横波测井的原理和方法研究

充液井孔中的偶极子声源能在周围岩层和土层中激发弯曲模式声波，它们在截止频率附近，沿井轴传播的速度为井壁介质的横波速度．使用可调声功率源使偶极子声波测井系统能适应软、硬地层的现场井孔测试．相关法算出横波声速，野外测试的结果和理论计算值相符．计算动弹模量和剪切模量，确定破碎层位置，可用于工程地质勘察中

STUDY ON THE PRINCIPLE AND METHOD OF SHEAR WAVE LOGGING

The theoretial calculations and field tests of shear wave logging using acoustic dipole soures are described in this paper.The fiexural modal acoustic wave can be excited by dipole sources in fluid-filled borehole which is embedded in rock or soil formation,and the speeds of the fiexural wave nearby the cut-off frequency along the axis of borehole are equal to those of shear wave.The dipole acoustic logging system with the adjustable acoustic power source can be used to meaure the shear wave velocity in the wells surrounded by hard or soft formations.The results of the field tests of the shear wave are in agreement with theoretical value calculated by the correlative method To caculate the dynamic modulus of elasticity and the shear modulus and determine the position of the fracture layer are very important for the engineering geologlcal investigation