A new discovery of Mesoproterozoic erathem oil, and oil–source correlation in the Niuyingzi area of western Liaoning Province, NE China. (December 2019)

• Record Type: Journal Article
• Authors: Sun, Qiushi; Xiao, Fei; Gao, Xiaoyong; Zong, Wenming; Li, Yongfei; Zhang, Jian; Sun, Shouliang; Chen, Shuwang
• Is Part Of: Marine and petroleum geology. Volume 110(2020)
• Page Start: 606
• Page End: 620
• Publication Date: 2019-12
• Subjects: Western Liaoning Province -- Mesoproterozoic erathem -- Oil–source correlation -- Biomarker -- Carbon isotope -- Hongshuizhuang Formation shale; Submarine geology -- Periodicals; Petroleum -- Geology -- Periodicals; Géologie sous-marine -- Périodiques; Pétrole -- Géologie -- Périodiques; Petroleum -- Geology; Submarine geology; Periodicals; Electronic journals; 551.468
• DOI: 10.1016/j.marpetgeo.2019.07.048
• Languages: English
• ISSNs: 0264-8172

Abstract

Abstract: The Yanliao Fault–Depression Belt is an important area for Precambrian oil and gas exploration in China. Through drilling of the Niu D1 well in the Niuyingzi area, located in western Liaoning Province (NE China), oil shows were discovered in the Mesoproterozoic Gaoyuzhuang carbonate reservoirs. In this study, we discuss the geochemical characteristics of the potential source rocks and oil-bearing rocks, as well as the relationship between the crude oil in the Niu D1 well and these source rocks, on the basis of organic geochemical analyses including biomarker compounds and stable carbon isotopes. The crude oil hosted in the limestone at depths of 341.65–362.00 m in the Niu D1 well underwent moderate biodegradation and shows three characteristic features: (i) the presence of the complete C18 –C23 13α( n -alkyl)-tricyclic terpane series; (ii) high abundances of the drimane series, C19 –C21 tricyclic terpanes, C24 tetracyclic terpane, and diahopanes, and low abundance of gammacerane; and (iii) depleted stable carbon isotopes of saturated and aromatic hydrocarbons (less than −30‰). All of these features suggest that the crude oil in the limestones of the Niu D1 well originated mainly from the organic-rich Hongshuizhuang Formation shale. Considering the lack of effective Neoproterozoic source rock, the detection of diversified steranes implies a degree of contamination from Phanerozoic sources with eukaryotic biological input. This is the first time that primary crude oil of Mesoproterozoic age has been discovered from wells drilled in the Yanliao Fault–Depression Belt, and demonstrates that Mesoproterozoic carbonates in this area have good hydrocarbon exploration potential. Highlights: Oil-rich limestone was discovered in the Mesoproterozoic Gaoyuzhuang Formation. Complete C18 ~C23 13α(n-alkyl)-tricyclic terpanes were detected in the oil. The oil has features of terpanes and carbon isotopes similar to the Hongshuizhuang shale. The oil is mainly derived from the organic-rich shale of Hongshuizhuang Formation. The detection of diversified steranes indicates extraneous oil contamination.