Compositions and Methods for Mitigation of Annular Pressure Buildup in Subterranean Wells

Abstract

Compositions and methods that mitigate pressure buildup in the annular space between two tubular bodies in subterranean wells. The composition of the invention comprises an aqueous solution of crosslinkable acrylamide-base polymer, a crosslinker and a gas. Once foamed and placed in the annular space, the composition provides a resilient, flexible, compressible and durable body that is able to compensate for pressure increases in the annular space, thereby protecting the integrity of the tubular bodies.

1 . A composition for controlling pressure buildup within an annular volume within a subterreanean wellbore, comprising at least one water-soluble acrylamide polymer, a crosslinker, a gas and water. 
     
     
         2 . The composition of  claim 1 , wherein the polymer comprises one or more members of the list comprising: polymethacrylamides, polyacrylamides, acrylic acid-acrylamide copolymers, acrylic acid-methacrylamide copolymers, acrylamide-sodium acrylate copolymers, partially hydrolyzed polymethacylamides and partially hydrolyzed polyacrylamides. 
     
     
         3 . The composition of  claim 1 , wherein the polymer is acrylamide-sodium acrylate copolymer. 
     
     
         4 . The composition of  claim 3 , wherein the polymer molecular weight is in the range from about 300,000 to 10,000,000. 
     
     
         5 . The composition of  claim 3 , wherein the polymer is present in the range between about 4% to about 7% by weight. 
     
     
         6 . The composition of  claim 1 , wherein the gas comprises one or more members of the list comprising: nitrogen, air and carbon dioxide. 
     
     
         7 . The composition of  claim 1 , wherein the gas is present at a concentration between about 5% to 50% by volume. 
     
     
         8 . The composition of  claim 1 , further comprising one or more particulate additives chosen from the list comprising: amorphous or crystalline silica, hematite, barite, ilmenite, manganese tetraoxide, calcium carbonate, bentonite, attapulgite, smectite, montmorillonite, kaolinite, illite, chlorite, zeolites, diatomaceous earth, perlite, coal and gilsonite. 
     
     
         9 . The composition of  claim 1 , wherein the crosslinker comprises at least one water soluble chromium (III) compound. 
     
     
         10 . The composition of  claim 9 , wherein the chromium (III) compound is chromium (III) acetate. 
     
     
         11 . The composition of  claim 10 , wherein the chromium (III) acetate is present in an amount between about 0.3% to about 1.2% by weight. 
     
     
         12 . The composition of  claim 9 , further comprising one or more carboxylate species, the carboxylate species chosen from the list comprising: formate, acetate, proprionate, lactate, lower substituted derivatives thereof, and mixtures thereof. 
     
     
         13 . The composition of  claim 12 , wherein the carboxylate species is sodium lactate. 
     
     
         14 . The composition of  claim 13 , wherein the sodium lactate is present in the range between about 0.25% to about 2.5% by volume. 
     
     
         15 . The composition of  claim 1 , wherein the crosslinker is one or more members of the list consisting of: amine compounds and phenyl compounds. 
     
     
         16 . The composition of  claim 15 , wherein the amine compound is hexamethylenetriamine. 
     
     
         17 . The composition of  claim 16 , wherein the hexamethylenetriamine is present in an amount between about 0.2% to about 0.5% by weight. 
     
     
         18 . The composition of  claim 15 , wherein the phenyl compound is phenyl acetate. 
     
     
         19 . The composition of  claim 18 , wherein the phenyl acetate is present in an amount between about 0.2% to about 1.0% by weight. 
     
     
         20 . The composition of  claim 15 , further comprising one or more members of the list consisting of: acetic acid, hydrochloric acid and sodium bicarbonate.