Evaluation of Jurassic-Cretaceous Marine Hydrocarbon Rocks in the
详细信息
- 责任者：Wang Licheng (School of Earth Sciences and Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Wang Chengshan
- 刊名：Petroleum Geology & Experiment
- 出版年：2010
- 卷期：32(3)
- 关键词：烃源岩 ; source rocks ; 西藏 ; Tibet
- 页码：p.276-281
- 图表：illus., 1 table, 36 refs.
- 分类号：1003
- issnNo：ISSN1001-6112
- isbnNo：CN32-1151/TE
摘要
The Bolin Basin, located on the southwestern margin of Tibetan Plateau, is a Mesozoic marine petroliferous basin covering an area of 30 000 km2. Measured section and geochemical analysis are combined to better understand the hydrocarbon potential. Two major source rock units have been identified: the Upper Jurassic Menkadun Formation and the Lower Cretaceous Gangba Group. Their potential source rock successions, mainly composed of dark shales during Oxfordian-Tithonian and Aptian, respectively, were deposited in outer shelf. TOC content ranges from 0.67 to 1.62 weight percent with an average value of about 1.03 weight percent for the Menkadun Formation and 0.7 to 1.08 weight percent with an average value of about 0.86 weight percent for the Gangba Group. All shale samples are composed of a mixed typeⅡ1(oil prone) kerogen. The vitrinite reflectance data and biomarker suggest that the Gangba Group is at late mature with respect to petroleum generation and the Menkadun Formation is overmature with respect to liquid hydrocarbon generation. These data indicate the shales of the units are good potential source rocks. Therefore, the good source rocks supply abundant matters for the formation of oil and gas in this area.