The prediction of viscosity in the extraction of heavy and viscous oil resources is essential for the economically viable production of these resources. A rheological and chemical investigation of oils from the McMurray formation produced at different depths was undertaken. Chemical analysis using high-resolution time-of-flight mass spectrometry (TOF MS), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance spectroscopy (NMR) suggested specific compounds representative of the compound classes observed in these heavy oils: [1] water, [2] sec-hexadecyl naphthalene, [3] 2,2',5,5'tetramethyl-1,1'-biphenyl, [4] 1-methylanthracene, and [5] cyclopentylcyclopentane. All three analytical techniques detected the monoaromatic, diaromatic, and triaromatic ring hydrocarbons as being the most abundant species in this heavy oil. Specific molecules with intense FTIR modes near 1600 cm(-1) and 1380 cm(-1) were not identified, and these may account for unknown species in asphaltene fractions. Correlations between heavy-oil chemistry and its viscosity were built using a partial linear square fit (PLS) regression from vibrational modes in the FTIR spectra, predicting an inverse correlation between water and viscosity.