Based on the differences in production mode and operation process between gas storage and gas reservoir, we established a phase balance test procedure and a theoretical simulation model of phase balance during multi-cycles of injection and production of underground gas storage (UGS) rebuilt from condensate gas reservoir to study the phase characteristics of produced and remaining fluids during multi-cycles of injection and production. Take condensate reservoir gas storage as example, the composition of produced fluid and remaining fluid, phase state of remaining fluid, retrograde condensate saturation and condensate recovery degree in the process of multi-cycles of injection-production were studied through multi-cycle injection-production experiment and phase equilibrium theory simulation. The injected gas could greatly improve the recovery of condensate oil in the gas reservoir, and the condensate oil recovery increased by 42% after 5 cycles of injection and production; the injected gas had significant evaporative and extraction effects on the condensate, especially during the first two cycles; the condensate oil saturation of the formation decreased with the increase of injection-production cycles, and the condensate oil saturation after multi-cycles of injection-production was almost 0; the storage capacity increased by about 7.5% after multi-cycles of injection and production, and the cumulative gas injection volume in the 5th cycle increased by about 25% compared with that in the 1st cycle.

针对储气库与储气库在生产方式和运行过程上的差异，建立了凝析液改造地下储气库（UGS）注入生产多周期的相平衡测试程序和相平衡理论模拟模型。气藏，以研究在注入和生产的多个周期中产出的和剩余的流体的相特征。以凝析气藏储气为例，通过多周期注采研究了注采多周期过程中采出液和剩余液的组成，剩余液的相态，凝析油饱和度和凝结水回收度。实验和相平衡理论模拟。注入的气体可以大大提高气藏中凝析油的采收率，经过5次注入和生产循环后，凝析油的采收率提高了42％。注入的气体对凝结水有明显的蒸发和抽气作用，尤其是在前两个循环中；随着注入生产周期的增加，地层凝析油饱和度降低，经过多周期注入生产后，凝析油饱和度几乎为0。经过多次注入和生产循环后，储气量增加了约7.5％，与第一个循环相比，第五个循环的累计注气量增加了约25％。注入的气体对凝结水有明显的蒸发和抽气作用，尤其是在前两个循环中；随着注入生产周期的增加，地层凝析油饱和度降低，经过多周期注入生产后，凝析油饱和度几乎为0。经过多次注入和生产循环后，储气量增加了约7.5％，与第一个循环相比，第五个循环的累计注气量增加了约25％。注入的气体对凝结水有明显的蒸发和抽气作用，尤其是在前两个循环中；随着注入生产周期的增加，地层凝析油饱和度降低，经过多周期注入生产后，凝析油饱和度几乎为0。经过多次注入和生产循环后，储气量增加了约7.5％，与第一个循环相比，第五个循环的累计注气量增加了约25％。