After more than a calendar year round water injection, Tahe oilfield No.4 district Ordovician reservoirs single well unit oil-water interface is continuous lifting of oil, the majority has entered the stage of failure, the remaining oil in the structural highs gathered to form a so-called"attic oil". Based on the theory of gas injection alternate"attic oil", and in order to further enhance the recovery efficiency of Tahe oilfield No.4 district, it carries out chooses nitrogen gas injection development by choosing independent wewing hole structure,better effect for pre-injection and current failed single well unit. At present, gas injection oil recovery is still in the experimental stage in Tahe oilfield No.4 district, only selecting TK404, T415CH, T416 and TK489 well small-scale injection, and taking TK404 well for example, through the optimization ofgas injection, bored wells time, ways of gas injection oil recovery and speed of gas injection, the reasonable methods of gas injection were summed up; and by the analysis of produce dynamic changes condition after gas injection, it obtained the conclusion that gas injection improves oil recovery in Tahe oilfield No.4 district.% 塔河油田4区奥陶系油藏单井单元经过历年多轮次注水替油，油水界面不断抬升，多数已进入失效阶段，剩余油在构造高部位聚集，形成所谓的“阁楼油”。在注气驱替“阁楼油”的理论基础上，为进一步提高塔河4区采收率，选择具有独立缝洞结构，前期注水替油效果较好且目前已失效的单井单元，进行注氮气开发。目前注气采油在塔河4区仍处于实验阶段，仅选取TK404、T415CH、T416及TK489井小范围试注，以TK404井为例，通过对注气量、闷井时间、注气采油方式、注气速度进行优化，总结出合理的注气方法；通过对注气后生产动态变化情况的分析，得出注气提高采收率在塔河4区切实可行的结论。
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