Abstract: Water cut curve is the basic curve used to research the water-yielding rules of the water drive oilfield. This paper reviews the existing research methods for the water-yielding rules, presents the difference between the lab core and the real reservoir in macroscopic and microscopic geologic characteristics, integrated with the relative permeability curve and the methods for determination of the volumetric conformance efficiency of lab core and the real reservoir, and proposes a new method-conformance efficiency modification method that can be used to determine the theoretic water cut curve of the water drive oilfield. The case study indicates that the calculated theoretic water cut curve is more accordant with the actual performance than the existing methods.

Key words: water cut, recovery percent, relative permeability curve, volumetric conformance efficiency