Average molecular parameters of heavy crude oils and their fractions using NMR spectroscopy

In this work, a new procedure for obtaining a full set of average molecular parameters (AMPs) of heavy crude oils and their fractions is proposed. Initially, a definition of the nomenclature for the identification of structural groups is presented, followed by the development of the scheme to obtain the AMPs. Corrections to parameters fa, RN, RT, n Alk ¯ , which are common in the literature, and new parameters for samples with a high grade of aromatic condensation and alkyl ramification, η, ϕ, and ξ, are revisited. The aromatic factor, fa, has been revised in detail to include the heteroaromatic species sulfur, nitrogen, and oxygen, which were not considered in any previous work. This new procedure allows the calculation of the AMPs from convenient analytical data, including the average molecular weight, elemental analyses results, and 1H- and 13C-NMR spectroscopy data.