摘要
鄂尔多斯盆地东缘临兴地区太原组桥头砂岩的沉积特征及其在层序格架中的位置,决定了储层类型和圈闭范围的评价。结合地震、测井、露头和岩心资料,通过层序界面和海泛面的识别,将太原组划分为1个完整的长期旋回(LSC1)和4个完整的中期旋回(MSC1,MSC2,MSC3,MSC4)。其中桥头砂岩位于MSC1下降半旋回中,以粗粒和中-粗粒的石英砂岩为主;粒度概率累积曲线呈典型双向水流特征;岩心见典型潮汐水流沉积构造,发育羽状、块状、粒序和复合层理等;剖面上砂体呈透镜状,平面上呈平行岸线条带状分布特征。综合分析认为桥头砂岩为潮汐水道及障壁砂坝沉积,属海相成因优质储层。该砂体呈北东-南西平行岸线方向分布,气井钻遇砂体均见高产气流。圈闭范围受砂体边界控制,呈现岩性圈闭的特征。太原组桥头砂岩层序划分和沉积特征的研究,对临兴地区和鄂尔多斯盆地东缘致密气的勘探开发具有指导意义。
Sedimentary characteristics and location within sequence framework of the Qiaotou sandstone of the Taiyuan Formation in Linxing area,eastern margin of Ordos Basin,determine the reservoir type and trap area. The Taiyuan Formation is divided into one complete long-term cycle( LSC1) and four complete medium-term cycles( MSC1,MSC2,MSC3,MSC4) based on identification of sequence boundaries and flooding surfaces by using seismic,logging,outcrop and outcrop data. The Qiaotou sandstone is within the descending half cycle of MSC1 and is dominated by coarse-grained and coarse-to-medium grained quartz sandstones. The cumulative probability curve of the grain size is typical of the two-way flow. Core observation reveals typical tidal current sedimentary structure and pinnate,massive,graded and composite bedding. The sand bodies show lenticular geometry on section and appear as bands parallel with shorelines on map. The Qiaotou sandstone is believed based on a comprehensive analysis to be tidal channel and barrier bar deposits,which are quality reservoirs of marine facies. The sand body parallels shoreline in northwest-southwest direction and all wells that penetrate it test high gas flow. The area of traps are controlled by the sand body boundary and show the characteristics of lithologic traps. This study is of great significance for guiding exploration and development of tight sand gas in Linxing area,eastern margin of Ordos Basin.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2018年第1期66-76,共11页
Oil & Gas Geology
基金
国家科技重大专项(2011ZX05042
2016ZX05066)
中海油重大专项(CNOOC-KJ 135ZDXMLTD14)
关键词
沉积相
桥头砂岩
层序地层
太原组
鄂尔多斯盆地
sedimentary facies, Qiaotou sandstone, sequence stratigraphy, Taiyuan Formation, Ordos Basin