Viscoelastic surfactant fluids and related methods of use

Abstract

Viscoelastic surfactant based aqueous fluid systems useful as thickening agents in various applications, e.g. to suspend particles produced during the excavation of geologic formations. The surfactants are zwitterionic/amphoteric surfactants such as dihydroxyl alkyl glycinate, alkyl ampho acetate or propionate, alkyl betaine, alkyl amidopropyl betaine and alkylimino mono- or di-propionates derived from certain waxes, fats and oils. The thickening agent is used in conjunction with an inorganic water-soluble salt or organic additive such as phthalic acid, salicylic acid or their salts.

What is claimed is:  
     
         1 . A viscoelastic fluid comprising: 
 (1) an aqueous medium;    (2) a zwitterionic surfactant; and    (3) a member selected from the group consisting of organic acids, organic acid salts, inorganic salts, and combinations of one or more organic acids or organic acid salts with one or more inorganic salts;    wherein the zwitterionic surfactant constitutes 77% or more by weight of all surfactants present in the fluid;    wherein the fluid exhibits the property of viscoelasticity.    
     
     
         2 . The fluid as claimed in  claim 1  wherein the amount of the zwitterionic surfactant is present at about 0.5% to about 10% by weight of the fluid.  
     
     
         3 . The fluid as claimed in  claim 1  wherein the amount of the zwitterionic surfactant is present at about 0.5% to about 8% by weight of the fluid.  
     
     
         4 . The fluid as claimed in  claim 1  wherein the amount of the zwitterionic surfactant is present at about 0.5% to about 6% by weight of the fluid.  
     
     
         5 . The fluid of  claim 1  wherein the zwitterionic surfactant constitutes 89% or more by weight of all surfactants present in the fluid.  
     
     
         6 . The fluid of  claim 1  wherein the zwitterionic surfactant constitutes 92% or more by weight of all surfactants present in the fluid.  
     
     
         7 . The fluid of  claim 1  further comprising an anionic surfactant, the anionic surfactant being present at 1.2% or less by weight of the fluid.  
     
     
         8 . The fluid of  claim 7  wherein the anionic surfactant is present at 0.9% or less by weight of the fluid.  
     
     
         9 . The fluid of  claim 7  wherein the anionic surfactant is present at about 0.5% or less by weight of the fluid.  
     
     
         10 . The fluid as claimed in  claim 1  wherein the zwitterionic surfactant has a quaternary ammonium hydrophilic moiety.  
     
     
         11 . The fluid as claimed in  claim 1  wherein the surfactant has a carboxylate hydrophilic moiety.  
     
     
         12 . The fluid as claimed in  claim 1  wherein the member is an inorganic salt and is present at about 0.1% to about 30% by weight.  
     
     
         13 . The fluid as claimed in  claim 1  wherein the member is an organic acid or salt thereof and is present at about 0.1% to about 10% by weight.  
     
     
         14 . The fluid as in  claim 1  wherein the surfactant is represented by the formula (I):  
       
         
           
           
               
               
           
         
       
       wherein R 1  represents alkyl, alkenyl, alkylarylalkylene, alkenylarylalkylene, alkylaminoalkylene, alkenylaminoalkylene, alkylamidoalkylene, or alkenylamidoalkylene, wherein each of the alkyl groups have from about 14 to about 24 carbon atoms and may be branched or straight chained and saturated or unsaturated, and wherein the alkylene groups have from about 1 to about 6 carbon atoms, 
 R 2  and R 3  are independently aliphatic chains having from about 1 to about 30 carbon atoms, and  
 R 4  is a hydrocarbyl radical with a chain length of about 1 to about 4.  
 
     
     
         15 . The fluid of  claim 14  wherein R 1  is selected from the group consisting of tetradecyl, hexadecyl, octadecenyl, and octadecyl.  
     
     
         16 . The fluid of  claim 15  wherein R 1  is an alkyl group derived from tallow, coco, soya bean, or rapeseed oil.  
     
     
         17 . The fluid of  claim 14  wherein the alkyl and alkenyl groups of R 1  are selected from alkyl groups and alkenyl groups respectively having from about 16 to about 22 carbon atoms.  
     
