| The conventional gas resources in China is about 50.6×1012m3 based on the recent evaluation. Among 6 largest gas fields with proved geological reserves over 500×108m3, the top 4 are coal-related gasfields with the total reserves of 5000×108m3 about one-forth of China's total gas reserves, indicating the importance of coal-related gas.The gas reserves in China mainly distributes in the mid-western area where is underdeveloped and has a sparse population. In order to find more gas reserves in the eastern part of China, the paper studies the migration and accumulation of hydrocarbons from coal in Linqing Depression in Bohai Bay Basin. The purpose of research is to illustrate the coal-related gas reserves potential in rift basin and to provide the prospective target for further exploration and development. It is accomplished on the basis of the joint project-'Petroleum Resources Evaluation in West Linqing Depression" cooperated with Shengli Oilfield.Linqing Depression, with an area of 18000km2, is located in the joint boundaries of Shandong, Henan and Hebei provinces. The study area is in the eastern part of Linqing Depression, with an area of 5910km2. It is a Mesozoic-Tertiary rift basin, located in the southwestern end of Bohai Bay Basin.Under the guide of dynamic system for pool-forming and petroleum system, this research has fully taken advantage of every kinds of data from the area, applied the new idea, new technology, new methods to study tectonic, sedimentary and resource rock. The results suggest that the source rock of Permo-Carboniferous has undergone three evolution periods. The first gas generation occurs at the end of Triassic and the generation stopped during Jurassic-Cretaceous. The second gas generation starts at the beginning of Tertiary and it continues till present. The vertical carrying system and lateral carrying system have been thoroughly investigated for the first time in the study area. Their characteristics and evolution history are studied integratedly, synthetically, dynamically, and quantitatively from both bulk properties and micro-features. The vertical carrying faults are divided into five types according to the structural characteristics of fault belts and the layer which the fault cut through. The carrying system in the area, dominated by the vertical carrying system, especially type I and type II carrying faults, linking to every other types of carrying systems each other, composed a three-dimensional network carrying system. The evolution of the carrying system has been undergone three stages: the formation and destruction of lateral carrying system, the evolution of vertical carrying system and the completion of three-dimensional network carrying system. Meanwhile seven hydrocarbon expulsion types and three accumulation types are classified based on the top surface features of source rock, and the relationships between source rock-block and carrying faults, respectively.The volume of diffusion gas has been calculated with the application for the Pick's theorem to the local geological features, which proved that the gasfiields formed before Tertiary has entirely been destroyed. It is concluded that medium or small gas-pools might be found in the depression. Finally, the paper proposes some plays.The new concepts of migration and accumulation network dynamic system and three-dimensional network carrying system have been brought forward on the basis of comprehensive investigation of literature and geological conditions of the study area, which are of significant for the research, exploration and production in the oil/gas basins of tension types in east China.
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