Annular barrier

Abstract

The present invention relates to an annular barrier for providing zonal isolation in an annulus downhole between a well tubular metal structure and another well tubular metal structure or a wall of a borehole, comprising a tubular metal part configured to be mounted as part of the well tubular metal structure, an expandable metal tubular surrounding the tubular metal part forming an expandable space there between, the expandable metal tubular is configured to be expanded in a well downhole from a first outer diameter to a second outer diameter to abut against the well tubular metal structure or the wall of the borehole, the expandable metal tubular having a first end, a second end, an outer face and a longitudinal extension and comprising a plurality of first circumferential grooves provided in the outer face, a plurality of sealing units, each sealing unit comprising a sealing element arranged in the first circumferential grooves, so that each first circumferential groove comprises one of the sealing units occupying the first circumferential groove along the longitudinal extension, a second circumferential groove provided between two circumferential edges provided on the outer face and defining a first grooved tubular part of the expandable metal tubular between the circumferential edges, the second circumferential groove being closer to the first end than the first circumferential grooves with the sealing units, a split ring-shaped support element having a plurality of windings, so that when the expandable metal tubular is expanded from the first outer diameter to the second outer diameter, the split ring-shaped support element partly unwinds, the split ring-shaped support element is arranged in the second circumferential groove for supporting the first grooved tubular part of the expandable metal tubular during expansion. The invention also relates to a downhole completion comprising a well tubular metal structure and an annular barrier, where the tubular metal part of the annular barriers is mounted as part of the well tubular metal structure.

1 . An annular barrier for providing zonal isolation in an annulus downhole between a well tubular metal structure and another well tubular metal structure or a wall of a borehole, comprising:
 a tubular metal part configured to be mounted as part of the well tubular metal structure,   an expandable metal tubular surrounding the tubular metal part forming an expandable space therebetween, the expandable metal tubular is configured to be expanded in a well downhole from a first outer diameter to a second outer diameter to abut against the well tubular metal structure or the wall of the borehole, the expandable metal tubular having a first end, a second end, an outer face and a longitudinal extension, comprising:   a plurality of first circumferential grooves provided in the outer face,   a plurality of sealing units, each sealing unit comprising a sealing element arranged in the first circumferential grooves, so that each first circumferential groove comprises one of the sealing units occupying the first circumferential groove along the longitudinal extension,   a second circumferential groove without a sealing element and provided between two circumferential edges provided on the outer face and defining a first grooved tubular part of the expandable metal tubular between the circumferential edges, the second circumferential groove being closer to the first end than the first circumferential grooves with the sealing units,   a split ring-shaped support element having a plurality of windings, so that when the expandable metal tubular is expanded from the first outer diameter to the second outer diameter, the split ring-shaped support element partly unwinds, the split ring-shaped support element is arranged in the second circumferential groove for supporting the first grooved tubular part of the expandable metal tubular during expansion.   
     
     
         2 . An annular barrier according to  claim 1 , wherein the second circumferential groove comprises only one or more split ring-shaped support element. 
     
     
         3 . An annular barrier according to  claim 1 , wherein the second circumferential groove comprises only one or more split ring-shaped support element and an intermediate element arranged between the split ring-shaped support element and the grooved tubular part. 
     
     
         4 . An annular barrier according to  claim 1 , wherein a third circumferential groove provided between two circumferential edges provided on the outer face and defining a second grooved tubular part of the expandable metal tubular between the circumferential edges, the third circumferential groove being closer to the second end than the first circumferential grooves with the sealing units, the third circumferential groove comprises another split ring-shaped support element having a plurality of windings, so that when the expandable metal tubular is expanded from the first outer diameter to the second outer diameter, the split ring-shaped support element partly unwinds, the split ring-shaped support element is arranged in the third circumferential groove for supporting the second grooved tubular part of the expandable metal tubular during expansion. 
     
     
         5 . An annular barrier according to  claim 1 , wherein the split ring-shaped support element is a helically wounded ring-shaped element. 
     
     
         6 . An annular barrier according to  claim 1 , wherein the split ring-shaped support element has at least 6 windings, preferably at least 10 windings. 
     
     
         7 . An annular barrier according to  claim 1 , wherein the split ring-shaped support element is made of a spring material. 
     
     
         8 . An annular barrier according to  claim 1 , wherein the split ring-shaped support element is preferably made of a material having a yield strength of at least 70 MPa, preferably at least 100 MPa, more preferably at least 200 MPa. 
     
     
         9 . An annular barrier according to  claim 1 , wherein the ring-shaped support element is one split ring. 
     
     
         10 . An annular barrier according to  claim 1 , wherein the expandable metal tubular at the first end comprises an end sleeve surrounding the expandable metal tubular in order to increase a collapse rating of the annular barrier. 
     
     
         11 . An annular barrier according to  claim 1 , wherein the end sleeve abuts the expandable metal tubular and the first end of the end sleeve is welded onto the outer face of the tubular metal part. 
     
     
         12 . An annular barrier according to  claim 1 , wherein each of the plurality of sealing units comprises both the sealing element and a split ring-shaped retaining element arranged in the first circumferential grooves, the split ring-shaped retaining element forms a back-up for the sealing element, and the split ring-shaped retaining element has more than one winding so that when the expandable metal tubular is expanded from the first outer diameter to the second outer diameter, the split ring-shaped retaining element partly unwinds. 
     
     
         13 . An annular barrier according to  claim 1 , wherein the ends of the expandable metal tubular have a thickness greater than the grooved tubular part of the expandable metal tubular. 
     
     
         14 . An annular barrier according to  claim 1 , wherein the split ring-shaped support element has at least 6 windings, preferably at least 10 windings. 
     
     
         15 . An annular barrier according to any  claim 1 , wherein an intermediate element is arranged between the split ring-shaped support element and the grooved tubular part. 
     
     
         16 . An annular barrier according to  claim 1 , further comprising a tubular metal element connecting the expandable metal tubular with the tubular metal part and having an extension in the longitudinal extension and a first end part connected with the tubular metal part and a second end part connected with the expandable metal tubular, wherein the first end part is arranged closer to the sealing units along the longitudinal extension of the tubular metal part than the second end part. 
     
     
         17 . A downhole completion comprising a well tubular metal structure and an annular barrier according to  claim 1 , where the tubular metal part of the annular barriers is mounted as part of the well tubular metal structure.