聚驱油藏后续水驱阶段低效循环判定方法

Method of judging low efficient circulation in sequent water flooding period of polymer flooding oilfield

油田进行聚驱开发时,注入的聚合物会对油水井间已经形成的窜流通道起一定的改善作用,但是转后续水驱开发后,油水井间会再次形成窜流通道,在油水井间形成注入水的低效循环场。根据聚驱后续水驱阶段油水井的动态特征,结合实际油田的井史数据,选取注水井注入压力的下降程度,生产井见聚浓度的增长速率,采注比增长速率以及生产井采液突进强度作为判断后续水驱阶段形成低效循环的动态指标,采用层次分析法求取各指标权重,并利用模糊综合判定方法建立判定后续水驱阶段低效循环形成时机的模型。应用该模型对胜利GD油田后续水驱生产井组进行判定,结果表明,所建模型科学合理,计算结果可靠。

The polymer can remedy the low efficiency circulation which has formed while the field is developed by polymer flooding, but the low efficiency circulation may arouse again during the sequent water flooding. According to the performance of oil and water wells after low efficient circulation formed during the sequent water flooding, combined with the historical data in actual block, selecting declining degree of injection pressure, growing rate of polymer concentration, ascending factor of production factor per flooding unit and dashing level of liquid production as the dynamic indexes and weighting all of the indexes by applying analytical hierarchy process, a judging model for the forming time of low efficient circulation during the sequent water flooding was established by using the fuzzy integrated evaluation. The model is applied to distinguish the well groups of Shengli GD Oilfield, and the results show that the established model is reasonable and dependable.