Multi-Stage Methods and Compositions for Desensitizing Subterranean Formations Faces

Abstract

A method of desensitizing a subterranean formation may include introducing a leading-edge fluid comprising a first base fluid and a first desensitizing agent into at least a portion of the subterranean formation, wherein the first desensitizing agent is present in the first base fluid at a first concentration; and then introducing a treatment fluid comprising a second base fluid and a second desensitizing agent into at least a portion of the subterranean formation, wherein the second desensitizing agent is present in the second base fluid at a second concentration, and wherein the first concentration is higher than the second concentration.

1 . A method of desensitizing a subterranean formation, the method comprising:
 providing a wellbore penetrating a subterranean formation;   introducing a leading-edge fluid comprising a first base fluid and a first desensitizing agent into at least a portion of the subterranean formation, wherein the first desensitizing agent is present in the first base fluid at a first concentration; and   then introducing a treatment fluid comprising a second base fluid and a second desensitizing agent into at least a portion of the subterranean formation, wherein the second desensitizing agent is present in the second base fluid at a second concentration, and wherein the first concentration is higher than the second concentration.   
     
     
         2 . The method of  claim 1 , wherein the first concentration ranges from about 0.01% to about 60% v/v of the first desensitizing agent to the first base fluid. 
     
     
         3 . The method of  claim 1 , wherein the first concentration changes over time in a manner selected from the group consisting of a gradient change, a step-wise change, and any combination thereof. 
     
     
         4 . The method of  claim 1 , wherein the first concentration is about 2 to about 5000 times greater than the second concentration. 
     
     
         5 . The method of  claim 1 , wherein the second concentration ranges from about 0.0001% to about 20% v/v of the second desensitizing agent to the second base fluid. 
     
     
         6 . The method of  claim 1 , wherein the second concentration changes over time in a manner selected from the group consisting of a gradient change, a step-wise change, and any combination thereof. 
     
     
         7 . The method of  claim 1  further comprising:
 introducing a transition fluid comprising a third base fluid and a third desensitizing solution that comprises a third desensitizing agent between the introduction of the leading-edge fluid and the treatment fluid, wherein the third desensitizing agent is present in the third base fluid at a third concentration. 
 
     
     
         8 . The method of  claim 7 , wherein the third concentration changes over time in a manner selected from the group consisting of a gradient change, a step-wise change, and any combination thereof. 
     
     
         9 . The method of  claim 1 , wherein the first desensitizing agent comprises at least one selected from the group consisting of: an inorganic acid, a salt, a polyelectrolyte, a multivalent ion, an inorganic base, a strong base, an oxide, a resin, a surfactant, a cationic polymer, a methyl glucoside, a polyglycerol, a polyglycol, an emulsion facilitating particle, a chelating agent, a phosphine, a soluble organic stabilizing compound, a silica control agent, an embrittlement modification agent, a surface modification agent, a microparticle, a nanoparticle, and any combination thereof. 
     
     
         10 . The method of  claim 1 , wherein the second desensitizing agent comprises at least one selected from the group consisting of: an inorganic acid, a salt, a polyelectrolyte, a multivalent ion, an inorganic base, a strong base, an oxide, a resin, a surfactant, a cationic polymer, a methyl glucoside, a polyglycerol, a polyglycol, an emulsion facilitating particle, a chelating agent, a phosphine, a soluble organic stabilizing compound, a silica control agent, an embrittlement modification agent, a surface modification agent, a microparticle, a nanoparticle, and any combination thereof. 
     
     
         11 . The method of  claim 1 , wherein the first desensitizing agent and the second desensitizing agent are different compositions. 
     
     
         12 . The method of  claim 1 , wherein the leading-edge fluid and treatment fluid contain a same desensitizing agent such that the same desensitizing agent is from about 0.01% to about 60% v/v in the leading-edge fluid and the same desensitizing agent is from about 0.0001% to about 20% v/v in the treatment fluid. 
     
     
         13 . The method of  claim 1 , wherein introducing the leading-edge fluid is performed at a fracture pressure. 
     
     
         14 . The method of  claim 1 , wherein the leading-edge fluid further comprises a proppant. 
     
     
         15 . The method of  claim 1 , wherein introducing the treatment fluid is performed at a fracture pressure. 
     
     
         16 . The method of  claim 1 , wherein the treatment fluid further comprises a proppant. 
     
     
         17 . A method of remedially desensitizing a subterranean formation, the method comprising:
 providing a wellbore penetrating a subterranean formation that comprises a plurality of formation faces, the formation faces having undergone deleterious chemical and/or physical changes;   introducing a leading-edge fluid comprising a first base fluid and a first desensitizing agent into at least a portion of the subterranean formation, wherein the first desensitizing agent is present in the first base fluid at a first concentration; and   then introducing a treatment fluid comprising a second base fluid and a second desensitizing agent into at least a portion of the subterranean formation, wherein the second desensitizing agent is present in the second base fluid at a second concentration, and wherein the first concentration is higher than the second concentration.   
     
     
         18 . A method of desensitizing a subterranean formation, the method comprising:
 providing a wellbore penetrating a subterranean formation;   introducing a leading-edge fluid comprising a first base fluid and a first desensitizing agent into a first portion of the subterranean formation, wherein the first desensitizing agent is present in the first base fluid at a first concentration;   then introducing a treatment fluid comprising a second base fluid and a second desensitizing agent into the first portion of the subterranean formation, wherein the second desensitizing agent is present in the second base fluid at a second concentration, and wherein the first concentration is higher than the second concentration;   then diverting fluid flow from the first portion of the subterranean formation to a second portion of the subterranean formation;   then introducing a second leading-edge fluid comprising a third base fluid and a third desensitizing agent into the second portion of the subterranean formation, wherein the third desensitizing agent is present in the third base fluid at a third concentration; and   then second introducing a treatment fluid comprising a fourth base fluid and a fourth desensitizing agent into the second portion of the subterranean formation, wherein the fourth desensitizing agent is present in the fourth base fluid at a second concentration, and wherein the third concentration is higher than the fourth concentration.   
     
     
         19 . The method of  claim 18 , wherein diverting the fluid flow involves at least one selected from the group consisting of: a plugging agent, a plug, a packer, a bridge plug, a frac plug, plugging agent, a perf ball, a gel, a plugging foam, a diverting agent, a degradable diverting agent, and any combination thereof.