Abstract: The author replies to related refutations in the article “Study on the relation between formation oil viscosity and water drive curve method", and points out that it is not true that “ predicting results are the same basically” for same oilfield using four water drive curves by Sazonov, Maximov-Tong, Sipachev and Nazarov, which will be a misguidance to application of the curves. In terms of this viewpoint of the article, some reservoir engineers could be misguidance to select one of the curves on big side to make calculations for outstanding effectiveness of oilfield development and adjustment, thus leading to the incorrect knowledge and decision to be made,being harmful to oilfield development. This paper presents the derived process of water cut vs recovery percent of recoverable reserves corresponding to water drive curve, and shows that the viewpoint of using crude oil viscosity to select water drive curve has been commonly acknowledged by the researchers at home and abroad. The results calculated by applying MaximovTong and Nazarov's water drive curves are somewhat on big side compared with the actual values, but both of them are not first choice even in former Soviet Union and in Russia. Two new generalized water drive curves proposed by Chinese researchers, which have far exceeded these four important water drive curves in performance presented by former USSR, should be spread as soon and fast as possible in China. It is of utmost importance to guide our oilfield development with proper predicted results. .

Key words: Water drive curve, Viscosity, Selection, Development index, Recoverable reserves