Abstract: By applying basic theory of production-cost-profit analysis and reservoir engineering method, the cost structure of well stimulation is analyzed, the critical IOR model, investment ceiling model and production critical sale price model are developed. Based on high investment of old well stimulation and greater risk in decision making, the concepts and analytical models of old well stimulation critical balance point operational efficiency and well stimulation safety marginal production rate are introduced for the first time. According to the practical experience, a general procedure for well stimulation decision making is presented, and some cases are given. The study shows that results from these models accord with the economical operational law for the well stimulation, hence they provide useful tools for evaluation/imple- mentation of old oilfield stimulation and integrated adjustment.

Key words: production-cost-profit analysis, oil well, safety marginal production rate, stimulation, decision making