--> Abstract: Petroleum Migration Pathways in the Central Part of Junggar Basin, Northwestern China, by Ming Zha, Jiangxiu Qu, and Kongyou Wu; #90039 (2005)

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Petroleum Migration Pathways in the Central Part of Junggar Basin, Northwestern China

Ming Zha1, Jiangxiu Qu2, and Kongyou Wu2
1 University of Petroleum, Dongying, Shandong 257061, China
2 University of Petroleum, east China, Dong Ying, China

Migration pathway is a key factor that links source rocks and traps in the central part of Junggar basin. The deep, large reverse faults that cut source rocks and the regional unconformities on the top of Permian strata constituted petroleum migration passages from oil-generating depression to uplifts in the area. In particular, weathering and erosion makes the unconformity a zone of typical laminated architecture. The eluvium and semi-decayed rock layers above and beneath the unconformity surface were effective pathways along which hydrocarbon could migrate for long distance, which controlled petroleum accumulation in Jurassic reservoirs. In addition, the small normal faults within Jurassic reservoirs connect well to the thick sand bodies at base of Cretaceous, resulting in petroleum accumulation in Cretaceous reservoirs. Under the influence of Tertiary Himalayan Movement, the whole basin tilted to a great extent. During the tilting process, Cretaceous and younger strata developed many microfractures, leading to petroleum escaping or re-accumulating in small structural and stratigraphic traps. That explains why so far no large-scale petroleum accumulations have been found in Cretaceous although rich oil and gas showings are presented in many wells.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005