Development Characteristics and Genetic Analysis of Sand-bodies in Taiyuan Formation of Eastern Ordos Basin

Abstract

On the basis of fully understanding the regional geological background, the changes of lithology, bedding type and sedimentary facies sequence are analyzed according to core, logging and logging data。The three sets of sandstones and their internal structural characteristics of Taiyuan Formation in Ordos Basin are defined. Qiaotou sandstone body is mainly developed in delta distributary channel, which is characterized by large thickness and wide distribution of sandstone body and multi-stage channel superimposition. Malan sandstone and Qiligou sandstone are mainly developed in submarine distributary channel of marine delta. They are relatively small in distribution scale, complex in internal structure of sand bodies, single massive sand bodies or composite sand bodies with thin mudstone interbeds. There are sand dams controlled by marine delta in Taiyuan Formation, which have different shapes and poor continuity. Based on the above results, it is considered that the sand body characteristics are mainly affected by paleo structuer topography, sedimentary environment and local uplift. These understandings are of great significance for judging the development position of high-quality reservoirs in sand bodies and improving the actual effect of oil and gas exploration and development in reservoir sand bodies.