特高含水期剩余油分布及形成机理

发布时间：2018-08-21 13:08

【摘要】：目前我国东部老油区普遍进入特高含水阶段,水驱开发效果变差,采收率明显下降,有效挖掘剩余油潜力是当前开发的重点所在.特高含水期油相主要以非连续状态存在于孔隙空间内,基于宏观认识的达西定律很难准确描述地下剩余油的真实流动状态.为摸清特高含水期剩余油分布状况,研究剩余油形成机理并挖掘剩余油潜力,基于N-S方程模拟油水两相在微尺度多孔介质内流动,运用相场方法实时追踪驱替过程中的两相界面,建立微观流动模型.研究特高含水期剩余油分布,并从力学角度分析残余油形成机理.结果表明特高含水期多孔介质内剩余油主要可以分为5种类型:孤立油滴、孔喉残余油、簇状非均质残余油、油膜、盲端残余油.毛管力,孔隙结构以及壁面润湿性是影响特高含水期剩余油的分布与类型的主要因素.孔隙尺度流动模拟得到的水驱曲线与矿场规律基本一致.特高含水期增注与注入表面活性剂均是通过驱替出簇状非均质剩余油,孔喉残余油以及孤立油滴达到提高剩余油采收程度的目的.簇状非均质剩余油的减少是采收程度提高的主要原因.矿场增注时机对经济开发有重要影响.该研究初步揭示了特高含水期剩余油分布及形成机理,为水驱油藏的后期开发提供有效指导.
[Abstract]:At present, the old oil area in the east of China has generally entered the stage of super high water cut, the effect of water drive development has become worse, and the oil recovery is obviously decreased. The key point of current development is to effectively tap the potential of remaining oil. The oil facies in ultra-high water-cut period mainly exist in the pore space in discontinuous state. Darcy's law based on macroscopic understanding is difficult to accurately describe the true flow state of underground remaining oil. In order to find out the distribution of residual oil in high water cut period, study the formation mechanism of residual oil and exploit the potential of remaining oil, the oil-water two-phase flow in microporous media was simulated based on N-S equation. The micro flow model was established by using phase field method to track the two phase interface in the displacement process in real time. The distribution of residual oil in super high water cut period was studied, and the mechanism of residual oil formation was analyzed from the point of view of mechanics. The results show that the remaining oil in porous media can be divided into five types: isolated oil droplets, pore throat residual oil, cluster heterogeneous residual oil, oil film and blind end residual oil. Capillary force, pore structure and wall wettability are the main factors that influence the distribution and type of remaining oil in super high water cut period. The water drive curve obtained by pore scale flow simulation is basically consistent with the field law. Both injection and injection of surfactants in ultra-high water cut stage are achieved by flooding out cluster heterogeneous residual oil, pore throat residual oil and isolated oil droplets to improve the recovery degree of remaining oil. The decrease of cluster heterogeneous residual oil is the main reason for the increase of recovery degree. The timing of increasing injection has an important effect on economic development. This study initially reveals the distribution and formation mechanism of remaining oil in ultra-high water cut period, and provides effective guidance for the later development of water drive reservoir.
【作者单位】：中国石油大学(华东)石油工程学院;
【基金】：国家科技重大专项(2016ZX05011-001,2016ZX05061) 国家自然科学基金(51490654,51504276,61573018);国家自然科学基金(51404291) 泰山学者建设工程专项山东省自然科学基金(ZR2016EL09) 中国石油大学研究生创新工程(YCX2017021)资助
【分类号】：TE327

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