Redressing method and redressed completion system

Abstract

A redressing method for arranging an inner production casing within an existing production casing in order to re-establish production of hydrocarbon-containing fluid in a well, comprises providing the inner production casing to having a substantially constant inner diameter, the inner production casing comprising spaced first and second annular barriers. Each annular barrier has a tubular metal part and an expandable metal sleeve surrounding the tubular metal part. Each barrier has an inner face facing the tubular metal part and an outer face facing an inner wall of the existing production casing. The inner production casing has an outer unexpanded diameter which is smaller than the first inner diameter of the existing production casing. The existing production casing is redressed by introducing the inner production casing into the existing production casing, arranging the first annular barrier on one side of the first inflow section and the second annular barrier on the other side of the inflow section, thereby isolating an inflow of fluid from the first inflow section, encapsulating the first inflow section of the existing production casing by expanding the expandable metal sleeves of the first annular barrier and the second annular barrier, thereby isolating the first inflow section.

1 . A redressing method for arranging an inner production casing within an existing production casing in order to re-establish production of hydrocarbon-containing fluid in a malfunctioning or underperforming well having a top part, the existing production casing having a first inner diameter and being arranged in a borehole, the redressing method comprising:
 determining a first inflow section of the existing production casing opposite a first production zone, the first production zone being isolated from a second zone,   providing the inner production casing, the inner production casing having an inner diameter which is substantially the same along an extension of the inner production casing, the inner production casing comprising a first annular barrier and a second annular barrier having a distance between them, each annular barrier comprising:
 a tubular metal part for mounting as part of the inner production casing, 
 an expandable metal sleeve surrounding the tubular metal part and having an inner face facing the tubular metal part and an outer face facing an inner wall of the existing production casing, each end of the expandable metal sleeve being connected with the tubular metal part, and 
 an annular space between the inner face of the expandable metal sleeve and the tubular metal part, 
   
       the inner production casing having an outer unexpanded diameter which is smaller than the first inner diameter of the existing production casing,
 redressing the existing production casing by introducing the inner production casing into the existing production casing, 
 arranging the first annular barrier on one side of the first inflow section and the second annular barrier on the other side of the inflow section, thereby isolating an inflow of fluid from the first inflow section, 
 encapsulating the first inflow section of the existing production casing by expanding the expandable metal sleeves of the first annular barrier and the second annular barrier, thereby isolating the first inflow section, 
 anchoring the inner production casing in the top part of the well, 
 providing a first inner inflow section in the inner production casing opposite the first inflow section of the existing production casing or opposite the second zone, and 
 initiating production of hydrocarbon-containing fluid through the inner production casing from the first production zone or the second zone. 
 
     
     
         2 . A redressing method according to  claim 1 , further comprising determining if the existing production casing is damaged. 
     
     
         3 . A redressing method according to  claim 1 , further comprising stopping the production of hydrocarbon-containing fluid. 
     
     
         4 . A redressing method according to  claim 3 , further comprising pressuring at least part of the casing to expand the annular barriers. 
     
     
         5 . A redressing method according to  claim 1 , further comprising reducing a hydrostatic pressure of the well by redressing the existing production casing by means of the inner production casing. 
     
     
         6 . A redressing method according to  claim 1 , wherein the initiating production of hydrocarbon-containing fluid through the inner production casing from the second zone includes perforating the inner production casing opposite the second zone. 
     
     
         7 . A redressing method according to  claim 6 , further comprising perforating the second zone before introducing the inner production casing into the existing production casing. 
     
     
         8 . A redressing method according to  claim 1 , further comprising:
 determining a second inflow section of the existing production casing opposite a second production zone,   
       wherein the providing an inner production casing further comprises providing a third annular barrier, and
 arranging the second annular barrier on one side of the second inflow section and the third annular barrier on the other side of the second inflow section of the existing production casing. 
 
     
     
         9 . A redressing method according to  claim 8 , comprising:
 determining a third inflow section of the existing production casing opposite a third production zone,   
       wherein the providing an inner production casing further comprises providing a fourth annular barrier, and
 arranging the third annular barrier on one side of the third inflow section and the fourth annular barrier on the other side of the third inflow section of the existing production casing. 
 
     
     
         10 . A redressing method according to  claim 1 , wherein the inner production casing extends to the top of the well. 
     
     
         11 . A redressing method according to  claim 1 , wherein the inner production casing overlaps most of the existing production casing. 
     
     
         12 . A redressing method according to  claim 1 , wherein the anchoring the inner production casing in the top part of the well comprises the step of providing the inner production casing with an anchoring annular barrier. 
     
     
         13 . A redressing method according to  claim 1 , wherein the redressing method further comprises the step of detecting a depleted production zone. 
     
     
         14 . A redressing method according to  claim 1 , wherein the redressing method further comprises fracturing or stimulating the first production zone or the second zone from within the inner production casing. 
     
     
         15 . A redressed completion system for re-establishing production of hydrocarbon-containing fluid in an existing production casing having a first inflow section arranged opposite a first production zone in a malfunctioning or underperforming well having a top part, the system comprising:
 an inner production casing comprising a first annular barrier and a second annular barrier having a distance between them, each annular barrier comprising:
 a tubular metal part for mounting as part of the inner production casing, and 
 an expandable metal sleeve surrounding the tubular metal part and having an inner face facing the tubular metal part and an outer face adapted to face an inner wall of the existing production casing, each end of the expandable metal sleeve being connected with the tubular metal part, and 
   an annular space between the inner face of the expandable metal sleeve and the tubular metal part,   
       wherein the inner production casing comprises a first inner inflow section arranged between the first annular barrier and the second annular barrier, the inner production casing being adapted to extend inside the existing production casing, and wherein the first annular barrier is expanded on one side of the first inflow section and the second annular barrier is expanded on the other side of the first inflow section of the existing production casing, thereby isolating the first inflow section and allowing the hydrocarbon-containing fluid to flow from the first production zone into the inner production casing through the first inflow section and the first inner inflow section. 
     
     
         16 . A redressed completion system according to  claim 15 , wherein the inner production casing has an unexpanded outer diameter dimensioned to be smaller than a first inner diameter of the existing production casing, thereby reducing the hydrostatic pressure of the well. 
     
     
         17 . A redressed completion system according to  claim 15 , wherein the inner production casing is adapted to be anchored to the top part of the well. 
     
     
         18 . A redressed completion system according to  claim 15 , wherein the inner production casing is adapted and dimensioned to extend to a top of the well. 
     
     
         19 . A redressed completion system according to  claim 15 , wherein the existing production casing has a second inflow section opposite a second production zone, and the inner production casing comprises a third annular barrier and a second inner inflow section arranged between the second annular barrier and the third annular barrier, the second annular barrier being expanded on one side of the second inflow section and the third annular barrier being expandable on the other side of the second inflow section of the existing production casing, thereby isolating the second inflow section. 
     
     
         20 . A redressed completion system according to  claim 15 , further comprising a detection tool configured to determine the inflow sections of the existing production casing.