摘要
核磁共振测井仪器在向地层发射脉冲时,天线流过的交变电流与探头静磁场相互作用,引起仪器产生机械振动,导致接收到的回波信号叠加了振铃噪声。振铃噪声极大地影响了回波信号的信噪比。利用回波信号对于发射脉冲具有相敏性这一特点,运用交替相位对的数据处理方法,结合泄放电路对天线发射后残余能量的衰减作用,来抑制振铃噪声。实验室和现场测试的结果表明,运用该综合性的解决方案,能有效降低振铃噪声,取得合格测井资料。
The alternating current flowing in the antenna interacts with the static magnetic field in probe while NMR well logging tools transmitting RF pulses to the formation,which results in mechanical vibration of the tools.As a result,the received echo signal is superimposed with ringing noise.Ringing affects the SNR of the echo signals severely.This thesis takes advantage of the phase-sensitive property of echo signals to corresponding transmitted pulses;use the phase-alternate pulse sequence technique of data processing method,along with the bleeder circuit which attenuates the energy remaining in the antenna after transmitting,to suppress ringing.The results of laboratory and field tests indicate that the implementation of this comprehensive solution can effectively improve the SNR of echo signals of well logging.
出处
《国外电子测量技术》
2014年第7期29-31,63,共4页
Foreign Electronic Measurement Technology
