| Oil upgrading at reservoir conditions via chemical reactions that break long hydrocarbon chains and improve viscosity is highly desirable for transportability of crude oils.;Previous studies showed C-S and C-O bonds as main participants in reactions between water and organic compounds present in heavy oils, causing upgrading of crude oil at temperatures used in in-situ recovery processes. The rupture of C-C bonds in the heaviest molecular components seems also needed to reach the viscosity required for transportation.;Thermodynamic calculations presented here for representative molecules of Athabasca Bitumen group families in presence of water illustrate the feasibility of primary reactions involving C-C bonds at relatively low (T>250ºC) in-situ temperatures.;Transition metal oxide particle catalysts involving Ni, Mo and Fe were tested, with a Ni-Fe oxides combination yielding the highest upgrading level of Athabasca bitumen. Results under different hydrogen partial pressure atmospheres suggest it may prevent water dissociation.;The Ni-Fe catalyst was used in reactions with a model molecule (propylbenzene), to initiate the analysis of the chemistry behind the heavy oil tests performed. |