     
         18 . The fluid of  claim 14  wherein R 2  and R 3  are independently alkyl, alkenyl, arylalkyl, hydroxyalkyl, carboxyalkyl, or hydroxyalkylpolyoxyalkylene, each having about 1 to about 10 carbon atoms.  
     
     
         19 . The fluid of  claim 14  wherein R 2  and R 3  are independently methyl, ethyl, benzyl, hydroxyethyl, hydroxypropyl, carboxymethyl, or carboxyethyl.  
     
     
         20 . The fluid of  claim 14  wherein R 4  is methylene or ethylene.  
     
     
         21 . The fluid of  claim 14  wherein R 2  and R 3  are each beta-hydroxyethyl.  
     
     
         22 . The fluid of  claim 21  wherein R 1  is RCONHCH 2 CH 2 CH 2 — wherein R is an alkyl group having from about 14 to about 24 carbon atoms which may be branched or straight chained and which may be saturated or unsaturated.  
     
     
         23 . The fluid of  claim 14  wherein R 2  and R 3  are each methyl.  
     
     
         24 . The fluid of  claim 23  wherein R 1  is RCONHCH 2 CH 2 CH 2 — wherein R is an alkyl group having from about 14 to about 24 carbon atoms which may be branched or straight chained and which may be saturated or unsaturated.  
     
     
         25 . The fluid of  claim 14  wherein the zwitterionic surfactant is selected from the group consisting of dihydroxyethyl glycinates and alkylamidopropyl betaines.  
     
     
         26 . The fluid of  claim 25  wherein the zwitterionic surfactant is oleamidopropyl betaine.  
     
     
         27 . The fluid of  claim 14  wherein the zwitterionic surfactant is present at from about 0.5% to about 6% by weight in the fluid.  
     
     
         28 . The fluid of  claim 27  further comprising an anionic surfactant, the anionic surfactant being present at 1.2% or less by weight of the fluid.  
     
     
         29 . The fluid of  claim 28  wherein the anionic surfactant is present at 0.9% or less by weight of the fluid, the zwitterionic surfactant being present at 89% or more by weight of the fluid.  
     
     
         30 . The fluid of  claim 25  wherein the zwitterionic surfactant is present at from about 0.5% to about 6% by weight in the fluid, the fluid further comprising an anionic surfactant, the anionic surfactant being present at 1.2% or less by weight of the fluid.  
     
     
         31 . A viscoelastic fluid comprising: 
 (1) an aqueous medium;    (2) a zwitterionic surfactant; and    (3) a member selected from the group consisting of organic acids, organic acid salts, inorganic salts, and combinations of one or more organic acids or organic acid salts with one or more inorganic salts;    (4) an anionic surfactant, wherein the ratio of zwitterionic surfactant to anionic surfactant is 3 ⅓ to 1 or greater;    wherein the fluid exhibits the property of viscoelasticity.    
     
     
         32 . The fluid as claimed in  claim 31  wherein the amount of the zwitterionic surfactant is from about 0.5% to about 10% by weight of the fluid.  
     
     
         33 . The fluid as claimed in  claim 31  wherein the amount of the zwitterionic surfactant is from about 0.5% to about 8% by weight of the fluid.  
     
     
         34 . The fluid as claimed in  claim 31  wherein the amount of the zwitterionic surfactant is from about 0.5% to about 6% by weight of the fluid.  
     
     
         35 . The fluid of  claim 31  wherein the ratio of zwitterionic surfactant to anionic surfactant is greater than 5 to 1.  
     
     
         36 . The fluid of  claim 31  wherein the ratio of zwitterionic surfactant to anionic surfactant is 8 to 1 or greater.  
     
     
         37 . The fluid of  claim 31  wherein the ratio of zwitterionic surfactant to anionic surfactant is 12 to 1 or greater.  
     
     
         38 . The fluid as claimed in  claim 31  wherein the zwitterionic surfactant has a quaternary ammonium hydrophilic moiety.  
     
     
         39 . The fluid as claimed in  claim 31  wherein the surfactant has a carboxylate hydrophilic moiety.  
     
