Abstract: In the cast of China, there are five medium to small oilfields (yearly production under 4 million tons). This paper analyzes the current situations of geologic exploration and development and the characteristics of rescrvoir management, discusses their stable production period and levcls and the development patterns, presents economic and technical development feasibility study of the undevcloped reserves by using risk modeling method,and sets targets for stabilizing production in these oilfields by applying technical economy theory. Several measures are put forward for realizing stablc produetion and elongating stable production period in these oilfields.