Circuit Optimization Of Electrode Electric Frequency Spectrum Logging Tool

Electric Frequency Spectrum Logging is a new method for well logging based on the dispersion property of rock,which has better capability than general specific resistance logging on identifying oil-water layer and reflecting the stratum oiliness,and also has promising application prospect.Electric Frequency Spectrum Logging is the important part of the sub-project of national 12 th Five-Year oil reservoir special project.Laboratory has made a theoretical stud y and design on its low frequency part,completed electrode frequency spectrum detector's testing breadboard,and conducted the debugging and well descending experiment.The debugging and well descending result has verified the feasibility of electric freq uency spectrum logging but also disclosed some hidden problems of the first version electrode frequency spectrum detector's testing breadboard.Therefore it requires optimizing and improving urgently to establish an electrode electric frequency spectrum logging detector circuit.This thesis,based on systematically analyzing the principle of the first version electrode frequency spectrum detector's circuit and potential problems,optimize the detector's circuit from three parts: balance monitoring system,digital signal acquisition system,and electrical system PCB board partition and locating and wiring.1)For balance monitoring system,make optimization design on instrument amplification module,effective value testing module,modulation amplification module and amplitude control model.And the article analyzes the current condition of the circuit,and provides the improved circuit diagram and specific circuit parameter.2)For digital signal acquisition system,the article provides optimization solution from the collection method and detection algorithm: the former applies LF direct sampling and HF equivalent sampling based on variable sampling clock to reduce the requirement for A/DC chip and improve the sampling precision.Detection algorithm uses digital phase sensitive detection algorithm which takes short time and has good noise immunity.3)Optimized electric circuit system partitioning is more reasonable and simplifies the circuit board amount from 11 pieces to 4 pieces.It has greatly shortened t he signal transmission path and improved the electromagnetic compatibility and anti-interference property from the aspect of PCB board locating and wiring.In the end,the article completes the plate-making debugging on the optimized detector circuit.The result shows that the design of optimized circuit performance has reached the design requirement.