Corrosion inhibitor intensifier and method of using the same

Abstract

An aqueous organic acid composition containing a terpene as corrosion inhibitor intensifier is especially suitable for use in acidizing subterranean formations and wellbores. The composition substantially reduces the corrosive effects of the acidic solution on metals in contact with the acidic solution. Suitable terpenes include carotene, limonene, pinene, farnesene, camphor, cymene and menthol.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an aqueous acid composition containing a terpene and methods of using the composition to inhibit or reduce the corrosion of metals. BACKGROUND OF THE INVENTION [0002] Some well stimulation techniques, such as pickling, acid washing, matrix acidizing and acid fracturing, require the use of corrosion inhibitors to reduce the rate of acid attack on metal components and to protect wellbore tubular goods. In some instances, such as in stimulation processes requiring strong acids, high temperatures, long duration jobs and / or special alloys, the cost of corrosion inhibitors may be so high that it becomes a significant portion of total costs. In such scenarios, corrosion inhibitor intensifiers, also known as corrosion inhibitor aids and corrosion inhibitor boosters, are included in the formulation in order to reduce costs and ensure that the stimulation job can be performed cost effectively while complying with technical require...

AI Technical Summary

Benefits of technology

[0009] An acid composition, suitable for use in acidizing a subterranean formation or wellbore, contains, in addition to an aqueous organic acid solution and corrosion inhibitor, a corrosion inhibitor intensifier. The corrosion inhibitor intensifier contains a terpene. Such compositions substantially reduce the corrosive effects of the acidic solution on metals in contact with the acidic solution.

Problems solved by technology

In some instances, such as in stimulation processes requiring strong acids, high temperatures, long duration jobs and / or special alloys, the cost of corrosion inhibitors may be so high that it becomes a significant portion of total costs.

However, synergistic effects are typically only evident when the corrosion inhibitor intensifier is used at relatively high concentrations.

Corrosion inhibitor intensifiers further are often incompatible with certain corrosion inhibitors.

Thus, the ability to formulate compositions at their requisite concentration levels is often compromised.

Weak organic acids, like formic acid, have limited application since their low pH makes them more difficult to handle.

Further, such acids are only useful at high concentrations.

Further, formic acid has limited applicability because it is only useful as an inhibitor intensifier in mineral acid, such as HCl systems.

The use of salts, such as salts of arsenic and mercury, as inhibitor intensifiers has further been unsuccessful in light of their toxicity.

Further, salts are not typically cost effective since they must be used at high concentrations and coupled with a chelating agent in order to avoid precipitation upon transformation into liquids.

Such salts, when used in conjunction with HF-containing acid systems in sandstone acidizing, must be used at such high concentrations that unacceptable levels of precipitation occur.