大庆油田二类油层复合驱注入方式优化

三元复合驱技术在大庆油田的应用对象将主要集中于剩余地质储量相对较大的二类油层。与主力油层相比，二类油层储层物性条件明显变差，平面、纵向非均质性更为严重。针对二类油层非均质性更为严重的特点，系统地开展了二类油层复合驱注入方式优化研究，并找到了一种更适合于二类油层的复合驱注入方式，即不同分子量聚合物组合的高黏度聚合物段塞与低黏度三元体系交替注入方式，并对该注入方式进行了优化研究。研究结果表明，采用该注入方式进一步扩大了复合驱波及效率，提高了复合体系在低渗层的吸液量，有效改善了3种化学剂的利用率。与三元体系笼统注入方式相比，采用该注入方式进一步提高采收率5%（OOIP），同时化学剂费用降低近20%。

Optimization of the ASP flooding injection pattern for sub-layers in Daqing oilfield

In the Daqing Oilfield,the alkaline-surfactant-polymer(ASP) flooding will mainly be applied in sub-layers that have relatively large remaining geological reserves.Compared with major oil layers,sub-layers show obviously poor reservoir properties and their plane and vertical heterogeneity becomes more severe.In view of these characteristics of sub-layers,we systematically studied the optimization of the ASP flooding injection in sub-layers and proposed an ASP flooding injection method more suitable for sub-layers,i.e.alternative injecting the different molecular-weight polymer slug with high viscosity and the ASP slug with low viscosity.The optimization for this alternative injection method was studied in detail.The result shows that this injection further expands the sweep efficiency of the ASP flooding,enhances the accepting fluid amount of the ASP system in low-permeability layers and effectively improves the utilization of these three chemicals.Compared with the conventional ASP injection,this novel approach further enhances the oil recovery by about 5% of OOIP and reduces the chemical cost approximately by 20%.