Expandable polymer grout for wellbore applications

Abstract

An expandable polymer grout system comprises an isocyanate component and an organic polyol component that when combined form a grout for bonding to equipment used in a wellbore. In a first instance, the grout is used with a retrieval system to bond to an obstruction in a wellbore for retrieving the obstruction from the wellbore. In a second instance, the grout is used with a deployment system to secure a sensor to downhole equipment within a wellbore. In a third instance, the grout is used to secure a casing centralizer to an outer surface of a casing before the casing is placed in a wellbore. In a fourth instance, the grout is molded to form a casing centralizer on an outer surface of a casing before the casing is placed in a wellbore.

We claim: 
     
         1 . A method of retrieving an obstruction from a wellbore, the method comprising:
 deploying a retrieval system in the wellbore, the retrieval system comprising a retrieval tool;   combining, with the retrieval system, components of an expandable polymer grout system to form a grout;   engaging the obstruction with the retrieval tool and the grout; and   retracting the obstruction with the retrieval system from the wellbore.   
     
     
         2 . The method of  claim 1 , wherein the retrieval tool is one of a spear, a hook, an overshot tool, or a grasping tool. 
     
     
         3 . The method of  claim 1 , wherein the retrieval system comprises a cannister system that mixes the components of the expandable polymer grout system within the wellbore to form the grout. 
     
     
         4 . The method of  claim 3 , wherein the cannister system comprises an isocyanate cannister, an organic polyol cannister, and a mixer. 
     
     
         5 . The method of  claim 4 , wherein the cannister system further comprises a lubricant cannister comprising a lubricant. 
     
     
         6 . The method of  claim 1 , wherein the retrieval system comprises a conduit system for delivering the components of the expandable polymer grout system from a surface of the wellbore to a target location. 
     
     
         7 . The method of  claim 6 , wherein the retrieval system further comprises a mixer that receives the components of the expandable polymer grout system from the conduit system and mixes the components of the expandable polymer grout system. 
     
     
         8 . A method of attaching a sensor to downhole equipment in a wellbore, the method comprising:
 identifying a target location within the wellbore for the sensor;   providing, with a deployment system, an expandable polymer grout system to the target location within the wellbore;   combining, with the deployment system, components of the expandable polymer grout system within the wellbore to form a grout;   delivering the grout to the target location within the wellbore; and   allowing the grout to cure thereby securing the sensor to the downhole equipment within the wellbore.   
     
     
         9 . The method of  claim 8 , wherein the deployment system comprises a tailpipe that delivers the grout to the sensor and the downhole equipment. 
     
     
         10 . The method of  claim 8 , wherein the deployment system comprises a conduit system for delivering the components of the expandable polymer grout system to the target location. 
     
     
         11 . The method of  claim 10 , wherein the deployment system further comprises a mixer that receives the components of the expandable polymer grout system from the conduit system and mixes the components of the expandable polymer grout system. 
     
     
         12 . The method of  claim 8 , wherein the deployment system comprises a cannister system that mixes the components of the expandable polymer grout system within the wellbore to form the grout. 
     
     
         13 . The method of  claim 12 , wherein the cannister system comprises an isocyanate cannister, an organic polyol cannister, and a mixer. 
     
     
         14 . A method of deploying a casing in a wellbore, the method comprising:
 placing a casing centralizer onto an outer surface of a casing:   combining, with a deployment system, components of an expandable polymer grout system to form a grout;   delivering the grout to a contact point at which the casing centralizer contacts the outer surface of the casing;   allowing the grout to cure thereby securing the casing centralizer to the outer surface of the casing; and   placing the casing with the casing centralizer into the wellbore.   
     
     
         15 . The method of  claim 14 , wherein the deployment system comprises:
 a mixer that combines the components of the expandable polymer grout system to form the grout; and   a conduit that delivers the grout to the contact point.   
     
     
         16 . The method of  claim 14 , wherein the components of the expandable polymer grout system comprise an isocyanate component, an organic polyol component, and a blowing agent. 
     
     
         17 . A method of deploying a casing in a wellbore, the method comprising:
 placing a centralizer mold onto an outer surface of a casing;   combining, with a deployment system, components of an expandable polymer grout system to form a grout;   delivering the grout to an annulus between the centralizer mold and the outer surface of the casing;   allowing the grout to cure thereby forming a casing centralizer on the outer surface of the casing;   after curing the grout, removing the centralizer mold from the outer surface of the casing; and   placing the casing with the casing centralizer into the wellbore.   
     
     
         18 . The method of  claim 17 , wherein the deployment system comprises:
 a mixer that combines the components of the expandable polymer grout system to form the grout; and   a conduit that delivers the grout to the contact point.   
     
     
         19 . The method of  claim 17 , wherein the components of the expandable polymer grout system comprise an isocyanate component, an organic polyol component, and a blowing agent. 
     
     
         20 . The method of  claim 19 , wherein the components of the expandable polymer grout system further comprise a lubricant to increase a lubricity of the casing centralizer thereby facilitating placement of the casing into the wellbore.