凝析气田自流注气的数值模拟研究

凝析气藏通常采用衰竭式开发，或采用循环注气以保持压力的方式进行开发。利用气藏气对凝析气藏进行自流注气无疑是一种经济有效的开采方法。将三维三相拟四组分模型改进为气藏井筒气藏模型，定量描述了自流注气过程中自流注气量及气藏压力的变化。研究表明，自流注气是两个气藏压力平衡过程。数值模拟的结果表明，压力平衡时间与气藏系统的产气速度、两个气藏的储量、地层压差，以及边底水能量大小有关。自流注气过程中的自流注气量是动态变化的，其变化符合产量的调和递减规律。该研究成果可为实际气田自流注气开采方案设计提供理论依据

RESERVOIR SIMULATION OF ARTESIAN GAS INJECTION IN CONDENSATE GAS FIELD

In order to simulate the behavior of the artesian gas injection, a new model of gas reservoir wellbore gas reservoir system (GWGS) was developed. With this model, a gas condensate reservoir is simulated by a pseudo four compositional three phase three dimensional model, and the flow rate and the pressure of injected gas are described by a pseudo single phase gas flow model. The volume of the artesian gas injection is determined by an interactive scheme. The combination of GWGS model with gas condensate material balance equation shows that the balance of pressure between the two reservoirs will take a long period of time, which depends on producing rate, initial gas in place and pressure difference between reservoirs. The simulation of actural gas condensate field by using above mentioned method showed a satisfactory performance.