塔里木盆地寒武系两类优质烃源岩及其形成的含油气系统

寒武系烃源岩是塔里木盆地主要烃源岩之一,包括泥页岩和碳酸盐岩。泥页岩类烃源岩有机碳平均含量为1.87%,发育于欠补偿盆地环境,主要分布于盆地的东部,有效厚度120～415m;碳酸盐岩类烃源岩有机碳平均含量为0.42%,发育于台地内的蒸发泻湖环境,主要分布于盆地西部,有效厚度288～324m。两类烃源岩形成了不同的油气系统,盆地相泥页岩类烃源岩的油气系统以满加尔凹陷为生烃中心,储层主要为寒武系-奥陶系碳酸盐岩和志留系、石炭系、三叠系和侏罗系砂岩;台地相碳酸盐岩烃源岩油气系统的生烃中心可能在巴楚凸起一带,主要储集层为下奥陶统和石炭系。

Two types of Cambrian source rocks and related petroleum systems in Tarim basin

Cambrian source rocks,including mud shales and carbonates,are among the main source rocks in Tarim basin.The mud shales,developed in an under-compensation environment,are mainly distributed in the eastern part of the basin and have an average TOC of 1.87% and an effective thickness ranging from 120m to 415m;while the carbonates,developed in an intra-platform evaporative lagoonal environment,are mainly distributed in the western part of the basin and have an average TOC of 0.42% and an effective thickness between 288m and 324m.The two types of source rocks gave rise to different petroleum systems.The hydrocarbon generating center of the petroleum system with basin facies mud shales to be the source rocks,was located in Manjiaer sag,and the reservoirs are mainly Cambrian-Ordovician carbonates and Silurian,Carboniferous,Triassic and Jurassic sandstones;while that of the petroleum system with the platform facies carbonates to be the source rocks might be located in Bachu high and the surrounding area,and the reservoirs are mainly Lower Ordovician and Carboniferous.