Abstract: By waterflooding process, the water storage rate and the water drive index are significant indices that reflect utilization status of injected water energy and comprehensively evaluate waterflooding effectiveness of oilfields. In view of existence of wrong correlation formula between cumulative water storage rate, cumulative water drive index and water cut on many literatures, this paper deduces correct theoretical relationships or formulae between them in terms of definitions of cumulative water storage rate and cumulative water drive index, integrated with six water drive characteristic curves recommended by the Oil and Natural Gas Standard. Using the series of formulae, the effective evaluation of water injection adaptability and waterfooding effectiveness in waterflooding oilfields can be made correctly.

Key words: water drive characteristic curve, water storage rate, water drive index, water cut