关键词: 低渗透油藏, 动态渗透率效应, 试井解释模型, 数值方法, 启动压力

Abstract:

The permeability and start-up pressure gradient will increase with the increase of the displacement pressure gradient when the displacement pressure is low in the low-permeability reservoir.However,those parameters will become constant numbers as the displacement pressure gradient is over a critical value.A well test interpretation model was established by taking into account the mutative permeability effect.This model was solved with simulation method.The calculation showed that the shorter lasting time of mutative permeability corresponded a greater start-up pressure gradient,and the double log pressure and derivative pressure curves were more obviously upward,when the maximum value of permeability was equal with the minimum value.The curves calculated with the new model were more gentle than those obtained from the start-up pressure gradient method.More logical and reliable results could be obtained.The pressure curve of mutative permeability effect was more gentle,and the upward time of the curves was earlier than that obtained from the closed boundary effect,and the distinction point was obvious on the curves.

Key words: low-permeability reservoir, mutative permeability effect, well test interpretation model, numerical method, start-up pressure