摘要
为了突破目前声波远探测技术存在的局限性,提出了一种新的偶极横波远探测方法,即利用井中偶极子产生的井中弯曲波存在低频截止频率的现象,在声源截止频率以下激发偶极声波.通过对比分析井中偶极声源分别在截止频率上、下激发时,井孔内外产生的辐射声场,明确了截止频率以下井中偶极声源的远场辐射特征和低频截止频率激发偶极横波的优势,结合数值模拟,进一步对其反射声场进行了分析.结果表明,该方法可以避免艾里相的巨大振幅对数据量化产生的"饱和"效应,相比传统的远探测测井方式更具优势,常规源距即可满足专门的远探测测井仪器需求.
Acoustic remote sensing technology utilizes a borehole acoustic wave to radiate and receive elastic waves to and from a near-borehole geological structure or abnormity body. This paper aims to break through current limitations of single-well reflection imaging logging, proposes a new acoustic remote acoustic sensing method, i. e. , the cut-off frequency phenomenon of the borehole flexural wave is used to emit acoustic wave of a borehole dipole source exciting below the cut-off frequency. Through the comparison and analysis of the radiation field inside and outside the borehole excited by a borehole dipole source above and below the cut-off frequency, we has pinpointed the far-field radiation characteristics and advantages of dipole shear wave below cut-off frequency excitation. Combined with numerical simulation, the paper analyzes further the reflected wave field above and below the cut-off frequency. These analysis results show that this method can avoid the ＂saturation＂ effect in the quantitative data because of the ＂airy phase＂ great amplitude, and it is more advantageous compared to the traditional measurement mode. Reflection wave amplitude is strong for near-offset and decreases when receiver offset increases and we do not need long offset tools for the imaging application.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第10期3572-3580,共9页
Chinese Journal of Geophysics
基金
山东省自然科学基金项目(ZR2011DQ020)资助
关键词
远探测测井
偶极声源
截止频率
横波辐射
反射声场
Remote sensing logging, Dipole source, Cutoff frequency, Shear wave radiation,-Reflection wave
