南堡凹陷南堡1-5区东一段储层层次结构分析

Analysis on reservoir hierarchical structure in Nanpu 1-5 area of Nanpu sag

南堡凹陷南堡1-5区主力开发层系东一段为浅水环境下的辫状河三角洲前缘沉积,其发育砂体的层数多、接触关系复杂.根据层次结构分析的原理,将研究区东一段储层划分为9级层次,研究重点为第5至第7级层次储层,即单砂层—单成因砂体—单河道砂体.在小层研究的基础上,根据夹层特征完成沉积时间单元的细分（单砂层划分）;根据单砂层的沉积微相特征,识别出单成因砂体;根据测井曲线的形态、高程和厚度差异特征,在最主要的单成因砂体（水下分流河道砂体）中识别出单河道砂体.研究结果表明,南堡1-5区东一段单河道砂体呈条带状展布,砂体厚度为3～5m,最大宽度为400 m,且多条单河道砂体交切形成广泛分布的水下分流河道砂体发育区;受波浪作用的改造和后期水下分流河道的破坏,研究区水下分流河道边缘砂体呈席状化展布;河口坝砂体不发育,仅在水下分流河道间和河道边缘部位局部残留.

The layer series of development in NP1-5 area of Nanpu sag is braided delta front deposits. It consists of a large number of layers with complex contact relationship. Based on the principle of reservoir hierarchical structure, the reservoir formation in the study area has been divided into 9 hierarchies. The 5th to 7th hierarchies are the focus of this study, which are single delta-front sand body,single genesis sand body, single channel sand body. According to the characteristic of the interbed, the deposition time unit(singles and bed) was subdivided based on analyses of layers; according to the characteristic of microfacies, single genesis sand body was identified; according to the characteristic of well log, altitude and thickness, the single channel sand body in the main single genesis sand(underwater distributary channel) was identified. Findings show the single-channel sand bodies in the study area are always lay banded with a thickness of 3-5 m and a maximum width of 400 m. The single-channel sands cut into each other and build up the wide range of underwater distributary channel; by reworking from wave action and later erosion of underwater distributary channel, the channel border sand presents a sheet-like distribution; the mouth bar sand is rare and remainremains only in the interchannel.