Self-breaking retarded acid emulsion
AssigneeThe Dow Chemical Company
InventorGary A. Scherubel
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Abstract
A subterranean formation is acidized with an emulsion comprising an aqueous acidizing solution, an oil, an effective amount each of an alkyl C.sub.8 to C.sub.18 primary fatty amine and at least one diethanolamide of at least one C.sub.8 to C.sub.18 fatty acid.
Claims41
In a method of acidizing an acid-soluble subterranean formation by contacting said formation with a retarded aqueous acid solution-in-oil emulsion, said emulsion including an effective retarding amount of at least one alkyl C.sub.8 to C.sub.18 primary amine, the improvement which comprises:
- including in said emulsion, an effective amount of at least one diethanolamide of at least one C.sub.8 to C.sub.18 fatty acid so that said emulsion breaks upon the substantial depletion of the acidizing capacity of the emulsion after contact with the formation.
A method for stimulating the production of fluids from a subterranean formation, at least part of which is soluble in acid at the temperature of the formation, which comprises contacting said formation with a retarded acidizing emulsion comprising an aqueous acidizing solution dispersed in oil, said emulsion containing by weight of said emulsion, from about 0.01 to about 10 percent a primary C.sub.8 to C.sub.18 alkyl amine and from about 0.85 to about 2 parts of at least one diethanolamide of at least one C.sub.8 to C.sub.18 fatty acid, per part by weight of said primary amine.
In a composition for acidizing a subterranean formation, said composition being of the aqueous acidizing solution-in-oil emulsion type containing an effective amount of an alkyl C.sub.8 to C.sub.18 primary amine to reduce the normal reaction rate of said emulsion, the improvement which comprises:
- in said emulsion, an effective amount of at least one diethanolamide of at least one C.sub.8 to C.sub.18 fatty acid so that said emulsion substantially completely breaks when the acidizing capacity of the emulsion becomes substantially spent as a result of reaction with such a formation.
A retarded acidizing emulsion suitable for use in methods for increasing the permeability of at least partially acid soluble subterranean formations, comprising:
- an aqueous acidizing solution dispersed in oil, said emulsion containing by weight of said emulsion, from about 0.01 to about 10 percent a primary C.sub.8 to C.sub.18 alkyl amine and from about 0.85 to about 2 parts of at least one diethanolamide of at least one C.sub.8 to C.sub.18 fatty acid, per part by weight of said primary amine.
Dependencies are inferred from the claim text.