低渗透储层油水相对渗透率最优目标函数处理方法

对于非均质和亲水性强的低渗透岩心,使用常规JBN方法整理非稳态实验数据得到的相对渗透率曲线,存在因计算失效导致的水相相对渗透率曲线出现"驼峰"等异常现象.除了岩样的非均质性、出口端提前见水、驱替速度不合适以及难以测定油水黏度比等实验因素,利用JBN等常规方法处理非稳态水驱油实验资料的局限性是产生相对渗透率曲线异常形态的...

Optimal Objective Function Processing Method for Oil-Water Relative Permeability of Low-Permeability Reservoirs

For heterogeneous and hydrophilic cores with permeability,the relative permeability curve was obtained from the non-stationary experimental data by the conventional JBN method,and there were some anomalies such as"humps"in the water relative permeability curve caused by calculation failure.In addition to experimental factors such as heterogeneity of rock samples,early water breakthrough at the outlet,inappropriate displacement velocity,and difficulties in determining the oil-water viscosity ratio,the limitation of conventional methods such as JBN in processing the experimental data of unsteady water-oil displacement is the root cause for the abnormal shape of the relative permeability curve.To solve the above problems,an oil-water seepage model of low-permeability reservoir was established considering the effect of capillary force.The experimental data of oil-water relative permeability were processed by automatic historical fitting method,and the effects of different methods on the oil-water relative permeability of low-permeability core were compared and analyzed.The results showed that,compared with the JBN and Jones methods,the automatic history fitting method for oil-water relative permeability in low-permeability reservoir based on the optimal objective function was advantaged by smooth curve and obvious rules,and reduced the errors in the calculation of relative permeability in low-permeability reservoir to the greatest extent;when capillary force was considered,the results obtained by the three methods were that the oil relative permeability was increased,the water relative permeability was basically unchanged,and the automatic history fitting method reflected the trend of oil relative permeability in a more reasonable and uniform way.The automatic history fitting method overcame the limitations of conventional methods such as JBN,with better applicability,providing important parameters for subsequent numerical simulation and other studies.