【摘要】 本文详细研究了充流体井中由不同类型轴对称震源激发的弹性波的低频辐射能量,导出了管波、纵波和横波能量的解析解表达式。文中指出,膨胀源辐射能量的99％在井内是以管波形式传播的,在软地层中辐射纵波和横波能量比在硬地层中要强,辐射进入地层的横波能量大于纵波能量;径向应力源辐射能量的95％在井内以管波形式传播(f=200Hz),在硬地层中辐射纵波和横波能量比在软地层中要强,在硬地层中辐射纵波能量小于辐射横渡能量,在软地层中辐射纵波能量大于辐射横波能量;切向应力源在井内不激发管波,仅在地层中激发纵波和横波,对大多数沉积岩而言,辐射进入地层的横波能量约为纵波能量的10倍.随着频率的增高,点膨胀源、径向应力源和切向应力源的辐射纵波和横渡能量都有显著增加。由相同的单震源组成的阵列源可大大提高其辐射能量。更多还原

【Abstract】 We detailedly analyse the low-frequency radiative energies of the elastic waves which are generated by different axially symmetric sources in fluid — filled boreholes, and formulize the energies of tube,compressional and shear waves. Point volume sourec radiates 99% downhole energy in the form of tube wave, and its radiative compressional wave and shear wave have stronger energy in soft formation than in hard formation, with shear wave energy being higher than compressional wave energy in the formations. 95% borehole radiative energy from radial stress source propagates in the form of tube wave (f= 200Hz), the radiative compressional and shear wave energies are more powerful in hard formation than in soft formation,and radiative compressional wave energy is weaker than shear wave ener gy in hard formation,but stronger than shear wave energy in soft formation. Tangential stress source does not create tube wave in borehole;it causes compressional and shear waves in formations. and the shear wave energy is ususlly 10 times as high as the compressional wave energy in most sedimentary formations. Both radiative compressional and shear wave energies from point volume,radial shear and tangential stress sources greatly increase with the raise of their frequencies. Array source consisting of similar elementary sources greatly enhances radiative energy.更多还原