Downhole sealing devices having a shape-memory material and methods of manufacturing and using same

Abstract

Sealing devices such as packers comprise a shape-memory material having a compressed run-in position or shape and an original expanded position or shape. The shape-memory material may comprise a polyurethane foam material held in the compressed run-in position by an adhesion material that is dissolvable by a fluid. The fluid may be a wellbore fluid already present in the wellbore or a fluid pumped down the wellbore after the sealing device is disposed within the wellbore. The fluid may also be a production fluid from the well. Upon being contacted by the fluid, the adhesion material dissolves and the shape-memory material expands to its original expanded position or shape, thereby sealing and dividing the annulus of the wellbore.

1 . A sealing device for use in a wellbore to isolate an annulus of the wellbore, the sealing device comprising:
 a shape-memory material, the shape-memory material having a compressed position and an expanded position and the shape-memory material being maintained in the compressed position by a dissolvable adhesion material,   wherein the dissolvable adhesion material is dissolvable by a wellbore fluid placed in contact with the adhesion material.   
   
   
       2 . The sealing device of  claim 1 , wherein the shape-memory material comprises a polyurethane foam material. 
   
   
       3 . The sealing device of  claim 1 , wherein the dissolvable adhesion material comprises a polymer. 
   
   
       4 . A method of manufacturing a sealing device for use in a wellbore to divide an annulus of the wellbore, the method comprising the steps of:
 (a) combining an isocyanate with a polyol;   (b) mixing the isocyanate with the polyol to form a polyurethane foam material having an original expanded thickness;   (c) contacting the polyurethane foam material with a dissolvable adhesion material to form an adhesion material impregnated polyurethane foam material;   (d) compressing the adhesion material impregnated polyurethane foam material to reduce the original expanded thickness to a compressed run-in thickness; and   (e) installing the adhesion material impregnated polyurethane foam material on a downhole tool capable of being disposed within a wellbore;   
   
   
       5 . The method of  claim 4 , wherein the polyol comprises a mixture of polyol and water. 
   
   
       6 . The method of  claim 5 , wherein the mixture of polyol and water further includes a chain extender. 
   
   
       7 . The method of  claim 6 , wherein the chain extender comprises an aromatic diamine. 
   
   
       8 . The method of  claim 6 , wherein the mixture of polyol, water, and the chain extender further includes a catalyst. 
   
   
       9 . The method of  claim 8 , wherein the catalyst comprises an amine-based catalyst. 
   
   
       10 . The method of  claim 8 , wherein the catalyst comprises a metal-based catalyst. 
   
   
       11 . The method of  claim 8 , wherein the mixture of polyol, water, the chain extender, and the catalyst further includes a surfactant. 
   
   
       12 . The method of  claim 4 , wherein the polyol is preheated to at least 100° C. prior to being combined with the isocyanate. 
   
   
       13 . The method of  claim 4 , wherein step (b) comprises curing the polyurethane foam material in a mold and then heating the polyurethane foam material at a temperature greater than 80° C. 
   
   
       14 . The method of  claim 4 , wherein step (a) comprises combining equivalent weights of the isocyanate and the polyol. 
   
   
       15 . The method of  claim 4 , wherein step (b) comprises mixing the isocyanate and polyol in a mixer for at least about 20 seconds and curing the polyurethane foam material in a mold for at least about 2 hours. 
   
   
       16 . The method of  claim 15 , wherein step (b) further comprises heating the polyurethane foam material at a temperature of at least about 100° C. for at least about 6 hours. 
   
   
       17 . The method of  claim 4 , wherein step (c) comprises applying a vacuum to polyurethane foam material while in contact with the dissolvable adhesion material. 
   
   
       18 . The method of  claim 4 , wherein step (d) comprises placing the adhesion material impregnated polyurethane foam material in a vacuum oven. 
   
   
       19 . The method of  claim 18 , wherein the adhesion material impregnated polyurethane foam material is placed in the vacuum oven at a temperature of at least about 80° C. for at least about 8 hours. 
   
   
       20 . A method of sealing wellbore to divide an annulus of the wellbore, the method comprising:
 (a) securing a downhole tool to a string of tubing, the downhole tool comprising a sealing device comprising a shape-memory material, the shape-memory material having a compressed run-in position and an original expanded position, wherein the shape-memory material is maintained in the compressed run-in position by a dissolvable adhesion material;   (b) running the downhole tool in a wellbore;   (c) contacting the shape-memory material and dissolvable adhesion material with a fluid;   (d) dissolving the dissolvable adhesion material with the fluid;   (e) expanding the shape-memory material from the compressed run-in position to the original expanded position, thereby sealing and dividing the annulus of wellbore with the shape-memory material in the original expanded position.   
   
   
       21 . The method of  claim 20 , wherein the fluid is water. 
   
   
       22 . The method of  claim 20 , wherein the fluid is oil.