Sealing of a Wellbore Device in a Tubular Element

Abstract

A method of operating a wellbore formed in an earth formation is disclosed. The wellbore is provided with a tubular element in which a wellbore device is to be arranged such that the wellbore device is sealed to the inner surface of the tubular element, and whereby an elongate member is to be extended through the tubular element for carrying out a wellbore operation. The method comprises extending the elongate member through the tubular element so as to carry out said wellbore operation, removing the elongate member from the tubular element, providing the wellbore device at the outer surface thereof with a swelleable seal susceptible of swelling upon contact with a selected fluid, and installing the wellbore device in the tubular element, and inducing the swelleable seal to swell by virtue of contact of the swelleable seal with the selected fluid.

1 . A method of operating a wellbore formed in an earth formation, the wellbore being provided with a tubular element in which a wellbore device is to be arranged such that the wellbore device is sealed to the inner surface of the tubular element, and whereby an elongate member is to be extended through the tubular element for carrying out a wellbore operation, the method comprising: 
 extending the elongate member through the tubular element so as to carry out said wellbore operation;    removing the elongate member from the tubular element;    providing the wellbore device at the outer surface thereof with a swelleable seal susceptible of swelling upon contact with a selected fluid, and installing the wellbore device in the tubular element; and    inducing the swelleable seal to swell by virtue of contact of the swelleable seal with the selected fluid;    wherein the tubular element is a production tubing for transporting hydrocarbon fluid produced from the earth formation to surface, wherein the tubular element includes a landing nipple for receiving said wellbore device, and wherein the step of installing the wellbore device in the tubular element comprises installing the wellbore device in the landing nipple.    
   
   
       2 . The method of  claim 1 , wherein the wellbore device is a safety valve assembly for selectively controlling flow of hydrocarbon fluid through the production tubing.  
   
   
       3 . The method of  claim 1 , wherein the tubular element is a polished bore receptacle (PBR), and the wellbore device is a seal assembly of a production tubing for transporting hydrocarbon fluid produced from the earth formation to surface.  
   
   
       4 . The method of  claim 1 , wherein the selected fluid is hydrocarbon fluid, and wherein the swelleable seal comprises a material selected from the group consisting of natural rubber, nitrile rubber, hydrogenated nitrile rubber, acrylate butadiene rubber, poly acrylate rubber, butyl rubber, brominated butyl rubber, chlorinated butyl rubber, chlorinated polyethylene, neoprene rubber, styrene butadiene copolymer rubber, sulphonated polyethylene, ethylene acrylate rubber, epichlorohydrin ethylene oxide copolymer, ethylene-propylene-copolymer (peroxide crosslinked), ethylene-propylene-copolymer (sulphur crosslinked), ethylene-propylene-diene terpolymer rubber, ethylene vinyl acetate copolymer, fluoro rubbers, fluoro silicone rubber, and silicone rubbers.  
   
   
       5 . The method of  claim 4 , wherein said material is selected from the group consisting of EP(D)M rubber (ethylene-propylene-copolymer, either peroxide or sulphur crosslinked), EPT rubber (ethylene-propylene-diene terpolymer rubber), butyl rubber, brominated butyl rubber, chlorinated butyl rubber, and chlorinated polyethylene.  
   
   
       6 . The method  claim 1 , wherein the selected fluid is water, and wherein the swelleable seal comprises a material selected from the group consisting of NBR, HNBR, XNBR, FKM, FFKM, TFE/P and EPDM base rubber.  
   
   
       7 . The method of  claim 6 , wherein said material is a matrix material, and wherein a compound soluble in water is incorporated in the matrix material in a manner that the matrix material substantially prevents or restricts migration of the compound out of the swelleable seal and allows migration of water into the swelleable seal by osmosis so as to induce swelling of the swelleable seal upon migration of said water into the swelleable seal.  
   
   
       8 . The method of  claim 7 , wherein said compound comprises a salt.  
   
   
       9 . The method of  claim 8 , wherein the swelleable seal contains at least 20 weight % salt based on the combined weight of the matrix material and the salt.  
   
   
       10 . The method of  claim 7 , wherein said matrix material is substantially impermeable to said compound.  
   
   
       11 . The method of claims  7 , wherein the compound is present in the matrix material in the form of a plurality of compound particles dispersed in the matrix material.  
   
   
       12 . The method of claims  1 , wherein the selected fluid is hydraulic fluid and the wellbore device is controllable by a hydraulic control system operated by a stream of said hydraulic fluid which is in contact with the swelleable seal, and wherein the step of inducing the swelleable seal to swell comprises supplying the stream of hydraulic fluid to the hydraulic control system.  
   
   
       13 . A wellbore device for use in a wellbore formed in an earth formation whereby the wellbore is provided with a tubular element in which the wellbore device is to be arranged in a manner that the wellbore device is sealed to the inner surface of the tubular element, and whereby an elongate member is to be extended through the tubular element for carrying out a wellbore operation, the wellbore device being provided at the outer surface thereof with a swelleable seal susceptible of swelling upon contact with a selected fluid, wherein the tubular element is a production tubing for transporting hydrocarbon fluid produced from the earth formation to surface, and wherein the tubular element includes a landing nipple for receiving the wellbore device, the wellbore device being installed in the landing nipple.  
   
   
       14 . The wellbore device of  claim 13 , wherein the wellbore device is arranged in the tubular element, the tubular element having an inner surface which is damaged due to carrying out a wellbore operation whereby an elongate member has been extended through the tubular element, and wherein the swelleable seal is swollen due to contact with the selected fluid so as to seal the wellbore device to the inner surface of the tubular element.  
   
   
       15 . (canceled)  
   
   
       16 . (canceled)  
   
   
       17 . The method of  claim 8 , wherein the swellable seal contains at least 35 weight % salt based on the combined weight of the matrix material and the salt.  
   
   
       18 . The method of  claim 7 , wherein said matrix material is substantially impermeable to ions of said compound.