Comparative study of organic rich solids present in Utah and Athabasca oil sands

The presence of humic matter modifies the hydrophilic character of some oil sand solids surfaces and thereby results in serious problems in bitumen recovery using water-based processes. In the present work the fraction enriched with humic matter was separated from the bulk of Utah oil sand solids, using the cold water agitation test (CWAT), and was characterized by various techniques. The results obtained are discussed in comparison with those for Athabasca samples of different geological origin. By means of solid state I3C NMR it was demonstrated that the humic matter present in the separated solids is predominantly aliphatic in nature with the aromaticity much lower compared to that for Athabasca humic matter. These results suggest that in the case of Utah samples terrestrial input into the formation of humic material is not as significant as it is for Athabasca oil sands. The main inorganic components of the solids separated from Utah oil sand were iron-bearing x-ray amorphous material (possibly iron oxide), and also calcite and dolomite. The distribution of organic and carbonate as well as amorphous matter among size fractions derived from Utah fines (fraction < 38 |im), both before and after the CWAT treatment, were studied. It is suggested that, similarly to Athabasca oil sands, humic matter in Utah samples occurs in association with x-ray amorphous inorganic components. As in the case of Athabasca samples of marine origin, these organic-rich solids are of importance in the formation and stabilization of hydrophobic globules which have high affinity to bitumen and therefore adversely affect bitumen separability.