塔里木盆地牙哈凝析气田循环注气开发研究

牙哈凝析气田位于塔里木盆地库车坳陷，是国内已发现的最大凝析气田。牙哈凝析气田的凝析气富含凝析油，地层压力与露点压力非常接近，地层压力与饱和压力之差为2～5MPa，若采用衰竭式开发，随着地层压力下降会出现反凝析，重组分大多损失在地层中，需要采取循环注气方式保持压力开发。根据实际资料建立了气藏产出、注入方程，优化循环注气开发方式、布井方式。优化结果，部分循环注气保持压力开发效果最好，合理注采井距为800～1100m。牙哈凝析气田实施循环注气开发1．5a，年产凝析油50万t以上，凝析油的采出程度比衰竭式开发方式提高25％以上，实现了凝析气田的高效开发。图1表3参6

Gas recycling project of Yaha condensate gas field in Tarim Basin

Yaha condensate gas reservoir is located in the Kuche Depression in Tarim Basin, and is the largest condensate gas field discovered presently in China. The dew point pressure is just 2 to 5MPa lower than the reservoir pressure. During the depletion process, the retrograde liquid will condense with decreasing pressure, resulting in the loss of heavy components in the porous media. Therefore, the pressure maintenance by gas recycling is demanded. By using the actual field data, the equations are obtained describing gas production and injection, the cycling scheme and well pattern are optimized. The optimization results show that the partial pressure maintenance is the best scheme, the reasonable well spacing ranges from 800m to 1100m. So far Yaha condensate gas field has been put on production for 1. 5 years, the condensate production in 2001 was annually over 500 thousand tons, the same period production percentage of condensate is increased by 25% relative to the depletion case.