After years of development, X oilfield has entered a period of medium–high water cut, with a recovery rate of 14.98%. The tectonic position is located in the west slope of the X inclination, with a complex distribution of oil and water. The original single parameter oil–water layer identification chart cannot effectively identify the oil and water layers. Due to unclear identification of oil and water layers, some layers with developed effective thickness have not been perforated, and these layers are the main targets for potential exploration measures. In order to improve the crude oil recovery rate and analyze the production potential of the oilfield, this paper establishes a new oil–water layer identification chart by constructing composite parameters. Using three methods: oil–water layer identification chart, comparison between the upper and lower layers of this well, and comparison of adjacent wells at the same layer, combined with production dynamic data and various monitoring data, oil–water correction is carried out on 237 unperforated effective layers in X oilfield. After correction, there are 62 oil layers, 77 oil–water layers with oil bias, 90 oil–water layers with water bias, and 8 water layers. Based on the correction results of the oil–water properties of the layers, the oil layers and the oil–water layers with biased oil are selected as the potential layer for hole filling. A total of 95 wells are selected, including 42 wells with oil layer hole filling potential and 53 wells with oil–water layer hole filling potential.