The Feixianguan Formation in the southern Sichuan Basin was studied to understand its sequence stratigraphy. By analyzing different types of data, researchers identified 11 sequence boundaries and divided the formation into two main sequences and ten smaller sequences. These sequences show a pattern of rapid transgression followed by gradual regression, with no lowstand systems tract or condensed section. The fourth-order sequences III and VIII are the main reservoirs, characterized by highstand oolite bank deposits that form shallowing-upward sequences.