Permeability-Modifying Drilling Fluids and Methods of Use

Abstract

Drilling fluids comprising a base fluid and a hydrophobically modified polymer. The hydrophobically modified polymer consisting of alkyl chains having a carbon chain length between about 4 and about 22 carbons bound to a hydrophilic polymer. The hydrophilic polymer (1) consists of a polymer backbone that contains polar heteroatoms, at least one of which is not a nitrogen atom, and at least a portion of the polar heteroatoms are functionalized with the alkyl chains; and, (2) comprises at least one hydrophilic polymer selected from the group consisting of a cellulose, a chitosan, a polyetheramine, a polyhydroxyetheramine, a polylysine, and a polysulfone.

1 .- 68 . (canceled) 
     
     
         69 . A drilling fluid for use in a well bore in a subterranean formation comprising:
 a base fluid and a hydrophobically modified polymer,
 the hydrophobically modified polymer consisting of alkyl chains having a carbon chain length between about 4 and about 22 carbons bound to a hydrophilic polymer, wherein the hydrophilic polymer:
 consists of a polymer backbone that contains polar heteroatoms, at least one of which is not a nitrogen atom, and at least a portion of the polar heteroatoms are functionalized with the alkyl chains; and, 
 comprises at least one hydrophilic polymer selected from the group consisting of a cellulose, a chitosan, a polyetheramine, a polyhydroxyetheramine, a polylysine, and a polysulfone. 
 
   
     
     
         70 . The drilling fluid of  claim 69  wherein the hydrophobically modified polymer has a molecular weight in the range of from about 100,000 to about 10,000,000. 
     
     
         71 . The drilling fluid of  claim 69  wherein the polar heteroatoms comprise at least one polar heteroatom selected from the group consisting of oxygen, nitrogen, sulfur, and phosphorous. 
     
     
         72 . The drilling fluid of  claim 69  wherein the hydrophobic compound is selected from the group consisting of an alkyl halide, a sulfonate, an organic acid derivative, and a combination thereof. 
     
     
         73 . The drilling fluid of  claim 69  wherein the hydrophobic compound is an organic acid derivative selected from the group consisting of an octenyl succinic acid; a dodecenyl succinic acid; an anhydride; an ester; an amide of octenyl succinic acid; an amide of dodecenyl succinic acid; and combinations thereof. 
     
     
         74 . The drilling fluid of  claim 69  wherein the water-soluble relative permeability modifier is present in the drilling fluid in an amount in the range of from about 0.02% to about 10% by weight of the drilling fluid. 
     
     
         75 . The drilling fluid of  claim 69  wherein the water-soluble relative permeability modifier is present in the drilling fluid in an amount in the range of from about 0.05% to about 1% by weight of the drilling fluid. 
     
     
         76 . A drilling fluid for use in a well bore in a subterranean formation comprising:
 a base fluid and a hydrophobically modified polymer,
 the hydrophobic compound consisting of an alkyl halide having a carbon chain length between about 4 and about 22 carbons, and 
 the hydrophilic polymer:
 consists of a polymer backbone that contains polar heteroatoms, at least one of which is not a nitrogen atom, and at least a portion of the polar heteroatoms are functionalized with the alkyl chains; and, 
 comprises at least one hydrophilic polymer selected from the group consisting of a cellulose, a chitosan, a polyetheramine, a polyhydroxyetheramine, a polylysine, and a polysulfone. 
 
   
     
     
         77 . The drilling fluid of  claim 76  wherein the hydrophobically modified polymer has a molecular weight in the range of from about 100,000 to about 10,000,000. 
     
     
         78 . The drilling fluid of  claim 76  wherein the polar heteroatoms comprise at least one polar heteroatom selected from the group consisting of oxygen, nitrogen, sulfur, and phosphorous. 
     
     
         79 . The drilling fluid of  claim 76  wherein the water-soluble relative permeability modifier is present in the drilling fluid in an amount in the range of from about 0.02% to about 10% by weight of the drilling fluid. 
     
     
         80 . The drilling fluid of  claim 76  wherein the water-soluble relative permeability modifier is present in the drilling fluid in an amount in the range of from about 0.05% to about 1% by weight of the drilling fluid.