DPSD技术在随钻电阻率测井中的应用

Application of Digital Phase Sensitive Demodulation for Electromagnetic Propagation Resistivity Logging While Drilling

钻进时产生的强烈电磁干扰使传统的模拟相敏检波(APSD)方法无法准确获取随钻测井的电磁波信号。数字相敏检波(DPSD)利用高速浮点数字信号处理(DSP)和高速现场可编程门阵列(FPGA)芯片,分别处理所采集的测井信息的实部和虚部,改变了传统的计算方法,提高了运算速度和计算精度。采用可编程逻辑技术充分利用了测井信息,简化了控制逻辑,提高了时序控制精度和测量精度。讨论了新设计的数字相敏检波的原理、特点、电路实现以及实验数据分析。实验证明,该检波方法能有效利用测井信息,优化随钻测井系统。

Intense electromagnetic interference while drilling prevents traditional analog phase sensitive demodulation （APSE）） from correctly acquiring electromagnetic wave signal of logging while drilling （LWD）. A digital phase sensitive demodulation （DPSD） utilizes high-performance floating-point DSP and FPGA to separately process real part and imaginary part of the acquired logging signal, changes traditional calculating method, improves processing speed and calculating precision. The programmable technique used can fully utilize logging information, simplify con- trol logic, improve precision of timing control and measuring precision. Discussed are the principle, characteristics, implement of circuit and analysis of experimental data. Testing result shows that the DPSD may utilize logging information effectively and optimize the LWD system.