页岩油气储集空间差异及赋存方式比较研究

Comparative Study on Reservoir Spaces and Occurrence Ways of Shale Gas and Oil

同为非常规资源的页岩油、气在储集空间和赋存方式上具有较大的差别。由于页岩气有机质的演化程度较高,成岩作用较强烈,原生孔隙和次生孔隙保存较少,储集空间以有机质孔隙为主,裂缝的主要作用是增加渗流能力和提高解析速度,较大的比表面积决定了页岩气的赋存方式以吸附状态为主;对页岩油而言,由于分子量较大,黏度较高,有机孔发育较页岩气低,呈吸附状态下的原油难以像页岩气一样解析流动,其有效储集空间主要来自于无机孔隙(裂缝),赋存方式也主要为游离态。

Both shale gas and shale oil are unconventional resources, but their reservoir spaces and occurrence ways are very different. For shale gas, due to the high degree of organic matter evolution and relatively strong diagene- sis, primary pores and secondary pores are difficult to save. So organic pores become the main reservoir space of shale gas. In addition, larger surface area to volume ratio of organic matter and clay minerals also means that the main occurrence way of shale gas is adsorption state. For shale oil, because of its high molecular weight and viscos- ity and relatively low content of organic pores, the adsorption state of oil is hard to exploit in the current economical and technical condition. So the effective reservoir space is mainly determined by the contribution of inorganic space and fractures, and the occurrence way is mainly free.