Abstract: Up to now, the logging evaluations of medium-high porosity reservoirs have gained wealth experiences in Xihu sag in East China Sea. However, how to evaluate medium-low porosity reservoirs, which are becoming key objects in the future, is still in the experimental and exploratory stage. Based on the logging data from the recently exploratory wells, we analyzed the logging response characteristics of medium-low porosity reservoirs, studied the porosity, permeability, saturation and pore structure characteristics of the reservoirs, searched for the relationship among the pore structure, permeability and production ability, and eventually achieved the goals of evaluating the low permeable reservoirs directly.