振动对岩石及地层渗透率的影响

Effect of vibration on permeability of rock and stratum

基于已有的岩心实验数据,构造了振动采油条件下两相介质相对渗透率的变化率函数。利用该函数,分析了振动频率、振幅和时间对渗透率的影响,并将其推广到实际地层。采用向前差分方法,对地层中振动波的传播进行了模拟计算。在简化一维、轴对称二维和球对称三维模型下,运用弱可压缩液体的动力学方程,对波在两相介质中的传播以及相对渗透率在整个地层介质中的分布特征的结果表明,振动的作用主要集中在近井地带,频率为10Hz的振动对地层渗透率的影响范围大,且可以使井口处渗透率提高2倍;较低频率振动波的传播距离稍远一些。

The experimental data available in literature were employed to build the incremental ratio function for relative permeability of two-phase medium. The effects of frequency, amplitude and time of vibration on permeability were analyzed by using this func tion. The relevant approach was assumed to be valid to the whole stratum. The forward difference method was used to simulate the wave propagation in stratum. In the simplified 1 D model, axial symmetric 2-D model and spherically symmetric 3 D model, the wave propagation in the two phase medium with weak-condensability liquid and the distribution of relative permeability in stratum were an alyzed. The effective range of vibration is close to the well bore. The vibration with the frequency of 10Hz makes the permeability in- crease by two times at the well head. The propagation distance of a wave is longer under low frequency vibration.