Study on the Source of Oils in Yongjin Area，Junggar Basin

Key words: 
• Junggar Basin /
• Yongjin area /
• source of oil /
• biomarker /
• stable carbon isotope

Abstract: Based on the analysis and induction of the organic geochemical characteristics of the potential source rocks as well as the test results of the oil samples, the source of oils in Yongjin area was first systematically studied mainly using the indications of biomarker and stable carbon isotope. It is considered that the oils in Yongjin area were mainly generated from the midPermian and midtolowerJurassic source rocks, partly from the lowerPermian source rock, and potentially from the Cretaceous source rock. In detail, the normal oils in the container beds of midJurassic's Xishanyao Formation which are above the coal layer, as well as in the most Cretaceous container beds, mainly came from the midPermian source rock; the normal oils in the container beds of midJurassic's Xishanyao Formation which are beneath the coal layer, as well as in the container beds of lower Jurassic Sangonghe Formation, mainly came from the midtolower Jurassic source rock; the oils, which account for a small proportion in the pool and experienced serious biodegradation, came from the lowerPermian source rock; and the oil in the Cretaceous container rock of Well Yong 6 probably came from the lowerCretaceous source rock, but the hydrocarbonsupplying power of this source rock may be weak. 