凝析气藏开发中后期反凝析治理技术
Measurements to retrograde condensation during the middle and late production periods of condensate gas reservoirs
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摘要: 在衰竭开发的凝析气藏中,当井底流压低于露点压力时,储层凝析油会析出并且逐渐聚集在近井地带。凝析油的聚集一方面使得凝析气渗透率和气井产能急剧下降,另一方面使得近井地带产生反凝析污染,从而严重影响气藏的最终采收率,故解除近井地带反凝析污染对提高凝析气藏采收率尤为重要。治理反凝析污染的通常做法是注气混相抽提,通过开发实践,探索出大排量、高强度注气驱油解反凝析、单井注气吞吐突破近井地带反凝析油墙解反凝析、酸化改善近井地带储层渗流能力解反凝析等3种技术,既简单经济,又大大提升了解反凝析效果。Abstract: For depleted condensate gas reservoirs, when bottom flow pressure in condensate gas wells is below dew point pressure, condensate oil will occur and gather in the near wellbore area gradually, resulting in not only the sharp decrease of reservoir permeability and production, but also retrograde condensate pollution, which res-tricts gas reservoir recovery. As a result, it is very important to retrograde condensation pollution in the near wellbore area. Several measurements are taken to retrograde condensation. A large amount of gas can be injected with high strength to drive oil. Gas injection huff and puff in single well can break through condensate oil wall. Acidification can improve reservoir permeability. These methods are easy and cheap to carry out, and can retrograde condensation effectively.
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