应用CT技术研究交联聚合物驱油机理

Research on Oil Displacement Mechanism of Crosslinked Polymer Using CT Technique

为了进一步明确交联聚合物在岩心驱替中的运移特征,深入分析其驱油机理,用河南油田天然岩心,开展了交联聚合物驱油实验。利用计算机断层扫描(CT)技术,对交联聚合物的驱油过程进行跟踪扫描,重建了干岩心的孔隙结构,获得了在不同驱替时刻下,在岩心不同位置的交联聚合物运移特征图像。实验结果表明,CT技术可以用于研究交联聚合物溶液的运移特征,由CT扫描后经计算得出的孔隙度相对误差很小;交联聚合物在非均质性较强的岩心中仍以近活塞的形式向前运移,注入压力在上升一段时间后即保持平稳,表明交联聚合物可以有效扩大波及体积,提高微观驱油效率。

In order to further clear the migration feature of crosslinked polymer flooding in the core, analyzing thoroughly its flooding mech- anism, taking a natural core from an oilfield as research object, the crosslinked polymer flooding experiment was made using computed tomography （CT） technique, the tracking scanning of the process of crosslinked polymer flooding was used for rebuilding the pore structure of dry core and migration feature images of crosslinked polymer at different displacement time and different locations in the core. Experiment results show that CT technique can be used for study of the migration feature of crosslinked polymer, the porosity calculated by the CT is very accurate, the relative error is only 0.93% compared with the measured value; the displacement front of crosslinked polymer in a strong heterogeneity core is still close to the piston, and the injection pressure is increasing for the initial time and then holding steady, indicating that crosslinked polymer can be used for expanding swept volume effectively, and improving microscopic oil displacement efficiency.