Abstract: This paper presents a new method for evaluation of oilfield development effectiveness by waterflooding, that is directly using the ratio of instantaneous composite water cut vs corresponding recovery percent to do it. This method is simple and plenty of data are available. The estimated parameters are of distinctive resolution for different types of reservoirs; for the same reservoir, the parameters are either characterized by changing with time, or by coherence and evident varied patterns. In particular, during mid-late period of oilfield development, these parameters tend towards being constant, which provide real evaluation of waterflooding efficiency; in late period of field exploitation, the method can be used for better evaluation of ultimate efficiency of an oilfield by waterflooding process.

Key words: oil field, water drive, raise velocity of water cut, development efficiency, evaluation