渤海BZ凝析气藏属国内外罕见的潜山裂缝高饱和、高含凝析油凝析气藏，其储层具有高温高压、特低孔、特低渗特征，且流体地露压差小，极易析出凝析油，造成近井地带污染。BZ气藏试验区初期采用天然能量开发，地层压力低于露点压力后反凝析污染加重，导致生产气油比快速上升，产量递减加大，亟待开展该类凝析气藏反凝析污染评价及解除污染方法研究。采用复配凝析气开展高温高压条件下岩心衰竭实验，模拟反凝析油污染，测试不同衰竭压力点对应的气相渗透率并评价反凝析污染程度，同时开展注气解除反凝析污染实验机理研究。实验结果表明：随着地层压力的下降，岩心中的反凝析液增多，气相有效渗透率下降幅度明显，最终反凝析储层伤害程度达到65.8%~70.2%。注气可降低凝析油的黏度，提高地层流体体积膨胀系数，对反凝析油实施反蒸发，降低反凝析液量及反凝析油饱和度，起到解除反凝析堵塞、提高储层岩心气相有效渗透率的作用，注入的N₂、伴生气、CO₂渗透率恢复程度分别为48.1%、78.6%、81.7%，凝析油的最终采出程度分别达到43.7%、66.8%、69.2%。研究成果为BZ潜山凝析气藏试验区注气开发提供技术支撑，有效减缓了气藏产量递减，取得了较好成效，对后续区域整体注气高效开发具有重要的指导意义。

The BZ condensate gas reservoir in the Bohai Sea, China, is a rare fractured buried hill condensate gas reservoir with high saturation and high content of condensate oil. The reservoir features high temperature, high pressure, ultra-low porosity, and ultra-low permeability. Due to the small difference between the fluid dew point and the pressure in the gas reservoir, it is prone to condensate oil precipitation, causing contamination in the near-wellbore zone. In the early development stage, the BZ gas reservoir pilot area was produced using natural energy. When the reservoir pressure drops below the dew point, retrograde condensation intensifies, leading to a rapid increase in the gas-oil ratio and an accelerated decline in production. Therefore, there is an urgent need for the evaluation of retrograde condensation damage and effective remediation methods. Core depletion experiments were conducted under high-temperature and high-pressure conditions using compound condensate gas to simulate retrograde condensate oil contamination. Gas-phase permeability was tested at different depletion pressure points to evaluate the degree of retrograde condensate contamination. Additionally, gas injection experiments were carried out to investigate the mechanisms of damage mitigation. Experimental results showed that as the reservoir pressure decreased, the amount of retrograde condensate in the core increased, and the effective gas-phase permeability decreased significantly. Ultimately, the resulting retrograde condensate damage to the reservoir reached 65.8% to 70.2%. Gas injection could reduce the viscosity of condensate oil, increase the volume expansion coefficient of reservoir fluids, and induce re-vaporization of retrograde condensate oil. This process reduced the amount and saturation of retrograde condensate liquid, relieved retrograde condensate blockage, and improved the effective gas-phase permeability of reservoir cores. The permeability recovery rates for N₂, associated gas, and CO₂ were 48.1%, 78.6%, and 81.7%, respectively. The final recovery rates for condensate oil reached 43.7%, 66.8%, and 69.2%, respectively. The research results provide technical support for gas injection development in the pilot zone of the BZ buried hill condensate gas reservoir. This approach effectively mitigates production decline and achieves good results, offering important guidance for the efficient large-scale gas injection development in the future.