英台地区水下决口扇特征及成因模式

CHARACTERISTICS AND GENETIC MODELS OF THE UNDERWATER CREVASSE SPLAY IN YINGTAI REGION

针对英台地区开发井网与砂体匹配关系不适应的问题，在大量岩心观察分析的基础上，对研究区水下决口扇砂体的成因和特征进行了研究。描述了水下决口扇砂体的识别标志，并结合水动力分析，将水下决口扇的发育过程划分为发生期、稳定期和萎缩期3个阶段。根据3个阶段发育的不同序列特征，总结了水下决口扇砂体的典型沉积序列模式。根据典型沉积序列模式在英台地区识别出大量水下决口扇，较好地解释了该地区砂体广泛分布但连通性差和油水关系复杂的地质现象，水下决口扇的识别对开发井网优化设计具有重要意义。

For the problem that the development well pattern is not match well with the sand bodies in Yingtai region, the geneses and characteristics of the underwater crevasse-splay sand bodies are studied on the basis of the observation and analyses of a large number of cores. The identifying markers of the underwater crevasse-splay sandbodies are described, and meanwhile integrating with the hydrodynamic analysis, the development process of the underwater splay is divided into three stages： occurrence, stability, and shrink. Finally, accord to the different sequence characteristics of the three stages, the typical sedimentary sequence models of the underwater crevasse-splay sandbodies are summed up. As a result, a number of underwater crevasse splays are identified by the above models, so the geological phenomena of the widespread distribution of sand bodies, but poor connectivity and complex oil-water relations are explained, so the identification of the underwater crevasse splay is very important for the design optimization of the development well patterns.