聚合物驱油之后剩余油分布规律研究

DISTRIBUTION REGULARITIES OF REMAINING OIL IN HETEROGENEOUS RESERVOIRS AFTER POLYMER FLOODING

聚合物驱是一种有效的提高采收率方法，大庆油田所用的聚合物是聚丙烯酰胺。聚合物驱提高采收率主要是靠增加注入水粘度，改善驱替液和被驱替液的流度比，进而扩大波及体积。聚合物驱通常可以提高采收率约１０％，它之后仍然有的５０％的原油残留地下，还需要采用其它方法，以进一步提高采收率。本文利用核磁成像技术、现代物理模拟和数值模拟方法，在具有大庆油层地质特征的物理模型和地质模型上对聚合物驱后剩余油分布规律进行了研究。结果表明，对于韵律油层，从纵向上看剩余油主要分布在中低渗透层，从平面上看主要分布在主流线两翼，这些认识对于进一步提高采收率方法选择具有参考价值。

Polymer－flooding is an effective way to enhance oil recover, polyacrylamide is frequently used for polymer－flooding in Daqing oilfield. Enhancing oil recovery in polymer flooding mainly depends on increasing the viscosity of injected water and improving the mobility ratio of driving liquid to displaced liquid with the sweep volume enlarged. After polymer flooding ,recovery ratio is raised 10%,but 50% of geological reserves still remains in original reservoirs. which needs to be produced by other methods for EOR. In this paper, NMR imaging techniques,modern physics and numerical simulation methods have been used to study the distribution of remaining oil in the heterogeneous physical model with geological characteristics of reservoirs of Daqing oilfield after polymer flooding. The results show that remaining oil after polymer flooding mainly distributes in middle－low permeable layers along longitudinal direction and in the areas far from main stream line on the plane level for rhythmic pay.These conclusions will provide experimental basis for choosing other methods to increase oil recovery after polymer flooding.