Sequence stratigraphic division based on well logs and seismic data: An example from the upper submember of the 4th member of the Shahejie Formation in the Yangxin depression

The sequence stratigraphic division in this study is conducted on the basis of well logs and seismic data for the upper submember of the 4th member of the Shahejie Formation in the Yangxin depression. The sequence division is firstly made with the aid of time-frequency analysis of the seismic data, and then followed by the wavelet transformation analysis of the well logs for the study area. According to the integrated interpretation of 3D seismic data and well logs, three fourth-grade sequences and nine fifth-grade sequences have been distinguished for the upper submember of the 4th member of the Shahejie Formation in the Yangxin depression. The analytical methods outlined above may increase the efficiency of petroleum exploration due to high horizontal resolution of the seismic data and high longitudinal resolution of the well logs, and thus may apply to the sequence division in the stable continental downwarped lacustrine basins.