Sensitivity study on CO 2 flooding well productivity in shale oil reservoirs

Abstract CO 2 injection parameters significantly impact the productivity of shale oil wells. This study first established a numerical model to analyze the influence of CO 2 injection parameters on the gas‐oil ratio (GOR). Next, it elucidated the macroscopic characteristics of CO 2 injection modes on shale oil well production. Third, it examined the effect of CO 2 injection parameters on water cut, revealing the dynamic changes in water cut under different CO 2 injection modes. The results indicate: (a) When the relative CO 2 injection volume is 1, the initial GOR during production is 1800 m 3 /m 3 , reaching a peak of approximately 2800 m 3 /m 3 . When the relative CO 2 injection volume is 5, the initial GOR is less than 1700 m 3 /m 3 , suggesting that excessive injection damages the reservoir to some extent, though the peak values remain similar. (b) Appropriate CO 2 injection enhances oil recovery, while excessive injection damages the reservoir, leading to reduced rather than increased production. (c) CO 2 injection helps reduce water cut during long‐term production, but overall, the water cut values under CO 2 injection are lower than those without injection.