Study On Enhance Oil Recovery By Air Foam Flooding In QKX Reservoir

At present,the water cut of QKX reservoir increases and the oil production is low at the late stage of water injection development.The technology of air foam flooding can improve the displacement effect of general reservoirs after water flooding,and also has strong adaptability to heterogeneous reservoirs.Based on the questions of QKX reservoir,the experiments of crude oil low temperature oxidation,foaming agent evaluation and core displacement experiments were carried out.Based on the experimental data,the conceptual model of air foam flooding reservoir was established,and the effect of air foam displacement was analyzed and evaluated,finally the parameters of air foam injection were optimized.The experimental study on the oxidation of crude oil at low temperature shows that the oxidation characteristics of QKX reservoir crude oil are relatively good,and the crude oil will also undergo oxidation reaction under the condition of external temperature and pressure difference.Three kinds of foaming agents provided by the reservoir are screened and evaluated.It is found that X-4 foaming agent has good foaming and stability,also has better temperature and salt resistance,and the optimal concentration is 0.6%.Under the condition of QKX reservoir temperature 105 degree and 11128mg/L of the reservoir level,the foam index of X-4 foaming agent is489204m L.s,which can meet the development needs.The core displacement experiment based on QKX reservoir conditions shows that the recovery rate of 15.78%and 14.9%can be increased by using air foam continuous injection or slug injection development after the water flooding rate reaches 98%.The oil recovery effect is better than that of the air drive.Finally,the concept model of air foam flooding reservoir was built by CMG software,and the parameters of air foam injection were optimized.The injection scheme was:foam concentration is 0.6%,injection rate is 0.024PV/year,total injection volume is 0.14PV,gas-liquid ratio is 1.5:1,and injection slug combination is foam flooding(2 months)and water flooding(2 months).According to the prediction of displacement effect,the minimum moisture content can be reduced to 55.6%after the development of air foam,and the maximum oil recovery rate is 5.2m~3/d.After 12 years of development,the recovery rate is 13.4%and the final recovery is 45.2%.