Downhole Packer Having Swellable Sleeve

Abstract

A packer seals a wellbore annulus. The packer has a body defining a bore therethrough and has a swellable element disposed on the body. An expander movably disposed on the body adjacent the swellable element is actuated by fluid pressure communicated through a port in the body's bore. When actuated, the expander fits between the swellable element and the body to expand the swellable element radially outward an initial expansion amount. While downhole, the swellable element swells in the presence of an agent downhole and expands radially outward a subsequent expansion amount to produce a seal with a surrounding surface. With further fluid pressure, the expander can also compress the swellable element to further increase the expansion amount of the swellable element.

1 . A packer for sealing an annulus, comprising:
 a body defining a bore therethrough;   a swellable element disposed on the body; and   an expander movably disposed on the body adjacent the swellable element, the expander actuatable to fit between the swellable element and the body,   the expander expanding the swellable element radially outward an initial expansion amount,   the swellable element being swellable in the presence of an agent downhole radially outward to produce a seal with a surrounding surface.   
     
     
         2 . The packer of  claim 1 , wherein the expander is hydraulically actuatable by fluid pumped through the bore of the body. 
     
     
         3 . The packer of  claim 1 , wherein the swellable element comprises a sleeve disposed about an outer surface of the body. 
     
     
         4 . The packer of  claim 1 , wherein the swellable element comprises an elastomeric material. 
     
     
         5 . The packer of  claim 4 , wherein the elastomeric material swells in the presence of the agent selected from the group consisting of a fluid, a gas, an oil, water, production fluid, and drilling fluid. 
     
     
         6 . The packer of  claim 1 , wherein the expander is actuatable to compress the swellable element against a shoulder disposed on the body. 
     
     
         7 . The packer of  claim 1 , wherein the body defines a port from the bore, and wherein the expander comprises a piston axially movable along the body and having first and second ends, the first end acted upon by fluid pressure communicating from the port, the second end fitting between the swellable element and the body and expanding the swellable element the initial expansion amount. 
     
     
         8 . The packer of  claim 7 , wherein a connection temporarily affixes the piston to the body until a predetermined fluid pressure is applied to the piston. 
     
     
         9 . The packer of  claim 7 , wherein the expander comprises an outer housing engageble by the piston and movable along the body with the piston, the outer housing compressing the swellable element against a shoulder on the body and expanding the swellable element a subsequent expansion amount. 
     
     
         10 . The packer of  claim 9 , wherein a connection temporarily affixes the outer housing to the body until a predetermined fluid pressure is applied. 
     
     
         11 . A packer for sealing an annulus, comprising:
 a body defining a bore therethrough;   means disposed on the body for swelling radially outward in the presence of an agent to produce a seal with a surrounding surface; and   means disposed on the body for expanding the swelling means radially outward an initial expansion amount.   
     
     
         12 . The packer of  claim 11 , wherein the means for expanding comprises means for fitting between the swelling means and the body to expand the swelling means the initial expansion amount. 
     
     
         13 . The packer of  claim 11 , wherein the means for expanding comprises means for compressing the swelling means to expand the swelling means a subsequent expansion amount. 
     
     
         14 . The packer of  claim 11 , wherein the agent is introduced downhole. 
     
     
         15 . The packer of  claim 11 , wherein the agent is naturally occurring downhole. 
     
     
         16 . A packer actuating method, comprising:
 running a packer into a wellbore;   expanding a swellable element on the packer an initial expansion amount in an annulus of the wellbore; and   creating a seal in the annulus of the wellbore with the swellable element by interacting the swellable element with an agent swelling the swellable element against a surrounding surface.   
     
     
         17 . The method of  claim 16 , further comprising compressing the swellable element to expand a subsequent expansion amount. 
     
     
         18 . The method of  claim 16 , wherein expanding the swellable element comprises actuating a piston disposed on the packer by pumping fluid pressure to the packer. 
     
     
         19 . The method of  claim 18 , wherein expanding the swellable element comprises fitting a first portion of the piston between the swellable element and a body of the packer and expanding the swellable element the initial expansion amount. 
     
     
         20 . The method of  claim 19 , wherein expanding the swellable element further comprises compressing the swellable element with a second portion of the piston against a shoulder on the packer and expanding the swellable element a subsequent expansion amount. 
     
     
         21 . The method of  claim 16 , wherein interacting the swellable element on the packer with the agent comprises pumping the agent downhole. 
     
     
         22 . The method of  claim 16 , wherein interacting the swellable element on the packer with the agent comprises subjecting the swellable element to the agent as naturally occurring downhole.