Optimization design of gas injection and brine discharge process parameters in salt cavern gas storage

The gas injection and brine discharge technology, as a key technique in salt cavern construction, is crucial for effectively removing brine from the cavern to optimize storage capacity. However, during the later stage of gas injection and brine discharge, the presence of insoluble particles in the salt rock formation poses a risk of clogging the brine discharge pipe as the pipe extends deeper into the cavern to maximize brine removal. To address this, numerical simulations using Fluent software were conducted, employing the enhanced realizable k-epsilon turbulent model and Eulerian multiphase flow model to analyze the transport behavior of gas, liquid, and solid phases in the salt cavern, as well as the gas injection and brine discharge strategies. By integrating numerical simulations with orthogonal experimental methods, the influence of gas injection pressure and brine discharge pipe diameter on the gas injection and brine discharge process was investigated. The results indicate that, under higher gas injection pressures, particularly at 14 MPa, the risk of brine discharge pipe clogging due to sediment deposition at the pipe inlet is reduced, with lower sediment mound heights observed. Additionally, smaller brine discharge pipe diameters, such as 114.3 mm, result in decreased sediment mound heights and reduced risk of pipe clogging. These findings provide theoretical insights and technical guidance for practical applications and construction practices in the field.