Identification and geochemical significance of polarized macromolecular compounds in lacustrine and marine oils

Abstract

Polarized macromolecular compounds in typical lacustrine and marine shale oils collected from the Ordos Basin and Tarim Basin of China were analyzed by FT-ICR-MS. Maturity was taken into consideration by diagenesis physical simulation experiments on shale oils, which had been collected at various temperature and pressure stages. The results showed that similar components existed in non-hydrocarbon and asphaltenes and the main peak compound classes of N 1 and O 2 were potential parameters for identifying typical marine oil and lacustrine oil in China. Nitrogen compounds/(nitrogen compounds and oxygen compounds), such as ) are the maturity indicators, which are related with C-N and C-O bond energy. Differences in molecular components and weights between marine and lacustrine oils are the effective index to identify source maturity and sedimentary environment.

Implications of microbial enhanced oil recovery and waterflooding for geochemical interpretation of recovered oils

“…In general, an A/C ratio higher than 1, as presented for oils I and II, corresponds to a non-biodegraded oil (Kim et al 2005). This follows in agreement with previous studies that applied ESI(-) FT-ICR MS (Hughey et al 2002, Cui et al 2014, Mahlstedt et al 2016, Wan et al 2017, Rocha et al 2017, which indicate a predominance of N species in non-biodegraded crude oils (Fig. 6a).…”

“…The O class has the second greatest abundance, which encompasses likely components with a hydroxyl functional group able to be deprotonated (Oldenburg et al 2014), mostly related to phenolic compounds (Shi et al 2010). The O class occurrence is generally reported in source rocks and crude oils (Vaz et al 2013, Poetz et al 2014, Cui et al 2014, Mahlstedt et al 2016, Oldenburg et al 2017, Wan et al 2017, Rocha et al 2017). The O 2 class is also in high abundance, mainly composed of naphthenic carboxylic acids (Larter et al 1997, Kim et al 2005.…”