沙埝油田沙7断块阜三段低渗储层孔隙结构研究

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

在铸体薄片、扫描电镜研究的基础上,采用高压压汞和恒速压汞方法对沙7断块E1f3储层的孔隙结构进行了研究。研究区储层的孔隙类型主要为粒间孔、长石溶孔和岩屑溶孔,喉道类型以点状喉道为主,次为片状、弯片状喉道。高压压汞研究发现,研究区储层的孔隙结构非均质性较强,不同部位岩心的孔隙结构特征差异较大:由于胶结作用而使孔隙连通性变差的岩心其储集和渗流性能较差,而溶蚀作用较为发育的岩心,其孔隙极为发育且连通性好,因此其储集和渗流性能较好。恒速压汞实验表明,研究区储层岩石孔隙半径分布范围为100~200μm;不同孔渗的样品之间孔隙分布特征相差不大,但其喉道分布特征却迥然不同。喉道对渗透率起主要控制作用,砂岩储层的微观非均质性主要由喉道的非均质性引起。

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.