Design And Implementation Of Main Time Sequence And Data Processing Method Of Nuclear Magnetic Resonance Control System While Drilling

Compared with the conventional wireline nuclear magnetic logging tool,the drilling while drilling nuclear magnetic resonance logging tool can measure the formation fluid during the drilling process,effectively reducing the impact of drilling fluid and mud invasion on the downhole reservoir fluid,and improving the logging quality Nuclear magnetic resonance logging while drilling is playing an increasingly important role in exploration technology.Based on the FPGA control module of the main control circuit of the NMR tool while drilling,this paper further improves the design of the main control circuit of the NMR tool while drilling according to the operation requirements of the LWD and the particularity of data processing.The DSP processor is used as an intermediary between the FPGA and the host computer.The DSP is used to design the timing sequence of the downhole self-starting operation of the entire instrument,preprocess and invert the T?2spectral distribution of the collected echo data,and the FPGA Issue work instructions and transfer data with the host computer.FPGA is used to collect the spin echo signal and perform digital phase sensitive detection,cross-phase pair,phase rotation and other data preprocessing on the collected data to separate the signal and noise in the echo signal.The firmware design of the main control system is based on the integrated development environment of CCS and Quartus,and the programs are written in C language and Verilog HDL hardware description language,respectively.Control of analog-to-digital conversion chip.The main control system adopts the working mode of DSP + FPGA dual processor.After the test and experiment,the hardware circuit meets the work requirements of self-starting and real-time data processing of the nuclear magnetic resonance logging tool while drilling.The system communication module has also been verified and can Transfer work instructions and collected data between processors.The research work plays an important role in the workflow and data processing of the nuclear magnetic resonance logging tool while drilling.