Abstract: Changxing formation in YB area is an ultra-deep and high-sulfur organic reef gas reservoir, which belongs to platform edge reef beach deposition with multiple stages of superposition and complex gas-water relationship. Based on core, well logging and seismic data, the study on development period, sedimentary characteristics and reservoir development characteristics of beach body were carried out. The results show that there are three periods of bioclastic shoal vertically developed in Changxing formation, which belongs to three different genetic types: Shallow gentle slope high energy shoal, low energy shoal behind reef and open platform low energy shoal. Shallow gentle slope and high energy shoal are favorable facies zones for reservoir development, which are mainly distributed in Y12 well and Y5 well block. Through comprehensive evaluation, the shoal area with high water cut does not have development potential, but the shoal water production has a great impact on the reef production wells, and the reef gas wells with shoal development have the risk of water production with the extension of production time.