一种数字高分辨率感应测井仪

A Digital High Resolution Induction Logging Tool

感应测井仪新设计的线圈系和采用的先进制造工艺在提高其探测效率和稳定性的同时,保持了较好的纵向分辨率。数字相敏检波将接收到的信号分离成实部信号R和虚部信号X,并利用X信号进行趋肤效应和邻层影响校正,使其对地层电阻率的测量更为精确。用FPGA和DSP实现发射-接收自动控制和测量信号数字处理,并进行井下电路自动校准和信号归一化处理,以消除电路不稳定和相位漂移对测量的影响。

The properties of formation signal measured by an induction logging tool have been improved with digital technique. New design of the coil system and its advanced manufacturing techniques improve its efficiency and stability, and keep its excellent vertical resolution as well. The digital phase-sensitive detector （DPSD） separates signals received into real part （R） and imaginary part （X）, the X part is utilized to correct skin effect and shoulder bed effect, so as to have the formation resistivity measured more precisely. FPGA and DSP are used to carry out transmitting-receiving automatic control and digital process of signals received, as well as to realize automatic calibration and signal normalization for eliminating influences of un-stability and phrase drift of downhole circuits.