川西坳陷富有机质页岩孔隙特征

采用低温氮气吸附法和场发射扫描电镜对川西坳陷富有机质页岩进行孔隙特征研究。结果表明:川西坳陷富有机质页岩比表面积为3.404~19.473 m2/g,远大于常规储层比表面积,大多数比表面积由微孔和过渡孔提供;页岩具有从微孔到中孔等一系列连续性孔隙,孔隙平均孔径为3.06~7.82 nm,孔隙类型以平行板状孔和一端封闭的盲孔为主,同时有一定量的墨水瓶状孔;页岩比表面积与有机碳含量呈正相关,有机碳含量、热演化程度与孔径呈负相关性,石英等脆性矿物和比表面积有弱正相关性。

Organic rich shale pore characteristics of Western Sichuan Depression

The pore characteristics of the organic rich shale in Western Sichuan Depression were studied by using low temperature nitrogen adsorption method and field emission scanning electron microscopy. The results show that the surface area of organic rich shale in Western Sichuan Depression ranges from 3.404 m²/g to 19.473 m²/g, which is far more than that of conventional reservoir. The surface area of shale is mainly provided by micropore and transition pore. The shale develops a series of continuous porosity from micropore to mesoporous. The average pore diameter ranges from 3.06 nm to 7.82 nm. The pore types are mainly parallel-plate pore and blind pore, which is closed at one end with certain amounts of ink-bottle pore at the same time. The surface area of shale and content of organic carbon form positive correlation. The content of organic carbon and degree of thermal evolution are negatively correlated with aperture. Lastly fragile mineral such as quartz is weak positively correlated with surface area.