     
         40 . The fluid as claimed in  claim 31  wherein the member is an inorganic salt and is present in an amount of from about 0.1% to about 30% by weight.  
     
     
         41 . The fluid as claimed in  claim 31  wherein the member is an organic acid or salt thereof and is present in an amount of from about 0.1% to about 10% by weight.  
     
     
         42 . The fluid as in  claim 31  wherein the surfactant is represented by the formula (I):  
       
         
           
           
               
               
           
         
       
       wherein R 1  represents alkyl, alkenyl, alkylarylalkylene, alkenylarylalkylene, alkylaminoalkylene, alkenylaminoalkylene, alkylamidoalkylene, or alkenylamidoalkylene, wherein each of the alkyl groups have from about 14 to about 24 carbon atoms and may be branched or straight chained and saturated or unsaturated, and wherein the alkylene groups have from about 1 to about 6 carbon atoms, 
 R 2  and R 3  are independently aliphatic chains having from about 1 to about 30 carbon atoms, and  
 R 4  is a hydrocarbyl radical with a chain length of about 1 to about 4.  
 
     
     
         43 . The fluid of  claim 42  wherein R 1  is selected from the group consisting of tetradecyl, hexadecyl, octadecenyl, and octadecyl.  
     
     
         44 . The fluid of  claim 42  wherein R 1  is an alkyl group derived from tallow, coco, soya bean, or rapeseed oil.  
     
     
         45 . The fluid of  claim 42  wherein the alkyl and alkenyl groups of R 1  are selected from alkyl groups and 
 alkenyl groups respectively having from about 16 to about 22 carbon atoms.  
 
     
     
         46 . The fluid of  claim 42  wherein R 2  and R 3  are independently alkyl, alkenyl, arylalkyl, hydroxyalkyl, carboxyalkyl, or hydroxyalkylpolyoxyalkylene, each having about 1 to about 10 carbon atoms.  
     
     
         47 . The fluid of  claim 42  wherein R 2  and R 3  are independently methyl, ethyl, benzyl, hydroxyethyl, hydroxypropyl, carboxymethyl, or carboxyethyl.  
     
     
         48 . The fluid of  claim 42  wherein R 4  is methylene or ethylene  
     
     
         49 . The fluid of  claim 42  wherein R 2  and R 3  are each beta-hydroxyethyl.  
     
     
         50 . The fluid of  claim 49  wherein R 1  is RCONHCH 2 CH 2 CH 2 — wherein R is an alkyl group having from about 14 to about 24 carbon atoms which may be branched or straight chained and which may be saturated or unsaturated.  
     
     
         51 . The fluid of  claim 42  wherein R 2  and R 3  are each methyl.  
     
     
         52 . The fluid of  claim 51  wherein R 1  is RCONHCH 2 CH 2 CH 2 — wherein R is an alkyl group having from about 14 to about 24 carbon atoms which may be branched or straight chained and which may be saturated or unsaturated.  
     
     
         53 . The fluid of  claim 42  wherein the zwitterionic surfactant is selected from the group consisting of dihydroxyethyl glycinates and alkylamidopropyl betaines.  
     
     
         54 . The fluid of  claim 53  wherein the zwitterionic surfactant is oleamidopropyl betaine.  
     
     
         55 . The fluid of  claim 42  wherein the zwitterionic surfactant is present at about 0.5% to about 6.0% by weight of the fluid.  
     
     
         56 . The fluid of  claim 55  wherein the ratio of zwitterionic surfactant to anionic surfactant is greater than 5 to 1.  
     
     
         57 . The fluid of  claim 56  wherein the anionic surfactant is present at 1.2% or less by weight of the fluid.  
     
     
         58 . The fluid of  claim 57  wherein the anionic surfactant is present at 0.9% or less by weight of the fluid.  
     
     
         59 . The fluid of  claim 53  wherein the zwitterionic surfactant is present at about 0.5% to about 6.0% by weight of the fluid.  
     
     
         60 . The fluid of  claim 59  wherein the ratio of zwitterionic surfactant to anionic surfactant is greater than 5 to 1.  
     
