At present, Daqing Oilfield is in the stage of post oil reservoir and unconventional development, with large initial investment in production capacity projects, high depreciation and consumption, and a high proportion of low production and inefficient wells in the oilfield. At the same time, due to uncertain factors such as international economy, geopolitics, periodic fluctuations in oil prices, and strict control of investment scale by the state, the economic decision-making risks of oilfield production capacity projects are relatively high. The article combines relevant theories such as economics, development planning methods, and reservoir management decision-making techniques to construct a new decision-making method for integrated evaluation of investment and cost. Firstly, using economic statistical methods, suitable economic evaluation indicators are determined for different projects with new production capacity and measures adjusted. Then, the DEA analysis method is applied to conduct an integrated evaluation of investment and cost for each project. Different projects are ranked according to input-output indicators, and a cumulative net present value and cumulative investment relationship chart are formed. Finally, based on the production target, an optimization configuration plan for different projects is provided through a relationship diagram. This decision-making method has played a positive role in how to allocate production and construction investment and measure investment in oilfields, meeting the needs of oilfield investment decision-making. Using the 2023 planning arrangement of a certain oilfield in Daqing, two oilfield investment decision-making models under oil price scenarios are proposed to provide new ideas and methods for oilfield investment allocation.