Method for improving the clean-up of emulsified acid fluid systems
First Claim
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1. A complex emulsion comprising:
- from about 10 to about 90 vol%, based on total volume, of an oil external phase,from about 90 to about 10 vol%, based on the total volume, of an internal aqueous acid phase containing a microemulsion, andfrom about 0.1 to about 40 vol%, based on total volume, of an emulsifier in the hydrocarbon phase.
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Abstract
Using a complex emulsion for treating a subterranean formation, such as to dissolve minerals therein (e.g. carbonates, scales, and/or filter cake) to improve permeability, substantially improves post treatment fluid clean-up for improved hydrocarbon production. The complex emulsion is made by 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. Then the initial product is mixed with a second oil (e.g. xylene, diesel, toluene, kerosene, other aromatics, refined hydrocarbons and the like) containing an emulsifier to make a complex emulsion.
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Citations
21 Claims
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1. A complex emulsion comprising:
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from about 10 to about 90 vol%, based on total volume, of an oil external phase, from about 90 to about 10 vol%, based on the total volume, of an internal aqueous acid phase containing a microemulsion, and from about 0.1 to about 40 vol%, based on total volume, of an emulsifier in the hydrocarbon phase. - View Dependent Claims (2, 3, 4, 5)
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6. A complex emulsion comprising:
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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.
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7. A method for making a complex emulsion comprising:
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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. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A method of treating a subterranean formation comprising:
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injecting a complex emulsion into a subterranean formation, where the complex emulsion has been made by 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; and wherein the complex emulsion comprises;
from about 10 to about 90 vol%, based on total volume, of an oil external phase, the oil external phase originating from the second oil, from about 90 to about 10 vol%, based on the total volume, of an internal aqueous acid phase containing a microemulsion, and from about 0.1 to about 40 vol%, based on total volume, of an emulsifier in the hydrocarbon phase;dissolving at least a portion of the formation with the acid. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification