The controls on the composition of biodegraded oils in the deep subsurface - Part 4. Destruction and production of high molecular weight non-hydrocarbon species and destruction of aromatic hydrocarbons during progressive in-reservoir biodegradation

Nitrogen isotope systematics indicate that nitrogen-containing compounds might act as nitrogen nutrient sources or mainly as carbon sources for the microorganisms causing in-situ reservoir biodegradation depending level of biodegradation. Distributions of some heterocyclic species add a very biodegradation resistant parameter set, to the petroleum geochemists arsenal.