Development of a logging-while-drilling inclination-gamma system for sandstone-type uranium deposits exploration
To monitor the drilling quality in real-time and enhance uranium exploration efficiency during core free drilling in sandstone-type uranium deposits exploration,this study developed a Logging-While-Drilling(LWD)Inclination-Gamma system.This system provides real-time,accurate measurements of well inclination and gamma data during drilling.An inclination measurement module was integrated with a high-precision triaxial digital accelerometer sensor,and the calibration software based on a twelve-position algorithm was utilized to optimize the accuracy of the inclination measurements.Due to the size limitations of downhole drilling,a compact gamma detector was developed by utilizing a photomultiplier tube and NaI scintillation crystal.To ensure real-time data transmission and processing,a driller controller with high-speed mud pulse signal reception and a host computer software were developed with wireless data communication.The developed LWD inclination-gamma system features a probe diameter of 38.15 mm,a pressure tolerance up to 50 MPa.and operates within a temperature range of-20℃ to 85℃.Calibration tests showed that the inclination measurement ranges from 0 to 90°with an accuracy of±0.12°,and the gamma measurement range is(0～10930)×10-6 eU with a relative error of 3.1％.In field experiments conducted in the Qianjiadian uranium deposit in Tongliao,the gamma anomaly positions detected by the LWD system were consistent with results from wireline logging.Therefore,the developed LWD Inclination-Gamma system can meet the needs of coreless drilling in sandstone-type uranium depositsnexploration which provides the equipment and technical support for the field of coreless exploration technology.
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