渤海油田早期聚合物驱动态规律及见效时间判断方法

Dynamic law and method of judging effective time of early polymer flooding in Bohai Oilfield

基于渤海某油田数据,建立典型模型,进行不同时机聚合物驱含水率、产油量变化规律研究。提出无因次见效时间的定义,判断早期聚驱的见效时间,分析注聚时机、纵向变异系数和流度比对无因次见效时间的影响,提出不同时机聚合物驱见效时间判断原则。结果表明:早期聚驱存在临界注聚时机,大于该临界值时,含水率曲线形态与中后期聚驱一致,有明显的下降漏斗;小于该临界值时,在整个开发过程中不会出现下降漏斗,而处于缓慢上升趋势;是否出现含水率下降漏斗不能作为判断注聚见效以及确定见效时间的唯一标准。利用生产数据对数学模型进行检验,相对误差小于10%,能够满足工程精度要求。

A typical model was constructed based on data in Bohai Oilfield, and the variation laws of water cut and oil pro- duction rate with different polymer injection time were studied. The definition of dimensionless effective time was proposed to judge the effective time of early polymer flooding. And the influences of polymer injection time, coefficient of variation and mobility ratio on the dimensionless effective time were analyzed. The judgement standard of effective time for polymer flooding with different polymer injection time was proposed. The results show that early polymer flooding exists a critical injection time, and if injection time is greater than the critical value, water cut curve would have significant decrease funnel, if less, it would not show decrease funnel. So the appearance of decrease funnel could not be the only standard to determine the ef- fective time. The model was tested based on the available production data, and the relative error is about less than 10%, which can meet the engineering precision demands.