# A Review of Evaporite Beds Potential for Storage Caverns: Uncovering New Opportunities
## 1 Introduction  
Salt caverns are known to be suitable for subsurface gas storage purposes due to their essential characteristics such as impermeability, a lower cushion gas requirement compared to other storage media, and high injectivity and deliverability rates [1]. They have long been used for the storage of crude oil [2, 3], natural gas [4, 5], and compressed air energy (CAES) [6, 7]. Additionally, salt caverns serve as disposal sites for nuclear waste [8, 9] and industrial waste [10, 11]. With the shift towards cleaner energy, salt caverns are also being studied and considered for carbon dioxide (CO\({}_{2}\)) storage [12, 13, 14] and hydrogen (H\({}_{2}\)) storage [15, 16, 17]. Regardless of the storage application, the integrity and stability of salt caverns heavily depend on a comprehensive understanding of geomechanics, which is essential throughout the design, construction, storage, and abandonment phases [18, 19, 20, 21, 22]. While several review papers briefly mention and describe the geomechanics of salt cavern storage [23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36], others examine the topic in greater detail. Table 1 provides a summary of review papers discussing the geomechanics of salt cavern storage and the associated parameters [37, 38, 39, 40, 41, 42, 43, 44, 45]. \begin{table}
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**Author(s) and Year** & **Title** & **Focus of Paper** \\ \hline \multirow{6}{*}{[PERSON] and [PERSON] (2024)[37]} & The potential of hydrogen storage in salt & The potential of hydrogen storage in salt \\  & & caverns; the integrity of caverns with respect to geochemical reactions, microbial activities, and geochemical considerations; risks associated with salt cavern hydrogen storage; experimental works for underground hydrogen storage in salt caverns from the geomechanics perspective; and cavern design. & \\ \multirow{6}{*}{[PERSON] et al. (2024)[38]} & Review of the creep constitutive models for rocks and the application of creep analysis in geomechanics & \\  & & \\ \  
As shown in Table 1, the studies reviewed here primarily focus on salt caverns and related geomechanical issues. However, most of these studies either broadly define salt formations without differentiating the geomechanical challenges of bedded salt caverns or address bedded salts only briefly. Specifically, the salt formations in these studies are mostly halite [46], with little attention given to various bedded salt deposits, including beds with potash and trona. It is worth noting that while salt domes are recommended for storage purposes (e.g., for hydrogen storage in [39]), the limited presence of this salt structure in certain geographical regions [31] highlights the need for further investigation into bedded evaporites. This along with the suitability of salt caverns for underground gas storage, underscores the importance of smaller caverns in bedded salts that are available in different regions for local use, such as those in Teesside, UK [16]. It is also important to note that the areal extent of evaporite beds can play an important role in constructing multiple smaller caverns, such as those in trona beds in Wyoming [47]. The current status of research shows a lack of thorough investigation of bedded evaporites, including variations in their properties and associated geomechanical characteristics. Therefore, this review provides a broader perspective on bedded evaporites and geomechanical studies related to salt caverns across various evaporite formations. This review paper examines the geomechanics of bedded salt caverns. First, a review of the origin of evaporites, their depositional environment, and mineralogy is provided. The main soluble minerals in those evaporite beds, including halite, potash, and trona, and their impurities are described in this section. After that, a list of bedded evaporite deposits, including their depth, thickness, present caverns, and their usage in the U.S. and Canada, is presented.