Downhole Packer Having Tandem Packer Elements for Isolating Frac Zones

Abstract

A tandem packer seals a wellbore annulus with first and second seals. The packer has a body defining a bore therethrough and has a shoulder disposed on the body. A compressible element is disposed on the body adjacent the shoulder. A piston is movably disposed on the body adjacent the compressible element and is activated by fluid pressure communicated through a port in the packer's bore. When actuated, the piston fits between the compressible element and the body to initially expand it outward. With further fluid pressure, the piston compresses the compressible element against the shoulder to expand the element radially outward and produce a first seal with a surrounding surface. A swellable element also disposed on the body is swellable in the presence of an agent and expands radially outward to produce a second seal with the surrounding surface.

1 . A downhole packer for sealing an annulus, comprising:
 a body defining a bore therethrough;   a first sealing element disposed on the body,   an actuator movably disposed on the body adjacent the first sealing element, the actuator actuatable to compress the first sealing element, the first sealing element expandable radially outward when compressed to produce a first seal with a surrounding surface; and   a second sealing element disposed on the body, the second sealing element being engorgable by an agent radially outward to produce a second seal with the surrounding surface.   
     
     
         2 . The packer of  claim 1 , wherein the actuator is hydraulically actuatable by fluid pumped through the bore of the body. 
     
     
         3 . The packer of  claim 1 , wherein the first sealing element comprises a compressible sleeve disposed on the body and composed of metal, plastic, elastomer, or combination thereof. 
     
     
         4 . The packer of  claim 1 , wherein the second sealing element comprises a swellable sleeve disposed on the body and composed of an elastomeric material swellable by the agent selected from the group consisting of a liquid, a gas, an oil, water, production fluid, and drilling fluid. 
     
     
         5 . The packer of  claim 4 , wherein a first shoulder on the body retains one end of the swellable sleeve, and a second shoulder on the body retains another end of the swellable sleeve. 
     
     
         6 . The packer of  claim 1 , wherein the second sealing element comprises an inflatable sleeve disposed on the body and inflatable by pumped fluid as the agent filing the inflatable sleeve. 
     
     
         7 . The packer of  claim 1 , wherein the first sealing element has a first axial length along the body, and wherein the second sealing element has a second axial length along the body that is greater than the first axial length. 
     
     
         8 . The packer of  claim 1 , wherein the second sealing element is disposed on a downhole portion of the body, and wherein the first sealing element is disposed on an uphole portion of the body. 
     
     
         9 . The packer of  claim 1 , further comprising a third sealing element disposed on the body so that the first sealing element is interposed on the body between the second and third sealing elements, the third sealing element being engorgable by the agent radially outward to produce a third seal with the surrounding surface. 
     
     
         10 . The packer of  claim 1 , wherein the body defines a port from the bore, and wherein the actuator comprises a piston axially movable along the body, the piston acted upon by fluid pressure communicating from the port, a portion of the piston fitting between the first sealing element and the body and expanding the first sealing element an initial expansion amount. 
     
     
         11 . The packer of  claim 10 , wherein a connection temporarily affixes the piston to the body until a predetermined fluid pressure is applied to the piston. 
     
     
         12 . The packer of  claim 10 , wherein the actuator comprises an outer housing disposed about the body and the piston, the outer housing being engageble by the piston and being movable with the piston, the outer housing compressing the first sealing element against a shoulder on the body and expanding the first sealing element a subsequent expansion amount. 
     
     
         13 . The packer of  claim 12 , wherein a connection temporarily affixes the outer housing to the body until a predetermined fluid pressure is applied. 
     
     
         14 . The packer of  claim 12 , wherein a connection temporarily affixes the shoulder to the body until a predetermined force is applied. 
     
     
         15 . A downhole packer for sealing an annulus, comprising:
 a body defining a bore therethrough;   first means being compressible on the body for expanding radially outward to produce a first seal with a surrounding surface;   means for actuating the first means; and   second means being engorgable on the body by an agent for expanding radially outward to produce a second seal with the surrounding surface.   
     
     
         16 . The packer of  claim 15 , wherein the means for actuating the first means comprises means fitting between the first means and the body for expanding the first means an initial expansion amount. 
     
     
         17 . The packer of  claim 16 , wherein the means for actuating the first means comprises means for compressing the first means to expand the first means a subsequent expansion amount. 
     
     
         18 . The packer of  claim 15 , wherein the second means comprises means for swelling on the body in the presence of the agent. 
     
     
         19 . The packer of  claim 18 , wherein the agent is introduced downhole. 
     
     
         20 . The packer of  claim 18 , wherein the agent is naturally occurring downhole. 
     
     
         21 . The packer of  claim 15 , wherein the second means comprises means for inflating on the body by interaction with pumped fluid as the agent. 
     
     
         22 . A packer actuating method, comprising:
 running a packer into a borehole;   creating a first seal in an annulus of the borehole with the packer by compressing a first sealing element on the packer and expanding the compressed first sealing element against a surrounding surface; and   creating a second seal in the annulus of the borehole with the packer by engorging a second sealing element on the packer with an agent and expanding the engorged second sealing element against the surrounding surface.   
     
     
         23 . The method of  claim 22 , wherein compressing the first sealing element comprises actuating a piston disposed on the packer by pumping fluid pressure to the packer. 
     
     
         24 . The method of  claim 23 , wherein actuating the piston comprises fitting a first portion of the piston between the first sealing element and a body of the packer and expanding the first sealing element an initial expansion amount. 
     
     
         25 . The method of  claim 24 , wherein actuating the piston comprises compressing the first sealing element with a second portion of the piston against a shoulder on the packer and expanding the first sealing element a subsequent expansion amount. 
     
     
         26 . The method of  claim 22 , wherein engorging the second sealing element comprises swelling the second sealing element by interacting an agent with the second sealing element. 
     
     
         27 . The method of  claim 26 , wherein interacting the agent comprises pumping the agent downhole. 
     
     
         28 . The method of  claim 22 , wherein interacting the agent comprises subjecting the swellable element to the agent as naturally occurring downhole. 
     
     
         29 . The method of  claim 22 , wherein engorging the second sealing element comprises inflating the second sealing element by filling the second sealing element with pumped fluid as the agent. 
     
     
         30 . The method of  claim 22 , wherein creating the first and second seals comprises creating the second seal with a greater axial length along the packer than the first seal.