Acidizing and scale treatment of subterranean formation
OwnerEdward R. Freiterinventor
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Abstract
A one step squeeze treatment of a subterranean formation involves the treatment with a treating solution comprising an acid, a scale inhibitor, and a reducing agent. The presence of the reducing agent prevents the iron ions in the system from reacting with and forming a precipitate with the scale inhibitor and maintains the iron ions in the ferrous state.
Claims15
In a method of treating a subterranean formation with a treating solution containing acid and iron ions, the improvement wherein the treating solution further contains
- (a) a scale inhibitor, and
- (b) an additive capable of preventing or inhibiting the iron ions from forming a precipitate with the scale inhibitor:
A method of treating a subterranean formation comprising the steps of
- (a) mixing an aqueous solution of
- (i) HCl,
- (ii) a scale inhibitor, and
- (iii) an additive for preventing or inhibiting the scale inhibitor from forming a precipitate with any iron ions in the water,
- (b) injecting the treating solution into the formation whereby the reaction of the HCl with downhole equipment or materials forms iron ions and whereby the presence of an effective amount of the additive (iii) inhibits the iron ions from reacting with and forming a precipitate with the scale inhibitor.
An aqueous solution for treating a subterranean formation which comprises:
- (a) From 5 to 28 wt. % HCl,
- (b) From 0.5 to 10 wt. % of a scale inhibitor, and
- (c) From 0.05 to 5 wt. % of a reducing agent for maintaining any iron in the treating solution in the ferrous state.
Dependencies are inferred from the claim text.