SOLID-STATE C-13 NMR OF ISRAELI OIL SHALES

Representative samples from a wide range of ail shale occurrences in I srael, aging from Campanian to middle Maastrichtian, were analysed for their solid state C-13 NMR pattern and for some additional properties in an attempt to assess their energy potential and to examine if sign ificant differentiations between various basins and strata can be dete rmined. The results demonstrate a great similarity which prevails betw een all subsurface samples from the different sampled basins and strat a; thus, the aliphatic and aromatic carbon ratios determined by NMR do es not show significant variations. The average Fischer assay to oil c onversion value of all the samples is about 59 %, a value which copes well with the relatively narrow range (0.6-0.7) of the aliphatic carbo n fraction. The conversion amount of organic carbon to oil found in th e Israeli samples is quite below that of the Green River oil shales bu t is considerably higher than that of the US Eastern oil shales. Highe r trends of the aromaticity in the rocks and the specific gravity of t he generated oils are indicated in the Mishash (Campanian) samples whe n compared to those of the Ghareb (Maastrichtian). One surface sample gave a unique NMR spectrum. It may be due to severe oxidation causing a partial decomposition of the organic material, or due to a different source material input. The NMR spectrum resemble those of oil shales from other basins around the Mediterranean, in Turkey, Jordan, Morocco and Spain.