Analytical study on the Critical Water Cut for Water Plugging: Water cut increasing control and production enhancement

During the high water-cut period, water plugging treatment is a commonly selected development strategy to reduce the production decline rate. However, determination of the appropriate water-cut to implement water plugging is rarely studied and therefore it is often decided based on the experience of reservoir engineers, which could result in potential oil production loss and ineffective water plugging treatment. In this paper, an analytical model to predict water-cut increasing was derived and the increase in water-cut under different pressure drawdown multipliers was examined. Then, an approach to determine the critical water cut to apply plugging was proposed and the critical condition of water plugging in high water-cut formation was analyzed. Based on the sensitivity study conducted at different water-cut and different pressure drawdown multipliers, the lower oil viscosity leads to a lower critical plugging water cut, which implies that water plugging treatment might not be suitable for all types of reservoirs. Furthermore, this finding is practiced in actual oilfield extraction and the critical plugging water-cut calculation method does improve production performance. Thus, this analytical approach is capable to enhance oilfield production performance and optimize the effectiveness of water plugging.