PORE STRUCTURE CHARACTERIZATION IN ROCK-SALT

The pore space of rock salt from the Lower Salt Unit of the Cardona Sa line Fm. (Spain) was characterized using three independent methods (me rcury injection porosimetry, saturation in a low viscosity isoparaffin and gas adsorption). The total porosity in the studied samples ranged from 0.97 to 3.09%. Pores may be present as macropores (> 7.5 mu m), micropores (between 7.5 mu m and 100 nm) and infrapores ((100 nm). The porosity is mainly associated with a well developed microporous syste m, which, in turn, is related to the presence of clay minerals in the rock salt. Macropores are randomly distributed throughout the rock bod y. They are sheet-like rather than cylindrical. The degree of connecti vity of the porous network is variable. Infraporosity consists of a bu ndle of non-intersecting pores, whereas microporosity can be considere d as a network of pores and throats. Macro and micropores exhibit a fr actal pore-surface structure, whereas infrapores have a non-fractal (E uclidean) structure.