Methods and compositions for stimulating the production of hydrocarbons from subterranean formations

Abstract

Emulsion or microemulsion for treating an oil or gas well having a wellbore are provided, and related methods. In some embodiments, the emulsion or microemulsion comprises an aqueous phase; a surfactant; and a non-aqueous phase comprising a first type of solvent and a second type of solvent. In some embodiments, the first type of solvent is a long chain hydrocarbon. In some embodiments, the second type of solvent is an oxygenated solvent. The emulsion or microemulsion may comprise additional components (e.g., at least one type of co-solvent).

What is claimed is: 
     
         1 . A microemulsion for treating an oil or gas well having a wellbore, comprising:
 a surfactant comprising a nonionic surfactant;   an aqueous phase; and   a non-aqueous phase comprising a first type of solvent and a second type of solvent, wherein the first type of solvent is a long chain hydrocarbon solvent, and the second type of solvent is an oxygenated solvent;   wherein the second type of solvent is present in an amount of about 1 wt % to about 15 wt % versus the total microemulsion.   
     
     
         2 . The microemulsion of  claim 1 , further comprising a terpene. 
     
     
         3 . The microemulsion of  claim 2 , wherein the terpene comprises d-limonene and/or dipentene. 
     
     
         4 . The microemulsion of  claim 1 , wherein the nonionic surfactant comprises an alcohol ethoxylate containing a hydrocarbon group of 10 to 18 carbon atoms and an ethoxylate group of 5 to 12 ethylene oxide units. 
     
     
         5 . The microemulsion of  claim 1 , wherein the surfactant comprises the nonionic surfactant and an alcohol ethoxylate. 
     
     
         6 . The microemulsion of  claim 5 , wherein the alcohol ethoxylate comprises ethoxylated tristyrylphenol. 
     
     
         7 . The microemulsion of  claim 1 , wherein the oxygenated solvent comprises a cyclic or acyclic, branched or unbranched alkane having 6 to 12 carbons and substituted with a hydroxyl group. 
     
     
         8 . The microemulsion of  claim 1 , wherein the oxygenated solvent comprises isomers of heptanol, isomers of octanol, isomers of nonanol, isomers of decanol, isomers of undecanol, and/or isomers of dodecanol. 
     
     
         9 . The microemulsion of  claim 1 , wherein the oxygenated solvent comprises octanol or an isomer thereof. 
     
     
         10 . The microemulsion of  claim 1 , wherein the oxygenated solvent comprises isooctanol. 
     
     
         11 . The microemulsion of  claim 1 , further comprising a terpene, a first co-solvent, and a second co-solvent, wherein the terpene comprises d-limonene and/or dipentene, the first co-solvent comprises isopropanol, and the second co-solvent comprises propylene glycol. 
     
     
         12 . The microemulsion of  claim 11 , wherein the oxygenated solvent comprises isooctanol and is present in an amount of about 1 wt % to about 3 wt % versus the total microemulsion. 
     
     
         13 . The microemulsion of  claim 12 , wherein:
 the surfactant comprises the nonionic surfactant and an alcohol ethoxylate;   the alcohol ethoxylate comprises ethoxylated tristyrylphenol; and   the nonionic surfactant comprises an alcohol ethoxylate containing a hydrocarbon group of 10 to 18 carbon atoms and an ethoxylate group of 5 to 12 ethylene oxide units.   
     
     
         14 . The microemulsion of  claim 1 , wherein:
 the first type of solvent is present in an amount of about 1 wt % to about 20 wt % versus the total microemulsion;   the aqueous phase is present in an amount of about 5 wt % to about 75 wt % versus the total microemulsion;   the surfactant is present in an amount of about 5 wt % to about 40 wt % versus the total microemulsion;   the microemulsion comprises from about 1 wt % and about 5 wt % of a first type of co-solvent, versus the total microemulsion;   the microemulsion comprises from about 15 wt % to about 25% of a second type of co-solvent, versus the total microemulsion.   
     
     
         15 . The microemulsion of  claim 1 , wherein the first type of solvent comprises a C 12-22  hydrocarbon compound, a plurality of C 12-22  hydrocarbon compounds, a C 12-18  alpha-olefin solvent, a plurality of C 12-18  alpha-olefin solvents, and/or a C 12-18  hydrocarbon solvent. 
     
     
         16 . The microemulsion of  claim 1 , wherein the microemulsion further comprises at least one co-solvent. 
     
     
         17 . The microemulsion of  claim 16 , wherein the at least one co-solvent comprises a C 1-6  alcohol and/or a C 1-7  alkylene glycol. 
     
     
         18 . The microemulsion of  claim 16 , wherein the at least one co-solvent comprises isopropanol and/or propylene glycol. 
     
     
         19 . The microemulsion of  claim 1 , wherein the ratio of the first type of solvent to the second type of solvent is between about 11:4 to about 1:1 or between about 5:1 to about 1:5 by weight. 
     
     
         20 . The microemulsion of  claim 1 , wherein the second type of solvent is isooctanol and is present in an amount of about 1 wt % to about 3 wt % versus the total microemulsion.