特低渗透油藏CO_2驱室内实验研究

RESEARCH ON LABORATORY EXPERIMENTS OF CO_2 DRIVE IN ULTRA-LOW PERMEABILITY RESERVOIR

针对大庆外围油田特低渗透油藏剩余油潜力大、井网加密效益差、水驱采收率低等问题,提出了特低渗透油藏CO2驱技术。通过细管实验和天然岩芯CO2驱油实验,确定了CO2与高台子油田原油的最小混相压力,评价了特低渗透砂岩油藏CO2驱油效果。实验结果表明,CO2驱可以应用于高台子油田,并取得较好的驱油效果。当天然岩芯空气渗透率为0.58 mD时,在水驱基础上,气驱可以进一步提高采收率8%以上,特低渗透油藏实施CO2驱油技术是可行的。

Aiming at the following problems in the ultra-low permeability reservoir in Daqing external field,such as big residual potential,poor infilling effect,low oil recovery ratio of water flooding,the CO2 flooding technology of the ultra-low permeability reservoir is put forward.Through the slim tube experiment and the CO2 displacement experiment of natural core,the minim miscibility pressure of CO2 and oil of Gaotaizi Oilfield is obtained.The displacement effects of CO2 flooding on ultra-low permeability reservoir are evaluated.Laboratory study results show that CO2 flooding can be applied in Gaotaizi reservoir,and good displacement effects can be obtained.When the airperme ability of naturalcoreis 0.51 mD,the CO2 flooding canenhan ceoilrecovery formore than 8 percentages after water flooding.It is feasible to carry out CO2 flooding in ultra-low permeability reservoir.