海上高含CO_2高含凝析油气顶油藏提高采收率研究

Research on Enhancing Oil Recovery for Gas Cap Reservoir with High CO_2 and Condensate Oil & Gas on the Sea

基于高含CO_2高含凝析油气体样品的室内PVT实验结果,利用Eclipse数值模拟软件进行模拟注CO_2和CH_4膨胀对凝析气相态的影响,同时对该油田进行合理开发方式和开发井型井位优选,研究发现CO_2和CH_4均能使凝析气体系的弹性膨胀能力增强、最大反凝析压力降低及最大反凝析油量减少;循环回注采出气开发比衰竭开发提高油环油采收率约11.0%、提高凝析油采收率约45.0%;水平井开发效果好于直井,形成了一套此类气顶油藏高效开发的模式。结果表明,循环回注采出气对于高含CO_2高含凝析油的凝析气顶,一方面可以保持凝析气顶的压力;另一方面CO_2和CH_4可以降低凝析气体系的露点压力、抑制凝析油的反凝析,从而提高凝析油采收率,同时CO_2和CH_4较强的弹性膨胀有利于气顶对油环油的驱替,提高油环油采收率,是最为合理的开发方式;水平井平行气油界面布井对于小跨度、低油柱高度的油环可以有效延缓气水锥进,提高油环油采收率,是最为合理的开发井型和井位。

Based on the indoor PVT experimental result of gas samples with high CO_2-containing and condensate oil & gas,using Eclipse simulation software to simulate the effects of inflation on injecting CO_2 and CH_4 condensate vapor state,while the rational development of the oil field and the way development wells type wells preferably,the study found that CO_2 and CH_4 are elastic expansion capability enables the gas condensate system enhancement,the maximum counter-pressure condensate and reduce the maximum reduction in fuel anti-condensate; produces gas reinjection development cycle than the failure to improve development oil recovery oil ring about 11. 0%,increases condensate recovery of about 45. 0%; horizontal well is better than vertical wells,which forms s set of high effective development model. The results show that the produced gas for re-injection cycle of condensate gas cap with high CO_2-content and condensate gas &oil cap,on the one hand to keep the top of the condensate gas pressure; the other hand,CO_2 and CH_4 can reduce the dew point pressure of condensate gas system,suppressing anti-condensate condensate,thereby increasing condensate recovery,while CO_2 and CH_4 strong elastic expansion of the gas cap can be beneficial to the oil ring oil flooding,enhancing oil recovery oil ring,which is the most rational development approach. The horizontal wells parallel gas-oil interface cloth well for small span,low oil column height of the oil ring can effectively delay the gas and water coning,enhanced oil recovery oil ring,to be the most reasonable type of development wells and wells.