页岩气其实是自由气

针对目前页岩气的很多认识误区，研究了页岩气的赋存状态。页岩是由基质泥岩和微型砂岩条带组成的岩石类型，具有页理结构，是非均质泥岩。砂岩备带尺度小，连续性差，是微型岩性圈闭。基质生成的甲烷气，短距离运移进入砂岩条带并聚集成藏。页岩气是储集在微型砂岩条带中的自由气，页岩基质和砂岩条带中都没有吸附气。页岩气藏不是连续型气藏，而是由无数微型气藏组成的大型气藏。微型气藏之间没有连通关系．开发页岩气需要采用水平井加多级压裂的办法方可将尽量多的微型气藏连通起来。页岩气只有甲烷一种组分．因此没有浓度的概念，也不存在扩散现象。页岩气的开发主要靠压力差驱动的流体流动。页岩气藏是典型的单一介质，而不是双重介质。

Shale gas is free gas underground

In order to clarify some misunderstandings of shale gas, the occurrence state of shale gas was studied. Shale is a type of rock consisting of matrix mudstone and micro sandsliees, which is heterogeneous mudstone with stratification structures. Sandslices are microscopic and poorly continuous, which are the micro traps of lithology in shale. The methane generated in matrix of shale migrates a short distance into sandsilees and accumulates and forms reservoirs. Shale gas is free gas stored in micro sandslices. There is no adsorption gas in shale matrix and sandslices. Shale gas reservoirs are not continuous reservoirs, which consist of numerous micro gas reservoirs. There is no connection between micro gas reservoirs. The development of shale gas needs to use horizontal wells with multiple macrofracturing which can connect mirco gas reservoirs as more as possible. Because there is only one component of methane in shale gas, the concept of concentration is not appropriate and the diffusion phenomenon can not take place in shale gas development. Gas flow driven by pressure difference is the main mechanism of shale gas production. Shale gas reservoirs are typical single-pore media, but not dual-pore media.