Abstract: The Y1 water drive curve, which is a generalized water drive curve, can reflect different laws of water cut raising by its slope b. In terms of varying oil viscosity μ₀ in different formations obtained from domestic oilfields, it can be divided into low viscosity (μ₀< 3 mPa·s), medium viscosity (3 mPa·s<μ₀< 30 mPa·s) and high viscosity (μ₀> 30 mPa·s). According to data of 34 oilfields with low viscosity, 35 oilfields with medium viscosity and 19 oilfields with high viscosity, calculation of b for these fields are made by using Y1 water drive curve. After constructing the contact of b and permeability K, it is found that these fields can be divided into three types in terms of low permeability (K< 100×10^-3 μm²),medium permeability (100×10^-3 μm²<K< 600×10^-3 μm²) and high permeability (K> 600×10^-3 μum²). According to b, K and μ₀ from these 88 oilfields, binary regression method is applied to obtain regression equations for calculating b,which can be used to predict the relationship of water cut Vs recovery of recoverable reserves for development evaluation and design of the new oilfields. An example shows that the results calculated by using these equations have a certain accuracy.

Key words: water drive curve, water cut, recovery factor, prediction