高含水期水平井提高水驱采收率机制

以孤岛油田地质及开发动态特征为基础,应用水驱油相似原理,建立三维大型物理胶结正韵律多层模型。当井组物理模型生产至高含水阶段,应用水平井以及直井在剩余油富集区进行挖潜,并结合数值模拟方法,研究不同储层参数以及工作制度条件下,水平井相对于直井扩大波及系数与提高驱油效率对提高采收率的贡献程度。结果表明:应用水平井进行高含水期剩余油挖潜,相对直井有着较大的优势;水平井相对于直井主要是通过扩大波及系数来提高水驱采收率,并且储层条件以及工作制度对波及系数与驱油效率的贡献率差异程度有着较大影响;随着含水率的上升,波及系数与驱油效率贡献率差异程度逐渐减小,但二者贡献率比值始终大于1。

Mechanisms of improving oil recovery efficiency by horizontal well in high water-cut stage

Based on the geological and production performance data in Gudao Oilfield, a large scale artificial consolidated multi-layer model reflecting the normal rhythm was established according to the similar principle of waterflooding. Considering different reservoir parameters and working system, horizontal and vertical wells were used to tap the potential respectively when well group physical model reaches high water-cut stage. And combined with numerical simulation, mechanisms of both sweep and displacement efficiency contributing to improving oil recovery with horizontal well compared with vertical well were studied. The results show that the effect of horizontal well tapping remaining oil is better than that of vertical well. Contribution of sweep efficiency to improving oil recovery with horizontal well compared with vertical well occupies main position, and difference between sweep efficiency and displacement efficiency contribution is affected by reservoir parameters and working system. With the increase of water cut, though the contribution differentiation degree between sweep efficiency and displacement efficiency becomes smaller and smaller, contribution ratio of sweep efficiency to displacement efficiency is always more than 1.