多层非均质储层聚合物驱剖面返转特征实验

Experiment of polymer flooding profile inversion characteristics in commingled heterogeneous reservoirs

多层非均质储层聚合物驱剖面存在吸液剖面返转现象,影响最终采收率。文中基于三层非均质并联岩心聚合物驱实验,总结了双层并联模型剖面返转特征,研究了非均质程度对剖面返转的影响,对比了层内和层间非均质剖面返转及聚合物驱效果的差异性,并给出了多层非均质储层聚合物驱开发建议。实验表明:多层非均质储层中的剖面返转呈现逐级启动的规律,低渗层可延缓中渗层返转时机,聚合物驱采收率提高1.78百分点;储层非均质性越强,中渗层返转时机越早,返转幅度越低,渗透率变异系数大于界限值(1.34~1.75),低渗层延缓返转作用失效;相比层间非均质储层,层内非均质储层返转时机更早,聚合物驱效果更差。研究成果为多层非均质储层聚合物驱剖面返转的预测及开发对策提供了借鉴。

The effect of entry profile inversion during the process of polymer flooding in commingled heterogeneous reservoirs significantly affects the ultimate recovery.Firstly,based on the triple parallel heterogeneous cores,polymer flooding experiments were carried out and the profile inversion characteristics were summarized.Then the influence of heterogeneity of commingled reservoir on profile reversion and development performance was studied.Finally,the difference of profile inversion and polymer flooding performance between inner and interlayer heterogeneous reservoirs was compared,and corresponding development suggestions were given.The results show that the entry profile inversion in commingled reservoirs presents a mode of progressive starting,and low permeability formation can delay the inversion timing and enhance the oil recovery by 1.78%.The stronger the heterogeneity is,the earlier the inversion timing and the lower the inversion magnitude are.When the permeability variation coefficient is greater than the threshold value(between 1.34 and 1.75),the inversion delaying effect of low permeability formation is disabled.Compared with interlayer heterogeneous reservoirs,the inner-layer heterogeneous reservoir has earlier inversion timing,and worse production performance.The results provide references for prediction and prevention of profile inversion effect during polymer flooding in commingled heterogeneous reservoirs.