Source correlation between biodegraded oil seeps and a commercial crude oil from the Punjab Basin, Pakistan

The biomarker composition of biodegraded petroleum in an oil seep was determined using GC and GC–MS techniques. The results show that many important biomarker compounds are eliminated or highly altered by biodegradation. In order to establish a correlation between the seep sample and a non-biodegraded crude oil sample from the Dhurnal field, asphaltenes were isolated from the seep and subjected to hydrous pyrolysis. The biomarker composition of the pyrolysate and the Dhurnal oil is similar, suggesting that they are generated by similar source rocks.

Research Highlights
► Biodegraded oil seep, asphaltene pyrolysate and crude oil were analyzed.
► Biomarkers: drimanes, tricyclic terpanes, hopanes and steranes were examined.
► Source, thermal maturity and depositional environment were evaluated.
► Correlation was discerned on the basis of geochemical parameters.
► Origin of oil seeps in the Punjab Basin, Pakistan was uncovered.