The researchers studied the sedimentary facies of Chang7 in Huanjiang area, Erdos basin. They found that the main depositional system of Chang7 reservoir in the area is Shallow Lakes-Delta deposition system, with delta front and turbidite fan facies. The main microfacies types include underwater distributary channels, underwater natural levee, shunt bay, turbidite channels, and the leading edge of the turbidite channels. The depositional model of the study area was determined based on the spread and evolution of sedimentary microfacies.