In the conventional logging interpretation, contradictory layers of “similar porosity and similar resistivity” often appear, that is, the oil tested under the same conventional logging response is oil layer or oil–water layer, which seriously affects the identification of oil layer and the process of reservoir exploration and development in this area. To solve these problems, a method combining the distribution of large, small and medium pore throats with conventional resistivity was established to identify fluid qualitatively and quantitatively. Reservoir physical property is the main controlling factor of oil content in R sag. The evaluation of reservoir physical property and pore structure is the key technology of oil layer and water layer identification. The key factor controlling the pore structure of a rock is the percentage of pores within a certain pore size range in the entire pore system. The interpretation method of qualitative and quantitative determination of oil layer and water layer is established by combining the distribution percentage of different pore throats of nuclear magnetic with the conventional resistivity value. Based on this evaluation method, the pore throats size evaluation method based on the conventional logging curve is established, which continues the research achievements of nuclear magnetic logging. This method effectively identifies macroscopic confused contradictory layers, excludes the pseudo-oil and gas signals caused by “large hole effect” in nuclear magnetic logging, and identifies low-resistivity oil layers with medium and small holes. This method can effectively identify fluid properties in the logging interpretation work of this block with complex oil–water relationship, and accurately supports the exploration and development work of this depression.