The Influence of Reservoir Architecture on the Connectivity of the Shahejie Formation in the Liuzhong Oilfield

Abstract

The lack of research on fine reservoir structure and sand body patterns in the Jidong Oilfield currently restricts the efficient development of the oilfield. Therefore, this article mainly focuses on the study of the main types of facies of the Shahejie Formation, sand body splicing patterns, and the degree of sand-body connectivity. The interpretation and analysis of well-logging, three-dimensional (3D) seismic, and production data were used to lay the foundation for the study and evaluate the remaining oil distribution. The results indicate that the reservoir sandstones in the study area were mainly deposited in a submerged distributary channel, mouth bar, and distributary channel flank. Using logging information to identify individual sands, a deltaic sand assemblage pattern is proposed by analyzing the sedimentary architecture. In the vertical direction, the deltaic sand body collocation style can be divided into cut-and-stack and separated types. In the lateral direction, the multi-stage sand bodies exhibit three collocation patterns: the side-cutting type, the mouth bar contact type, and the submerged distributary channel flank contact type. The degree of sand-body connectivity under different splicing patterns was analyzed and verified using production dynamic data. It was found that the sand body splicing pattern with a vertical up-cut stack and the sand body splicing pattern with a lateral up-cut had the best inter-sand-body connectivity.