The main oil producing zone of W oilfield in Weixinan sag of Beibu Gulf Basin is the first member of Paleogene Liushagang Formation. Its reservoir distribution is complicated, sand body connectivity and favorable sweet spot are not clear, and reservoir heterogeneity is strong, resulting in poor oilfield development effect. In order to clarify the characteristics of reservoir distribution and sand body connectivity in the first member of the current formation of the oilfield, to find the favorable potential areas of the reservoir, and to guide the subsequent production adjustment and optimization of the potential. Based on the core and logging data, this paper studies and characterizing the reservoir characteristics of the first member of the oilfield flow from the aspects of sedimentary facies, reservoir physical properties and heterogeneity. Choose to fully reflect the characteristics of the reservoir sandstone thickness, effective thickness of sand body and sedimentary microfacies, porosity, density of interlayer and permeability variation coefficient, seven factors as evaluation parameters, the grey correlation analysis method to determine the weight coefficient, set up comprehensive evaluation of reservoir classification system, and finally with reservoir evaluation method for comprehensive evaluation of reservoir, to clarify the distribution of favorable reservoir, The evaluation results are verified by using the multi-parameter superposition advantage region comparison method. According to the comprehensive evaluation method, the comprehensive index of the two main oil reservoirs is scored. According to the comprehensive evaluation score, reservoir parameters and actual production, the reservoirs are divided into three categories. The corresponding score interval of each category is more than 40 for type Ⅰ, 20~40 for type Ⅱ and less than 20 for type Ⅲ. The L1 medium to Ⅲ-1 small reservoirs are better, and the Ⅰ type reservoirs have a large development range. A class Ⅰ favorable reservoir area without well control was found in the south and east of the L1 medium-III-2 stratum. After adjusting and deploying one production and one injection well pattern, the reserve scale and oil content were implemented. After implementing the adjustment well pattern, the injection, production and production effect of the well pattern were good, which improved the economic benefits of the oilfield and helped the oilfield to increase production and reservoir. The comprehensive reservoir evaluation method and evaluation results combined with the method of multi-parameter superposition and comparative verification of dominant reservoirs make the range of favorable areas more accurate and the evaluation results more reliable.