安塞油田延长组长10_1油层段沉积微相特征分析

STUDY ON THE FEATURES OF SEDIMENTARY MICROFACIES OF CHANG 10_1 SECTION OF YANCHANG FORMATION IN ANSAI OILFIELD

鄂尔多斯盆地安塞油田晚三叠世延长组长101油层段为勘探新层系,本文着重对安塞油田延长组长101期沉积类型、沉积微相进行系统研究认为,研究区长101油层段发育曲流河三角洲沉积体系,主要为三角洲平原亚相,进一步划分出分流河道、天然堤、决口扇、河漫滩4种沉积微相并对不同微相的特征进行了详细的论述。进而分析了研究区长101油层段3个小层平面展布规律,认为分流河道是主要的油气储集砂体。

Chang 101 oil-bearing is a new exploration series in Ansai oilfield,Ordos Basin.The author emphasized sedimentation type and microfacies in Chang 101.Firstly,through the analysis the core observation,the author found there were dominance of symbols of shallow-water environment,such as leaves,root systems,worm hole and sedimentary structures in the cores.All the symbols indicated the relatively shallow water during its deposition process.Additional well-log information and test analysis information showed that Chang 101 section in Ansai oilfield developed meandering river delta deposit system,mainly delta plain facies.The author divided four microfacies and discussed the characteristics of the four microfacies,such as distributary channel,natural levee,crevasse-splay and alluvial flat.Then analyzed space distribution of 3 layers of Chang 101 in the area and considered distributary channels were the primary sand body.