低渗透裂缝性油藏水气交注非混相驱提高采收率研究

低渗透油田进入注水开发以后,由于储层天然裂缝发育,导致油井含水急剧上升,产量迅速下降,油藏采出程度低。为进一步提高油藏采收率,达到降水稳油的目的,进行了水气交注非混相提高采收率室内试验,通过实验分析了注入方式、气液比及温度对采收率的影响。实验结果表明,氮气驱+水-氮气交替注入段塞效果最好;气液比在1∶1至3∶1范围变化时,随着气液比增大,最终驱油效率提高,并且提高效果较明显;温度对水-氮气交注非混相驱的驱油效率有一定的影响但不明显。在低渗透裂缝性油藏实施水气交注非混相驱是切实可行的,具有较好推广应用价值。

Experiment research of Water alternating gas immiscible displacement EOR technology in fractured low permeability reservoir

After the water flood development of low permeability reservoir,water cut increased sharply,production decreased rapidly and caused low recovery because of the natural fracture.For the purpose of further improving oil recovery,reducing water cut and stabilizing oil production rate,a laboratory experiment of water alternating gas immiscible displacement is carried out.The influence of recovery on injection module,gas liquid ratio and temperature is analyzed.The results show that the injection of nitrogen flooding,water alternating nitrogen has a better effect.The improvement of recovery ratio is obvious with the gas liquid ratio increasing when the gas liquid ratio ranges from 1:1 to 3:1.The temperature is inconspicuous to the sweep efficiency of water alternating gas immiscible displacement. Therefore it is advisable to implement water alternating gas immiscible displacement in fractured low permeability reservoir and is value to extend and apply.