommodate jetting fluid returned to the host facility ( 16 ).

1 . A method of boosting production from a wellbore ( 4 ) having a downhole jet pump ( 14 ) and a remote host facility ( 16 ), the method comprising the steps of: 
 (a) providing a separation facility ( 6 ) substantially closer to the wellbore ( 4 ) than the host facility ( 16 );    (b) providing means ( 38 ,  68 , . . . ) to deliver jetting fluid ( 60 ) under pressure to the jet pump ( 14 );    (c) entraining wellbore production fluid with the flow of the jetting fluid in the jet pump ( 14 ) and conveying the resulting mixture to the separation facility ( 6 );    (d) separating a majority of the jetting fluid ( 60 ) from the mixture by means of the separation facility ( 6 ); and    (e) recirculating the separated jetting fluid ( 60 ) back to the jet pump ( 14 ) and entraining further production fluid therewith.    
     
     
         2 . The method according to  claim 1  wherein at least 90% of the jetting fluid ( 60 ) is separated from the mixture by the separation facility ( 6 ).  
     
     
         3 . The method according to  claim 2  wherein substantially all of the jetting fluid ( 60 ) is separated from the mixture by the separation facility ( 6 ).  
     
     
         4 . The method according to any preceding claim wherein the separation facility ( 6 ) is situated at or close to the wellbore ( 4 ).  
     
     
         5 . The method according to any preceding claim wherein the separation facility ( 6 ) includes a pump ( 38 ) which is used to pressurise separated jetting fluid ( 60 ) for assisting its recirculation.  
     
     
         6 . The method according to any preceding claim wherein the separation is effected by gravity separation.  
     
     
         7 . A system for boosting production from a wellbore ( 4 ) situated remotely from a host facility ( 16 ) comprising a downhole jet pump ( 14 ), pressurising means ( 38 ,  68 ) for supplying the jet pump ( 14 ) with pressurised jetting fluid ( 60 ) for forming a mixture of jetting fluid ( 60 ) and wellbore production fluid, a separation facility ( 6 ) situated substantially closer to the wellbore ( 4 ) than the host facility ( 16 ) including separation means ( 22 ,  24 ) for separating a majority of the jetting fluid ( 60 ) from the mixture and recirculation means ( 10 ,  12 ,  38 ,  39 ) for delivering the separated jetting fluid ( 60 ) back to the jet pump ( 14 ) for entraining further production fluid therewith.  
     
     
         8 . The system according to  claim 7  wherein the separation means ( 22 ,  24 ) includes at least one gravity separation chamber ( 32 ).  
     
     
         9 . The system according to  claim 7  or  8  wherein the separation means ( 22 ,  24 ) includes at least two separators ( 32 ) for separating the mixture which are connected in parallel with each other.  
     
     
         10 . The system according to  claim 7 ,  8  or  9  wherein the separation means ( 22 ,  24 ) includes throttling means ( 40 ,  52 ) arranged to control flows of production fluid and jetting fluid ( 60 ) from the separation means ( 22 ,  24 ).