Abstract: The basis of the application of water-drive characteristic equation is the empirical research. This method shows the better linear relationship to the whole historical data. The forecasted semi-logarithmic water-drive characteristic curve is in accordance with the result of numerical simulation. By means of this method, the status and characteristics of an oil field development could be better described. This paper presents an optimum to the current linear water-drive characteristic equations and puts forward a method for forecasting the incremental trend of recoverable reserves with envelope-tangent approach. The case study shows that this method is reliable for evaluating the effect of stimulation in a waterflood oil field.

Key words: water drive, waterflood, characteristic curve, recoverable reserve, forecast, prediction, method, approach