摘要
在岩心描述的基础上,对杏河地区长6油层沉积相进行了分析,提出了该区主要沉积相为湖泊环境的河控三角洲体系,主要为三角洲前缘亚相沉积,主要沉积微相有水下分流河道、分流河口砂坝、前缘砂席和分流间等,分流河道和河口砂坝是本区占主导地位的骨架砂体。该区长6油层的三角洲体系是安塞三角洲体系最早发育的一支,早期分流来自于北部,后期分流转由东北方向进入,由于各期分流河道迁移、袭夺、决口以及因压实的均衡调整等,从而形成三角洲复合体内部各分流三角洲砂体的相互叠置交错。根据岩心微相分析、小层砂体形态和测井剖面对比分析,对该区长6油层砂组及小层的沉积微相进行了研究,掌握了沉积微相的时空展布和变化规律。
Based on core descriptions and logging data, the origins of Chang-6 reservoir of Yanchang Formation in Xinghe area of Ansai Oil Field are analyzed.The reservoir in this area represents a river-dominated delta progredation. Deposits consist of distributary channel, distributary mouthbar, front santsheet and interdistributary deposits. The distributary channel and distributary mouthbar sands constitute the dominated reservoirs. Grain-size distributions of the sandstones are discussed in detail on the basis of cumulative curve, skewness-sdandard deviation, C-M pattern, and other distinction approaches. Earlier delta built out into the lacustrine shallow water from north of the area. Frequent division of distributaries produced many small distributaries and a lobate delta. Later progradation produced cyclic alternations of distributary and interdistributary deposits from northeast of the area. The development of deltaic sedimentation produced overlapping sand bodies of a delta-complex. The sedimentary microfacies of individual sand bodies are described in detail based on depositional sequence and sand body geometry.
出处
《西北地质》
CAS
CSCD
2004年第4期15-21,共7页
Northwestern Geology
关键词
安塞油田
河流三角洲
沉积层序
沉积微相
Ansai Oil Field
delta
depositional sequence
sedimentary microfacies
