【摘要】 本文在文献[4]的基础上分析了低速地层(地层横波速度低于井内流体速度)裸眼井中由点源激发的弹性波的传播。指出在这种情况下井内传播的波仅有共振纵波、斯通利波和衰减的反射波,共振横波和伪瑞利波将不再出现。由数值计算得出了相速度和群速度频散曲线,给出了势函数的振幅表达式和反射波随井轴的衰减规律。更多还原

【Abstract】 In this paper, phenomena of elastic wave propagation from a point source located in fluid-filled borehole in a low velocity formation (the shear velocity of the formation is lower than the compressional velocity of the fluid) are analyzed. It is pointed out that in fluid-filled borehole under this condition, there exists a resonance compression-al wave (with the compressional velocity) ; a Stonely wave (with a velocity lower than the shear velocity) and an attenuated-reflected wave, while the resonance shear and pseudo-Rayleigh wave do not appear. Dispersion curves for phase velocity and group velocity are calculated. Expressions for the dilatational and shear wave potentials are given, and a formula for the attenuation of the reflected wave are also derived.更多还原