南华201区块注CO_(2)最小混相压力预测

Prediction of minimum miscibility pressure for CO_(2) injection in Nanhua 201 block

本文主要通过细管实验,研究不同压力下注入CO_(2)的采出率、气油比随注入CO_(2)孔隙体积的变化规律,确定南华201区块CO_(2)注入的最小混相压力。结果表明:在非混相驱时,采出程度与注入孔隙体积呈正相关,注入气体突破后,采出程度增加幅度不大;在混相驱时,气油比在注入气体突破后迅速上升,充分表明了注入气的整个过程是经过多次接触并不断使注入CO_(2)更加富化的过程。与非混相驱对比,混相驱的采出程度趋势相同但增加幅度大,采油效果更好。采出程度变化情况与注入压力相关,注入压力不同,采出程度也不相同。南华201区块注CO_(2)最小混相压力为23.7 MPa。

The minimum miscible pressure of CO_(2) injection in Nanhua 201 block was determined by studying the variation law of CO_(2) recovery rate and gas-oil ratio with the pore volume of CO_(2) injection under different pressures through the thin tube experiment.The experimental results show that in miscible flooding,the recovery degree was positively correlated with the injected pore volume,and the recovery degree increased slightly after the injected gas break through.In miscible flooding,the gas-oil ratio rose rapidly after the injected gas break through.It showed that the whole process of gas injection was a process of enriching CO_(2) injection continuously through multiple contacts.Compared with immiscible flooding,the recovery degree trend of miscible flooding was the same,but the increase range was large,and the oil recovery effect was better.The change of recovery degree was related to injection pressure,and recovery degree was different with injection pressure The minimum miscible pressure of CO_(2) injection in Nanhua 201 block was 23.7 MPa.