Swellable Apparatus and Method of Forming

Abstract

A swellable apparatus for filling a space in oil or gas apparatus and method of forming an apparatus is described. The apparatus comprises a hydrocarbon swellable body formed from an elastomeric material selected to expand on exposure to a hydrocarbon fluid such as EPDM. The swellable body has a first surface which is exposed to a hydrocarbon fluid, a first (inner) portion, and a second portion disposed between the first portion and the surface. The first portion comprises a fluid permeability structure which differs from the fluid permeability structure of the second portion. In one embodiment, the cross-linking density of an outer portion of the body is greater than the cross-linking density of an inner portion of the body.

1 - 29 . (canceled) 
     
     
         30 . A swellable apparatus for filling a space in an oil or gas apparatus, the swellable apparatus comprising:
 a unitary hydrocarbon swellable body formed from an elastomeric material selected to expand on exposure to a hydrocarbon fluid, the hydrocarbon swellable body having a first surface which is exposed to a hydrocarbon fluid during operation, a first portion, and a second portion disposed between the first portion and the first surface,   wherein the first portion comprises a fluid permeability structure which differs from a fluid permeability structure of the second portion.   
     
     
         31 . The apparatus as claimed in  claim 30 , wherein the cross-linking density of the elastomeric material in the first portion of the hydrocarbon swellable body differs from the cross-linking density of the elastomeric material in the second portion of the hydrocarbon swellable body. 
     
     
         32 . The apparatus as claimed in  claim 31 , wherein the cross-linking density of the elastomeric material in the second portion is greater than the cross-linking density of the elastomeric material in the first portion. 
     
     
         33 . The apparatus as claimed in  claim 31 , wherein the hydrocarbon swellable body comprises a second surface, and the extent of cross-linking in the hydrocarbon swellable body decreases in a direction from the first surface to the second surface. 
     
     
         34 . The apparatus as claimed in  claim 30 , wherein one of the first or second portions of the hydrocarbon swellable body comprises an additive comprising a semi-crystalline rubber. 
     
     
         35 . The apparatus as claimed in  claim 34 , wherein one of the first or second portions of the hydrocarbon swellable body comprises a polyoctenamer. 
     
     
         36 . The apparatus as claimed in  claim 35 , wherein the polyoctenamer comprises between about 5% and about 15% of a volume of the first or second portion of the hydrocarbon swellable body. 
     
     
         37 . The apparatus as claimed in  claim 30 , wherein one of the first or second portions of the hydrocarbon swellable body comprises an additive comprising one or more chemical foaming agents. 
     
     
         38 . The apparatus as claimed  claim 30 , further comprising a plurality of water swellable bodies embedded in the hydrocarbon swellable body. 
     
     
         39 . The apparatus as claimed in  claim 30 , wherein the hydrocarbon swellable body comprises at least one pathway for the passage of water in a wellbore fluid through the hydrocarbon swellable body. 
     
     
         40 . A method of forming a swellable apparatus for filling a space in an oil or gas apparatus, the method comprising the steps of:
 providing an elastomeric material selected to expand on exposure to a hydrocarbon fluid;   curing the elastomeric material to form a unitary hydrocarbon swellable body; and   treating the elastomeric material such that a first portion of the hydrocarbon swellable body comprises a fluid permeability structure which differs from the fluid permeability structure of a second portion of the hydrocarbon swellable body.   
     
     
         41 . The method as claimed in  claim 40 , comprising the additional steps of:
 providing a sheet of hydrocarbon swellable material; and   forming a substantially cylindrical mantle from the sheet of hydrocarbon swellable material.   
     
     
         42 . The method as claimed in  claim 41 , comprising the additional step of forming multiple layers of the hydrocarbon swellable material on a mandrel or tubular. 
     
     
         43 . The method as claimed in  claim 41 , comprising the additional step of wrapping a sheet of hydrocarbon swellable material onto a mandrel or tubular. 
     
     
         44 . The method as claimed in  claim 40 , comprising the additional step of incorporating an additive into the elastomeric material, the additive comprising a chemical foaming agent. 
     
     
         45 . The method as claimed in  claim 40 , comprising the additional step of incorporating an additive into the elastomeric material, the additive comprising a semi-crystalline rubber. 
     
     
         46 . The method as claimed in  claim 40 , comprising the additional step of treating the hydrocarbon swellable material such that a second portion of the hydrocarbon swellable body has a higher extent of cross-linking than a first portion of the hydrocarbon swellable body. 
     
     
         47 . The method as claimed in  claim 46 , comprising the additional step of applying a cross-linking agent selectively to parts of the hydrocarbon swellable body. 
     
     
         48 . The method as claimed in  claim 47 , comprising the additional steps of:
 forming multiple layers of the hydrocarbon swellable material on a mandrel or tubular; and   applying a cross-linking agent to the surface of one or more layers prior to curing the elastomeric material.   
     
     
         49 . A swellable apparatus for filling a space in an oil or gas apparatus, the swellable apparatus comprising:
 a hydrocarbon swellable body formed from a cross-linked elastomeric material selected to expand on exposure to a hydrocarbon fluid, the hydrocarbon swellable body having a first surface which is exposed to a hydrocarbon fluid during operation,   wherein the cross-linking density of the elastomeric material varies in the hydrocarbon swellable body.