System, method, and sleeve, for cladding an underground wellbore passage

Abstract

An inner surface of an underground wellbore or wellbore tubular is cladded by an elastic sleeve ( 1 ), which is placed by:—lowering the elastic sleeve ( 1 ) into the wellbore which sleeve is releasably connected to a stretching device ( 4 ) arranged within the sleeve ( 1 ) and stretched by the stretching device ( 4 ) in longitudinal direction thereby reducing its largest outer width such that it is less than the smallest width of the inner surface surrounding the elastic sleeve ( 1 );—releasing the sleeve ( 1 ) from the stretching device ( 4 ) thereby enlarging the outer width of the sleeve ( 1 ) and cladding the sleeve ( 1 ) against the inner surface.

1 . A method for cladding an inner surface of an underground wellbore passage, the method comprising:
 providing an elastic sleeve having a stretching device arranged within the sleeve which stretching device is connected to opposite ends of the sleeve;   inducing the stretching device to stretch the sleeve in a longitudinal direction, thereby reducing its largest outer width such that it is less than the smallest width of the inner surface;   lowering the stretching device and the stretched sleeve into the wellbore passage;   releasing the sleeve from the stretching device thereby enlarging the outer width of the sleeve and cladding the sleeve against the inner surface.   
     
     
         2 . The method of  claim 1 , whereby releasing the sleeve from the stretching device comprises detaching the sleeve from the stretching device. 
     
     
         3 . The method of  claim 1 , further comprising, after releasing the sleeve from the stretching device:
 withdrawing the stretching device from the sleeve.   
     
     
         4 . The method of  claim 1 , wherein underground wellbore passage is an uncased wellbore section or a well casing, liner or other wellbore tubular, whereby the sleeve is cladded against the inner surface of said uncased wellbore section or well casing, liner or other wellbore tubular section. 
     
     
         5 . The method of any  claim 1 , wherein the sleeve is configured to swell upon contact with a wellbore fluid. 
     
     
         6 . The method of  claim 5 , wherein wellbore fluid comprises water and the sleeve comprises an elastic elastomer and a water-absorbing swelling agent. 
     
     
         7 . The method of  claim 6 , wherein the water-absorbing swelling agent is a hygroscopic salt or a super absorbent polymer. 
     
     
         8 . The method of  claim 7 , wherein the hygroscopic salt is dispersed in the elastic elastomer as an array of finely divided solid particles. 
     
     
         9 . The method of  claim 4 , wherein the wellbore is a wellbore of an abandoned oil and/or gas production well and, after cladding the inner surface with the sleeve, a well bore plugging material is inserted into the sleeve and allowed to harden and form a plug to plug the wellbore whereby the sleeve forms a swellable sealing layer between the plug and the inner surface. 
     
     
         10 . The method of  claim 9 , wherein the swellable sealing layer is induced to swell and thereby seal any micro-annuli between the plug and the inner surface. 
     
     
         11 . The method of  claim 9 , wherein the well bore plugging material comprises of a cement slurry, whereby the resulting plug is a cement plug. 
     
     
         12 . The method of  claim 1 , wherein providing said elastic sleeve comprises:
 arranging a stretching device within the sleeve; and   connecting the stretching device to opposite ends of the sleeve.   
     
     
         13 . The method of  claim 1 , wherein the sleeve has end sections in which tensioning rods are embedded at regular circumferential intervals, which tensioning rods are configured to be coupled to the stretching device and to longitudinally stretch the sleeve in response to longitudinal expansion of the stretching device. 
     
     
         14 . An elastic sleeve for cladding an inner surface of an underground wellbore passage, the sleeve having a larger outer width than the width of the inner surface and being:
 connectable to a stretching device within the sleeve and to be longitudinally stretched by the stretching device thereby reducing its outer width such that it is less than the width of the inner surface; and   releasable from the stretching device after lowering with the stretching device in stretched condition into the wellbore passage, thereby enlarging its outer width and cladding the sleeve against the inner surface.   
     
     
         15 . The sleeve of  claim 14 , wherein the sleeve comprises an elastic elastomer and a swelling agent that induces the elastomer to swell upon contact with a wellbore fluid. 
     
     
         16 . The sleeve of  claim 15 , wherein the wellbore fluid is water and the swelling agent is a water-absorbing swelling agent. 
     
     
         17 . The sleeve of  claim 14 , wherein the stretching device is detachable from the sleeve when the sleeve is in released condition. 
     
     
         18 . The sleeve of  claim 14 , wherein the stretching device is arranged within the sleeve and connected to opposite ends of the sleeve. 
     
     
         19 . The sleeve of  claim 18 , wherein the sleeve has end sections in which tensioning rods are embedded at regular circumferential intervals, which tensioning rods are configured to be coupled to the stretching device and to longitudinally stretch the sleeve in response to longitudinal expansion of the stretching device, and wherein a V-shaped groove is arranged in each interval of each end section. 
     
     
         20 . A system for cladding an inner surface of an underground wellbore passage, comprising an elastic sleeve and a stretching device arranged within the sleeve, which stretching device is releasably connected to opposite ends of the sleeve, the sleeve having a larger outer width than the width of the inner surface and being:
 connectable to the stretching device within the sleeve and to be longitudinally stretched by the stretching device thereby reducing its outer width such that it is less than the width of the inner surface; and   releasable from the stretching device alter lowering with the stretching device in stretched condition into the wellbore passage, thereby enlarging its outer width and cladding the sleeve against the inner surface.   
     
     
         21 . The system of  claim 20 , wherein the sleeve has end sections in which tensioning rods are embedded at regular circumferential intervals, which tensioning rods are configured to be coupled to the stretching device and to longitudinally stretch the sleeve in response to longitudinal expansion of the stretching device, and wherein a V-shaped groove is arranged in each interval of each end section.