| dc.description.abstract | Porosity and permeability are important assessment factors for CO2 sequestration in reservoir rocks. In order to improve the assessment, properties of reservoir rock are important and need to be evaluated in advance. Porosity of sandstone is controlled by texture and degree of cementation, whereas permeability is controlled by pore-throat size, pore type and connectivity of pore throat. Sandstones aged Miocene to Pliocene in Miaoli area, NW Taiwan, were collected in this study. YOKO2 porosity/permeability detector is used to measure their permeability perpendicular and parallel to bedding planes under 3 to 60MPa confining pressure with Helium as media. Optical microscope and scanning electron microscope (SEM) were then used to observe the mineral composition, lithology, texture and pore type of sandstones, so as to explore the influence of rock properties on porosity and anisotropy of permeability, as well as the storage potential for CO2 sequestration in the future. The experimental results show that most of the horizontal permeability exceeds the vertical permeability and the anisotropy increases with increasing confining pressure. Mineral composition of sandstones studied were mainly quartz and lithic with little feldspar content. The pore types were mainly primary megapores and micropores in this study. The correlation between macropores and permeability were stronger than that of total porosity and permeability, mainly due to total porosity contains micropores which contribute little to permeability. | en_US |