This paper discusses the design of underground salt caverns, opened by solution mining, for the production of brine and storage of natural gas under high pressures. The caverns are located in a salt basin in the northeast region of Brazil. Special attention is given to the geomechanical analysis carried out by computer codes specially developed for the simulation of salt creep behavior under different initial stress states and temperatures. These codes were applied to the design of the underground potash mine in the state of Sergipe, overlying tachyhydrite and carnalite with very high creep strain rates and to the design of the pre-salt oil wells in Santos Basin. The constitutive creep equations implemented in the codes are based on a double mechanism creep law. The creep constants adopted in the simulation are taken from a previous investigation carried out on an experimental panel of the potash mine, considering the stratified geology with different salt rocks of the basin where the mine is located. The excavation of the caverns by solution mining is also simulated starting from a geostatic initial equilibrium state of stresses, imposed through a special formulation implemented in these computer codes.

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