Performance assessment on water curtain system for multiphase flow water-sealed underground liquefied petroleum storage caverns

To study the necessity of setting up water curtain system under complex geological conditions in the construction of water-sealed underground storage cavern, as well as the importance of strict water curtain efficiency test and air tightness test, the random permeability calculation, based on geostatistics principle, was conducted in the study area, the twodimensional sectional multiphase flow propane storage cavern was built taking into account the strong heterogeneity of permeability in the study area, and the transport simulation of the stored oil and gas leakage under different conditions was performed. The results indicate that propane is extremely easy to leak under the condition of natural groundwater sealing, with its pollution halo mainly transported above the storage cavern, and long-term leakage may bring about umbrella-shaped distribution throughout the aquifer above the storage cavern. The horizontal water curtain system is able to effectively inhibit the upward transport of the pollution halo, prevent the leakage from vaporing when coming to the low-pressure environment, and confine the pollution halo within a certain space range. The vertical water curtain system obviously inhibits the horizontal transport of pollution halos and significantly isolates pollution halos generated by different storage caverns. The simulation results of the model with through cracks suggest that, for the effective operation of water curtain system, it is crucial to carry out strict water curtain efficiency test and air tightness test, timely find out unsaturated cracks and take measures.