Evaluating Fluid/Rock Interactions for Energy Storage in Salt Caverns: Part I: Brine–Rock Salt Interactions

Abstract

Understanding the interaction between brine and impure salt rock is essential for the long-term stability of salt caverns used in energy storage. This knowledge is crucial for optimizing the design and ensuring the structural integrity of storage systems in bedded salt formations. We conducted immersion and batch reaction experiments to investigate the effect of brine on the integrity of the impure salt rock. We evaluated the interaction between impure salt rock and brine with salinities of 0 ppm, 50,000 ppm, 150,000 ppm, and 250,000 ppm over a 30 day period and observed significant weakening and cracking of the samples. Based on acquired SEM images of identical spots before and after reactions with brine, we observed that the presence of brine creates oversized pores of up to 50 μm. The results suggest that the damage to impure salt rock is attributed to (1) the combined dissolution and detachment of embedded halite crystals and (2) the combined dissolution and detachment of calcite and dolomite grains.