Numerical Simulation Optimization of Insoluble Sediment Discharge at the Bottom of Salt Cavern Gas Storage Facilities

Abstract

The accumulation of insoluble sediments at the bottom of salt caverns significantly affects the effective storage capacity and long-term operational stability of salt cavern gas storage facilities. To investigate the sediment accumulation processes under varying operating conditions and their impact on cavern performance, computational fluid dynamics (CFD) methods were employed to conduct two-dimensional numerical simulations using Fluent software. The Euler–Euler multiphase model and the standard k-ε turbulence model were adopted to quantify how parameters, including the distance between the brine discharge outlet and the sediment surface, sediment density, sediment height, and injection pressure, influence sediment deposition behavior. Simulation results indicate that numerical modeling is an effective approach for analyzing sediment flow and deposition processes under different conditions. The distance between the brine discharge outlet and the sediment surface critically governs the potential for sediment ingestion into the tubing. A shorter distance increases the likelihood of sediment being drawn into the tubing, whereas a greater distance promotes sediment deposition at the cavern bottom and minimizes entrainment, thus achieving optimal accumulation control. By optimizing the positioning of the brine discharge outlet relative to the sediment surface, the efficiency of sediment discharge can be significantly improved, thereby ensuring the long-term operational reliability of salt cavern gas storage facilities. The implementation of optimized discharge strategies effectively reduces adverse effects of sediment accumulation, enhances gas storage capacity and operational efficiency, and ensures the long-term safety and stability of the facility. These improvements yield substantial economic and social benefits for natural gas storage and peak-shaving operations.