陆相伦坡拉盆地牛堡组烃源岩特征分析与展布预测

Characterization and Distribution Prediction of Source-Rocks in the Niubao Formation of Continental Lunpola Basin

针对牛堡组地层有效烃源岩识别方法存在不足及展布认识不清的问题,通过岩心观察、测井识别和地震层位追踪等手段,得到地球化学和测井响应特征关系方程,建立烃源岩厚度模型并对展布特征进行预测。研究表明:蒋日阿错凹陷烃源岩相对较厚,厚度向江加错、爬错凹陷逐渐减薄。其中,牛二中亚段的烃源岩厚度最大,其次为牛二上亚段、牛三下亚段;蒋日阿错凹陷中部、东部和江加错凹陷的中西部地层厚度大,受控于浅湖—半深湖沉积相环境,发育有较厚的烃源岩,为伦坡拉盆地烃源岩聚集的有利区带。该研究对下步研究区勘探部署具有一定的指导意义。

In order to improve the net source-rock identification means and clarify its distribution in the Niubao Formation,a relationship between geochemical and logging response was gained by laboratory core observation,logging identification,seismic horizon tracking,etc.A source-rock thickness model was established to predict its distribution.Research indicates that the source-rock in the Jiangriacuo Sag shows a relatively large thickness,which gradually decreases to the Jiangjiacuo Sag and Pacuo Sag.The source-rock in the sub-member of middle Niu-2 Member shows the maximum thickness,followed by the sub-member of upper Niu-2 Member and the sub-member of lower Niu-2 Member.The central and eastern Jiangriacuo Sag and the central and western Jiangjiacuo Sag are characterized by large stratum thickness,which were controlled by the shallow-lake—semi-deep lake sedimentary facies.The source-rocks with relatively large thickness are considered as the favorable source-rock zones.This research could provide certain guidance for the further exploration deployment in this region.