The self-healing property of rock salt damage in underground gas storage: A review

Abstract

Deep underground energy storage represents a crucial avenue for future energy reserve development. Rock salt is globally acknowledged as an optimal medium for energy storage due to its good creep, low permeability, and self-healing capabilities. However, underground compressed air salt caverns are susceptible to damage due to disturbances such as injection and production pressure, leading to increased permeability and compromising the sealing and stability of the reservoir. Rock salt exhibits strong self-healing capabilities and can recover under favorable conditions. This study examines the progress of research on the self-healing characteristics of rock salt damage and systematically reviews the mechanisms, influencing factors, and constitutive models of rock salt self-healing. The primary factors influencing rock salt self-healing include pressure, temperature, humidity, damage, and microstructure. Pressure and humidity facilitate rock salt self-healing, whereas temperature and damage exhibit threshold-dependent effects on the process. Crack tips, necking regions, and surface impurity zones of the crystal are particularly susceptible to healing. The self-healing constitutive models of rock salt were systematically reviewed, and key research challenges and future directions were discussed to provide critical references for ensuring the long-term stability and safe operation of underground rock salt gas storage.