Experiment on soluble properties of different types of salt rocks

Salt strata in China are characterized by multiple interbeds and high impurity content. Due to the different impurity contents and diagenetic conditions of different types of salt rocks in different regions, the soluble properties of the salt rocks vary, which further affect the solution mining rate and the morphology control in cavity construction of salt cavern gas storage. Typical salt rock samples from Pingdingshan, Huai'an and Anning were selected to conduct composition and water solubility experiments on different types of salt rock. The results show that the dissolution rate of salt rock in low concentration brine is faster, and the solution concentration increases rapidly within 5-10 h after injection of clean water, but with the increase of brine concentration, the dissolution rate decreases and the solution concentration growth rate slows down. Comparing the dissolution results of salt rocks in different regions, it can be learnt that Anning salt rocks have faster dissolution rate, and are easier to dissolve than Pingdingshan and Huai'an salt rocks. For salt rocks and mud-containing salt rocks with low impurity content (less than 40% of water insoluble matter) and uniform distribution, the impurity content has little effect on corrosion rate, while the salt-containing mud rocks and glauberite rocks with high insoluble matter content have low corrosion rate and are difficult to be dissolved. The research results are of great guiding significance for the solution mining cavity scheme design and site construction of salt cavern gas storage.