对吐哈盆地台北西部主要勘探目的层系中侏罗统三间房―七克台组沉积相类型与特征、沉积相模式及沉积演化规律进行了研究,结果表明:三间房组―七克台组主要发育辫状河三角洲和湖泊2种沉积相类型,并存在5种微相组合模式;辫状河三角洲沉积体系主要发育在盆地短轴方向凹陷西部的湖岸缓坡带,主要微相是水下分支河道、河口坝、席状砂、滩砂、泥滩等;从中侏罗统三间房期至七克台期,研究区整体表现出湖域逐渐扩大、湖水变深的过程并发育了呈下粗上细旋回的三角洲―滨浅湖沉积体系。还探讨了沉积相带与油气聚集的关系,认为三角洲前缘的水下分支河道、河口坝及前缘席状砂等沉积微相是研究区较好的油气聚集场所,是今后油气勘探开发的主要方向。

Research have been made on the type of sedimentary facies, the sedimentary features, the model of sedimentary facies and the sedimentary evolution of Sanjianfang and Qiketai formation of middle Jurassic in north of Taibei, Tuha basin, and the research result shows that two types of sedimentary facies—braided stream delta facies and lake facies, and five types of compositional models of mirco-facies develops in Sanjianfang and Qiketai formation. The sedimentary system of braided stream delta mainly develops on offshore slope belts of lake in north depression, and composes the following five micro-facies: branched channel, debouchure ban, reef sand, waterfront sand and mud flat. So that delta-offshore and shallow lake sedimentary system with a positive cycle is available. In the paper, the author discusses the relationship between distribution of sedimentary facies belts and gathering of oil and gas, and concludes that the micro-facies of branched channel, debouchure ban, reef sand is the better gathering sites of oil and gas in the research area which points out the direction of exploration and exploitation in the future.