The article explores how deltas formed in the western Huimin Depression during the Palaeogene period. The researchers studied the sedimentary layers and sand bodies in the Shahejie-3 Member to understand the history of delta systems in the area. They found that deltas played a crucial role in petroleum accumulation, with sand bodies serving as potential reservoirs for oil and gas. The Shahejie-3 Member shows a pattern of deep-lake, prodelta, and delta front and plain subfacies, indicating a complex depositional history in the region.