The study focused on sediment types in the Yanchang Formation in the Hujianshan Area. By examining cores, logs, and experimental data, researchers identified sedimentary facies in the area. They found that a lacustrine-delta depositional system is prevalent, with delta front subfacies being most common. The distribution of sand, controlled by sedimentary microfacies, plays a crucial role in the distribution and enrichment of hydrocarbons. Identifying the correct sedimentary facies subdivisions can help pinpoint favorable reservoirs in the area.