聚合物驱能否提高驱油效率的几点认识

通过对相距只有30m的检查水驱效果的北1-6-检27井与检查聚合物驱效果的1-6-检26井驱替效果的对比分析,认为聚合物驱只是改变了油水流度比,扩大波及体积,进而提高了驱油效果。但是,由于聚合物并不能降低表面张力,因此,从道理上讲也不能减少油膜损失或者说提高驱油效率。与水驱相比,虽然人们观察到的现象是驱油效率的提高,在岩心分析中表现出来的是将中水洗变为强水洗,基于两口井中小层驱油效率最高值的一致性,可以推论如果继续水驱,那么将中水洗逐渐变为强水洗也是完全可能的,只是时间的长短而已,这是因为驱油效率定义本身并不受时间的限制。因此,确切地说聚合物驱可以提高波及效率,但不能认为聚合物驱可以提高驱油效率。

UNDERSTANDINGS FOR WHETHER POLYMER FLOODING CAN IMPROVE DISPLACEMENT EFFI-CIENCY OR NOT

Through comparison and analysis on flooding result of two inspection wells only 30m apart,i.e.north 1 6 inspection well 27 for inspecting water flooding result and north 1 6 inspection well 26 for inspecting polymer flooding result,this paper deems that the polymer flooding only changes mobility ratio between oil and water,enlarge a sweeping volume and improves oil displacement efficiency.But because polymer could not decrease surface tension, it theoretically could not decrease oil film loss or improve oil displacement efficiency.Although we can see the improvement of a displacement efficiency compared with water flooding,core analysis shows that oil bearing layer changes from medium water flushed to strong water flushed,and based on the identical maximum value of sweep efficiency of small layers in the two wells,we can infer that if water flooding is continued for long time,it is quite possible to change medium water flushed to strong water flushed gradually because the definition of a displacement efficiency itself is not limited by time.Therefore,we can make sure that polymer flooding can obviously improve a sweeping efficiency,but do not think it can improve oil displacement efficiency.