Methods for placement of sealant in subterranean intervals

Abstract

Of the many methods provided herein, one method includes a method of treating an interval of a subterranean formation having a permeability that varies comprising: identifying the interval to be treated; introducing a relative-permeability modifier into the interval, wherein the relative-permeability modifier modifies the interval to have a more uniform effective permeability to water, wherein the relative permeability modifier comprises a water-soluble polymer; and introducing a sealant into the interval, wherein the more uniform effective permeability of the interval allows for a more uniform treatment of the interval by the than would be allowed without treatment of the interval with the relative-permeability modifier.

1 . A method of treating an interval of a subterranean formation having a permeability that varies, the method comprising:
 identifying the interval to be treated and   introducing a sealant composition that comprises a relative-permeability modifier into the interval, wherein the relative-permeability modifier modifies the interval to have a more uniform effective permeability to water-based fluids, wherein the relative-permeability modifier comprises a water-soluble polymer, and wherein the more uniform effective permeability of the interval allows for a more uniform treatment of the interval by the sealant composition than would be allowed without treatment of the interval with the relative-permeability modifier.   
   
   
       2 . The method of  claim 1 ,
 wherein the interval comprises a first portion and a second portion;   wherein, prior to contacting the interval with the relative-permeability modifier, the first portion has a first water permeability and the second portion has a second water permeability; and   wherein, after contacting the interval with the relative-permeability modifier, the first portion and the second portion have about the same permeability.   
   
   
       3 . The method of  claim 1 , wherein, after contacting the interval with the relative-permeability modifier, the effective permeability of the interval to water varies by up to about 40%. 
   
   
       4 . The method of  claim 1 , wherein the water-soluble polymer comprises a polymer containing a backbone, the backbone comprising polar heteroatoms. 
   
   
       5 . The method of  claim 1 , wherein the water-soluble polymer comprises a polymer that has been hydrophobically modified with an alkyl group with 4 carbons to 22 carbons present on an amino group in quaternized form. 
   
   
       6 . The method of  claim 5 , wherein the alkyl group has from 12 carbons to 18 carbons. 
   
   
       7 . The method of  claim 5 , wherein the amino group comprises a dialkyl amino pendant group. 
   
   
       8 . The method of  claim 5 , wherein the amino group comprises a dimethyl amino pendant group. 
   
   
       9 . The method of  claim 1 , wherein the water-soluble polymer comprises a polydimethylaminoethylmethacrylate or polydimethylaminopropylmethacrylamide, wherein either the polydimethylaminoethylmethacrylate or polydimethylaminopropylmethacrylamide has been hydrophobically modified with an alkyl group with 4 carbons to 22 carbons on a dimethylamino group present therein. 
   
   
       10 . The method of  claim 1 , wherein the water-soluble polymer comprises an amino methacrylate/alkyl amino methacrylate copolymer. 
   
   
       11 . The method of  claim 1 , wherein the water-soluble polymer comprises a hydrophobically modified polymer, the hydrophobically modified polymer comprises a polymer backbone and a hydrophobic branch, the hydrophobic branch comprising an alkyl chain of from about 4 to about 22 carbons. 
   
   
       12 . The method of  claim 1 , wherein the water-soluble polymer comprises a hydrophobically modified polymer. 
   
   
       13 . The method of  claim 1 , wherein the water-soluble polymer comprises a hydrophilically modified polymer. 
   
   
       14 . The method of  claim 1 , wherein the sealant composition comprises a gelable aqueous silicate composition, wherein the gelable aqueous silicate composition comprises water, an alkali metal silicate solution, and a catalyst. 
   
   
       15 . The method of  claim 1 , wherein the sealant composition comprises a crosslinkable aqueous polymer composition, wherein the crosslinkable aqueous polymer composition comprises water, a crosslinkable polymer, and a crosslinking agent. 
   
   
       16 . The method of  claim 1 , wherein the sealant composition comprises a polymerizable organic monomer composition, wherein the polymerizable organic monomer composition comprises water, a water-soluble polymerizable organic monomer, an oxygen scavenger, and a primary initiator. 
   
   
       17 . The method of  claim 1 , wherein the sealant composition comprises a resin. 
   
   
       18 . The method of  claim 1 , comprising shutting in a well bore penetrating the subterranean formation, after the step of introducing the sealant composition into the interval. 
   
   
       19 . The method of  claim 1 , wherein an elbow or a junction of a multi-lateral well bore is present in the interval. 
   
   
       20 . The method of  claim 1 , wherein the interval comprises a water-producing interval of the subterranean formation. 
   
   
       21 . (canceled) 
   
   
       22 . A method of treating an interval of a subterranean formation having a permeability that varies, the method comprising:
 identifying the interval to be treated;   introducing a relative-permeability modifier into the interval, wherein the relative-permeability modifier modifies the interval to have a more uniform effective permeability to water-based fluids, wherein the relative-permeability modifier is water soluble and comprises a polymer that has been hydrophobically modified with an alkyl group with 4 carbons to 22 carbons present on an amino group in quaternized form;   monitoring the pressure of the interval;   adjusting the introducing of the relative permeability modifier into the interval based at least partially on the monitored pressure so that the interval retains a water permeability sufficient to allow injection of water at a rate of about ¼ barrel per minute at a differential pressure no more than 90% of a fracture gradient of the interval; and   introducing an aqueous-based sealant into the interval, wherein the more uniform effective permeability of the interval allows for a more uniform treatment of the interval by the aqueous-based sealant than would be allowed without treatment of the interval with the relative-permeability modifier.   
   
   
       23 . The method of  claim 22 , wherein the alkyl group has from 12 carbons to 18 carbons. 
   
   
       24 . The method of  claim 22 , wherein the amino group comprises a dialkyl amino pendant group. 
   
   
       25 . The method of  claim 22 , wherein the polymer that has been hydrophobically modified present in the relative permeability modified comprises a polydimethylaminoethylmethacrylate or polydimethylaminopropylmethacrylamide.