水平井泡沫酸分布模型

Distribution model of foamed acid in horizontal well

泡沫酸对于水平井均匀酸化解堵具有重要作用,成功运用泡沫酸酸化技术的关键是充分了解泡沫酸沿水平井的流动机理。为此,根据水平井变质量流以及泡沫酸在地层中的分流特点,建立了数学模型,并利用数值方法对所建模型进行了求解;同时提出了半径增量比的概念,并据此对分流效果进行了分析。结果表明:泡沫酸渗透半径逐渐增大,跟端的增长幅度高于趾端;水平井井底压力随时间逐渐升高,相同时间内沿水平井筒逐渐降低。影响泡沫酸分流效果的因素有注入速度、井眼半径及渗透率级差。

Foamed acid is important to equably unblock in horizontal well.The key in successful use of acidizing technology for foamed acid is full understanding the flow mechanism of foamed acid in horizontal well.Based on variable mass pipe flow in horizontal well and foam diversion in the formation,furthermore,a mathematical model is established and the model is solved by numerical method.The concept for ratio of radius increase is presented and the distribution law of foamed acid diversion in horizontal well is discussed.The results show that the radius of foamed acid increases with time,but the radius near the heel has a lager increasing range than the radius near the toe.The bottomhole pressure increases with time,but the pressure along the horizontal wellbore decreases at the same time.The diversion effect is affected by injection rate,radius of wellbore and permeability ratio.