Abstract: On the basis of a new oil phase relative permeability curves,combined with the material balance equation and Welge equation,a new model for predicting water cut is derived.Under certain conditions,it can be converted to the Logistic model.In the new model,the relationship between undetermined coefficients,development dynamic and geological static parameters is clear,so many water control measures have become more theoretically supported.Meanwhile,combined with water-oil relative permeability curves and Welge equation,either the Logistic model,the Goempertz model or Usher model cannot be deduced.Furthermore,some limiting conditions remain in our solution,such the new model requires that the number of wells still not be changed.However,coupling and direct methods have been proposed to build prediction model of water cut.By means of expanding the two methods,with rich,diverse prediction models of water cut,it has been fully possible to describe the complex and diverse water content and process of time change.After field applications of the model,positive results are acquired,and thus may be applied to other oil fields.

Key words: water cut, prediction model, permeable flow theory, coupling method, water-flooding field