不同凝析气井米无阻流量预测方法

Open-flow Potential per Meter Prediction between Different Gas Condensate Wells

凝析气藏开发过程中,气井的绝对无阻流量会随着地层压力的降低而降低。当地层压力降至露点压力以下时,凝析气体的组成将会发生变化,不仅导致凝析气的黏度、密度和偏差系数发生变化,同时凝析油的析出也会降低储层的气相渗透率。考虑凝析气藏的相态变化对凝析气高压物性、气相相对渗透率的影响,以及不同气井间产气厚度、井点渗透率、泄气半径等参数的差异性,基于二项式气井产能方程的系数变化,建立了不同凝析气井在不同地层压力下的米无阻流量预测方法。应用实例表明,与不考虑相态变化影响的预测方法对比,该方法得到的米无阻流量更接近实际产能试井结果;而且考虑相态变化影响时得到的不同地层压力下的气井米无阻流量偏低。同时绘制出了不同渗透率条件下气井米无阻流量与地层压力的关系图版。

The open-flow potential decreases with the reservoir pressure during the development of gas conden- sate reservoir. When reservoir pressure drops below the dew point pressure, the composition of condensate gas changes, which could lead to the change of other physical parameters such as viscosity, density and Z-factor of con- densate gas. Meanwhile, the retrograde of condensate oil could decline the relative permeability of gas phase. Con- sidering the influence of the phase change on physical property of condensate gas and relative permeability of gas phase, a new prediction method of open-flow potential per meter at different reservoir pressure between different gas condensate wells is established based on the binomial deliverability equation of gas well. This prediction method al- so involves the difference of net thickness, average permeability and gas drainage radius between difference gas con- densate wells. Application example shows that, compared to the prediction method than doesn＇ t consider phase changes, the open-flow potential per meter obtained by the above method gets closer to the real value of deliver- ability test. Furthermore, the application indicates that open-flow potential per meter at different reservoir pressure calculated by considering phase changes is much smaller than the one that doesn＇ t consider phase changes. In ad- dition, the chart of the relationship between open-flow potential per meter and reservoir pressure under different permeability is also made.