Development and application of three lateral resistivity logging module with constant current source
In order to further improve the application effect of resistivity parameters in logging interpretation for sandstone type uranium deposits,especially for fine measurement and identification of sand-mud interaction thin layers,a new type of three lateral resistivity logging module with constant current source based on OPA547 amplifier was studied in the development of a new generation digital comprehensive logging system.A digital excitation control circuit with OPA547 as the constant current source was designed to achieve sinusoidal excitation signal output;a constant current feedback circuit for sine detection signals was designed to achieve stable excitation output of the constant current source;a voltage detection circuit was designed to achieve low-pass filtering and signal half wave rectification;finally,the coefficient calibration of the development module was carried out by using a standard calibrator in the laboratory,and actual logging applications were compared in sandstone type uranium deposit boreholes.After comparative analysis,the newly developed three lateral resistivity logging module can be used in the combination with other parameters for measurement in the new generation comprehensive logging system.The output excitation current is adjustable,and it has high recognition ability for lithology and lithological interfaces,more obvious response to the lithological changes in interactive thin layers,calcareous interlayers and other formations.
constant current sourcethree lateral resistivityOPA547geophysical logging
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