样品尺寸对脉冲穿透法声速测量误差的影响  

Effect of Sample Size on Sound Velocity Measurement Error by Pulse Transmission Method

作　　者：李嘉慧 陈德华[1,2,3] 何晓 张秀梅[1,2,3] LI Jiahui;CHEN Dehua;HE Xiao;ZHANG Xiumei(State Key Laboratory of Acoustics,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Beijing Engineering Research Center for Deep Drilling Exploration and Measurement,Beijing 100190,China)

机构地区：[1]中国科学院声学研究所声场声信息国家重点实验室,北京100190 [2]中国科学院大学,北京100049 [3]北京市海洋深部钻探测量工程技术研究中心,北京100190

出　　处：《测井技术》2024年第3期290-300,共11页Well Logging Technology

基　　金：国家自然科学基金项目“利用音叉测量井中高温高压流体特性参数的方法研究”(42074174)。

摘　　要：岩心的声速测量能够提供关键的储层地质信息,对储层评价和地质模型构建具有实际应用价值。脉冲穿透法是一种常用的声速测量方法,但它要求样品尺寸远大于波长(约10倍)。当特殊场景如需在测井信号主频8~20 kHz下测量样品声速时,被测样品长达数米,不仅制备困难,还存在声波信号衰减大的问题。关于试样尺寸能否缩小或能缩小到什么程度的定量研究很少见到公开报道。该文将数值模拟和实验测量相结合,系统定量地研究了圆柱状样品长度及直径与波长之间的比值对脉冲穿透法声速测量精度的影响。研究表明:为确保脉冲穿透法声速测量的准确性,建议样品沿传播方向上的长度不低于4倍声波波长,横向尺寸不低于2倍波长。研究结果突破了传统脉冲穿透法要求样品尺寸远大于波长的限制,为优化声速测量方法和提高测量精度提供了理论支持。The acoustic velocity measurement of core samples can provide crucial reservoir geological information,with practical application value in reservoir evaluation and geological model construction.The pulsed transmission method is a commonly used method for measuring sound velocity,but it often requires a sample size much larger than the wavelength(about 10 times larger).In instances where specific conditions require the measurement of sample sound velocity at the logging main frequency range of 8~20 kHz,it is necessary for the sample being measured to have a length of several meters.Not only the sample preparation is difficult,but also the problem of large attenuation of acoustic signal.There are few published reports of targeted quantitative studies on whether or to what extent the size of the specimen can be reduced.This study integrates numerical simulations with experimental measurements to systematically and quantitatively explore the impact of the ratio between the length and diameter of cylindrical samples and the wavelength on the precision of the pulse transmission method for sound velocity assessment.The researches indicate that for accurate measurement of sound velocity using the pulse transmission method,it is advisable to have the sample length along the propagation direction be at least four times the wavelength of the sound wave,and the transverse size to be at least twice the wavelength.The research results have overcome the constraint associated with the conventional pulse transmission technique,which necessitates the sample size to be significantly larger than the wavelength.These results offer theoretical underpinning for enhancing the measurement approach of sound velocity and elevating the precision of measurements.

关 键 词：声速测量 低频 脉冲穿透法 样品尺寸 误差分析 

分 类 号：P631.84[天文地球—地质矿产勘探]