Tieback cementing plug system

Abstract

A method for casing a subsea wellbore includes running a tieback casing string into the subsea wellbore using a workstring including first, second, and third wiper plugs. The method further includes: launching a first release plug or tag into the workstring; pumping cement slurry into the workstring, thereby driving the first release plug or tag along the workstring; after pumping the cement slurry, launching a second release plug or tag into the workstring; and pumping chaser fluid into the workstring, thereby driving the release plugs or tags and cement slurry through the workstring. The release plugs or tags engage and release the respective wiper plugs from the workstring. The first wiper plug or release plug ruptures, thereby allowing the cement slurry to flow therethrough. The method further includes: stabbing the tieback casing string into a liner string; and retrieving the workstring, the workstring still including the third wiper plug.

What is claimed is: 
     
         1 . A method for casing a subsea wellbore, comprising:
 running a tieback casing string into the subsea wellbore using a workstring, the workstring including a first wiper plug, a second wiper plug, and a third wiper plug;   launching a first release plug or tag into the workstring;   pumping cement slurry into the workstring, thereby driving the first release plug or tag along the workstring;   after pumping the cement slurry, launching a second release plug or tag into the workstring;   pumping chaser fluid into the workstring, thereby driving the release plugs or tags and cement slurry through the workstring, wherein:
 the release plugs or tags engage the respective wiper plugs and release the respective wiper plugs from the workstring, and 
 the first wiper plug or first release plug ruptures, thereby allowing the cement slurry to flow therethrough and into an annulus formed between the tieback casing string and an outer casing string; 
   stabbing the tieback casing string into a liner string; and   retrieving the workstring, the workstring still including the third wiper plug.   
     
     
         2 . The method of  claim 1 , wherein:
 the second wiper plug has a bypass port and burst tube closing the bypass port, and   the burst tube is intact when retrieving the workstring.   
     
     
         3 . The method of  claim 2 , wherein a rupture pressure of the burst tube is substantially greater than release pressures of the wiper plugs. 
     
     
         4 . The method of  claim 1 , wherein:
 the tieback casing string includes a float collar, and   the first wiper plug ruptures after bumping the float collar.   
     
     
         5 . The method of  claim 2 , wherein the float collar includes a poppet having a bypass slot formed therein for preventing hydraulic lock during stabbing. 
     
     
         6 . The method of  claim 1 , wherein:
 the tieback casing string includes a guide shoe and a seal stem,   the tieback casing string is run until the guide shoe is proximately above a polished bore receptacle of the liner string, thereby forming a gap therebetween, and   the cement slurry flows into the annulus via the gap.   
     
     
         7 . The method of  claim 1 , wherein:
 the tieback casing string includes a hanger and a packer, and   the method further comprises setting the hanger and packer after stabbing.   
     
     
         8 . The method of  claim 1 , wherein:
 the tieback casing string includes an equalization valve, and   the third wiper plug is releasably connected to the equalization valve.   
     
     
         9 . The method of  claim 1 , wherein the release plug or tag is a dart. 
     
     
         10 . A method for casing a subsea wellbore, comprising:
 running a tieback casing string into the subsea wellbore using a workstring, the workstring including a first wiper plug, a second wiper plug, and a third wiper plug;   launching a first release plug or tag into the workstring;   pumping cement slurry into the workstring, thereby driving the first release plug or tag along the workstring;   after pumping the cement slurry, launching a second release plug or tag into the workstring;   pumping chaser fluid into the workstring, thereby driving the release plugs or tags and cement slurry through the workstring, wherein:
 the release plugs or tags engage the respective wiper plugs and release the respective wiper plugs from the workstring, and 
 the first wiper plug or first release plug ruptures, thereby allowing the cement slurry to flow therethrough and into an annulus formed between the tieback casing string and an outer casing string; 
   pumping conditioner fluid into the workstring, thereby rupturing the second wiper plug or second release plug and flushing the cement slurry from the annulus;   pumping remedial cement slurry into the workstring;   after pumping the remedial cement slurry, launching a third release plug or tag into the workstring;   pumping the chaser fluid into workstring, thereby driving the third release plug or tag and remedial cement slurry through the workstring, wherein:
 the third release plug or tag engages the third wiper plug and releases the third wiper plug, and 
 the third wiper plug drives the remedial cement slurry into the annulus; 
   stabbing the tieback casing string into a liner string; and   retrieving the workstring.   
     
     
         11 . The method of  claim 10 , wherein the second wiper plug is ruptured before stabbing. 
     
     
         12 . The method of  claim 10 , wherein:
 the method further comprises attempting to stab the tieback casing string into the liner string, and   the second wiper plug is ruptured after the attempted stabbing.   
     
     
         13 . The method of  claim 10 , wherein a rupture pressure of the burst tube is substantially greater than release pressures of the wiper plugs. 
     
     
         14 . The method of  claim 10 , wherein:
 the tieback casing string includes a float collar, and   the first wiper plug ruptures after bumping the float collar.   
     
     
         15 . The method of  claim 14 , wherein the float collar includes a poppet having a bypass slot formed therein for preventing hydraulic lock during stabbing. 
     
     
         16 . The method of  claim 10 , wherein:
 the tieback casing string includes a guide shoe and a seal stem,   the tieback casing string is run until the guide shoe is proximately above a polished bore receptacle of the liner string, thereby forming a gap therebetween, and   the cement slurry flows into the annulus via the gap.   
     
     
         17 . The method of  claim 10 , wherein:
 the tieback casing string includes a hanger and a packer, and   the method further comprises setting the hanger and packer after stabbing.   
     
     
         18 . The method of  claim 10 , wherein:
 the tieback casing string includes an equalization valve, and   the third wiper plug is released from the equalization valve.   
     
     
         19 . The method of  claim 10 , wherein the release plug or tag is a dart. 
     
     
         20 . A plug release system, comprising:
 a first wiper plug including a burst tube, the first burst tube adapted to burst at a pressure between 900 psi and 1100 psi;   a second wiper plug including a burst tube, the second burst tube adapted to burst at a pressure between 3500 psi and 5000 psi; and   a third wiper plug;   wherein:
 the first wiper plug is coupled to the second wiper plug by a shearable fastener, the shearable fastener adapted to shear at a pressure between 500 psi and 700 psi; and 
 the second wiper plug is coupled to the third wiper plug by a shearable fastener, the shearable fastener adapted to shear at a pressure between 1300 psi and 1700 psi.