随钻声波测井隔声体刻槽影响的数值模拟研究  

Numerical simulation study on the influence of groove cutting on acoustic isolators in acoustic logging while drilling

作　　者：杨培年 陈德华[1,2,3] 潘钥 张咪 YANG Peinian;CHEN Dehua;PAN Yue;ZHANG Mi(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 of Sea Deep Drilling and Exploration,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研究中心,北京100190

出　　处：《应用声学》2020年第5期775-783,共9页Journal of Applied Acoustics

基　　金：国家自然科学基金项目(11734017)。

摘　　要：针对随钻声波测井中钻铤波干扰以及刻槽后散射波问题,该文利用时域有限差分法模拟钻铤波在随钻隔声体中的传播规律,首先考察在无限大流体中钻铤波在凹槽分界面处的散射特征,利用波场快照直观显示了钻铤波会有一部分能量在刻槽的固液界面转化为斯通利波。同时在有地层时分别对比了均匀内刻槽和外刻槽对钻铤波的衰减效果,发现在选择均匀内刻槽还是外刻槽时结果不仅与频率范围有关,而且与刻槽的深度也有关系。最后对比了槽宽较大的均匀凹槽隔声体和槽宽较小的渐变凹槽隔声体。可以得出结论,在设计随钻隔声体时,在10 kHz以下选择均匀外刻槽方式相对于内刻槽隔声效果会更好。随着刻槽槽深增加,外刻槽在10 kHz以下相比于内刻槽隔声性能优势更加明显。渐变刻槽在满足衰减钻铤波幅度要求的同时,散射波对后续地层波和斯通利波影响也更小。Aiming at the problem of interference of drill collar waves and scattered wave after grooving in acoustic logging while drilling,this paper uses the finite-difference time-domain method to simulate the propagation law of drill collar wave in the acoustic isolator.The scattering properties at the groove interface,using wave field snapshots,intuitively show that a part of the energy in the drill collar wave is converted into Stoneley waves at the solid-liquid interface of the groove.At the same time,in the presence of formation,the attenuation effects of the uniform inner and outer grooves on the drill collar waves were compared.It was found that when the uniform inner or outer grooves were selected,the results were not only related to the frequency range,but also the depth of the groove.Finally,a comparison is made between a uniform groove acoustic isolator with a larger groove width and a graded grooved isolator with a smaller groove width.It can be concluded that when designing a sound insulation body in acoustic logging while drilling,it is better to choose a uniform outer groove below 10 kHz rather than an inner groove.With the increase of groove depth,the external groove under 10 kHz has more obvious acoustic performance advantages than the internal groove.The graded groove not only satisfies the amplitude of the attenuated drill collar wave,but also has multiple reflection waves that have less impact on subsequent formation waves and Stoneley waves.

关 键 词：随钻声波测井 钻铤波 时域有限差分 渐变凹槽 

分 类 号：TE19[石油与天然气工程—油气勘探]