摘要
针对偶极横波远探测测量模式开展相关的实验研究,模拟研究了井中偶极声源激励下来自井旁地层界面的反射横波,分别测量了不同声源位置、不同声源振动方向和不同地层界面特性下的地层和井孔全波。实验结果表明:井中偶极声源除了激发出沿井传播的直达弯曲波之外,还会向地层中辐射SH和SV两种类型的横波。随着偶极声源振动方向与地层界面走向的夹角从0°增至90°,反射横波幅度逐渐减小,验证了偶极声源对于井旁反射体具有明显的方位指向特性,可以用来反演井旁反射体的走向。在固–液或固–气地层界面特性下,SH波在界面处会发生全反射,而SV波则会在界面处发生模式转换,SH反射横波更有利于进行远探测反射波成像,尤其对于井旁裂缝研究具有独特的优势。
Through related experimental studies on dipole shear wave remote detection measurement-mode, we study shear wave reflection of a borehole dipole source excitation from near-borehole formation interface, and measure full waveform inside and outside borehole under different source positions, different polarization directions and different formation interface characteristics. The experimental results show that a dipole source in a fluid-filled borehole excites direct flexural wave propagating along borehole and outside borehole, but also radiates two types of shear wave, which are SH-wave and SV-wave, respectively. Along with the dipole polarization direction from 0° to 90°, reflected shear wave amplitude gradually decreases, and verified that the dipole source for near-borehole reflector has obvious azimuthal directivity characteristics, which can be used for determining near-borehole geological structure strike. Under the solid-liquid or solid-gas formation interface characteristic, total reflection of SH-wave at the reflector interface will happen, and mode conversion occurs to SV wave, so SH-wave reflection helps to remote detection imaging, and has unique advantages for fractures.
出处
《西南石油大学学报（自然科学版）》
CAS
CSCD
北大核心
2013年第6期1-8,共8页
Journal of Southwest Petroleum University(Science & Technology Edition)
基金
山东省自然科学基金(ZR2011DQ020)
关键词
偶极声源
反射横波
物理模拟
振动方向
界面特性
dipole source
reflected shear wave
physical simulation
polarization directions
interface properties
