A billion-dollar corrosion problem plaguing the oil and gas industry could potentially be solved with expired pharmaceuticals, according to oil company Saudi Aramco.

Researchers from Saudi Aramco have reportedly identified a common prescription drug — which has so-far gone unnamed — as an effective alternative to commonly used corrosion inhibitors.

Source: Saudi Aramco

According to the researchers, the medication in question could potentially be deployed downhole during acid stimulation processes, which are performed to enhance permeability within deep carbonate reservoirs. Typically, hydrochloric acid is used in this process, but the corrosiveness of hydrochloric acid threatens the integrity of the steel casing and tubing.

The Aramco researchers suggest that although standard corrosion inhibitors are effective, they are toxic and expensive. Meanwhile, the expired medications solution could be less expensive and redirect medications from being flushed down the toilet.

The team tested nine different common prescription medications and split them into three groups including herbal-based drugs, stimulants, and hormonal and immune system boosters. All of them were ground into a powder and mixed with a hydrochloric acid solution.

“Sample 7” from the group of hormonal and immune system boosters proved to be most effective, achieving an almost 100% corrosion inhibition efficiency rate at room temperature.

The Aramco team is preparing to conduct more tests on the expired medications and have detailed their findings in the article: SPE 216036 Expired Medications as Corrosion Inhibitors in the Oil and Gas Industry.