塔里木盆地下寒武统烃源岩沉积相研究及其油气勘探指导意义

Sedimentary Facies Research and Implications to Advantaged Exploration Regions on Lower Cambrian Source Rocks,Tarim Basin

塔里木盆地内多区块、多层系含油气,油气资源十分丰富。下寒武统烃源岩是塔里木盆地内非常重要的烃源岩,然而其分布研究十分薄弱,严重制约着有利勘探区带的选择。通过野外露头、钻孔资料与地震资料的综合研究,认为塔里木盆地下寒武统玉尔吐斯组沉积期沉积模式主要为缓坡模式,烃源岩优势发育在中下缓坡与深水陆棚相带。建立在资料点分析、地震剖面追踪基础上,识别出下寒武统烃源岩2个分布中心:其一位于北部坳陷内;其二位于塔西南坳陷的南缘,呈NW向条带展布。关于烃源岩的分布与已发现油气田/藏的平面分布吻合,为回答主力烃源岩问题提供了支撑性证据;同时结合继承性古隆起的分布,指明了满西低凸起、巴东地区与塔西南坳陷内烃源岩分布区是下一步原生油气藏勘探的有利区带。

In recent years,large amount of hydrocarbon reserves have been discovered in the Tarim Basin. However,selection of advantaged exploration regions becomes more and more difficult because of poor knowledge of the distribution of source rocks. In this paper, outcrop profiles, drilling cores, and seismic ma- terials were studied. The results show mild slope sedimentary models are more suitable for yutertusi For- mation, and source rocks mainly distribute in middle-lower mild slope and deep water shelf facies. Based on materials points and seismic profile studies, two sets of source rocks were distinguished： one lies in the northern depression, the other distributes in the south edge of southwestern depression. Distribution of source rocks in the study area coincide with discovered hydrocarbon reserves, providing new evidence for major source rocks. Meanwhile, the distributions of paleo-uplifts were considered. Three exploration re- gions of Manxi Lower Uplifts,Badong areas,and southwestern depression have been regarded as the most advantaged regions.