Review and Evaluation of Corrosion Inhibitors Used in Well Stimulation

Abstract

Abstract Corrosion inhibitors are an indispensable part of the fluid mix pumped downhole when a well is acidized. Of the various approaches to mitigate corrosion, the best way to reduce corrosion problems in the petroleum industry is to use corrosion inhibitors. Determining the most effective corrosion inhibitor for a given environment is essential. There are enormous examples of chemical inhibitors, which are propriety mixtures of several chemicals to induce synergistic effect. But basic function of corrosion inhibitors is by using some organic compounds containing oxygen, sulfur and nitrogen. This paper gives a complete vision of what the corrosion inhibitor is. How the structure of corrosion inhibitor molecule can affect the functionality of these molecules. This work discusses the effect of factors like chain length, degree of branching, substitution of multiple for single bond, using sulfur instead of nitrogen and other factors that affect the efficiency of corrosion inhibitor molecules. Depending on the mechanism of corrosion mitigation, corrosion inhibitors are classified as cathodic inhibitors, anodic inhibitors and mixed inhibitors which are explained in the paper. Corrosion inhibitors used in well stimulation acidizing are organic molecules, usually film-forming amines. They are classified as mixed inhibitors that affect both cathodic and anodic reactions and will decrease corrosion rates. Their effectiveness is largely a function of their ability to adsorb at the metal/metal-oxide surface. Adsorption occurs due to the polar or charge nature of organic molecules/ionic species first establishing a physisorbed surface film (through Vander walls forces), which may further stabilize through chemisorption to form a donor-type bond. This paper discusses and compares the performance of various corrosion inhibitors and intensifiers, addresses limitations of each inhibitor and give recommendations for field application.