Remaining economic recoverable reserves are based on the gradual change law of production of oil and gas, and it is forecasted and estimated according to SEC criterion. It is closely related with the output and replacement ratio of remaining economic recoverable reserves. However, recently, some misunderstandings exist in respects of two indexes and their mutual relationships, and the management and direction to enterprise is still influenced by these uncertainties. Taking the SEC reserves of Shengli oilfield for reference,and considering the related definition of output and replacement ratio on remaining economic recoverable reserves, influencing factors on general character and personality, and based on the overall idea and field example, the mutual relationship and sensitive difference to influencing factors of the two indexes were analyzed. In the meantime, the gradual change law of replacement ratio was discussed. Research results manifest that: from the annual change law of view, it is inconsistent for the relationship between replacement ratio and output, but it is consistent in respect of its overall gradual change trend. Its influencing factors mainly include SEC remaining economic recoverable reserves and its changes in the same year, output components, economic factors, evaluation conductions and difference of sensitivity etc. Based on this, we form the maco-framework on reserves estimation, which can be used as an important replenishment in analysis system of reserves estimation.