The middle and lower submembers of Sha-3 member and the upper submember of Sha-4 member in Jiyang Depression are the main gas source rocks.The burial depth is generally less than 3000 m.A german developed oil gas water phase simulation software(IES Petroflow)was used to simulate the gas migration and accummlation regularites of the depression.The result suggests that the gas could migrate in different phases.The primary migration was in solution phase;the second migration was in free phase and resulted in shallow secondary gas pools.The gas in Pingfangwang buried hill and its neighbouring areas as well as Dongxing Yonganzhen migrated in Minghuazhen Formation and Quaternary depostitional stages.The migration types could be divided into double faulted uplift zone type

single fault uplift zone type

fracture zone and slope zone types.