Swellable downhole packers

Abstract

A swellable packer including a tubular member and a swellable element. The tubular member is disposable on a mandrel configured to be deployed into a wellbore. The swellable element is disposed around the tubular member, and has a first region comprising a swellable material and a second region comprising a degradable or dissolvable material.

What is claimed is: 
     
         1 . A packer usable within a wellbore comprising:
 a tubular member;   a swellable member circumferentially disposed about an axis of the tubular member and adapted to swell in the presence of a triggering agent to form an annular seal in the wellbore, wherein the swellable member comprises a first region comprising a swellable material; and   a second region comprising a degradable or dissolvable material.   
     
     
         2 . The method of  claim 1 , wherein the first region and second region are alternated on the tubular member. 
     
     
         3 . The method of  claim 1 , wherein the swellable member is formed from a laminate composite material. 
     
     
         4 . The packer of  claim 1 , wherein the triggering agent is a predetermined fluid in the wellbore. 
     
     
         5 . The packer of  claim 1 , wherein the swellable material is one of an oil swellable material or a water swellable material. 
     
     
         6 . The packer of  claim 1 , wherein the first region and second region are bonded together. 
     
     
         7 . The packer of  claim 1 , wherein the swellable member has a first rate of swelling before the second region degrades or dissolves; and
 a second rate of swelling which is faster than the first rate of swelling after the second region degrades or dissolves.   
     
     
         8 . The packer of  claim 1 , wherein a surface area of the swellable material increases when the second region degrades or dissolves thus accelerating the rate of swelling. 
     
     
         9 . The packer of  claim 1 , further comprising:
 a plurality of first and second regions;   wherein the plurality of first regions each swell to different swelling ratios and conform to a geometry of the wellbore.   
     
     
         10 . The packer of  claim 1 , wherein the swellable member further comprises:
 a coating on an outer surface of the swellable member; wherein the coating comprises degradable or dissolvable material.   
     
     
         11 . The packer of  claim 1 , wherein the degradable or dissolvable material is a porous foam material. 
     
     
         12 . The packer of  claim 1 , wherein the swellable member further comprises:
 a coating on an inner surface of the swellable member;   wherein the coating comprises swellable material.   
     
     
         13 . The packer of  claim 1 , where the degradable or dissolvable material comprises a plurality of voids. 
     
     
         14 . The packer of  claim 1 , where the degradable or dissolvable material is selected from the group consisting of degradable polymers, degradable biopolymers, dissolvable polymers; and combinations thereof. 
     
     
         15 . The packer of  claim 1 , wherein the wellbore is an open hole wellbore. 
     
     
         16 . A method comprising:
 forming an annular seal using a swellable member longitudinally extending along a tubular member in a wellbore, wherein the swellable member comprises a first region comprising a swellable material;   a second region comprising a degradable or dissolvable material; and   wherein the swellable material is adapted to swell in the presence of a triggering agent to form the annular seal in the wellbore.   
     
     
         17 . The method of  claim 16 , further comprising:
 degrading or dissolving the second region; and   increasing a rate of swelling of the first region.   
     
     
         18 . The method of  claim 16 , wherein the first and second regions are alternatively wrapped about the tubular member. 
     
     
         19 . The method of  claim 16 , wherein the first and second regions are formed from a laminate composite material. 
     
     
         20 . A system usable within a well, comprising:
 a tubing string to extend downhole in the well; and   a packer to form an annular seal between the tubing string and a casing or wellbore wall, the packer comprising:
 an inner core; and 
 a swellable body mounted to the inner core to swell to form an annular seal in the well, the swellable body being mounted to and circumscribing the inner core and comprising:
 a first region comprising a swellable material; and 
 a second region comprising a degradable or dissolvable material. 
 
   
     
     
         21 . The system of  claim 20 , wherein the swellable member has a first rate of swelling before the second region degrades or dissolves; and
 a second rate of swelling which is faster than the first rate of swelling after the second region degrades or dissolves.