Plug device and method of using same

Abstract

A plug device and a method of using same is described for use when temporarily sealing a fluid bore in a pipe. The plug device includes a plug body disposed in a sealing manner in the fluid bore, wherein the plug device, in order to disintegrate the plug body, further comprises a piston arrangement structured in a manner allowing it to provide a pressure increase in an activation fluid having been introduced to the plug body via at least one channel.

1 . A plug device for use when temporarily sealing a fluid bore in a pipe, wherein the plug device includes a plug body disposed in a sealing manner in the fluid bore, wherein the plug device further comprises a piston arrangement structured in a manner allowing it to provide a pressure increase in an activation fluid having been introduced to the plug body via at least one channel. 
     
     
         2 . The plug device in accordance with  claim 1 , wherein the piston arrangement is disposed between a drive fluid and the plug body, the drive fluid being arranged in a manner allowing it to drive the piston arrangement from a first position onto a second position. 
     
     
         3 . The plug device in accordance with  claim 1 , wherein the activation fluid is at a first pressure when the piston arrangement is located in the first position, and at a second, higher pressure when the piston arrangement is located in the second position, and wherein the plug body is structured to disintegrate at a disintegration pressure being equal to or lower than the second pressure. 
     
     
         4 . The plug device in accordance with  claim 1 , wherein the piston arrangement includes a first piston which, by means of a piston rod, is connected to a second piston. 
     
     
         5 . The plug device in accordance with  claim 4 , wherein the first piston is provided with an outer piston surface exposed to the drive fluid, and an inner piston surface exposed to a first fluid located in a first chamber, and wherein the second piston is exposed to the activation fluid located in a second fluid chamber. 
     
     
         6 . The plug device in accordance with  claim 5 , wherein the first fluid is more compressible than the activation fluid. 
     
     
         7 . The plug device in accordance with  claim 6 , wherein the first fluid is a gas, and the activation fluid is a liquid. 
     
     
         8 . The plug device in accordance with  claim 6  wherein the first fluid chamber contains air at atmospheric pressure. 
     
     
         9 . The plug device in accordance with  claim 6 , wherein the fluid pressure in the second fluid chamber initially is in the order of 1-500 bars, preferably 1-250 bars. 
     
     
         10 . The plug device in accordance with  claim 5 , wherein the area of the piston surface of the first piston, the area of which is exposed to the drive fluid, is larger than the area of the lower piston surface of the first piston, the area of which is exposed to the first fluid chamber. 
     
     
         11 . The plug device in accordance with  claim 5 , wherein the area of the piston surface of the first piston, the area of which is exposed to the drive fluid, is larger than the area of the portion of the second piston, the area which is exposed to the second fluid chamber containing the activation fluid. 
     
     
         12 . The plug device in accordance with  claim 1 , wherein the plug body is comprised of a hollow body made of a frangible material. 
     
     
         13 . The plug device in accordance with  claim 12 , wherein the hollow plug body is fluid-filled. 
     
     
         14 . The plug device in accordance with  claim 12 , wherein the frangible material is one of, or a combination of, a ceramic material, a glass material or a composite material. 
     
     
         15 . The plug device in accordance with  claim 1 , wherein at least portions of the plug body are provided with an outer surface being convex in the longitudinal direction of the fluid bore. 
     
     
         16 . The plug device in accordance with  claim 2 , wherein a rupture element is structured to fix the piston arrangement against movement until the drive fluid exceeds a predetermined pressure. 
     
     
         17 . A method of removing a plug body placed in a plug device and disposed in a sealing manner in a fluid bore in a pipe, wherein the method includes the steps of:
 pressurizing a drive fluid located at a downstream side of a fluid flow against which the plug body seals;   providing movement of a piston arrangement, which is included in the plug device, from a first position onto a second position in order to produce an increase in the fluid pressure of an activation fluid being in fluid communication with a portion of the plug body; and   allowing the pressure of the drive fluid to increase until the plug body disintegrates, and then terminating the pressurization at the downstream side of the plug device.   
     
     
         18 . The method in accordance with  claim 17 , wherein the method further includes producing the disintegrated plug body out of the well. 
     
     
         19 . Use of high pressure in order to disintegrate a plug body in a fluid bore.