用状态方程模拟注气对凝析气藏采收率的影响

提高凝析油采收率和整体开发效益是凝析气藏开发的目标,注气是防止凝析油析出从而提高凝析油采收率的较好方法。以一个真实的凝析气藏为例,使用自行开发的PVTCOG软件和PR状态方程研究和对比了凝析气藏定容衰竭不同阶段,注干气、氮气及二氧化碳对露点的影响、对注气时机、对凝析油储量和凝析油采收率的影响。研究表明不同注入气影响露点的趋势不同,随注入气增加凝析油储量下降,但凝析油采收率上升,注入时机不一定是在高于露点压力时最好。

RECOVERY STUDY ON GAS INJECTION SIMULATION BY EOS IN GAS CONDENSATE RESERVOIR

To improve the recovery of condensate oil is the primary purpose to develop gas condensate reservoir. Gas injection can prevent condensate oil from separating out from gas condensate reservoir. The PVTCOG application software developed by our-selves and the PR state equation were employed in a real closed condensate gas reservoir to study the depletion performance in different production stages, the influence of dry gas, the nitro-gen and carbon dioxide on the dew point pressure, the gas injec-tion time, the condensate oil reserve and the condensate oil re-covery. The results showed that: different injection gas has dif-ferent impact on dew point pressure; with more gas injection the condensate oil reserve will come down while the condensate oil recovery will go up; the optimum time for gas injection is notnecessarily at pressure higher than dew point pressure.