Method of providing an annular seal, and wellbore system

Abstract

A method of providing an annular seal around a tubular in a wellbore penetrating a subsurface formation, the method comprising providing a tubular in the wellbore, wherein an annular space ( 18 ) is formed around the tubular; providing an annular gravel pack in the annular space; wherein the method further comprises arranging a band ( 9 a , 9 b , 9 c , 9 d ) of gel-forming material around the tubular before providing the annular gravel pack, wherein the gel-forming material is swellable in a selected fluid, and wherein the annular seal is formed by contacting the band of gel-forming material with the selected fluid; and a wellbore system comprising a gravel-packed tubular in a wellbore, wherein the tubular is provided with a band of gel-forming material in a layer around the tubular, the band being surrounded by gravel ( 15 ), and wherein the gel-forming material is swellable in a selected fluid.

1 . A method of providing an annular seal around a tubular in a wellbore penetrating a subsurface formation, the wellbore having a wellbore wall and the method comprising:
 providing a tubular in the wellbore, wherein an annular space is formed between the tubular and the wellbore wall;   providing an annular gravel pack in the annular space;   wherein the method further comprises:   arranging a band of solid gel-forming material around the tubular before providing the annular gravel pack;   contacting the band of solid gel-forming material with a selected fluid, wherein the solid gel-forming material becomes a swellable gel;   swelling of the gel into the gravel to form the annular seal between the tubular and the wellbore wall.   
     
     
         2 . The method according to  claim 1 , wherein the selected fluid contacting the at least one band of gel-forming material is or forms part of a formation fluid entering the wellbore from the subsurface formation. 
     
     
         3 . The method according to  claim 1 , wherein the contacting takes place at the time of a breakthrough of an unwanted formation fluid into the wellbore. 
     
     
         4 . The method according to  claim 1 , wherein the band of gel-forming material forms a first band of a plurality of bands of gel-forming material which are arranged around the tubular in a longitudinally spaced manner, the plurality also including a second band of gel-forming material, and wherein two annular seals are formed by contacting the first and the second band with the selected fluid, so as to provide a zonal isolated annular space. 
     
     
         5 . The method according  claim 4 , wherein the method further comprises detecting which of the plurality of bands of gel-forming material has or have formed an annular seal. 
     
     
         6 . The method according to  claim 4 , wherein the method further comprises performing a remedial action in the zonal isolated annular space. 
     
     
         7 . The method according to  claim 1 , wherein the remedial action comprises at least one operation selected from the group consisting of shutting of fluid flow in or into that zone, chemical treatment, a repair operation of a well completion element. 
     
     
         8 . The method according to  claim 1 , wherein the tubular is provided with one or more bands of gel-forming material on surface, before installing the tubular in the wellbore. 
     
     
         9 . The method according to  claim 1 , wherein the tubular has a wall and comprises at least one open section with fluid inlet openings in the wall, and at least one closed section with impermeable wall towards the annular space, and wherein the band of gel-forming material is arranged in the at least one closed section. 
     
     
         10 . The method according to  claim 9 , wherein the swollen gel forming the annular seal includes gravel. 
     
     
         11 . The method according to  claim 1 , wherein the gel-forming material comprises a gel-forming component selected from the group consisting of a layered silicate, an inorganic polymer, a superabsorbent. 
     
     
         12 . The method according to  claim 1 , wherein the selected fluid causing the gel-forming material to swell when being contacted with the gel-forming material comprises water, hydrocarbon oil, or water and hydrocarbon oil. 
     
     
         13 . A wellbore system comprising a gravel-packed tubular in a wellbore, wherein the tubular is provided with
 a band of solid gel-forming material in a layer around the tubular, the band being surrounded by gravel, and wherein the solid gel-forming material is adapted to become a swellable gel when contacted with a selected fluid.   
     
     
         14 . The wellbore system according to  claim 13 , wherein the band of gel-forming material forms a first band of a plurality of bands of gel-forming materials which are arranged around the tubular in a longitudinally spaced manner, the plurality also including a second band of gel-forming material. 
     
     
         15 . The wellbore system according to  claim 13 , wherein the tubular has a wall and comprises at least one open section with fluid inlet openings in the wall, and at least one closed section with impermeable wall towards the annular space, and wherein the band of gel-forming material is arranged in the at least one chosen.