Effect of maturity and petroleum expulsion on pyrrolic nitrogen compound yields and distributions in Duvernay Formation petroleum source rocks in central Alberta, Canada

A quantitative study of pyrrolic nitrogen compounds was conducted on a series of marine carbonate petroleum source rock extracts taken from the Upper Devonian Duvernay Formation in the central Alberta portion of the Western Canada Sedimentary Basin. With increasing thermal maturity, concentrations of various pyrrolic nitrogen compounds in the rock extracts increase drastically, together with significant compositional variations related to alkyl substitution position. The study provides circumstantial evidence for adsorptive interactions operating between organic nitrogen compounds and solid organic/mineral phases in subsurface sedimentary rocks during petroleum generation and expulsion. The absolute concentrations and relative distributions of pyrrolic nitrogen compounds in the extracts of different maturity ranges provide background information for the calibration of such data in migrated petroleums, as an independent measurement of secondary oil migration range of Duvernaysourced oils in the basin