Abstract: It is well known that the change of the rock relative permeability will effect on oil and water flow in the formation, therefore, the change will greatly effect on the shape of well test curve. In this paper, a numerical well test method is presented to study the influnce of different relative permeability curves on the well test curve, PEBI grid is used to discretize control equations of oilwaterphase flow in FEBI grid, which couples the wellbore storage and skin effect into account. The flow model for pressure drawdown well test is derived. According to comparing and analyzing the result calculated by numerical well test model pointing to different relative permeability curves, it is shown that the relative permeability of oil phase drawing down or building up will lead to the change scope and velocity of bottomhole pressure correspondingly increasing or reducing, consequently, well test curves will warp up or drop down.

Key words: oil water phase flow, numerical well test, black oil model, PEBI Grid, relative permeability curve