The L reservoir is a reef limestone formation characterized by highly developed natural fractures and driven by strong bottom water. The reservoir has been in the ultra-high water cut stage after 20 years’ development, with horizontal wells initially producing at elevated water cuts. In recent years, to enhance development efficiency, a proprietary water control technology utilizing particle filling within fractures has been developed, yielding significant results in water control and oil production enhancement. To quantitatively evaluate incremental cumulative oil production, a methodology has been established based on the existing understanding of the water control mechanism. This involves developing a dual-porosity model to simulate fracture distribution around the wellbore and a mathematical model to characterize the process of particle infilling in fractures. Through iterative fitting of the wellhead pumping pressure, a dynamic numerical model for fracture infilling simulation has been developed, enabling the prediction of both controlled and uncontrolled water well production dynamics. This has allowed for the quantitative prediction of incremental cumulative oil production in water control wells. The predicting results are in accordance with the production performance after field tests, providing important basis for widespread application of the water control technology with particle filling.