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The lacustrine Beibuwan Basin contained large petroleum reserves in the northern continental shelf of the South China Sea. Due to the great sedimentologic complexity of the lacustrine basins, a significant financial risk associated with exploration needed to be reduced by specific techniques or significantly increasing knowledge of the lake system. Sedimentary infill, sequence stratigraphy, and organic geochemistry of the Fushan Depression in the Beibuwan Basin were studied, and enhanced our comprehension of the genetic relations between the sediment + water supply rates (climate change) and potential accommodation (tectonic subsidence and inherited topography) change. Here, we report two different lake‐type evolution cycles developed in two separated sags in the Fushan Depression, which are characterized by: (a) overfilled, (b) balanced‐fill, (c) overfilled, (d) balanced‐fill, and (e) overfilled in the Huangtong Sag, and (a) overfilled, (b) balanced‐fill, and (c) overfilled in the Bailian Sag and the centre Huachang Transfer Zone. Climate change is the dominant factor in the first three phases of the lake‐type evolution in both two sags, and transtensional tectonic setting is the controlling factor in the fourth and fifth phases of the lake‐type evolution in the Huangtong Sag. The same lake‐type with similar source rock and reservoir properties and observations indicate that these associations of source rock and reservoir play elements occur in a wide variety of tectonic settings. Moreover, the discovery of the cyclical process of the lake‐type evolution in the Fushan Depression can be a reference in the study of other similar lacustrine basins under an analogous tectonic and climate background. [ABSTRACT FROM AUTHOR]

After breakthroughs in U.S. shale gas exploration, the development of shale gas has been constantly promoted with core technologies, such as horizontal well volume fracturing, micro-seismic monitoring, and multi-well industrial exploitation. Unconventional natural gas production has grown rapidly, setting off a global “Shale Gas Revolution” in the field of energy. In this paper, the organic pore structure and sealing mechanisms of shale gas in the Sichuan Basin were studied. The results show that: (1) Organic pores, as principal reservoir space for shale gas, exist in hydrogen-rich organic matter and solid bitumen. (2) The match of formation time of closed shale gas system and gas-generation peak, as well as slight alteration degree of sealing conditions in the later stage, are key factors controlling the retention and accumulation of shale gas in the regions with high thermal maturity and complex structural areas; adsorption and slow diffusion of shale are the main microscopic mechanisms for the retention and accumulation of shale gas. [ABSTRACT FROM AUTHOR]