Abstract:The effects of pore structure on the fractal dimension were studied. Based on the similar dimension,the method of measuring the fractal dimension was brought forward in natural low-permeable cores through traditional intrusive mercury data or image analysis,and the calculated formula for the dimension was achieved. By using the intrusive mercury data from natural cores,the curves were protracted and the fractal dimensions in porous media were calculated. In some formation segments,where there are only compaction and solution under pressure,the fractal dimension has diagenesis;while in other segments,the pore structures become more complicated due to intensive epigenesises,such as secondary quartz enlargement,recrystallization,and corrosion. Therefore there are several dimension values.