海上稠油油田聚驱后二元复合驱注入时机与注入方式优选

模拟海上绥中36-1油田油层条件,进行了聚合物驱后二元复合驱注入时机、注入方式的优化实验研究。聚合物驱后在不同注入时机(直接转注、含水最低点、含水70%和含水95%时)转注二元复合体系,最终采收率分别为75.36%、73.32%、71.22%和68.61%,直接转注二元驱的采收率最高(42.61%)。在相同水驱条件下,以不同注入方式注入二元复合体系后发现,注入0.3 PV二元复合体系的驱油效果优于注入0.05 PV聚合物+0.2 PV二元复合体系+0.05 PV聚合物和0.1 PV聚合物+0.2 PV二元复合体系。但注入方式的改变对最终采收率的影响较小,以聚合物做保护段塞更有利于控制工业化成本。在相同段塞聚合物用量条件下,用前后保护段塞的效果好于单一前置段塞。在等经济的条件下,聚合物驱后进行0.3 PV二元复合驱可提高原油采收率19.05%,比等价的0.7 PV聚合物驱采收率高1.61%,使油田开发的整体效益最大化。

Optimization on Injection Timing and Pattern of Binary Composite Flooding after Polymer Flooding of Heavy Oil in Offshore Field

In this study, simulated the reservoir conditions of Suizhong 36-1 offshore oilfield, the optimization experiments of injection timing and injection pattern of the binary composite flooding after polymer flooding were developed. After polymer flooding, the launching of binary composite system was studied at different injection timing, including direct injection, water content ratio of the lowest point, 70% and 95%. The results showed that the ultimate recovery rate was 75.36%, 73.32%, 71.22% and 68.61%. The oil recovery of binary composite flooding in directly conversion after polymer flooding was the highest (42.61%). At the same water flooding conditions, the effect of injection mode of binary composite system on oil displacement efficiency was compared. The result showed that the oil displacement efficiency of 0.3 PV binary composite system was better than that of 0.05 PV polymer+0.2 PV binary composite system+0.05 PV polymer and that of 0.1 PV polymer+0.2 PV binary composite system. But the effect of injection mode on the ultimate recovery rate was not big. Using polymer as protection slug was more advantageous to control the cost of industrialization. And the flooding effect of before and after protection polymer slug was better than that of single front slug if polymer dosage of the slug was same. Under the same economic condition, the oil recovery ratio of polymer+0.3 PV binary composite flooding increased 19.05%, which was higher than that of the equivalent 0.7 PV polymer flooding by 1.61%, maximizing the overall effectiveness of oilfield development.