Failure Analysis
Acid Corrosion
Service
companies use acids for well stimulation and cleanout work.
All acid work should have an inhibitor mixed with the acid
prior to injection into the well. Spent acids are still corrosive
to steel and the well should be "flushed" long enough
to recover all acid. In rare instances,  some produced waters
contain organic acids that have formed downhole, such as acetic,
hydrochloric and sulfuric acids. Corrosion from acid is a general
thinning of metal, leaving the surface with the appearance
of sharp, feathery or web-like residual metal nodules. Metallic
scale will not be formed in the pits. The sample in Figure
5 is an example of acid corrosion.
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