随钻偶极远探测声场的辐射特性

发布时间：2018-05-11 20:45

本文选题：随钻测井 + 偶极声源　；参考：《地球物理学报》2016年09期

【摘要】：本文对偶极横波远探测技术在随钻测井中的应用进行了探讨.对于随钻远探测而言,井中声源向井外地层中的辐射性能是它的主控因素.本文从井孔内外声场出发,考察了随钻和电缆测井中偶极声源的辐射效率,即声源产生的辐射波能流与沿井传播的导波能流之比;分析了声源的远场辐射指向性;基于声源辐射与接收之间的互易性,快速模拟和处理了随钻测井下SH和SV横波远探测波形.研究结果表明,随钻条件下SH和SV横波的最大辐射效率受钻铤的影响较电缆的情况降低了70%左右,且横波最大辐射效率对应的优势激发频率也从电缆的3.5kHz降为2.5kHz左右;虽然随钻偶极的横波辐射效率明显降低,但由理论模拟的随钻远探测数据的成像结果可知,声源辐射到地层中的横波能量仍足以探测井外反射体,表明随钻偶极远探测技术在理论上是可行的,本文结果为随钻偶极远探测测井提供了理论依据.
[Abstract]:In this paper, the application of dipole S-wave remote detection technology in logging while drilling is discussed. For the detection while drilling, the radiation performance of the sound source in the well to the outfield layer is the main control factor. Based on the sound field inside and outside the well hole, the radiation efficiency of dipole sound source in drilling and cable logging is investigated, that is, the ratio of the radiation wave energy produced by the sound source to the guided wave energy flow propagating along the well, the far-field radiation directivity of the sound source is analyzed. Based on the reciprocity between the sound source radiation and the receiver, the detection waveforms of SH and SV transverse waves in the downhole while drilling are quickly simulated and processed. The results show that the maximum radiation efficiency of SH and SV waves is about 70% less than that of the cable under drilling condition, and the dominant excitation frequency corresponding to the maximum radiation efficiency of the shear wave is reduced from the 3.5kHz of the cable to about 2.5kHz. Although the shear wave radiation efficiency of the dipole while drilling is obviously reduced, the imaging results of the theoretical simulation data of the far detection while drilling show that the shear wave energy radiated by the sound source into the formation is still sufficient to detect the reflectors outside the well. It is shown that the dipole while drilling technique is feasible in theory, and the results in this paper provide a theoretical basis for dipole while drilling logging.
【作者单位】：中国石油大学(华东)地球科学与技术学院声学测井联合实验室;
【基金】：国家自然科学基金(41474092) 中央高校基本科研业务费专项资金(15CX06003A)资助
【分类号】：P631.81

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