Chemical analysis of North Sea oil and Kimmeridge immature source rock

Abstract

Thin layer chromatography, open column chromatography and soxhlet extraction were the three separation techniques used to fractionate the aliphatic and aromatic hydrocarbons from North Sea oil and Kimmeridge immature source rock. Gas chromatography was used to analyse the n- alkanes, pritane and phytane. The pristane and phytane ratio of the two different samples (North Sea oil and Kimmeridge immature source rock) were found to be 1.5 and 0.79 respectively. Values less than one indicate anoxic setting and greater than 1 indicates oxic setting. Carbon preference index (CPI) was also calculated to know the maturity of the North Sea soil. The Pr/Ph of the North Sea oil and Kimmeridge source rock show that North Sea oil was deposited in Oxic environment while Kimmeridge source rock was deposited under anoxic environment. The CPI value of the oil indicates maturity and non biodegraded oil.

Keywords: Anoxic, Carbon preference index, Immature source rock, North Sea oil, Oxic, Pr/Ph.