Downhole completion system

Abstract

The present invention relates to a downhole system for providing plug and abandonment of a well having a top, comprising a first well tubular metal structure arranged in a borehole, a barrier arranged inside or around the first well tubular metal structure, isolating a first volume from a second volume, the barrier having a top face facing the first volume and a bottom face facing the second volume, wherein the barrier has a temperature-activated bypass assembly comprising a bypass channel and an obstruction part, the bypass channel extending from the top face to the bottom face for providing fluid communication between the first volume and the second volume when the obstruction part is removed by being heated. The invention also relates to a downhole method for providing plug and abandonment of a downhole system.

1 . A downhole system for providing plug and abandonment of a well having a top, comprising:
 a first well tubular metal structure arranged in a borehole, and   a barrier arranged inside or around the first well tubular metal structure, isolating a first volume from a second volume, the barrier having a top face facing the first volume and a bottom face facing the second volume,   wherein the barrier has a temperature-activated bypass assembly comprising a bypass channel and an obstruction part, the obstruction part being arranged to obstruct fluid communication through the bypass channel, the bypass channel extending from the top face to the bottom face for providing fluid communication between the first volume and the second volume when the obstruction part is removed by being heated.   
     
     
         2 . A downhole system according to  claim 1 , wherein the obstruction part is arranged in the bypass channel or on top of the bypass channel. 
     
     
         3 . A downhole system according to  claim 1 , wherein the obstruction part is a meltable, moldable or fusible obstruction part. 
     
     
         4 . A downhole system according to  claim 1 , wherein the obstruction part is an internal obstruction part or a part of the bypass channel. 
     
     
         5 . A downhole system according to  claim 1 , wherein the barrier is a plug arranged inside the first well tubular metal structure so that the first and second volumes are arranged inside the first well tubular metal structure. 
     
     
         6 . A downhole system according to  claim 1 , wherein the barrier is an annular barrier arranged around the first well tubular metal structure between the first well tubular metal structure and a second well tubular metal structure or the borehole so that the first and second volumes are annular volumes. 
     
     
         7 . A downhole system according to  claim 6 , wherein the annular barrier is a production packer. 
     
     
         8 . A downhole system according to  claim 1 , wherein the barrier is a first barrier, and the downhole system further comprises a second barrier, the first barrier being arranged to surround the first well tubular metal structure, and the second barrier being arranged inside the first well tubular metal structure. 
     
     
         9 . A downhole system according to  claim 8 , wherein the second barrier is a plug arranged inside the first well tubular metal structure, isolating a third volume above the plug from a fourth volume below the plug inside the first well tubular metal structure. 
     
     
         10 . A downhole system according to  claim 8 , wherein the second barrier comprises a temperature-activated bypass assembly comprising a bypass channel and an obstruction part, the bypass channel extending from the top face to the bottom face for providing fluid communication in the bypass channel when the obstruction part is removed by being heated. 
     
     
         11 . A downhole system according to  claim 1 , wherein the barrier comprises bismuth material. 
     
     
         12 . A downhole system according to  claim 1 , further comprising a thermite composition arranged inside the first well tubular metal structure above the barrier. 
     
     
         13 . A downhole completion system according to  claim 12 , further comprising an ignitor for igniting the thermite composition. 
     
     
         14 . A downhole system according to  claim 12 , further comprising cement arranged on top of the first barrier and/or the second barrier after igniting the thermite composition and melting part of the first well tubular metal structure. 
     
     
         15 . A downhole system according to  claim 6 , wherein the annular barrier comprises a tubular metal part for mounting as part of the first well tubular metal structure, the tubular metal part having an outer face, comprising
 an expandable metal sleeve surrounding the tubular metal part and having an outer face facing towards the inner face of the borehole or the second well tubular metal structure and an inner face facing the outer face of the tubular metal part, and each end of the expandable metal sleeve being connected with the tubular metal part,   an annular space between the expandable metal sleeve and the tubular metal part, and   an expansion opening in the tubular metal part through which fluid may enter the annular space in order to expand the expandable metal sleeve.