河道砂体内部构型及剩余油分布特征

STRUCTURAL TYPES WITHIN RIVER CHANNEL SANDBODIES AND THE DISTRIBUTIONAL CHARACTERISTICS OF THE REMAINED OIL

针对大庆长垣油田特高含水后期辫状河、曲流河和分流河道3种典型河道砂体，依据现代沉积、野外露头和密井网丰富的岩心、测井和动态资料，应用层次和成因分析的基本思想，精细研究典型河道砂体内部构型及其地下储层分布模式，形成了河道砂体内部构型定量描述方法。依据大量岩心分析资料，发现了不同类型河道砂体层内水淹厚度动态变化特征及水淹厚度随开发时间的变化规律，总结出受砂体内部构型控制的辫状河“零散薄层状”、曲流河“叠瓦状”和分流河道砂体“窄条状”的层内剩余油分布模式，并针对不同剩余油分布模式提出了相应的挖潜措施，为特高含水期河流三角洲储层精细挖潜指明了方向。

In view of the three types of river channel sandbodies in braided, meandering and distributary rivers at the late period of extra-high watercut of Daqing Placanticline oilfields, according to the data of modern sedimenta- tion and field outcrop, and moreover the rich data of dense well patter, well logging and the performance, the structural types within the typical river channel sandbodies and the reservoir distribution modes are studied in detail with the help of the basic thoughts of hierarchical and genetic analyses. So the quantitative describing method of the structural types within the river channel sandbodies is established. Based on the great number of core analyses, the dynamic changing characteristics of the watered-out thickness within the different types of river channel sandbodies and the change laws with the time are discovered, and furthermore the remained oil distribution modes within the oil layers controlled by the structural types in the sandbodies are summarized as following： braided river- ＂scattered and thin occurrence＂, meandering river- ＂imbricate form＂ and distributary river- ＂narrow stripe configuration＂. At the same time, the corresponding tapping countermeasures are presented for the different forms of remained oil distribution modes, so the direction of fine tapping and improvement in river delta reservoir development at extra-high watercut period is made clear.