Research and application of eco-friendly chelating agents in plugging removal systems: A review

Ultra-deep carbonate formation play a crucial role in oil and gas exploitation. The use of traditional acid solutions for acidizing leads to surface reactions. Even if treated with conventional chelating agents, it may result in heavy metal contamination and groundwater eutrophication. Therefore, the development of environmentally benign acid systems is crucial. This study comprehensively reviewed the development and application of environmentally friendly chelating agents in plug removal, considering the specific requirements of high-temperature and offshore well acidizing. Their corrosion resistance, thermal stability, and dissolution power were described based on their mechanism of reaction and experimental evaluation. Lastly, a comparative analysis of their advantages, disadvantages and applicable conditions was conducted. The findings suggest that eco-friendly chelating agents have a minimal environmental impact. Besides functioning as an additive, it also has the potential for acidizing independently. However, the number of operational examples is limited, and further development must continue to progress toward high-temperature resistance, cost-effectiveness, and independent acidizing.