高温高压含水凝析气相态特征研究

通过独立设计的含水凝析气相态测试方法，研究了含水凝析气相态特征及气态水对凝析气体系相态特征的影响。在高温、高压地层条件下，凝析气中气态水含量随压力的降低急剧增大，当压力降至7.5 MPa时，气中的气态水含量高达539 m³／１０^４ｍ^３。气态水的存在使凝析气体系的露点压力降低了2.5 MPa。随着定容衰竭过程地层压力的降低，地层水以气态形式被蒸发而进入凝析气中的含量不断增加，由于水相的强极性，气态水不但使凝析气中重质烃更多地发生反凝析，也使凝析气中较轻烃类组分发生反凝析。虽然气态水的存在降低了凝析气体系的露点压力，但是一旦突破露点压力，气态水明显地增大了反凝析液量，加重了凝析油的损失。定容衰竭实验结果表明，富含气态水的凝析气样反凝析液量大于无水凝析气样，含气态水的凝析气中凝析液的采出程度低于不含水的情况，并随压力降低，两组样品的反凝析液量和凝析液采出程度的差别越来越大。

PHASE BEHAVIOR OF WET CONDENSATE GAS AT HIGH TEMPERATURE AND PRESSURE

Phase behavior of wet condensate gas and influences of gaseous water on phase behavior of condensate gas system are studied by using the self-designed test procedure of phase behavior of wet condensate gas. Content of gaseous water in condensate gas sharply increases along with decreasing pressure under high-temperature and high-pressure conditions, and it can reach up to 539 m~3/10~4m~3 when pressure lowers to 7.5 MPa. Dew point pressure of condensate gas system can decrease 2.5 MPa due to gaseous water. The amount of water that enters into condensate gas in gaseous state continuously increases along with decreasing formation pressure in the process of constant volume depletion. As water phase has strong polarity, the gaseous water may not only cause retrograde condensation of heavier hydrocarbons but also light hydrocarbons in condensate gas. Although gaseous water can lower dew point pressure of condensate gas system, once the dew point pressure is surpassed, the gaseous water can remarkably increase the amount of retrograde condensed liquid, resulting in a larger loss of condensate oil. Constant volume depletion experiment results show that the amount of retrograde condensed liquid of condensate gas samples with rich gaseous water is larger than that without water, but the degree of recovery of the former is lower than the latter, and the differences between the two groups of samples will enlarge along with lowering pressure.