Composition and method for treating a subterranean formation

The composition of claim l in which the aqueous mixture comprises from 1 to 20 percent BF4− anion.

A composition for treating a subterranean formation consisting essentially of an aqueous acidic mixture formed by blending an aqueous liquid;

• amounts of a fluoride ion source and a boron source sufficient to provide a concentration of BF4− anion effective to increase the permeability of the formation;
• and an effective amount of an acid, or mixture of acids, comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species, or an ammonium or potassium salt or salts of such acids, or a mixture thereof.

A composition for treating a subterranean formation consisting essentially of an aqueous mixture formed by blending an aqueous liquid, amounts of HCl, a fluoride ion source, and a boron source sufficient to provide a concentration of BF4− anion effective to increase the permeability of the formation, and an effective amount of an acid, or mixture of acids, comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species, or an ammonium or potassium salt or salt of such acids, or a mixture thereof.

A composition for treating a subterranean formation consisting essentially of an aqueous acidic mixture formed by blending an aqueous liquid, and amounts of HF and a boron source sufficient to provide a concentration of BF4− anion effective to increase the permeability of the formation, and an effective amount of a compound or compounds, comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species.

A method of treating a subterranean formation to increase permeability comprising injecting into the formation an effective amount of an aqueous acidic mixture formed by blending an aqueous liquid, an amount of fluoboric acid sufficient to increase the permeability of the formation, and an amount of an acid, or mixture of acids, comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species, or an ammonium or potassium salt or salts of such acids, or a mixture thereof, effective to increase the dissolution of clay.

A method of treating a subterranean formation to increase permeability comprising injecting into the formation an effective amount of an aqueous acidic mixture formed by blending an aqueous liquid, and amounts of a fluoride ion source and a boron source sufficient to provide a concentration of BF4− anion effective to increase the permeability of the formation, and an amount of an acid, or mixture of acids, comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species, or an ammonium or potassium salt or salts of such acids, or a mixture thereof, effective to increase the dissolution of clay.

A method of treating a subterranean formation to increase permeability comprising injecting into the formation an effective amount of an aqueous acidic mixture formed by blending an aqueous liquid, amounts of HCl, a fluoride ion source, and a boron source sufficient to provide a concentration of BF4− anion effective to increase the permeability of the formation, and an amount of an acid, or mixture of acids, comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species, or an ammonium or potassium salt or salt of such acids, or a mixture thereof, effective to increase the dissolution of clay.

A method of treating a subterranean formation to increase permeability comprising injecting into the formation an effective amount of an aqueous acidic mixture formed by blending an aqueous liquid, and amounts of HF and a boron source sufficient to provide a concentration of BF4− anion effective to increase the permeability of the formation, and an amount of a compound or compounds comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species, effective to increase the dissolution of clay.

A composition for treating a proppant pack in a fracture in a subterranean formation comprising an aqueous acidic mixture formed by blending an aqueous liquid;

• an amount of fluoboric acid sufficient to increase the permeability of the proppant pack;
• and an amount of an acid, or mixture of acids, comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species, or an ammonium or potassium salt or salts of such acids, or a mixture thereof, effective to increase the dissolution of clay.

A method of treating a proppant pack in a fracture in a subterranean formation to increase permeability of the proppant pack comprising injecting into the proppant pack an effective amount of an aqueous acidic mixture formed by blending an aqueous liquid, an amount of fluoboric acid sufficient to increase the permeability of the proppant pack, and an effective amount of an acid, or mixture of acids, comprising a monoaminopolycarboxylic acid, or mixture of monoaminopolycarboxylic acids, which chelate aluminum ions and aluminum fluoride species, or an ammonium or potassium salt or salts of such acids, or a mixture thereof.