     
         61 . The fluid of  claim 60  wherein the anionic surfactant is present at 1.2% or less by weight of the fluid.  
     
     
         62 . The fluid of  claim 61  wherein the anionic surfactant is present at 0.9% or less by weight of the fluid.  
     
     
         63 . A viscoelastic fluid comprising: 
 (1) an aqueous medium;    (2) a zwitterionic surfactant; and    (3) a member selected from the group consisting of organic acids, organic acid salts, inorganic salts, and combinations of one or more organic acids or organic acid salts with one or more inorganic salts; and    (4) an anionic surfactant, wherein the anionic surfactant is present at 1.2% or less by weight of the fluid;    wherein the fluid exhibits the property of viscoelasticity.    
     
     
         64 . The fluid as claimed in  claim 63  wherein the amount of the zwitterionic surfactant is from about 0.5% to about 10% by weight of the fluid.  
     
     
         65 . The fluid as claimed in  claim 63  wherein the amount of the zwitterionic surfactant is from about 0.5% to about 8% by weight of the fluid.  
     
     
         66 . The fluid as claimed in  claim 63  wherein the amount of the zwitterionic surfactant is from about 0.5% to about 6% by weight of the fluid.  
     
     
         67 . The fluid of  claim 63  wherein the anionic surfactant is present at 0.9% or less by weight of the fluid.  
     
     
         68 . The fluid of  claim 63  wherein the anionic surfactant is present at about 0.5% or less by weight of the fluid.  
     
     
         69 . The fluid as claimed in  claim 63  wherein the zwitterionic surfactant has a quaternary ammonium hydrophilic moiety.  
     
     
         70 . The fluid as claimed in  claim 63  wherein the surfactant has a carboxylate hydrophilic moiety.  
     
     
         71 . The fluid as claimed in  claim 63  wherein the member is an inorganic salt and is present in an amount of from about 0.1% to about 30% by weight.  
     
     
         72 . The fluid as claimed in  claim 63  wherein the member is an organic acid or salt thereof and is present in an amount of from about 0.1% to about 10% by weight.  
     
     
         73 . The fluid as in  claim 63  wherein the surfactant is represented by the formula (I)  
       
         
           
           
               
               
           
         
       
       wherein R 1  represents alkyl, alkenyl, alkylarylalkylene, alkenylarylalkylene, alkylaminoalkylene, alkenylaminoalkylene, alkylamidoalkylene, or alkenylamidoalkylene, wherein each of the alkyl groups have from about 14 to about 24 carbon atoms and may be branched or straight chained and saturated or unsaturated, and wherein the alkylene groups have from about 1 to about 6 carbon atoms, 
 R 2  and R 3  are independently aliphatic chains having from about 1 to about 30 carbon atoms, and  
 R 4  is a hydrocarbyl radical with a chain length of about 1 to about 4.  
 
     
     
         74 . The fluid of  claim 73  wherein R 1  is selected from the group consisting of tetradecyl, hexadecyl, octadecenyl, and octadecyl.  
     
     
         75 . The fluid of  claim 73  wherein R 1  is an alkyl group derived from tallow, coco, soya bean, or rapeseed oil.  
     
     
         76 . The fluid of  claim 73  wherein the alkyl and alkenyl groups of R 1  are selected from alkyl groups and alkenyl groups respectively having from about 16 to about 22 carbon atoms.  
     
     
         77 . The fluid of  claim 73  wherein R 2  and. R 3  are independently alkyl, alkenyl, arylalkyl, hydroxyalkyl, carboxyalkyl, or hydroxyalkylpolyoxyalkylene, each having about 1 to about 10 carbon atoms.  
     
     
         78 . The fluid of  claim 73  wherein R 2  and R 3  are independently methyl, ethyl, benzyl, hydroxyethyl, hydroxypropyl, carboxymethyl, or carboxyethyl.  
     
     
         79 . The fluid of  claim 73  wherein R 4  is methylene or ethylene.  
     
     
         80 . The fluid of  claim 73  wherein R 2  and R 3  are each beta-hydroxyethyl.  
     
