【摘要】 混合润湿孔隙介质普遍存在,使得多相流体渗流过程十分复杂,但对其研究和认识至今仍很肤浅,是油气运移成藏、剩余油气分布等方面研究中必须解决的关键难题。本文通过对饱和水的混合润湿模型进行油自吸实验,观察不同混合润湿程度条件下油自吸运移过程,分析认识混合润湿孔隙介质中多相渗流的机理。实验结果表明,在混合润湿孔隙介质中油是否能够自发地运移与介质中亲油颗粒的比例关系密切,但并非简单的单调变化关系。研究认为,亲油颗粒与亲水颗粒随机分布,导致多种与喉道配位颗粒的亲油-亲水关系,当亲油颗粒比例占优才表现为亲油喉道。机理上,混合润湿孔隙介质中油自吸运移的发生与否及程度取决于亲油喉道在空间上的连通程度,后者与孔隙介质中亲油颗粒比例相当。仅有当孔隙介质中亲油颗粒足够多,且组成的亲油喉道能够相互接触形成连续亲油通道时,油才能够通过自吸运移进入多孔介质。更多还原

【Abstract】 Mixed wetting phenomena are widely observed in porous medium.Multiple-phase expulsions in such medium are complicated.However,studies on such mixed wettability are still very rare even it is important for hydrocarbon migration and accumulation,as well as residual oil distributions in reservoirs.In this study,oil imbibition experiments were systematically conducted using glass tubes filled with mixed-wetting glass beans.The multiplephase flowing behaviors in mixed-wetting porous medium with different proportion of oil wetting glass beans were observed.Experiment results show that the threshold of oil imbibition seems to be related to the proportion of oil-wetting beans in the medium.It is deduced that the pore throat may behaves as oil-wetting or water wetting,depending on the number of oil wetting grains the pore throat contains.When the grains which comprise the throat are dominated by oil-wetting grains,the throat may behave as oil-wetting,and vice versa.And oil car continuously imbibe into the medium only when the wetting throats connect each other to form complete pathway through the medium.When oil-wetting and water-wetting grains distribute randomly within the medium,the occurrence of oil imbibition and corresponding oil saturatior in the mixed wetting medium depends largely on the proportion of oil-wetting grains.更多还原