公开(公告)号：US4928269A

公开(公告)日：1990-05-22

申请号：US368065

申请日：1989-06-15

申请人： Christopher V. Kimball ,  Fred E. Stanke ,  Curtis J. Randall ,  Andrew J. Hayman

发明人： Christopher V. Kimball ,  Fred E. Stanke ,  Curtis J. Randall ,  Andrew J. Hayman

IPC分类号： G01V1/30 ,  G01V1/50

CPC分类号： G01V1/50 ,  G01V1/306

摘要： The present invention is directed to a method of calculating the impedance of a material behind the section of a casing. An acoustic excitation pulse is directed towards a section of the casing, resulting in a return waveform having a reverberation segment and an initial reflection segment. The return waveform is analyzed to choose a resonance frequency indicative of the casing's nominal thickness. The return waveform is bandpass filtered about the chosen frequency. A time window of the reverberation segment is selected, and the energy content in the time window of the filtered reverberation segment is calculated. Both the bandpass filter and time windows are selected based on the chosen resonance frequency, thereby removing variations in the thickness of the casing. The energy content calculation produces a cementation signal indicative of the impedance of the cement behind the section of the casing. The impedance value is indicative of the cement quality. In accordance with another aspect, a time portion of the initial reflection segment is chosen, and the energy content in the time window of the filtered initial reflection segment is calculated. This energy is used to normalize the cementation signal calculated from the reverberation segment. In accordance with another aspect of the present invention, the impedance of the material behind the casing is determined.

摘要翻译： 本发明涉及一种计算外壳部分之后的材料的阻抗的方法。 声学激发脉冲指向壳体的一部分，导致具有混响段和初始反射段的返回波形。 分析返回波形以选择表示外壳标称厚度的共振频率。 返回波形关于所选择的频率进行带通滤波。 选择混响段的时间窗口，并计算滤波后的混响段的时间窗口中的能量内容。 基于所选择的共振频率来选择带通滤波器和时间窗，从而消除壳体厚度的变化。 能量含量计算产生表示水泥在套管部分后面的阻抗的胶结信号。 阻抗值表示水泥质量。 根据另一方面，选择初始反射段的时间部分，并且计算滤波后的初始反射段的时间窗中的能量含量。 该能量用于归一化从混响段计算的胶结信号。 根据本发明的另一方面，确定了壳体后面的材料的阻抗。