川东北龙潭(吴家坪)组沉积相与烃源岩发育

The sedimentary setting and the source rock of Longtan(Wujiaping) strata in the northeastern Sichuan Basin

黄大瑞 蔡忠贤 朱扬明

Huang Darui Cai Zhongxian Zhu Yangming

中国地质大学资源学院, 湖北武汉 430074; 浙江大学地球科学系, 浙江杭州 310058

The Faculty of Earth Resources, China University of Geosciences, Wuhan 430074; Zhejiang University, Hangzhou 310058

在海相碳酸盐岩沉积模式的指导下,以单井沉积相分析为基础,结合钻井、地表露头资料分析对川东北宣汉达县地区二叠系龙潭组沉积相进行了详细的研究,识别出宣汉达县沉积相具有缓坡滞留海环境的特征。在此环境下发育了大套的黑色泥岩夹暗色灰岩,地化分析证实,该套地层黑色页岩有机质丰度高,TOC含量变化在0.5%~27.1%之间,平均2.91%,多分布在3%~5%范围,类型好,为川东北地区非常重要的烃源岩之一。

Guided by the depositional models of marine carbonate rocks, the sedimentary facies of the Late Permian Longtan strata in the Xuanhan-Daxian region is interpreted on the basis of sedimentary facies of single wells, drilling as well as surface outcropping data. The sedimentary facies in the region is typical gen-tle slope stagnant sea which produced large scale black mudstone and dark limestone. Through geochemistry analysis, it is confirmed that this source rock is a type of the important source rocks in northeastern Sichuan. The kerogen of this source rock is very good. This source rock contains a great deal of organic matters. The content of TOC varies from 0.5% to 27.1%, the average TOC is 2.91%, and most Of them are 3%-5%.