Method for stabilizing wellbore, stabilized wellbore and wellbore stabilizing fluid

Abstract

A method for stabilizing a wellbore includes introducing a hardening agent into the wellbore, mixing the hardening agent with a carrier fluid in the wellbore to produce a wellbore stabilizing fluid, and treating a wellbore wall of the wellbore by contacting the wellbore stabilizing fluid to a surface of the wellbore wall for at least 48 hours. A wellbore stabilizing fluid includes a hardening agent and a carrier fluid. The hardening agent is selected from one of 10 to 100 g/L of the calcium hydroxide nanocrystals, 5 to 99.9% by volume of tetraethyl orthosilicate (TEOS), and 10 to 50 g/L of zinc sulfate. A stabilized wellbore includes a wellbore having a wellbore wall treated with a wellbore stabilizing fluid comprising a hardening agent. The Young's modulus of the treated wellbore wall is at least 5% higher than a Young's modulus of a non-treated wellbore wall.

What is claimed is: 
     
         1 . A method for stabilizing a wellbore, the method comprising a treatment cycle of:
 introducing a hardening agent into the wellbore;   mixing the hardening agent with a carrier fluid in the wellbore to produce a wellbore stabilizing fluid; and   treating a wellbore wall of the wellbore by contacting the wellbore stabilizing fluid to a surface of the wellbore wall and maintaining the contacting for at least 48 hours.   
     
     
         2 . The method of  claim 1 , wherein the wellbore stabilizing fluid comprises the hardening agent selected from one of calcium hydroxide nanocrystals, tetraethyl orthosilicate (TEOS), and zinc sulfate. 
     
     
         3 . The method of  claim 2 , wherein the hardening agent comprised in the wellbore stabilizing fluid is selected from one of:
 10 g/L to 100 g/L of the calcium hydroxide nanocrystals;   5% to 99.9% by volume of tetraethyl orthosilicate (TEOS); and   10 g/L to 50 g/L of zinc sulfate.   
     
     
         4 . The method of  claim 1 , wherein the wellbore stabilizing fluid further comprises a solvent comprising at least one of ethanol and isopropanol. 
     
     
         5 . The method of  claim 1 , wherein the method further comprises repeating the treatment cycle of the introducing the hardening agent, the mixing, and the treating at least once. 
     
     
         6 . The method of  claim 5 , wherein the hardening agent in the repeated treatment cycle is chemically different than a hardening agent of a treatment cycle immediately preceding treatment cycle. 
     
     
         7 . The method of  claim 1 , wherein the method is conducted at an elevated temperature ranging from 40° C. to 100° C. 
     
     
         8 . The method of  claim 1 , wherein a Young's modulus of the wellbore wall after the treating is at least 5% higher than a Young's modulus of the wellbore wall before the treating. 
     
     
         9 . A wellbore stabilizing fluid, comprising:
 a hardening agent; and   a carrier fluid,   wherein the hardening agent comprised in the wellbore stabilizing fluid is selected from one of:
 10 g/L to 100 g/L of calcium hydroxide nanocrystals; 
 5% to 99.9% by volume of tetraethyl orthosilicate (TEOS); and 
 10 g/L to 50 g/L of zinc sulfate. 
   
     
     
         10 . The wellbore stabilizing fluid of  claim 9 , further comprising a solvent comprising at least one of ethanol and isopropanol. 
     
     
         11 . A stabilized wellbore, comprising:
 a wellbore having a wellbore wall treated with a wellbore stabilizing fluid comprising a hardening agent,   wherein a Young's modulus of the wellbore wall treated with the wellbore stabilizing fluid is at least 5% higher than a Young's modulus of a wellbore wall of a wellbore not treated by the wellbore stabilizing fluid.   
     
     
         12 . The stabilized wellbore of  claim 11 , wherein the wellbore stabilizing fluid comprises the hardening agent selected from one of calcium hydroxide nanocrystals, tetraethyl orthosilicate (TEOS), and zinc sulfate. 
     
     
         13 . The stabilized wellbore of  claim 12 , wherein the hardening agent comprised in the wellbore stabilizing fluid is selected from one of:
 10 g/L to 100 g/L of the calcium hydroxide nanocrystals;   5% to 99.9% by volume of tetraethyl orthosilicate (TEOS); and   10 g/L to 50 g/L of zinc sulfate.   
     
     
         14 . The stabilized wellbore of  claim 11 , wherein the wellbore wall is treated with at least two of a first wellbore stabilizing fluid, a second wellbore stabilizing fluid and a third wellbore stabilizing fluid, the first wellbore stabilizing fluid comprising calcium hydroxide nanocrystals, the second wellbore stabilizing fluid comprising tetraethyl orthosilicate (TEOS), and the third stabilizing fluid comprising zinc sulfate.