The Shiniulan Formation in southeast Sichuan is a marine deposit with various sedimentary facies like platform margin shoals and organic reefs. The formation's depositional evolution was influenced by sea level changes, leading to the development of transgressive reef-beach bodies in the Changxing Formation. These bodies formed favorable reservoirs and migrated vertically in a zonal pattern. Overall, the southeast Sichuan deposition during the Shiniulan Age was characterized by carbonate slope and platform edge reef-bank facies.