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为研究套管刻度井中模拟地层有限、第一和第二界面都胶结良好时井孔声场的传播特点 ,采用实轴积分法计算了该模型井中由对称轴上的点状声源在不同中心频率、不同源距下激发的全波列 ,分析了刻度井几何尺寸、介质特性以及不同的外边界吸声材料对井孔声场的影响 .数值模拟结果表明 :源距为 1.0～ 1.5m及声源中心频率为 15～ 2 0kHz时 ,只有当模拟地层的半径大于 1.5m时 ,模拟井中的主要波列才不受最外层边界的影响 ,当最外层边界半径小于 1.0m时 ,边界的影响不容忽略 ,这影响程度还取决于最外层介质与模拟地层的波阻抗差别大小及模拟地层的吸收特性
In order to study the propagation characteristics of borehole sound field with limited formation and well-cemented first and second interfaces in the casing calibration well, the real axis integration method was used to calculate the distribution of the point-like sound source on the symmetry axis of the model well at different center frequencies , The full wave train excited at different source distances was analyzed and the influence of calibration well geometry, media characteristics and different outer boundary acoustic absorption materials on well bore sound field was analyzed.The numerical simulation results show that the source spacing is 1.0 ~ 1.5m and the sound source When the center frequency is between 15 and 20 kHz, the main wave train in a simulated well is not affected by the outermost boundary, only when the radius of the simulated formation is greater than 1.5 m. When the outermost boundary radius is less than 1.0 m, the influence of the boundary Can not be ignored, the degree of influence also depends on the difference between the impedance of the outermost medium and the simulated formation impedance and absorption characteristics of the simulated formation