With the promotion of China’s carbon peaking and carbon neutrality goals, the energy industry is transforming from traditional fossil energy to renewable energy, which is sustainable, clean and safe. The development of renewable energy is not only an important measure to achieve the above goals but also a significant factor to alleviate the global energy crisis. Salt caverns, with good air tightness, have been considered as the best choice for large-scale underground energy storage. To elaborate on the research and future development of salt cavern compressed air energy storage technology in China, this paper analyzes the mode and characteristics of compressed air energy storage, explores the current development, key technologies and engineering experience of the construction of underground salt caverns for compressed air energy storage at home and abroad. Focusing on salt cavern compressed air energy storage technology, this paper provides a deep analysis of large-diameter drilling and completion, solution mining and morphology control, and evaluates the factors affecting cavern tightness and wellbore integrity. The future development and challenges of underground salt caverns for compressed air energy storage in China are discussed, and the prospects for the three key technologies of large-diameter drilling and completion and wellbore integrity, solution mining morphology control and detection, and tubing corrosion and control are considered. This paper aims to provide a useful reference for the development of underground salt cavern compressed air energy storage technology, the transformation of green and renewable energy, and the realization of carbon neutral vision.

The detection of casing leakage in oil and gas wells or water injection wells is an important element of wellbore integrity management. Ultrasonic technology is suitable to detect and identify the position of leakage in oil and gas well shafts, providing engineering guidance for subsequent treatment. In this paper, the finite element calculation model of casing leakage in oil and gas wells is established by using the computational fluid dynamics method, and the large eddy simulation model and Ffowcs Williams-Hawkings acoustic model are utilized to simulate the casing leakage condition. The acoustic pressure signals of each monitoring point on the inner axis of the pipeline are obtained, and the influences of the pipeline pressure difference, the leakage hole diameter and the pipeline fluid on the leakage acoustic field are analyzed. The simulation results indicate that the acoustic pressure level measured on the pipeline axis rises with the increase of pipeline pressure difference and leakage hole diameter. The size and variation rule of acoustic pressure level also vary with the type of pipeline fluid. Overall, the results obtained show that ultrasonic logging can accurately locate and detect tubing leakage, and they provide theoretical guidance for practical casing leakage detection, assisting with wellbore integrity management.