李红一,
关威,,
胡恒山,
杨玉峰
哈尔滨工业大学航天学院, 哈尔滨 150001
基金项目: 国家自然科学基金（41674121，11734017，41574112），国家科技重大专项（2017ZX05019006-006）及黑龙江省博士后基金（LHB-Q17060）资助
详细信息
作者简介: 王军, 副教授, 主要从事岩石物理和声波/动电测井实验研究.E-mail:wangjun2012@hit.edu.cn
通讯作者: 关威, 副教授, 博导, 主要从事波动理论及声波/动电测井模拟研究.E-mail:guanw@hit.edu.cn
中图分类号: P631收稿日期:2018-01-30
修回日期:2018-05-23
上线日期:2019-04-05
Experimental studies on the mechanism of monopole acoustic collar wave
WANG Jun,LI HongYi,
GUAN Wei,,
HU HengShan,
YANG YuFeng
Department of Astronautics and Mechanics, Harbin Institute of Technology, Harbin 150001, China
More Information
Corresponding author: GUAN Wei,E-mail:guanw@hit.edu.cn
MSC: P631--> Received Date: 30 January 2018
Revised Date: 23 May 2018
Available Online: 05 April 2019
摘要
摘要:为了研究随钻声波测井中单极源钻铤波的传播特性，本文在水池中进行了缩小尺寸的随钻声波测井实验.首先建立了实验室内高分辨的数据采集系统（24位分辨率/1.25 MS/s采样率）和高精度三维运动控制系统（最小移动步长0.5 mm），并通过测量声源和接收换能器之间直达流体声波信号，验证了声源/接收探头和实验测量系统的有效性.之后对4种实验模型下单极源激发钻铤波的传播规律进行了实验分析，分别在钻铤内部和钻铤外流体中记录了钻铤波信号，重点分析了不同情况下钻铤内部直达钻铤波和钻铤外部泄漏钻铤波的幅值差异性及产生原因，讨论了泄漏钻铤波沿着井轴方向和直径方向的衰减规律.实验结果表明：钻铤波在声源和钻铤分离情况下依旧可以激发很强的钻铤波，但当钻铤被截断后两部分钻铤波同时消失，在截断位置转化成流体声波波群继续向前传播.此外，通过定量分析两部分钻铤波的幅值特性发现，泄漏钻铤波的幅值约为直达钻铤波幅值的1/4，两者处于同一量级，因此，泄漏钻铤波对测量纵横波的干扰是不可忽略的，进而本文提出一种随钻声波测井接收器的布置方法，以有效削弱测井全波中直达钻铤波和泄漏钻铤波信号的幅度.本文实验结果对认识单极源钻铤波的激发和传播机制具有重要意义.
关键词: 随钻声波测井/
直达钻铤波/
泄漏钻铤波/
衰减特性
Abstract:In this paper, the acoustic logging while drilling(LWD) measurements are conducted with a scaled LWD detector in the laboratory, in order to analyze the properties of monopole collar wave. We first build a high resolution data acquisition system (24 bit resolution and 1.25 MS/s sampling rate) and a high precision motorial system with the minimum movement of 0.5 mm. The detector and test system are validated by measuring acoustic signals propagated in the water. After that, the measurements with four different LWD models are conducted in a water pool. The time domain waveforms of the collar waves (direct collar wave in the collar and leaked collar wave out of the collar) in these models are recorded and analyzed. The properties of leaked collar wave, such as the amplitude differences and the attenuation along the axial direction and the radial direction, are further studied based on the experimental data. The results show that the collar wave can be excited even if the source and the collar are separated. However, when the collar is cut off, the collar wave disappears and transfers to liquid wave at the truncated section. In addition, we make a quantitative analysis on the amplitudes of the direct collar wave and leaked collar wave. Since the amplitude of the leaked collar wave is about a quarter of that of the direct collar wave, it is confirmed that the influence of leaked collar wave on the measurements of formation P and S waves can not be ignored in the acoustic LWD. Our experimental results are helpful for understanding the mechanism of the excitation and propagation of the monopole collar waves.
Key words:Acoustic LWD/
Direct collar wave/
Leaked collar wave/
Attenuation rule
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