Chang-3 member belongs to an environment of delta frontal subfacies.The primary types of the reservoirs include distributary channel sandbodies, river mouth bar sandbodies.

• 长3油层属于三角洲前缘亚相沉积环境 ，其储层的主要成因类型为水下分流河道砂体、河口坝砂体，次为前缘席状砂和远砂坝。