From the oil-reservoir carbonates of the Danish Upper Permian two bulky samples have been investigated by low-temperature nitrogen adsorption as function of initial high-vacuum degassing temperature. Compositionally, the samples differ in the relative content of dolomite and anhydrite. The adsorption-desorption isotherms were of multilayer type with a marked hysteresis. BET analysis shows two groups of adsorption sites each of which are characterized by their specific surface area (approx. 0.1 m2g−1) and C-constant (20–180). The adsorption sites are not mineral specific. The areas were only slightly influenced by vacuum-heat-treatment, while the pore volume was significantly increased for one of the samples.

Preben J. Møller

Papers

Surface Characterization of an Upper-Permian Carbonate Rock by N2 Adsorption