Stability analysis of different shaped salt caverns under operation pressure

In order to investigate the stability of salt caverns in long term operation, three different shapes of salt cavern models were analyzed with respect to the stress distribution of cavern wall and volume change of cavern under various running pressures. The simulation results showed that stress on the wall is at the highest level in the initial operation period of the cavern storage, and stress concentration occurs mainly in parts with higher curvature on the cavity wall. The stress relaxation is also noticeable under fluctuating operation pressure, and the stress in different parts becomes evenly distribution along the cavern wall with stress gradually declining. There is no obvious fluctuation in changing of cavern stress and cavern volume when the operation pressure varies from 4 to 14.5 MPa annually. After a time span of ten years simulation, volumes of pear-shaped cavern, ellipsoid-shaped cavern and cone-shaped cavern reduces 27%, 22% and 37% respectively, and the decrease rate of cavern volume becomes smaller and smaller.