The Miaoxi Sag in Bohai Sea was reshaped by geological forces, making it hard to assess oil resources. By analyzing seismic data and well logs, researchers restored the original sedimentary extent of the sag during the third member of Shahejie Formation. They found that a significant portion of the formation was eroded on the east side of the sag. The Northern and Southern Miaoxi Rises acted as source areas for sediment during this period. The sag was connected to other nearby sags, indicating huge potential for hydrocarbon resources in the area.