塔里木盆地东北部侏罗系烃源岩特征及初步评价

塔里木盆地是中国最大的含油气盆地,其东北部的侏罗系分布面积广、厚度大,主要发育一套煤系烃源岩.根据钻井及大量的实验测试等资料,研究了侏罗系煤系烃源岩的发育特征及其有机地球化学、有机岩石学特征,表明其有机质丰度较高,达到中等-好级别;有机质类型以Ⅲ型为主、Ⅱ型为辅;有机质热演化程度处于未成熟-低成熟阶段,部分地区可能达成熟阶段;烃源岩主要生烃显微组分为基质镜质体,少量孢子体、角质体和碎屑壳质体.综合分析表明,塔里木盆地侏罗系烃源岩具备一定的生烃条件和油气勘探前景.

Preliminary studies and characteristics of the Jurassic hydrocarbon source rocks in the northern Tarim basin

The Jurassic System with large thickness is ubiquitous in the northeastern part of the Tarim Basin, one of the biggest oil and gas basins in China. The hydrocarbon source rocks of coal measures developed in this basin were studied on the basis of drill cores, which involved in many fields such as geology, organic geochemistry and petrology. As suggested by the results, the source rocks were confined to the middle-good level in the organic abundance sense and the organic substances were grouped into grades III (dominant) and II (less common), respectively. The thermal evolution of those organic substances was speculated to have primarily been at the immature-to-low mature stage though some could reach the mature level in certain areas. A small quantity of sporinite and cutinite were identified in addition to the majority of the hydrocarbon-forming micro-components that mainly occurred as matrix vitrinites. Detailed synthetic analyses suggest that the Jurassic succession in the Northern Tarim Basin is a significant target of the oil and gas exploration due to its good hydrocarbon-forming conditions.