Method for improving the clean-up of emulsified acid fluid systems

A complex emulsion comprising:

• from about 10 to about 90 vol%, based on total volume, of an oil external phase selected from the group consisting of xylene, diesel, toluene, kerosene, other aromatics, refined hydrocarbons and mixtures there of,
• from about 90 to about 10 vol%, based on the total volume, of an internal aqueous acid phase containing a microemulsion internal to the aqueous acid phase, where the acid is selected from the group of acids consisting of hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, fluoroboric acid, formic acid, acetic acid, glycolic acid, dicarboxylic acid, tricarboxylic acids, aminocarboxylic acids and mixtures thereof, and
• from about 0.1 to about 40 vol%, based on total volume, an emulsifier in the hydrocarbon phase, where the emulsifier is selected from the group consisting of polysorbates, carboxylate amines, fatty acids, ethoxylated fatty acids, propoxylated fatty acids, fatty acid salts, tall oils, castor oils, triglycerides, glucosides and mixtures thereof.

A method for making a complex emulsion comprising:

• mixing an acid aqueous phase with an oil external microemulsion to give an initial product, where the acid aqueous phase is an external phase and the microemulsion is an internal phase;
• and
• mixing the initial product with a second oil containing an emulsifier to make the complex emulsion.