大芦家地区东二_1亚段砂体微相纵横向分布研究

STUDY ON MICROFACIES DISTRIBUTION OF THE TYPICAL DELTA FRONT SANDBODY OF THE FIRST SUBMEMBER OF THE SECOND MEMBER OF DONGYUN FORMATION, OLIGOCENE SERIES IN DALUJIA AREA

大芦家地区渐新统东二１亚段主要由三角洲前缘亚相组成，发育的微相类型包括河口坝、水下分流河道、水下决口扇及天然堤、远砂坝、席状砂、分流间湾等，它们在纵横向上表现出多次复合，多次叠加的特征，且各微相的界限和单砂层的界限并不一致；所有这些微相在垂向上的沉积序列可分为均一型、垂向减小型和垂向增大型三类；此外，该区三角洲体系沉积物源主要由河流从西北方向搬运而来，属高建设性的河控型三角洲，其平面呈朵状向东南方或南方延伸，其微相模式的特点是水下分流河道和河口坝沉积位于中心，其他微相分布在它们的外缘。

ongyun formation, Oligocene series in Dalujia area is one of the main production formation of Linpan oil field deposition system is mainly made up by the delta from part, and its sandbody genetic type includes river-mountain, sublacustrine distributary channel, sublacustrine levee, sublacustrine crevasse-splay, distal bar, sheet coveting in delta front subfacies, which have been identified through comprehensive use of core, logging and well log data. Vertically, all these microfacies can be induced into three typical depositional sequences; uniform, decreasing and increasing upward respectively. In addition, all these microfacies identified in the area are the result of multi-superstition in the geologic time. And the interfaces are not always the interfaces of single sand beds. Through all studies in this area and by the analysis of the deposition source from the west-north direction, the driving way of river, and the locate form extending to east-south or south, the data in this area is determined to be river-controlling type. Finally, a 3-D depositional faces model of this area has been induced, and in this model sublacustrine distributary channel and river-mouth bar are in the center and the other microfacies are around them.