中文摘要：

中原油田部分区块属于高压低渗透油藏,油层温度高、矿化度高、注入压力过高、注水开发困难。为改善CO2气驱开发效果,达到混相驱替,选取混相压力调节剂降低最小混相压力。实验测试不同浓度调节剂降低最小混相压力的效果,优选出混相压力调节剂浓度为0.3%（质量浓度）,最佳调节剂注入段塞为0.1孔隙体积,最佳注入方式为（当总注入量）大段塞注入。结果表明,混相压力调节剂能明显改善气驱开发效果,为提高类似油藏气驱采收率提供依据。

英文摘要：

Some high-pressure ＆ low-permeability blocks of Zhongyuan oilfield have the following characteristics： high pressure,high temperature,high salinity,and low permeability. The layer injection pressure is too high to water injection. In order to promote the recovery efficiency of CO2 flooding to achieve miscible displacement,it selects miscible modulator to reduce the minimum miscible pressure. Using experimental method to test the effect of different concentration and different slug of modulator to reduce the minimum miscible pressure,optimizing the appropriate miscible modulator concentration is 0. 3%（ mass concentration）,and the optimal modulator injection slug is 0. 1 pore volume. At the same time,we get the conclusion that the best injection way is long slug injection,when the injection slug is the same. The results show that the miscible modulator can significantly improve recovery efficiency of gas flooding. It has important guiding significance for the similar reservoir development.