The reservoir in Wei 42 block of PuchengOilfield was characterized by deep burial, poor physical properties, unclear sedimentary environment and sand body connectivity, strong heterogeneity, difficult water injection, imperfect well spacing and lowefficient development. Based on fine reservoir description and performance analysis of production, this paper studied the types and distribution of remaining oil. The remaining oil types were classified into interlayer interference type, structural high part type, imperfect injection-production type and lenticular sand body type. Aimed at the geological characteristics of reservoir and different types of remaining oil, manymeasures were carried out, such as enlargement adjustment, regrouping of layers, and adjustment of injection-production well spacing and well spacing density. The application result shows that well pattern optimization and well pattern thickening for different types of remaining oil distribution improved the development effect.