Article pubs.acs.org/EF
Occurrence and Geochemical Significance of Phenylnaphthalenes and Terphenyls in Oils and Condensates from the Yakela Faulted Uplift, Tarim Basin, Northwest China Meijun Li,*,† T.-G. Wang,† Hongbo Li,‡ Ronghui Fang,† Lu Yang,† Shengbao Shi,† and Jiang Kuang† †
State Key Laboratory of Petroleum Resources and Prospecting, College of Geosciences, China University of Petroleum, Beijing 102249, People’s Republic of China ‡ Key Laboratory of Exploration Technologies for Oil and Gas Resources, Ministry of Education, College of Earth Environment and Water Resources, Yangtze University, Wuhan, Hubei 430100, People’s Republic of China ABSTRACT: A total of 32 oils and condensates were collected from four gas/oil fields (Dalaoba, Luntai, Kuqa, and Yakela) in the Yakela Faulted Uplift (Tarim Basin, northwest China). The composition of biomarkers and a previous study show that oils and condensates in the Dalaoba, Luntai, and Kuqa gas/oil fields originated from lacustrine mudstone/shale source rocks deposited in an oxic environment. Oils and condensates from the Yakela gas/oil field are of typical marine carbonate origin. Some phenyl-substituted polycyclic aromatic hydrocarbons, including phenylnaphthalenes (PhNs) and terphenyls (TrPs), were unequivocally detected in most of these oils and condensates. They are present in significant abundance in oils and condensates from the Dalaoba, Luntai, and Kuqa gas/oil fields. However, the concentrations of PhNs and TrPs are relatively lower or below the detection limit in oils and condensates from the Yakela gas/oil field. The ratios of 2-PhN/2-MN and m-TrP/3-MBP are used in this study to describe the abundance of PhNs relative to their alkylated counterparts, i.e., methylnaphthalenes (MNs), and that of TrPs to methylbiphenyls (MBPs), respectively. Oils and condensates from the Dalaoba, Luntai, and Kuqa gas/oil fields have relatively higher 2-PhN/2-MN and m-Trp/3-MBP ratios. However, oils and condensates from the Yakela gas/oil field have comparably lower 2-PhN/2-MN ratios (
