Shape design and safety evaluation of salt caverns for CO2 storage in northeast Thailand

Abstract

Salt caverns are an adequate solution for the sequestration of CO2 (large capacity, safety and long-term operation). The large rock salt deposits of the Maha Sarakham Formation represent a very promising location. Designing salt caverns is still a complex issue. In this paper, the stability of typical cavern shapes (spherical, cylindrical, teardrop, bulb, and pear) was evaluated based on displacement, von Mises stress, safety factor, and volume change. The analysis aimed to find the optimal cavern shape for salt deposits at Ban Nong Plue, Borabue district, Maha Sarakham province, northeast Thailand. The Finite Element simulations investigating the cavern stability are carried out for a time span of 600 years (> 500 years is considered permanent storage). The bulb-shaped cavern yielded the best results, indicating that it constitutes the optimal shape in the given geological conditions. The stability of all analyzed caverns showed a dependence on the operating stage. Each stability factor exhibited large differences between the periods of cavern construction/brine discharge and pre-pressurization by CO2 injection. A lower cavern pressure negatively affected the evaluated factors. The results can be useful in planning future cavern fields for CO2 storage (and other gases) in salt deposits.