Abstract: As the most fundamental method for research of oilfield water cut, prediction of production index and calibration of recoverable reserves, the waterflood characteristic curve method comes to more than 70 types at home and abroad, among which some can be converted into others, and some can be simplified into another one by identical transforming and special parameter taking. This paper classifies the curves into a structure with five levels and nine types as well as corresponding inverse water cut and recovery percent diagram, which can be as a guide for the application (including programming), optimization, management and study of such characteristic curve methods in future.

Key words: waterflood characteristic curve, system, classification, water cut, recovery percent