A Review of the Corrosivity and Degradability of Aminopolycarboxylic Acids

Abstract

Abstract Aminopolycarboxylic acids (APCA) have been used in a variety of application in the oil and gas industry. These applications include scale removal, standalone stimulation, and iron control. Because of the recent developments in this industry, the chemicals are required to function under harsher conditions. Knowledge of APCA corrosivity and degradation properties is important in designing successful treatments. Understanding the degradability of fluids used is also important for proper post-treatment fluid disposal. The objective of this work is to give the reader a better understanding of APCA degradability and corrosivity in the oil and gas industry. This paper reviews results that were obtained through various laboratory tests, which aid in understanding chelating agent interactions with metals and their degradation. Results were obtained through a variety of tests including corrosion tests, Inductively Coupled Plasma (ICP), Mass Spectrometry (MS), Nuclear Magnetic Resonance (NMR), chromatography, and gel filtration. At high temperatures, conventional acids such as hydrochloric acid (HCl) show severe corrosion, lack of penetration and sludging characteristics. Several organic acids were proposed to solve these issues. However, even organic acids have shown solubility and incompatibility issues. Based on these shortcomings, chelating agents are often used and show good dissolving power, low corrosion, low sludging tendencies, excellent iron control, and some are highly degradable and environmentally friendly. This review summarizes work done in determining the corrosivity of chelating agents at bottomhole conditions and their susceptibility to photo-, bio-, and thermal degradation. Many papers were reviewed to provide a better understanding of corrosion caused by chelating agents, their operational limits, and their resistance to various degradation techniques. Readers can expand on this paper to further understand the wide range of applications chelating agents can offer the oil and gas industry and their impact on the environment.