高精度时差提取技术在薄互层中的应用

声波测井中,对于砂一泥岩薄互层井段,由于地层声速变化及仪器分辨率低等原因导致不同接收器接收到的波形相关性差,用传统的时差-时间相关法往往不能得到稳定可靠的时差结果。对于数字声波测井而言,单个接收器的波形质量良好,针对这一现象,本文通过利用改进的探测首波波至的方法获得高精度的时差。将该方法应用到现场实例数据中,结果表明该方法有效的提高了地层首波时差的精度,清晰的刻画了薄互层特性。并且该方法基本不需要人工干预,在大部分情况下可以得到稳定可靠的结果。

Application of high-precision slowness technique in the process of thin-bed sand-shale sequence model

During acoustic well logging, the logging waveforms are often distorted by formation velocity changes and the low precision of the logging machines, therefore, formation slowness which are obtained through techniques such as Slowness Time Coherence is not robust and reliable due to the poor signal coherence in thin-bed sand-shale formation. But the quality of logging waveforms received by single receiver is good. To improve the slowness estimation accuracy for this situation, we use an improved first arrival detection scheme that generates high-precision travel times. We have applied the technique to field logging data, the results show that this method improves the precision of first-wave slowness log curve effectively and detecting the thin-bed characteristics of sand-shale sequences in formation. And the technique does not require any human intervention and in most cases provides a robust and accurate travel times.