凝析气井气窜后的产能变化特征及调整效果

PRODUCTIVITY VARIATIONS AND ADJUSTMENT EFFECTS OF CONDENSATE GAS WELLS AFTER GAS BREAKTHROUGH

在凝析气藏循环注气驱替过程中，受储集层非均质性影响，注入干气易于流过高渗透带或天然裂缝而发生过早气窜。在简要介绍了凝析气井气窜的四类判别方法的基础上，通过分析牙哈凝析气田循环注气开发的现场资料，结合数值模拟方法，阐述了注入气突破至采气井井底后，采气井井流物组分及相态的变化规律，并研究了气窜发生后凝析气井产能的变化特征，总结了凝析气井气窜后的治理措施及措施效果。实例研究结果表明，采气井发生气窜后，其井流物相态特征变化显著，注气驱替效率不断下降，气井产能逐渐降低；对发生气窜的井组及时调整注、采量可有效减缓气窜的加剧程度；通过调整注采井网，可提高注气驱替效率，进一步提高凝析油采收率。

During the process of circulating gas injection displacement in condensate gas reservoirs, under the influences of reservoir heterogeneity, the injected dry gas is likely to pass through the high-permeable belts and natural fractures and cause rash gas breakthrough. Based on the introduction to 4 diagnoses methods of gas breakthrough in condensate gas wells, field data of circulating gas injection displacement in Yaha condensate gas reservoir have been analyzed and combined with numerical simulation, the effluent composition of gas production wells and phases variations have been deciphered after the arrival of the injected gas at the downhole of gas production wells. Moreover, the productivity changes of condensate gas wells after gas breakthrough have been analyzed and the treatments for gas breakthrough and adjustment effects have been summarized. The results of case studies indicate that after the gas breakthrough in gas production wells, the phases of effluents in the wells take on great changes, gas injection displacement efficiency drops down continuously and the deliverability of gas production wells declines gradual ly, but after in-time adjustment to the well groups with gas breakthrough, the production rate can effectively prevent gas breakthrough from worsening. Through adjusting production and injection well patterns, the gas injection displacement efficiency can be promoted, thereby; the recovery rate of condensate gas reservoirs can also be en-hanced.