中文摘要：

牙哈地区位于塔里木盆地北部海相含油气系统与陆相含油气系统过渡带，多期油气充注过程导致区内凝析气藏广泛发育。地球化学研究表明，牙哈地区凝析油的折算Ro在0．7g附近（远低于原生凝析油Ro=1．3％的热力学门限），反映出次生凝析气藏的特征；同时，牙哈地区原油轻质组分相对损失的特征，表明其发育典型的相分馏效应，即相分馏作用控制了其凝析气藏的形成。流体相态特征表明，牙哈地区凝析气藏分为两类：一类为饱和型凝析气藏，此类凝析气藏的地露压差较小，具油环，主要分布于YH7井；另一类为不饱和凝析气藏，此类凝析气藏的地露压差较大，在地下为纯气态，不具油环，主要分布于YH3以及YH6井区。其成藏过程受控于差异充注过程，即早期少量原油仅对于YH1、YH5等井区发生了充注，原油充注并未达到YH3井区；晚期大量干气对YH1、YH7井区的油藏发生持续侵入，而承载了大量轻质组分的天然气运移至较浅的YH3井区发生聚集，由于温压降低，转变为不饱和凝析气藏。

英文摘要：

Yaha Oilfield is the most hydrocarbon province in Tarim Basin, which widely developed the con- densates in the Triassic reservoir. Geochemical analysis illustrates that the condensate oil is low mature with Ro near 0.7%, which reflects the characteristic of the subsequent condensates. Moreover, the chan ging tendency of the light component describes a obvious figure of phase fractionation that controls the generation of the condensates. The phase characteristics of the condensates can be clarified into two types： first is the saturated condensates that have a small difference between the FMP and DPP, which mainly de- velop around the YH7 well; another is the unsaturated reservoir that have a large difference between the FMP and DPP, which develop in the YH3 well and YH6 well area. The generation of the secondary con- densates is controlled by the multiple episode of the hydrocarbon charging. Slight amount of the oil charged the YH1 and YH5 well without YH3 well area in the early episode. Moreover, great quantity of dry gas invaded the YH1 well and YH7 well area, which turned YH3 well area into unsaturated conden- sate by both the change of temperature and pressure and the light component migrated by dry gas.