Case Study of the Revolutionary Approach of the Middle East's First Sustainable Underground Salt Cavern Oil Storage, Well-Design, Drilling Challenges, and Mitigations

Abstract The strategic storage of crude oil in underground salt caverns is a practice that has been refined over decades. These caverns provide a secure and cost-effective method for stockpiling large quantities of oil, ensuring a reserve during times of supply disruption or economic instability. The creation and maintenance of these storage facilities involve complex engineering challenges, from well-design to drilling, and require continuous innovation to mitigate risks and enhance efficiency. Salt caverns have been employed for oil storage in salt-producing regions globally due to their low operating cost, typically efficient construction process, favourable geotechnical conditions, and an ideal location within existing oil industry infrastructure. The development of new salt cavern oil storage in certain regions, with various specific constraints, creates unique opportunities for advancement. This paper presents the main technical challenges of a new oil storage cavern constructed at an industrial complex at the United Arab Emirates (UAE) for the first time in the MENA region (Middle East and North Africa), a summary of the design and operational mitigation techniques adopted, and matter-of-fact, detailed comparisons to an adjacent state-of-the-art oil storage system built in similar geotechnical sequences. There are many strategic and important factors to develop underground storage compared to the conventional Above-ground storage tanks (ASTs) not only from energy security but also from an environmental perspective too as the underground salt caverns are considered to have a lower environmental footprint compared to above-ground tanks and other subsurface storage methods. The primary reason is that salt caverns are typically deep underground, isolated from the biosphere, and have a very low risk of leakage due to the impermeability of salt formations. This significantly reduces the risk of soil and water contamination, a concern that is more pronounced with above-ground storage tanks, which are susceptible to spills and leaks. Another advantage of salt caverns is their minimal land use impact. Unlike above-ground storage facilities that require large tracts of land, salt caverns are located underground, leaving the surface available for other uses. This is particularly beneficial in ecologically sensitive or densely populated areas where land use is a critical concern. The design of wells for oil storage in salt caverns is critical for operational safety and environmental protection. It involves the careful planning and arrangement of various components and structures that make up a well, considering the features of the well environment that make up the conduit between the drilling rig and the reservoir. Underground salt caverns are considered to have a lower environmental footprint compared to above-ground tanks and other subsurface storage methods. The primary reason is that salt caverns are typically deep underground, isolated from the biosphere, and have a very low risk of leakage due to the impermeability of salt formations. This significantly reduces the risk of soil and water contamination, a concern that is more pronounced with above-ground storage tanks, which are susceptible to spills and leaks. This paper will highlight the project difficulties and lessons learned from different perspectives on salt cavern design methodologies, criteria, and best practices for oil storage facilities for practitioners.