Abstract: This paper comprehensively analyzes construction standards of gas storages and basic development conditions of gas injection oil reservoirs, and presents selection criteria of oil reservoirs that can both meet the requirements of gas storage and EOR through gas injectioa The up - to - date achievements in fuzzy mathematics are used to establish a fuzzy hierarchy analysis - based three -stage comprehensive fuzzy appraisal method. It has been used to comprehensively appraise several oil reservoirs in an oilfield for gas storage and EOR through gas injectioa The appraisal results show that it can avoid the failures and errors of conventional methods.