剩余油分布的微观特征及其可动用程度的定量表征

目前微观剩余油定量表征研究存在宏观与微观分析结果差距大、图像不清晰、分析方法相对较少等问题。针对上述问题,利用岩心驱油实验、冷冻制片技术、岩心荧光分析等方法,对不同驱替方式、岩心不同位置、不同类型微观剩余油的分布特征和可动用程度进行了分析。结果表明:岩心注入端、中间端、采出端的剩余油比例依次升高。水驱后剩余油以自由态和束缚态为主,合计占比为93.65%,半束缚态只占6.35%。聚合物驱对簇状、粒间吸附状、孔表薄膜状、角隅状剩余油作用明显。三元复合驱后剩余油比例较高的是粒间吸附状、颗粒吸附状和孔表薄膜状。荧光分析与岩心驱油实验结果差别很小,验证了分析结果正确性。

Microscopic characteristics of remaining oil distribution and quantitative characterization of its producibility

At present,there are some problems in the quantitative characterization of microscopic remaining oil,such as large gap between macro and micro analysis results,unclear image and relatively few analysis methods.In view of the above problems,by means of core displacement experiment,frozen slicing technology and core fluorescence analysis system,the distribution characteristics and producing degree of microscopic remaining oil in different displacement modes,different core positions and different types were analyzed.The results show that the ratio of remaining oil in injection end,middle end and produced end of core increases in turn.After water flooding,the remaining oil is mainly in free state and bound state,accounting for 93.65%in total,and only 6.35%in semi bound state.Polymer flooding has obvious effect on remaining oil with cluster,intergranular adsorption,thin film on pore surface and corner.After ASP flooding,the proportion of remaining oil with granular adsorption and intergranular adsorption is high.There is little difference between the results of fluorescence analysis and core flooding experiment,which verifies the correctness of the analysis results.