虚拟质量力对酸性气体-钻井液两相流波速的影响

基于两流体模型、酸性气体和钻井液状态方程,考虑酸性气体与钻井液相间虚拟质量力、粘性剪切力、相间动量交换及狭义相间阻力等条件,建立酸性气体与钻井液两相中压力波传播速度的数学模型,依据小扰动原理,对波速模型求解,得到关于波数K的波速方程。结果表明,在一定范围内,随空隙率、频率的增大,虚拟质量力对波速的影响显著增强;在高空隙率下,压强增大,虚拟质量力对波速的影响减弱;增大流体的密度或不可压缩性,均可使两相压力波速增大;延长气液交换时间或减小波动频率使相间有足够时间进行动量交换,两相压力波波速随之减小。

Influence of virtual mass force on two-phase wave velocity in acid gas and mud

With consideration of interphase virtual mass force,viscous shearing force,narrow interphase momentum exchange,interphae resistance,a mathematical model for predicting the propagation velocity of pressure wave in two-phase flow of acid gas and drilling fluid was proposed based on the two-fluid model and equation of state for acid gas and drilling fluid.The p mathematical model was solved by using the small perturbation theory,and a model concerning wave number K was derived to calculate the wave velocity.Calculation results indicate that the influence of virtual mass force becomes more prominent with the increase of angular frequency and void fraction within a certain range.At high void fraction,the influence of virtual mass force appears a weakening trend with the increase of pressure.Both the increase of density and incompressibility of two-phase fluid contribute to the increase of pressure wave velocity.It is the prolongation of gas-liquid exchange time and decrease of fluctuation frequency that supply sufficient time for momentum exchange,and slow down the pressure wave velocity accordingly.