考虑井筒相态变化的凝析气井关井静压计算

Shut-in static pressure calculation of condensate gas wells considering phase behavior change in borehole

目前凝析气井关井静压计算仍在沿用常规气井的方法,由于对井筒相态考虑不充分,计算精度无法满足动态分析和生产管理的需求。为此,从关井瞬间井筒相态分析出发,结合凝析气井关井压力恢复过程中井筒的压力、温度分布变化,以气液平衡计算为基础,建立了凝析气井关井压力恢复过程考虑井筒相态变化的压力计算模型,并结合具体实例对凝析气井关井压力恢复过程井筒相态变化规律及压力分布进行了研究和计算。从计算结果看,该计算方法考虑凝析气井关井压力恢复过程中的相态变化,因而井底压力的计算结果与实际情况更接近,可以解决压力计无法下入产层中部或不能正常测试的问题,有时也可以替代凝析气井关井压力恢复测试,从而节省测试所需的大量人力、物力。

Up to now,researchers are still using the method used for conventional gas wells to calculate the shut-in static pressure of condensate gas wells,while the calculating accuracy can not meet the demand of performance analysis and production management without considering the phase behavior in borehole. From the analysis of the shut-in phase behavior change,combining with borehole pressure change and temperature distribution change,based on gas-liquid balance calculation,pressure calculation model considering borehole phase behavior change in the process of shut-in pressure recovery is established and phase behavior change law and pressure distribution in this process are studied. This calculating result agrees well with the practical and this shows that this calculating method considering the phase behavior change in the process of shut-in pressure recovery can not only solve the problem that pressure gauge could neither be put in the middle part of layer nor operate normally but also be a substitute to shut-in pressure build up test so as to save up a great deal of manpower and material resources.