Shengli Oilfield has a large scale of undeveloped reserves，which is an important backup for the sustainable production of the oilfield. However，many years of development practice show that there are lots of problems in the overall development of these reserves，which restricts the economic development and production of the reservoir. In view of the characteristics of some reservoirs with low grade， difficult production， and poor development effect， the types and distribution characteristics of undeveloped reserves in Shengli Oilfield were systematically sorted out， and the main types of undeveloped reserves and key research objectives were defined. Based on the development practice in recent years in the reservoirs such as glutenites，beach bar sands，and deep lowpermeability heavy oil，the paper analyzed three main technologies for undeveloped reserves，including large-scale fracturing of wells with high inclination in glutenite reservoirs，pressure flooding in low-permeability beach bar sand reservoirs，and cold production of heavy oil reservoirs by chemical viscosity reduction. The large-scale fracturing technology of wells with long sections and high inclination combined engineering sweet spots and geological sweet spots through the geology and engineering integration，and its application in the glutenite oil reservoirs with low grade has greatly improved reservoir productivity. The innovative development concept of pressure-driven water injection technology has achieved a breakthrough in replenishing energy and increasing the production of beach bar sand reservoirs with low-permeability. The development technology of viscosity reduction combined with pressure flooding has achieved a breakthrough in the economic development of deep heavy oil reservoirs with low-permeability by changing the development idea. These three reservoir types have been effectively produced of undeveloped reserves from single well production，reservoir energy replenishment，and low-cost development and have achieved good development results. The breakthrough of development technologies and the change of development concept are the only ways for the effective development of undeveloped reserves，which has an important demonstration and guiding significance for the development of other undeveloped reserves in Shengli Oilfield.