鄂尔多斯盆地桐川-太白梁地区延长组长3油层组沉积相

Sedimentary facies of the Chang 3 section in Yanchang Formation, Tongchuan - Taibailiang area ,Ordos Basin

桐川-太白梁地区位于鄂尔多斯盆地天环坳陷南段,延长组地层遭受部分剥蚀。通过古流向、砂岩骨架矿物、累计概率曲线及电镜照片等,并结合测录井资料准确地识别长3段地层厚度和沉积特征。本区岩石类型以近物源堆积的长石岩屑石英砂岩为主,粒度主要以跳跃及悬浮组分沉积,表明水动力较强。根据岩性特征、沉积构造、粒度分析、录井及测井资料,识别出桐川-太白梁地区为三角洲相及湖泊相,包括4种亚相和6种微相。

Tongchuan--Taibailiang area is located in the south of Tianhuan depress , Ordos basin, part of the Yanchang formation was denudated. Based on the filed outcrop palaeo--current measurement and the sandstone frame mineral,cumulative probability and statistic, electron micrograph ,with drilling and logging data as the main method to identify the thickness of Chang 3 section and sedimentary features. The main sandstone is debris--arkosic sandstone which sediments near the source, granularity is composed by suspension population and capriole population, signifies stronge hydrodynamic. According to lithology feature, sedimentary structure, granularity analysis, drilling and logging data, it is prove that the interval 3 of Yanchang formation was dominated by delta depositional system and lake depositional system , 4 kinds of sub--facies, 6 kinds of micro--facies.