Compositions and Methods for Servicing Subterranean Wells

Abstract

This invention relates to methods for servicing subterranean wells, in particular, fluid compositions and methods for remedial operations during which the fluid compositions are pumped into a wellbore and make contact with well cements placed during primary cementing or previous remedial cementing operations.

1 . A pumpable sealant composition for establishing hydraulic isolation in a cemented subterranean well, comprising a slurry of aluminosilicate particles, aluminum compound/silica particles, or aluminium compound/silicate particles, and combinations thereof. 
     
     
         2 . The composition of  claim 1 , wherein the aluminosilicate particles comprise one or more members of the list comprising: kaolin, metakaolin, fly ash, slag, natural zeolite, artificial zeolite, natural pozzolan and artificial pozzolan. 
     
     
         3 . The composition of  claim 1 , wherein the subterranean well has been cemented with Portland cement, a lime/silica blend, a lime/pozzolan blend, calcium aluminate cement, chemically bonded phosphate ceramic, or combinations thereof. 
     
     
         4 . The composition of  claim 1 , wherein the average size of the particles is less than or equal to 15 micrometers. 
     
     
         5 . The composition of  claim 1 , having a liquid phase wherein said liquid phase comprises water. 
     
     
         6 . The composition of  claim 1 , further comprising one or more weighting materials chosen from the list comprising: ilmenite, hematite, barite and manganese tetraoxide. 
     
     
         7 . The composition of  claim 1 , further comprising sodium hexametaphosphate. 
     
     
         8 . The composition of  claim 1 , further comprising a latex. 
     
     
         9 . The composition of  claim 1 , further comprising soluble silicate compounds. 
     
     
         10 . The composition of  claim 1 , further comprising hydroxide compounds. 
     
     
         11 . The composition of  claim 1 , further comprising alkali swellable polymers, superabsorbent polymers, or both. 
     
     
         12 . The composition of  claim 11 , wherein the alkali swellable polymers are latexes. 
     
     
         13 . A method of servicing a cemented wellbore in contact with a subterranean formation, comprising:
 i. preparing a sealant composition comprising a slurry including aluminosilicate particles, aluminum compound particle/silica particle blends, or aluminum-compound particle/silicate-particle blends and combinations thereof.   ii. pumping the sealant composition into voids in the wellbore that are adjacent to set cement; and   iii. allowing the sealant composition to react with the set-cement surfaces and form a set product, thereby forming a seal.   
     
     
         14 . The method of  claim 13 , wherein the wellbore has been cemented with Portland cement, a lime/silica blend, a lime/pozzolan blend, calcium aluminate cement, or chemically bonded phosphate ceramic, and combinations thereof. 
     
     
         15 . The method of  claim 13 , wherein the aluminosilicate particles comprise one or more members of the list comprising: kaolin, metakaolin, fly ash, slag, natural zeolite, artificial zeolite, natural pozzolan and artificial pozzolan. 
     
     
         16 . The method of  claim 13 , wherein the average size of the particles is less than or equal to 15 micrometers. 
     
     
         17 . The method of  claim 13 , wherein the composition comprises a liquid phase containing water. 
     
     
         18 . The method of  claim 13 , wherein the composition further comprises one or more weighting materials chosen from the list comprising: ilmenite, hematite, barite and manganese tetraoxide. 
     
     
         19 . The method of  claim 13 , wherein the composition further comprises sodium hexametaphosphate. 
     
     
         20 . The method of  claim 13 , wherein the composition further comprises a latex. 
     
     
         21 . The method of  claim 13 , wherein the composition further comprises soluble silicate compounds. 
     
     
         22 . The method of  claim 13 , wherein the composition further comprises hydroxide compounds. 
     
     
         23 . The method of  claim 13 , wherein the composition further comprises alkali swellable polymers, superabsorbent polymers, or both. 
     
     
         24 . The method of  claim 23 , wherein the alkali swellable polymers are latexes. 
     
     
         25 . A method of servicing a cemented wellbore in contact with a subterranean formation, comprising:
 i. preparing an aqueous sealant composition comprising a slurry of particles whose composition includes members chosen from the list comprising: kaolin, metakaolin, fly ash, slag, natural zeolite, artificial zeolite and natural pozzolan;   ii. pumping the sealant composition into voids in the wellbore that are adjacent to set Portland cement; and   iii. allowing the sealant composition to react with the set-cement surfaces and form a set product, thereby forming a seal.