Sedimentary Facies of the Chang 2 Member of Yanchang Formation in Area A of Northern Shaanxi

In order to promote the rolling exploration and development of oil reservoirs in northern Shaanxi, a fine study of sedimentary facies in area A has been carried out. Using core and logging data, on the basis of identifying different levels of sequence interfaces and lake flooding, the Chang 2 Member in Area A was divided into two base level cycles, and a high-resolution sequence stratigraphic correlation was established. On the basis of core description, the analysis of single-well sedimentary facies, continuous-well sedimentary facies and planar sedimentary facies are carried out. It is believed that the Chang 2 member of the study area is a delta plain deposit, dominated by distributary channels, inter-distributary depressions, and natural dike microfacies. There are two to three main rivers in the study area. Both the vertical and the plane show that the length of Chang 22 sand bodies is more developed than the length of Chang 21 sand bodies. Among the three small layers of Chang 22, Chang 221 sand body is relatively well developed, and the channel width and thickness are large, making it the most favorable reservoir.