Abstract: The recoverable reserves and the remaining recoverable reserves are important indices for oil-gas development. The remaining recoverable reserves should be as a material base for it in future. For waterflooding oilfields, the methods for prediction of recoverable reserves include water drive curve, production decline, forecast model and numerical simulation. However, when a oil-gas field gets into late stage, the production decline becomes lhe most forecast method, which is also one of generally applied methods for forecasting recoverable reserves in the world. Based on this method, this paper presents the methods for quickly forecasting the technologically recoverable reserves, economically recoverable reserves, remaining technologically recoverable reserves and remaining economically recoverable reserves. The practicability, effectiveness and reliability of these methods have been confimed by 12 oilfields in China.

Key words: forecast, oil-gas field, technologically recoverable reserves, economically recoverable reserves, remaining technologically recover-able reserves, remaining economically recoverable reserves