Caprock is the prerequisite for the accumulation of natural gas.Sealing of gas concentration is one of the important sealing mechanisms besides physical and pressure sealing.

• 盖层是天然气聚集的必要条件，盖层封闭作用除物性封闭、压力封闭之外，还有一种重要的封闭机理，即浓度封闭。