含水汽凝析气体系相态特征研究

Research on the phase state of the gas-condensate system with water vapour

贾天泽 熊钰 刘沣东 袁迎中 冯良 张智强

Jia Tianze Xiong Yu Liu Fengdong Yuan Yingzhong Feng Liang Zhang Zhiqiang

西南石油大学, 油气藏地质及开发工程国家重点实验室, 四川成都 610500; 中国石油陕西销售公司, 陕西西安 710004; 吉林石油集团第一钻井工程公司, 吉林松原 138000

State Key Laboratory of Oil and Gas Reservoir Geology and Exploration, Southwest Petroleum University, Chengdu 610500, China; PetroChina Shanxi Marketing Company, Xi'an 714004, China; Jilin Petroleum Group First Drilling Company, Songyuan 138000, China

凝析气藏中的水汽对凝析气体系相态变化有重大影响。在对某含水汽凝析气体系相态实验分析的基础上,分析了水汽对凝析油气相态的影响,总结了含水汽凝析气体系的相态特征。水汽存在时相包络线所围面积增大,反凝析区面积增大,初始凝析压力增大;水的极性很强,会加快凝析油的挥发;在恒质膨胀与定容衰竭中含水汽凝析气体系和普通凝析气体系的反凝析液量与压力曲线会出现交点。普通凝析气体系和含水汽凝析气体系的相态特征有很大差异。同温度压力条件下,含水时的偏差系数总是小于不含水时的偏差系数值,随着压力的下降,含水时天然气采出率,凝析油累积采出率,井流物重质含量和闪蒸汽中重质含量都大于不含水时的采出量值。

Water vapour in gas condensate reservoir has effect on the phase state of the gas condensate system. On the basis of phase state experimental analysis on the gas condensate system with water vapour, we analyze how water vapour has effect on the phase state of the gas-condensate system and summarize the phase behavior of the gas-condensate system with water vapour. If water vapour occurs in the gas- condensate system, the pressure-temperature figure area increases, the retrograde condensate area increases and initial retrograde condensate pressure increases in the phase diagram; serious polarity of the water vapour will accelerates condensate oil volatilization; the retrograde condensate-pressure figure of the gas- condensate system with water vapour and without water vapour will across each other in the constant composition expansion diagram and the constant volume depletion diagram. The phase state of the gas- condensate system with water vapour is different from that without water. Gas deviation factor of the gas- condensate system with water vapour is smaller than that without water vapour at the same pressure and temperature. Gas recovery coefficient, condensate oil recovery factor, heavy component content in well fluid and flash vapour of the gas-condensate system with water vapour is bigger than those of the gas- condensate system without water vapour.