松辽盆地北部江桥–阿拉新地区萨尔图油层沉积微相特征

Sedimentary Microfacies Characteristic of Saertu Oil Layers of Jiangqiao-Alaxin Area in North Songliao Basin

摘要: 应用岩心、测录井、三维地震及测试资料，开展松辽盆地北部西斜坡区江桥–阿拉新地区萨尔图油层沉积相类型及特征研究，总结出不同油层组沉积微相分布特征及其演化规律。结果表明，江桥–阿拉新地区以三角洲前缘亚相沉积为主，发育水下分流河道、河口坝及席状砂等微相。S_II+III沉积时期前缘砂体叠加连片，形成宽度1200~1800 m，厚度5~12 m的复合河道砂体；S_I沉积时期三角洲前缘水下分流河道砂体呈枝状、条带状展布，河道宽度200~800 m，厚度3~8 m，延伸距离远；S₀沉积时期为湖相沉积。分析沉积微相与油气关系，认为研究区最有利储集砂体为水下分流河道及河口坝砂体。

Abstract: A study was conducted on the sedimentary facies types and characteristic of Saertu oil layer in Jiangqiao-Alaxin area of the west slope area in north Songliao Basin, which based on the analysis data of core, logging, 3D seismic and testing data, and sedimentary micrfacies distribution and evolution regulars of different oil layer groups were summarized. The research displays that the Jiangqiao-Alaxin area is mainly composed of delta front subfacies sedimentation, with the development of underwater distributary channels, inter distributary bays, estuarine bars, and sheet-shaped sand sedimentary microfacies. During the S_II+III sedimentary period, the delta front sand bodies were superimposed and connected, forming a composite channel sand body with a width of 1200~1800 m and a thickness of 5~12 m; during the S_I sedimentary period, the underwater distributary channel sand bodies in the delta front were distributed in strips and branches, with a channel width of 200~800 m and a thickness of 3~8 m, extending for a long distance; the S₀ sedimentary period was characterized by shore shallow lacustrine sedimentation. To analyze the relationship between sedimentary microfacies and oil-gas, it’s believed that the most favorable reservoir sand bodies in the study area are underwater distributary channels and estuary bar.