The Distribution and Seismic-facies Characters of Reef and Bank of Changxing Formation in Western Hubei and Eastern Chongqing

There was a typical rimmed carbonate platform sedimentary system in Western Hubei and Eastern Chongqing in the late Permian, of which the platform margin and the internal of platform are the most favorable places for the development of reef and bank. The Changxing Formation can be divided into two third-order sequences. By the study of lithofacies and paleogeography within the sequence framework, it is believed that the HST is the most favorable development period for reef and bank, and the reef and bank mainly developed in the Sql-HST. In addition, the distribution of reef and bank has been ascertained preliminarily. By seismic facies tracing and correlation of the well-seismic sections, it is believed that the mainly seismic facies characters of reef and bank are blank (including weak amplitude), intermittent, disorder, bifurcation and foreset reflection of seismic event, and the seismic event amplitude of reef is stronger than bank. The comprehensive study of reef and bank reveals that the elaborate research of regional structure pattern and litho-paleogeography is helpful for improving the precision of reef and bank seismic prediction.