Downhole system

Abstract

The present invention relates to a downhole system for completing a well. The downhole system comprises a downhole well tubular structure having a wall and being configured to be arranged in a borehole of the well and a first annular barrier for being expanded in an annulus between the downhole well tubular structure and a wall of the borehole. The first annular barrier comprises a tubular part for mounting as part of the downhole well tubular structure, the tubular part having a first expansion opening and an outer face; an expandable metal sleeve surrounding the tubular part and having an inner face facing the tubular part and an outer face facing the wall of the borehole; a first connection part and a second connection part configured to connect a first end and a second end, respectively, of the expandable metal sleeve with the tubular part; and an annular space between the inner face of the expandable metal sleeve and the tubular part, the expandable metal sleeve being expanded by pressurising the annular space to an expansion pressure by pressurising the tubular part opposite the expansion opening. The downhole system further comprises a first aperture in the wall of the downhole well tubular structure. The aperture is at least partly plugged with an acid-soluble material. The present invention further relates to a completion method for completing a downhole system according to the present invention.

1 - 20 . (canceled) 
     
     
         21 . A downhole system for completing a well, comprising:
 a downhole well tubular structure having a wall and being configured to be arranged in a borehole of the well,   a first annular barrier for being expanded in an annulus between the downhole well tubular structure and a wall of the borehole, the first annular barrier comprising:
 a tubular part for mounting as part of the well tubular structure, the tubular part having a first expansion opening and an outer face, 
 an expandable metal sleeve surrounding the tubular part and having an inner face facing the tubular part and an outer face facing the wall of the borehole, 
 a first connection part and a second connection part configured to connect a first end and a second end, respectively, of the expandable metal sleeve with the tubular part, and 
 an annular space between the inner face of the expandable metal sleeve and the tubular part, the expandable metal sleeve being expanded by pressurising the annular space to an expansion pressure by pressurising the tubular part opposite the expansion opening, and 
   a first aperture in the wall of the downhole well tubular structure,   wherein the aperture is at least partly plugged with an acid-soluble material.   
     
     
         22 . A downhole system according to  claim 21 , wherein the downhole well tubular structure has a first end nearest a top of the well and a second end, the second end is configured to be closed, and the second end comprises a second aperture in which a burstable element is arranged for closing the second end. 
     
     
         23 . A downhole system according to  claim 21 , wherein the first aperture plugged with a plug of the material is configured to withstand a first pressure higher than the expansion pressure. 
     
     
         24 . A downhole system according to  claim 21 , wherein the plug has a body part and a flange, the body part extending into the aperture and the flange abutting an inner face of the well tubular structure. 
     
     
         25 . A downhole system according to  claim 21 , wherein the body part of the plug has a bore. 
     
     
         26 . A downhole system according to  claim 21 , wherein the body part has a notch. 
     
     
         27 . A downhole system according to  claim 21 , wherein the first aperture plugged with the material is configured to withstand a first pressure being higher than the expansion pressure. 
     
     
         28 . A downhole system according to  claim 21 , further comprising a second annular barrier, the aperture being arranged between the first annular barrier and the second annular barrier. 
     
     
         29 . A downhole system according to  claim 21 , further comprising a sliding sleeve arranged opposite the aperture and having a first initial position uncovering the aperture. 
     
     
         30 . A downhole system according to  claim 21 , further comprising:
 an inner well tubular structure arranged inside the downhole well tubular structure, the inner well tubular structure comprising a wall,   a first inner annular barrier and a second inner annular barrier, each inner annular barrier comprising:
 a tubular part for mounting as part of the inner well tubular structure, the tubular part having an inner expansion opening, 
 an expandable metal sleeve surrounding the tubular part and having an inner face facing the tubular part and an outer face facing the wall of the downhole well tubular structure, 
 a first connection part and a second connection part configured to connect a first end and a second end, respectively, of the expandable metal sleeve with the tubular part, and 
 an annular space between the inner face of the expandable metal sleeve and the tubular part, the expandable metal sleeve being expanded by pressurising the annular space to an inner expansion pressure by pressurising the tubular part opposite the inner expansion opening, and 
   a second aperture in the wall of the inner well tubular structure.   
     
     
         31 . A downhole system according to  claim 21 , wherein a burst disc is arranged in the second aperture and configured to burst at a burst pressure higher than the inner expansion pressure. 
     
     
         32 . A downhole system according to  claim 21 , wherein the inner well tubular structure comprises a sliding sleeve arranged opposite the second aperture. 
     
     
         33 . A downhole system according to  claim 21 , further comprising a dart tool having projecting elements for engaging a groove in the sliding sleeve and an inflatable element. 
     
     
         34 . A completion method for completing a downhole system according to  claim 21 , comprising:
 inserting the downhole well tubular structure into the borehole,   pressurising the downhole well tubular structure to expand the annular barriers, and   acidising the acid-soluble material to clear the first aperture.   
     
     
         35 . A completion method according to  claim 34 , which before acidising the acid-soluble material further comprises pressurising the well tubular structure to a pressure above the expansion pressure to burst a burstable element in a second end of the well tubular structure below the annular barrier. 
     
     
         36 . A completion method according to  claim 34 , wherein the well tubular structure comprises a sliding sleeve which is run in hole in an open position, uncovering the first aperture. 
     
     
         37 . A completion method according to  34 , which before acidising the acid-soluble material further comprises inserting an inner well tubular structure. 
     
     
         38 . A completion method according to  claim 37 , which before acidising the acid-soluble material and after inserting the inner well tubular structure further comprises pressurising the inner well tubular structure to the inner expansion pressure to expand inner annular barriers connected with the inner well tubular structure. 
     
     
         39 . A completion method according to  claim 38 , which before acidising the acid-soluble material and after pressurising the inner well tubular structure to the inner expansion pressure further comprises pressurising the inner well tubular structure to the burst pressure to burst a burst disc. 
     
     
         40 . A completion method according to  claim 38 , which after pressurising the inner well tubular structure to the burst pressure to burst the burst disc lets acid through a second aperture into a second annulus between the inner well tubular structure, the downhole well tubular structure and the inner annular barriers to acidise the acid-soluble material.