Research on low permeable reservoir pore struction of Sha 7 fault block Fu Ⅲ section in Shanian oilfield

Based on the study of the casting thin sliceand the scanning electron microscope,the pore struction ofSha 7 section fault block E1f3 reservoir has been studiedthrough the high pressure to press the mercury and the rate-controlled mercury penetration. Research area reservoirporosity type are mainly intergranular hole, feldspar dissolu tion pore and rock debris dissolution pore, throat type take punctual throat primarily, then as laminated shape, curved lamellar throat. The high pressure presses the mercury re search shows that research area reservoir hole structure ani- sotropism is strong, core sample's hole stractural feature difference is big in the different spot. Poor pore conneotions caused by cementation followed with bad core accumulation and the transfusion performance, but the core grows with the corrosion, its hole grows extremely, and the connectivity is good, therefore its accumulation and the transfusion per- formance are good. The rate-controlled mercury penetra- tion experiment indicated that the research area reservoir rock pore width distribution range is 100～200 μm; in the different pore penetration sample, the porosity distribution characteristic difference is not big, but the throat distribu- tion characteristic is actually totally different. The throat channel plays the primary control role to the penetration co- efficient, sandstone reservoir microscopic anisotropism main- ly causes by throat's anisotropism.