With the continuous deepening of oilfield development, the distribution of remaining oil is highly scattered, making it increasingly difficult to tap potential, the increasing production of oil well fracturing measures has been deteriorating year by year, and the cost and benefit scissors are becoming increasingly large. On the basis of precise well and layer selection in oil well fracturing, it is necessary to scientifically extend the effective period of measures in order to maximize the benefits of oil well fracturing. This article is based on the actual fracturing situation of 1075 water driven oil wells in M oilfield in the past eight years. Based on big data, a mathematical model of the decline law of oil well fracturing is established, and the decline law model of different well networks, layers, and initial oil increase in M oilfield is obtained, and predicting the cumulative oil increase after fracturing and verify the accuracy of the model. At the same time, by comprehensively analyzing the factors affecting production decline from geology, development, technology, etc., combined with the factors affecting production decline and existing decline models, effective methods for extending the validity period of measures are determined. Applying the above conclusion, the annual increase in oil production during fracturing in M oilfield in 2023 was 77,200 tons, an increase of 21,300 tons compared to 2022. Based on the decreasing law model of oil well fracturing, targeted measures can be taken to extend the validity period and consolidate the contribution of oil well fracturing to production.