Research on sequence division and Sedimentary characteristics of Shahezi formation in Xu Dong of Xujiaweizi fault depression

In view of the unclear division of sequence stratigraphy and the unclear understanding of sedimentary characteristics of Shahezi Formation in Xu Dong of Xujiaweizi fault depression, a detailed study on the division of sequence stratigraphy of Shahezi Formation in Xu Dong area of Xujiaweizi fault depression was carried out by using the data of Vail sequence stratigraphy. The sedimentary facies types and plane distribution characteristics of Xu Dong area were analyzed in combination with single well facies and material source supply, etc. The study showed that Shahezi Formation in Xu Dong area could be divided into a second-order sequence, and the interior could be further divided into four third-order sequences. At the early stage of sedimentation, the lake water was relatively deep and fan delta sedimentary system was mainly developed. In the middle period, the lake basin became wider and fan delta and braided river delta sedimentary systems developed. In the late period, the lake basin was basically stable and braided river delta sedimentary system was developed. (paper)