Petroleum Exploration and Development ( IF 7.5 ) Pub Date : 2020-06-18 , DOI: 10.1016/s1876-3804(20)60081-7 Zhi ZHANG , Jiawei WANG , Yanjun LI , Ming LUO , Chao ZHANG
Abstract
As the classical transient flow model cannot simulate the water hammer effect of gas well, a transient flow mathematical model of multiphase flow gas well is established based on the mechanism of water hammer effect and the theory of multiphase flow. With this model, the transient flow of gas well can be simulated by segmenting the curved part of tubing and calculating numerical solution with the method of characteristic curve. The results show that the higher the opening coefficient of the valve when closed, the larger the peak value of the wellhead pressure, the more gentle the pressure fluctuation, and the less obvious the pressure mutation area will be. On the premise of not exceeding the maximum shut-in pressure of the tubing, adopting large opening coefficient can reduce the impact of the pressure wave. The higher the cross-section liquid holdup, the greater the pressure wave speed, and the shorter the propagation period will be. The larger the liquid holdup, the larger the variation range of pressure, and the greater the pressure will be. In actual production, the production parameters can be adjusted to get the appropriate liquid holdup, control the magnitude and range of fluctuation pressure, and reduce the impact of water hammer effect. When the valve closing time increases, the maximum fluctuating pressure value of the wellhead decreases, the time of pressure peak delays, and the pressure mutation area gradually disappears. The shorter the valve closing time, the faster the pressure wave propagates. Case simulation proves that the transient flow model of gas well can optimize the reasonable valve opening coefficient and valve closing time, reduce the harm of water hammer impact on the wellhead device and tubing, and ensure the integrity of the wellbore.
中文翻译:
高产气井瞬时关闭对油管中流体流动的影响
摘要
由于经典的瞬态流模型不能模拟气井的水锤效应,因此,基于水锤效应的机理和多相流理论,建立了多相流气井的瞬态数学模型。通过该模型,可以通过将油管弯曲部分分段并用特征曲线方法计算数值解来模拟气井的瞬态流动。结果表明,关闭时阀门的开度系数越高,井口压力峰值越大,压力波动越平缓,压力突变区域越不明显。在不超过管路最大关闭压力的前提下,采用较大的开启系数可以减少压力波的影响。横截面液体滞留率越高,压力波速度越大,传播周期越短。液体滞留量越大,压力的变化范围越大,并且压力将越大。在实际生产中,可以调整生产参数以获得适当的液体滞留量,控制波动压力的大小和范围,并减少水锤效应的影响。当阀门关闭时间增加时,井口的最大波动压力值减小,压力峰值时间延迟,压力突变区域逐渐消失。阀门关闭时间越短,压力波传播得越快。实例仿真表明,气井瞬态流动模型可以优化合理的开阀系数和关闭时间,