Abstract: There is pressure sensitive effect in ultra⁃low permeability reservoirs. It is of great significance for the development of oil fields to study the variation of matrix permeability with pore fluid pressure. Through the core simulation experiment in Chaoyanggou area with changing the fluid pressure to change net pressure, which reflects the real situation of the formation, the curve of the permeability with the change of net pressure is obtained, and the model of the relationship between net pressure and permeability is regressed. The results of the study show that the permeability varies significantly with net pressure, and the percentage of permeability change is about 20% in the stage of decreasing fluid pressure. The permeability does not change significantly with net pressure, and the percentage of permeability change is about 5% in the stage of increasing fluid pressure. At the stage of increase or decrease of fluid pressure, subsection fitting is adopted, and the change rule of permeability with net pressure basically accords with binomial relation with the correlation coefficient more than 0.99.

Key words: Ultra?low permeability, Net pressure, Pressure?sensitive effect, Core experiment

摘要： 特低渗透储层中存在压敏效应，进行渗透率随孔隙内流体压力的变化规律的研究对油田开发意义重大。通过对朝阳沟地区岩心模拟实验，采用改变孔隙内流体压力改变净压力的方法，可以更真实地反映地层的真实状况，得出渗透率随净压力变化曲线，回归了净压力与渗透率的关系模型。结果表明，特低渗透油藏中，因压敏效应，在流体压力减少阶段，渗透率随净压力变化显著，渗透率变化率大约20%；在流体压力增加阶段，渗透率随净压力变化不明显，渗透率变化率大约5%；在流体压力增加或减少阶段采用分段拟合，得出渗透率随净压力变化规律基本符合二项式关系，相关系数达到0.99以上。

关键词: 特低渗透, 净压力, 压敏效应, 岩心实验