Morphological features and main influencing factors of cavities leached in layered salt rocks

Salt rocks in China are mostly layered and their geological conditions are complex and diverse, so the cavities leached in salt layers are morphologically different. Therefore, researching the morphological features of cavities leached in layered salt rocks and their main influencing factors can provide the reference for the optimal design of leaching engineering and the efficient construction of gas storage. In this paper, the effects of various factors on cavity morphologies were analyzed from the aspects of production mode, leaching displacement, burial depth, salt rock grade, interlayer thickness and stratigraphic dip using the geological data of salt layer, the production data and the sonar detection data of cavity in Jintan, Chuzhou, Wulipu and Yingcheng Salt Mine. It is shown that the cavities in Jintan and Chuzhou are morphologically more regular and those in Wulipu and Yingcheng are irregular. The cavities leached by single-well or double-well convection are morphologically similar. Cavity morphology is the combined result of many factors, among which, salt rock grade and interlayer are the main factors influencing the regularity of cavity morphology, and stratigraphic dip is the decisive factor causing the differential dissolution of cavity. The research results provide the basis for UGS well design and cavity leaching design of gas storage.