As oilfield enters middle and late stages of exploitation, the dynamic monitoring of oil saturation has become an essential part for grasping the distribution of remaining oil and improving the crude oil recovery. PNNPlus is a new saturation logging technology that adds two activated gamma probes on the basis of thermal neutron lifetime logging using neutron probes to assist in determining the water content of the reservoir, but its adaptability for residual oil saturation monitoring in low-porosity and low-permeability formation is unclear. Therefore, this paper researches and analyzes the adaptability of PNNPlus saturation logging technology by taking the Longdong Oilfield in the Ordos Basin as the research object. It is shown that: the PNNPlus logging technology is suitable for evaluating the remaining oil saturation of the mediumlow porosity reservoir in the Longdong Oilfield as the PNNPlus logging results are consistent with the oil saturation of completed wells and the interpretation conclusions can accurately evaluate the remaining oil saturation; The water saturation of the formation calculated by the oxygen content in the formation as detected by PNNPlus logging tool and the macro-capture cross-section Sigma, combined with the oil saturation, completion logging data, and geological data, can accurately identify and divide water-flooded layers; The formation porosity obtained from PNNPlus logging deviates from that obtained from completion logging by 0. 5%, but matches well with the oil saturation of the oil layer and water layer obtained from completion logging.
