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本文的实例研究表明,高频井间数据中含有反射波数据。利用类似于VSP数据处理的流程可增强这些反射波,从而生成分辨率很高的图像。对于几百英尺深的井来说,垂直分辨率有可能达到3～5英尺(1～1.5米)。 尽管这项研究得到的井间反射图像与声测井曲线很吻合,但在井间反射成像中还存在着某些技术难度。尤其是我们发现图像的信噪比随反射成像点离激发井距离的增加而减小。另外,假频管波以及横波和转换波是噪声的主要成分。我们还观测到,广角反射容易被误解,因为在成像中这些同相轴在水平方向和垂直方向上被大大地拉伸了。为提高井间反射图像的质量,我们需要改进数据采集(即更高的采样率、更多的叠加次数和更小的入射角)和处理成像(最佳地利用叠加)技术。根据单个道集的假频数据得到的初步结果表明,该方法是有前途的。
The case study in this paper shows that the high frequency crosswell data contains reflected wave data. These reflections are enhanced with processes similar to VSP data processing to produce highly resolved images. For wells hundreds of feet deep, the vertical resolution is likely to reach 3 to 5 feet (1 to 1.5 meters). Although the cross-well reflection images obtained from this study are in good agreement with acoustic logging curves, there are some technical difficulties in crosswell reflection imaging. In particular, we find that the signal-to-noise ratio of the image decreases as the reflection imaging point increases away from the excitation well. In addition, aliasing wave and shear wave and converted wave are the main components of noise. We have also observed that wide-angle reflections are easily misunderstood because these in-phase axes are greatly stretched in the horizontal and vertical directions during imaging. To improve the quality of the crosswell image, we need to improve data acquisition (ie, higher sample rates, more overlays and smaller angles of incidence) and processing imaging (best using overlay) techniques. The preliminary results from the aliasing data for a single gathers show that this approach is promising.