松辽盆地三肇凹陷葡萄花油层地层减薄模式及控油意义

松辽盆地三肇凹陷葡萄花油层地层厚度自北向南逐渐减薄,其减薄模式一直存在较大争议,造成油气垂向分布认识混乱。利用1 024口井测井曲线和10口井岩心对葡萄花油层层序格架和储层沉积特征进行了分析,其结果表明:葡萄花油层为三角洲末端边沉积边受构造抬升控制的顺源逐层减薄过程产物,其顶底砂泥突变面并不是其真实的顶底界面,而是自北向南砂岩相变为泥岩的砂泥对接面;葡萄花油层发育典型的河控浅水三角洲,微相类型主要为密集且连续的顺直型分流河道及末端河控席状砂;葡萄花油层垂向上发育先快速水退后缓慢水进的沉积演化序列,控制葡萄花油层中部(低水位期)分流河道砂体发育,组成了油气侧向运移优势输导通道和富集层位。

Formation Reduce Model and Govern Oil Significance of Putaohua Oil Layer in Sanzhao Depression,Songliao Basin

Formation thickness of Putaohua oil layer in Sanzhao depression,Songliao basin,reduces gradually from north to south,and the thinning mode is always controversial,result in understanding confusion of hydrocarbon vertical distribution.Log curves of 1 024 wells and core data of 10 wells analyzing formation structure of Putaohua oil layer and sedimentary features of reservoirs show formation of Putaohua oil layer is a process of gradually thinning by layers controlled by uplift of syndepositional structure at the end of deltas,and surfaces of sand-clay discontinuity at the top and bottom of Putaohua oil layer is a sand-clay interface formed by gradually changing from northern sand to southern clay rather than a genuine interfaces;shallow deltas typically developed in Putaohua oil layer,concentrated and continuous straightly-underwater channels and river-dominating extremity sheet sands are the main microfacies;Putaohua oil layer vertically develops sedimentary evolution of sequence with first fast dereliction then slowly transgression,the well developed distributary channel sand body is hydrocarbon preferential transporting channel of lateral migration and enriched layer in central Putaohua oil layer(lowstand).