     
         81 . The fluid of  claim 80  wherein R 1  is RCONHCH 2 CH 2 CH 2 — wherein R is an alkyl group having from about 14 to about 24 carbon atoms which may be branched or straight chained and which may be saturated or unsaturated.  
     
     
         82 . The fluid of  claim 81  wherein R 2  and R 3  are each methyl.  
     
     
         83 . The fluid of  claim 82  wherein R 1  is RCQNHCH 2 CH 2 CH 2 — wherein R is an alkyl group having from about 14 to about 24 carbon atom which may be branched or straight chained and which may be saturated or unsaturated.  
     
     
         84 . The fluid of  claim 63  wherein the zwitterionic surfactant is selected from the group consisting of dihydroxyethyl glycinates and alkylamidopropyl betaines.  
     
     
         85 . The fluid of  claim 84  wherein the zwitterionic surfactant is oleamidopropyl betaine.  
     
     
         86 . The fluid of  claim 73  wherein the amount of zwitterionic surfactant is from about 0.5% to about 6% by weight of the fluid.  
     
     
         87 . The fluid of  claim 73  wherein the anionic surfactant is present at 0.9% or less by weight of the fluid.  
     
     
         88 . The fluid of  claim 84  wherein the amount of zwitterionic surfactant is from about 0.5% to about 6% by weight of the fluid.  
     
     
         89 . The fluid of  claim 85  wherein the anionic surfactant is present at 0.9% or less by weight of the fluid.  
     
     
         90 . A viscoelastic fluid comprising: 
 (1) an aqueous medium;    (2) an amphoteric surfactant; and    (3) a member selected from the group consisting of organic acids, organic acid salts, inorganic salts, and combinations of one or more organic acids or organic acid salts with one or more inorganic salts;    wherein the fluid exhibits the property of viscoelasticity.    
     
     
         91 . The fluid as claimed in  claim 90  wherein the amount of the surfactant is from about 0.5% to about 10% by weight of the fluid.  
     
     
         92 . The fluid as claimed in  claim 90  wherein the member is an inorganic salt and is present in an amount of from about 0.1% to about 30% by weight.  
     
     
         93 . The fluid as claimed in  claim 90  wherein the member is an organic acid or salt thereof and is present in an amount of from about 0.1% to about 10% by weight.  
     
     
         94 . The fluid of  claim 90  wherein the surfactant is represented by formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  represents alkyl, alkenyl, alkylarylalkylene, alkenylarylalkylene, alkylaminoalkylene, alkenylaminoalkylene, alkylamidoalkylene, or alkenylamidoalkylene, wherein each of the alkyl groups have from about 14 to about 24 carbon atoms and may be branched or straight chained and saturated or unsaturated, and wherein the alkylene groups have from about 1 to about 6 carbon atoms, 
 R 2  is selected from the group of alkyl, alkenyl, arylalkyl, hydroxyalkyl, carboxyalkyl, and hydroxyalkyl polyoxyalkylene, each having from about 1 to about 10 carbon atoms, and  
 R 4  is a hydrocarbyl radical with chain length of about 1 to about 4.  
 
     
     
         95 . The viscoelastic fluid of  claim 90  wherein R 1  represents alkyl having from about 16 to about 22 carbon atoms or RCONHCH 2 CR 2 CH 2 —, wherein R is an alkyl group having from about 16 to about 22 carbon atoms, wherein R 2  and R 3  are, independently, methyl, ethyl, benzyl, hydroxyethyl, hydroxypropyl, carboxymethyl, or carboxyethyl, and wherein R 4  is methylene or ethylene.  
     
     
         96 . The fluid of  claim 90  wherein the surfactant is selected from among amphoteric imidazoline-derived dipropionates.  
     
     
         97 . The fluid of  claim 90  wherein the surfactant is disodium tallowiminodipropionate.  
     
     
         98 . The fluid of  claim 90  wherein the aqueous medium is water, the fluid comprising greater than or equal to about 50% water by weight.  
     
     
         99 . The fluid of  claim 94  wherein the aqueous medium is water, the fluid comprising greater than or equal to about 50% water by weight.