Method to Design Expandable Cement Based upon Specified Downhole Conditions

Abstract

A method of performing a cementing operation with an expandable cement deployable into a wellbore penetrating a subterranean formation is provided. The method involves determining design parameters of a wellsite, determining at least one estimated eigenstrain of the expandable cement based on the design parameters, selecting the expandable cement based on the estimated eigenstrain, and validating the selected expandable cement by comparing the estimated eigenstrain with the empirical eigenstrain. The design parameters includes a minimum pre-stress of the wellbore sufficient to prevent creation of a microannulus in the wellbore. The estimated eigenstrain is sufficient to generate the determined minimum pre-stress.

What is claimed is: 
     
         1 . A method of performing a cementing operation with an expandable cement deployable into a wellbore penetrating a subterranean formation, the method comprising:
 determining design parameters of a wellsite, the design parameters comprising a minimum pre-stress of the wellbore sufficient to prevent creation of a microannulus in the wellbore;   determining at least one estimated eigenstrain of the expandable cement based on the design parameters, the at least one estimated eigenstrain sufficient to generate the determined minimum pre-stress;   selecting the expandable cement based on the at least one estimated eigenstrain; and   validating the selected expandable cement by comparing the at least one estimated eigenstrain with the at least one empirical eigenstrain.   
     
     
         2 . The method of  claim 1 , further comprising performing at least one expansion test to generate the at least one empirical eigenstrain. 
     
     
         3 . The method of  claim 2 , wherein the at least one expansion test comprises at least one of an unconfined expansion test, a confined expansion test, and combinations thereof. 
     
     
         4 . The method of  claim 2 , wherein the performing comprises determining at least one isotropic eigenstrain using an unconfined expansion tester. 
     
     
         5 . The method of  claim 2 , wherein the at least one expansion test comprises determining at least one anisotropic eigenstrain tensor of the at least one empirical eigenstrain using a confined expansion tester. 
     
     
         6 . The method of  claim 1 , wherein the at least one estimated eigenstrain and the at least one empirical eigenstrain are unconfined. 
     
     
         7 . The method of  claim 1 , wherein the at least one estimated eigenstrain and the at least one empirical eigenstrain are confined. 
     
     
         8 . The method of  claim 1 , wherein the at least one empirical eigenstrain comprises an eigenstrain tensor, the eigenstrain tensor comprising a magnitude of anisotropy and a degree of anisotropy. 
     
     
         9 . The method of  claim 1 , further comprising measuring the at least one empirical eigenstrain using a cement expansion apparatus. 
     
     
         10 . The method of  claim 9 , wherein the cement expansion apparatus comprises one of an unconfined expansion tester, a confined expansion tester, and combinations thereof. 
     
     
         11 . The method of  claim 1 , further comprising selecting a new expandable cement when the at least one empirical eigenstrain is outside a pre-defined range of the at least one estimated eigenstrain. 
     
     
         12 . The method of  claim 11 , further comprising repeating the selecting and validating until the at least one empirical eigenstrain is within a pre-defined range of the at least one estimated eigenstrain for the new expandable cement. 
     
     
         13 . The method of  claim 1 , further comprising cementing the wellbore using the validated expandable cement. 
     
     
         14 . The method of  claim 1 , wherein the determining comprises measuring at least one of the design parameters at the wellbore. 
     
     
         15 . The method of  claim 1 , wherein the design parameters comprise wellbore geometry, casing stiffness, wellbore stiffness, and combinations thereof. 
     
     
         16 . A method of performing a cementing operation with an expandable cement deployable into a wellbore penetrating a subterranean formation, the method comprising:
 designing an expandable cement for cementing the wellbore, the designing comprising: determining design parameters of a wellsite, the design parameters comprising a
 minimum pre-stress of the wellbore sufficient to prevent creation of a microannulus in the wellbore; 
 determining at least one estimated eigenstrain of the expandable cement based on the design parameters, the at least one estimated eigenstrain sufficient to generate the determined minimum pre-stress; 
 selecting the expandable cement based on the at least one estimated eigenstrain; and 
 validating the selected expandable cement by comparing the at least one estimated eigenstrain with the at least one empirical eigenstrain; and 
   cementing the wellbore with the designed expandable cement.   
     
     
         17 . The method of  claim 16 , further comprising securing a casing in the wellbore with the cement. 
     
     
         18 . The method of  claim 16 , further comprising lining a portion of the wall of the wellbore with the cement. 
     
     
         19 . The method of  claim 16 , wherein the cementing comprises completing the wellbore using the designed expandable cement. 
     
     
         20 . A method of performing a cementing operation with an expandable cement deployable into a wellbore penetrating a subterranean formation, the method comprising:
 measuring at least one estimated eigenstrain of at least one expandable cement with at least one cement expansion apparatus;   designing an expandable cement for cementing the wellbore, the designing comprising: determining design parameters of a wellsite, the design parameters comprising a
 minimum pre-stress of the wellbore sufficient to prevent creation of a microannulus in the wellbore; 
 determining at least one estimated eigenstrain of the expandable cement based on the design parameters, the at least one estimated eigenstrain sufficient to generate the determined minimum pre-stress; 
 selecting the expandable cement based on the at least one estimated eigenstrain; and 
 validating the selected expandable cement by comparing the at least one estimated eigenstrain with the at least one empirical eigenstrain. 
   
     
     
         21 . A system of performing a cementing operation with an expandable cement deployable into a wellbore penetrating a subterranean formation, the method comprising:
 a cement expansion apparatus comprising an expandable body with sensors thereon, the expandable body having a cement cavity therein, the sensors positionable about the expandable body to measure expansion thereof; and   a cement tool operatively connectable to the cement expansion apparatus, the cement tool comprising a database to receive data from the cement expansion apparatus and a processor to determine cement parameters from the data whereby expansion of the cement is determinable thereby.   
     
     
         22 . The system of  claim 21 , wherein the cement tool is operatively connectable to a wellsite, the database to receive data from the wellsite and the processor to determining cement parameters from the data whereby cement parameters for cement operations are determinable thereby. 
     
     
         23 . The system of  claim 21 , wherein the cement expansion apparatus comprises one of a confined expansion tester having a split ring configuration and an unconfined expansion tester having a dual ring configuration.